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Sample records for cardiac 64-slice computed

  1. Effect of obesity on coronary artery plaque using 64 slice multidetector cardiac computed tomography angiography.

    PubMed

    Isma'eel, Hussain; Tellalian, David; Hamirani, Yasmin S; Kadakia, Jigar; Nasir, Khurram; Budoff, Matthew J

    2010-04-30

    Patients with a coronary artery calcification score (CACS) of zero and an intermediate risk of coronary artery disease have been shown to have a low prevalence of non-calcified coronary artery plaque (NCP). 181 consecutive patients with CAC 'zero', undergoing cardiac computed tomography angiography (CCTA) angiography at our center were evaluated. Presence of detectable NCP on CCTA in these patients was 13.8%. Mild non-obstructive disease (<30% and limited to one segment) was present in 76% of patients while only one patient (0.6%) had significant stenosis (>50%). Traditional risk factors were not found to be associated with the presence of NCP. However higher body mass index (BMI) was strongly found to be associated with NCP (31.6 in patients with NCP vs. 27.6 kg/m(2) in patients without NCP, p<.05). Obesity was 2.76 times more likely to be associated with NCP as compared to normal BMI (p<0.05).

  2. Comparison of accuracy of 64-slice cardiovascular computed tomography with coronary angiography in patients with suspected coronary artery disease.

    PubMed

    Fine, Jeffrey J; Hopkins, Christie B; Ruff, Nicol; Newton, F Carter

    2006-01-15

    Cardiovascular computed tomography (CVCT) with the recently released 64-slice technology increases spatial resolution and decreases acquisition times and slice thickness. We investigated the accuracy of 64-slice CVCT in relation to catheter angiography. We studied 66 sequential subjects who underwent 64-slice CVCT and catheter angiography within 30 days. Accuracy results were 94% for interpretable images, 95% for sensitivity, 96% for specificity, 97% for positive predictive value, and 92% for negative predictive value for lesions with >50% stenosis. We found 100% agreement between 64-slice CVCT and catheterization among vein graft evaluations (9 of 9). These metrics are vastly improved from the 16-slice generation and support 64-slice CVCT as a reliable diagnostic tool.

  3. Coronary artery fistula: 64-slice computed tomographic delineation and correlation with multiplane transesophageal echocardiography and surgical findings.

    PubMed

    Joshi, Jonathan K; Beache, Garth M; Slaughter, Mark S; Sobieski, Michael A; Schneider, William; Stoddard, Marcus F

    2012-03-01

    A 49-year-old female who presented with 3 weeks of exertional chest pain had an abnormal mediastinal finding at chest x-ray imaging. Conventional, nongated computed tomography of the chest revealed a "mass" in proximity to the right atrium. 64-slice, cardiac gated computed tomographic coronary angiography, and transesophageal echocardiography delineated the "mass" as a coronary artery fistula structure. The fistula originated from the left main as a tubular vessel that continued into an aneurysmal sac-like cavity that emptied into the superior vena cava near the right atrium. Computed tomographic coronary angiography showed otherwise normal coronary arteries. Findings were ultimately confirmed at cardiac catheterization. Coronary steal was clinically diagnosed and she underwent surgical ligation and resection of the fistula and aneurysm. Her subsequent course was uncomplicated.

  4. Assessments of Coronary Artery Visibility and Radiation Dose in Infants with Congenital Heart Disease on Cardiac 128-slice CT and on Cardiac 64-slice CT.

    PubMed

    Cui, Y; Huang, M; Zheng, J; Li, J; Liu, H; Liang, C

    2016-01-01

    The aim of this study was to compare the coronary artery visibility and radiation dose in infants with CHD on cardiac 128-slice CT and on cardiac 64-slice CT. The images of 200 patients were analyzed in this study, 100 patients were selected randomly from a group of 789 infants (<1 years old) with CHD undergoing 128-slice CT prospective ECG-triggered axial scan, and 100 were selected randomly from 911 infants with CHD undergoing 64-slice CT retrospective ECG-gated spiral scan. The visibility of coronary artery segments was graded on a four-point scale. The coronary arteries were considered to be detected or visible when grade was 2 or higher. The visibility of the coronary artery segments and the radiation dose was compared between the two groups. Except for the rate of LM (96 vs. 99%), the detection rates of the total, LAD, LCX, RCA, and the proximal segment of the RCA in the 256-slice CT group were significantly higher than those in the 64-slice CT group (51.7, 53.33, 33.67, 53.33, and 99 vs. 34.8, 34.33, 18, 30.67, and 75%, respectively). The counts of visibility score (4/3/2/1) for the LM and the proximal segment of the RCA were 62/22/12/4 and 56/20/17/7, respectively, in the 128-slice CT group and 17/42/30/1 and 9/30/38/25, respectively, in the 64-slice CT group. There were significant differences, especially for score 4 and 3, between the two groups. The radiation dose in the 128-slice CT group was significantly decreased than those in the 64-slice CT group (CTDIvol 1.88 ± 0.51 vs. 5.61 ± 0.63 mGy; SSDE 4.48 ± 1.15 vs. 13.97 ± 1.52 mGy; effective radiation dose 1.36 ± 0.44 vs. 4.06 ± 0.7 mSv). With reduced radiation dose, the visibility of the coronary artery in infants with CHD via prospective ECG-triggered mode on a 128-slice CT is superior to that of the 64-slice CT using retrospective ECG-gated spiral mode.

  5. Coronary calcium mass scores measured by identical 64-slice MDCT scanners are comparable: a cardiac phantom study.

    PubMed

    Dijkstra, Hildebrand; Greuter, Marcel J W; Groen, Jaap M; Vliegenthart-Proença, Rozemarijn; Renema, Klaasjan W K; de Lange, Frank; Oudkerk, Matthijs

    2010-01-01

    To assess whether absolute mass scores are comparable or differ between identical 64-slice MDCT scanners of the same manufacturer and to compare absolute mass scores to the physical mass and between scan modes using a calcified phantom. A non-moving anthropomorphic phantom with nine calcifications of three sizes and three densities was scanned 30 times on three 64-slice MDCT scanners of manufacturer A and on three 64-slice MDCT scanners of manufacturer B in both sequential and spiral scan mode. The mean mass scores and mass score variabilities of seven calcifications were determined for all scanners; two non-detectable calcifications were omitted. It was analyzed whether identical scanners yielded similar or significantly different mass scores. Furthermore mass scores were compared to the physical mass and mass scores were compared between scan modes. The mass score calibration factor was determined for all scanners. Mass scores obtained on identical scanners were similar for almost all calcifications. Overall, mass score differences between the scanners were small ranging from 1.5 to 3.4% for the total mass scores, and most differences between scanners were observed for high density calcifications. Mass scores were significantly different from the physical mass for almost all calcifications and all scanners. In sequential mode the total physical mass (167.8 mg) was significantly overestimated (+2.3%) for 4 out of 6 scanners. In spiral mode a significant overestimation (+2.5%) was found for system B and a significant underestimation (-1.8%) for two scanners of system A. Mass scores were dependent on the scan mode, for manufacturer A scores were higher in sequential mode and for manufacturer B in spiral mode. For system A using spiral scan mode no differences were found between identical scanners, whereas a few differences were found using sequential mode. For system B the scan mode did not affect the number of different mass scores between identical scanners. Mass

  6. 64-Slice spiral computed tomography and three-dimensional reconstruction in the diagnosis of cystic pancreatic tumors

    PubMed Central

    WEN, ZHAOXIA; YAO, FENGQING; WANG, YUXING

    2016-01-01

    The present study aimed to describe the characteristics of cystic pancreatic tumors using computed tomography (CT) and to evaluate the diagnostic accuracy (DA) of post-imaging three-dimensional (3D) reconstruction. Clinical and imaging data, including multi-slice spiral CT scans, enhanced scans and multi-faceted reconstruction, from 30 patients with pathologically confirmed cystic pancreatic tumors diagnosed at the Linyi People's Hospital between August 2008 and June 2014 were retrospectively analyzed. Following the injection of Ultravist® 300 contrast agent, arterial, portal venous and parenchymal phase scans were obtained at 28, 60 and 150 sec, respectively, and 3D reconstructions of the CT images were generated. The average age of the patients was 38.4 years (range, 16–77 years), and the cohort included 5 males and 25 females (ratio, 1:5). The patients included 8 cases of mucinous cystadenoma (DA), 80%]; 9 cases of cystadenocarcinoma (DA, 84%); 6 cases of serous cystadenoma (DA, 100%); 3 cases of solid pseudopapillary tumor (DA, 100%); and 4 cases of intraductal papillary mucinous neoplasm (DA, 100%). 3D reconstructions of CT images were generated and, in the 4 cases of intraductal papillary mucinous neoplasm, the tumor was connected to the main pancreatic duct and multiple mural nodules were detected in one of these cases. The DA of the 3D-reconstructed images of cystic pancreatic tumors was 89.3%. The 64-slice spiral CT and 3D-reconstructed CT images facilitated the visualization of cystic pancreatic tumor characteristics, in particular the connections between the tumor and the main pancreatic duct. In conclusion, the 3D reconstruction of multi-slice CT data may provide an important source of information for the surgical team, in combination with the available clinical data. PMID:27073473

  7. Non-invasive detection of aortic and coronary atherosclerosis in homozygous familial hypercholesterolemia by 64 slice multi-detector row computed tomography angiography.

    PubMed

    Santos, Raul D; Miname, Marcio H; Martinez, Lilton R C; Rochitte, Carlos E; Chacra, Ana P M; Nakandakare, Edna R; Chen, David; Schaefer, Ernst J

    2008-04-01

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector row computed tomographic coronary angiography (CTCA). We studied five HoFH patients (three females, two males, mean age 19.8+/-2.9 years, age range 15-23 years, with a mean low density lipoprotein (LDL) cholesterol 618+/-211 mg/dL) using 64 slice CTCA. None of the patients showed evidence of ischemia with standard exercise testing. Calcified and mixed atherosclerotic plaques adjacent to or compromising the coronary artery ostia were found in all study subjects. Coronary plaques causing significant obstruction were found in one patient, who had previously undergone coronary artery bypass surgery and aortic valve replacement. Two other patients were noted to have non-obstructive calcified, mixed and non-calcified coronary artery plaques. Our data suggest that CTCA could be a useful non-invasive method for detection of early aortic and coronary atherosclerosis specifically affecting the coronary ostia in HoFH subjects. PMID:17884061

  8. Non-invasive Detection of Aortic and Coronary Atherosclerosis in Homozygous Familial Hypercholesterolemia by 64 Slice Multi-detector Row Computed Tomography Angiography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector-row ...

  9. Non-invasive detection of aortic and coronary atherosclerosis in homozygous familial hypercholesterolemia by 64 slice multi-detector row computed tomography angiography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector row ...

  10. Usefulness of Cardiac Computed Tomography in the Diagnosis of Prosthetic Coronary Artery Graft with Interposition Procedure

    PubMed Central

    Wake, Ryotaro; Iwata, Shinichi; Nakagawa, Masashi; Doi, Atsushi; Sugioka, Kenichi; Otsuka, Ryo; Hozumi, Takeshi; Takemoto, Yasuhiko; Ehara, Shoichi; Hanatani, Akihisa; Muro, Takashi; Yoshiyama, Minoru

    2010-01-01

    An 80-year-old Japanese man was admitted with orthopnea and pitting edema of both lower legs. We diagnosed congestive heart failure (CHF) on the basis of a chest X-ray and an echocardiogram. An electrocardiogram showed a heart rate of 120 beats/min with atrial fibrillation rhythm (Af). The patient developed aortic valve failure and destruction of the base of right coronary artery (RCA) due to infectious endocarditis at 71 years of age. The patient underwent aortic valve replacement and coronary artery bypass grafting with an interposed graft with polyester vascular graft to RCA. The patient recovered from CHF after the 6 days of treatment with diuretics and verapamil. We confirmed the patency of coronary arteries and bypass grafts using a 64-slice cardiac computed tomography scan (CT) and diagnosed CHF due to Af. Here we describe the estimation of the prosthetic coronary artery graft patency with the interposition procedure using 64-slice cardiac CT. PMID:21079753

  11. Coronary artery dissection with rupture of aortic valve commissure following type A aortic dissection: the role of 64-slice MDCT.

    PubMed

    Das, K M; Abdou, Sayed M; El-Menyar, Ayman; Ayman, El Menyar; Khulaifi, A A; Nabti, A L

    2008-01-01

    A rare case of bilateral coronary artery dissection with rupture of aortic valve commissure following type A aortic dissection is described. 64-slice multidetector computed tomography (MDCT) was able to demonstrate both this findings along with involvement of other neck vessels. TEE demonstrated the severity and mechanisms of aortic valve damage and assisted the surgeon in valve repair. MDCT has played an invaluable role in the diagnosis of the abnormal details of such life-threatening vascular complications. PMID:18384568

  12. Dosimetric and image quality assessment of different acquisition protocols of a novel 64-slice CT scanner

    NASA Astrophysics Data System (ADS)

    Vite, Cristina; Mangini, Monica; Strocchi, Sabina; Novario, Raffaele; Tanzi, Fabio; Carrafiello, Gianpaolo; Conte, Leopoldo; Fugazzola, Carlo

    2006-03-01

    Dose and image quality assessment in computed tomography (CT) are almost affected by the vast variety of CT scanners (axial CT, spiral CT, low-multislice CT (2-16), high-multislice CT (32-64)) and imaging protocols in use. Very poor information is at the moment available on 64 slices CT scanners. Aim of this work is to assess image quality related to patient dose indexes and to investigate the achievable dose reduction for a commercially available 64 slices CT scanner. CT dose indexes (weighted computed tomography dose index, CTDI w and Dose Length Product, DLP) were measured with a standard CT phantom for the main protocols in use (head, chest, abdomen and pelvis) and compared with the values displayed by the scanner itself. The differences were always below 7%. All the indexes were below the Diagnostic Reference Levels defined by the European Council Directive 97/42. Effective doses were measured for each protocol with thermoluminescent dosimeters inserted in an anthropomorphic Alderson Rando phantom and compared with the same values computed by the ImPACT CT Patient Dosimetry Calculator software code and corrected by a factor taking in account the number of slices (from 16 to 64). The differences were always below 25%. The effective doses range from 1.5 mSv (head) to 21.8 mSv (abdomen). The dose reduction system of the scanner was assessed comparing the effective dose measured for a standard phantom-man (a cylinder phantom, 32 cm in diameter) to the mean dose evaluated on 46 patients. The standard phantom was considered as no dose reduction reference. The dose reduction factor range from 16% to 78% (mean of 46%) for all protocols, from 29% to 78% (mean of 55%) for chest protocol, from 16% to 76% (mean of 42%) for abdomen protocol. The possibility of a further dose reduction was investigated measuring image quality (spatial resolution, contrast and noise) as a function of CTDI w. This curve shows a quite flat trend decreasing the dose approximately to 90% and a

  13. Measurement of scattered radiation in a volumetric 64-slice CT scanner using three experimental techniques

    NASA Astrophysics Data System (ADS)

    Akbarzadeh, A.; Ay, M. R.; Ghadiri, H.; Sarkar, S.; Zaidi, H.

    2010-04-01

    Compton scatter poses a significant threat to volumetric x-ray computed tomography, bringing cupping and streak artefacts thus impacting qualitative and quantitative imaging procedures. To perform appropriate scatter compensation, it is necessary to estimate the magnitude and spatial distribution of x-ray scatter. The aim of this study is to compare three experimental methods for measurement of the scattered radiation profile in a 64-slice CT scanner. The explored techniques involve the use of collimator shadow, a single blocker (a lead bar that suppresses the primary radiation) and an array blocker. The latter was recently proposed and validated by our group. The collimator shadow technique was used as reference for comparison since it established itself as the most accurate experimental procedure available today. The mean relative error of measurements in all tube voltages was 3.9 ± 5.5% (with a maximum value of 20%) for the single blocker method whereas it was 1.4 ± 1.1% (with a maximum value of 5%) for the proposed blocker array method. The calculated scatter-to-primary ratio (SPR) using the blocker array method for the tube voltages of 140 kVp and 80 kVp was 0.148 and 1.034, respectively. For a larger polypropylene phantom, the maximum SPR achieved was 0.803 and 6.458 at 140 kVp and 80 kVp, respectively. Although the three compared methods present a reasonable accuracy for calculation of the scattered profile in the region corresponding to the object, the collimator shadow method is by far the most accurate empirical technique. Nevertheless, the blocker array method is relatively straightforward for scatter estimation providing minor additional radiation exposure to the patient.

  14. Radiation exposure of ovarian cancer patients: contribution of CT examinations performed on different MDCT (16 and 64 slices) scanners and image quality evaluation: an observational study.

    PubMed

    Rizzo, Stefania; Origgi, Daniela; Brambilla, Sarah; De Maria, Federica; Foà, Riccardo; Raimondi, Sara; Colombo, Nicoletta; Bellomi, Massimo

    2015-05-01

    The objective of this study is to compare radiation doses given to ovarian cancer patients by different computed tomographies (CTs) and to evaluate association between doses and subjective and objective image quality.CT examinations included were performed either on a 16-slice CT, equipped with automatic z-axis tube current modulation, or on a 64-slice CT, equipped with z-axis, xy-axis modulation, and adaptive statistical iterative algorithm (ASIR). Evaluation of dose included the following dose descriptors: volumetric CT dose index (CTDIvol), dose length product (DLP), and effective dose (E). Objective image noise was evaluated in abdominal aorta and liver. Subjective image quality was evaluated by assessment of image noise, spatial resolution and diagnostic acceptability.Mean and median CTDIvol, DLP, and E; correlation between CTDIvol and DLP and patients' weight; comparison of objective noise for the 2 scanners; association between dose descriptors and subjective image quality.The 64-slice CT delivered to patients 24.5% lower dose (P < 0.0001) than 16-slice CT. There was a significant correlation between all dose descriptors (CTDIvol, DLP, E) and weight (P < 0.0001). Objective noise was comparable for the 2 CT scanners. There was a significant correlation between dose descriptors and image noise for the 64-slice CT, and between dose descriptors and spatial resolution for the 16-slice CT.Current dose reduction systems may reduce radiation dose without significantly affecting image quality and diagnostic acceptability of CT exams. PMID:25929914

  15. Radiation Exposure of Ovarian Cancer Patients: Contribution of CT Examinations Performed on Different MDCT (16 and 64 Slices) Scanners and Image Quality Evaluation

    PubMed Central

    Rizzo, Stefania; Origgi, Daniela; Brambilla, Sarah; De Maria, Federica; Foà, Riccardo; Raimondi, Sara; Colombo, Nicoletta; Bellomi, Massimo

    2015-01-01

    Abstract The objective of this study is to compare radiation doses given to ovarian cancer patients by different computed tomographies (CTs) and to evaluate association between doses and subjective and objective image quality. CT examinations included were performed either on a 16-slice CT, equipped with automatic z-axis tube current modulation, or on a 64-slice CT, equipped with z-axis, xy-axis modulation, and adaptive statistical iterative algorithm (ASIR). Evaluation of dose included the following dose descriptors: volumetric CT dose index (CTDIvol), dose length product (DLP), and effective dose (E). Objective image noise was evaluated in abdominal aorta and liver. Subjective image quality was evaluated by assessment of image noise, spatial resolution and diagnostic acceptability. Mean and median CTDIvol, DLP, and E; correlation between CTDIvol and DLP and patients’ weight; comparison of objective noise for the 2 scanners; association between dose descriptors and subjective image quality. The 64-slice CT delivered to patients 24.5% lower dose (P < 0.0001) than 16-slice CT. There was a significant correlation between all dose descriptors (CTDIvol, DLP, E) and weight (P < 0.0001). Objective noise was comparable for the 2 CT scanners. There was a significant correlation between dose descriptors and image noise for the 64-slice CT, and between dose descriptors and spatial resolution for the 16-slice CT. Current dose reduction systems may reduce radiation dose without significantly affecting image quality and diagnostic acceptability of CT exams. PMID:25929914

  16. Carotid stenosis evaluation by 64-slice CTA: comparison of NASCET, ECST and CC grading methods.

    PubMed

    Kılıçkap, Gülsüm; Ergun, Elif; Başbay, Elif; Koşar, Pınar; Kosar, Uğur

    2012-06-01

    Purpose is to evaluate the intraobserver and interobserver variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET), European Carotid Surgery Trial (ECST) and Common Carotid (CC) methods, which are used to measure the degree of ICA stenosis, using 64-slice CT angiography and to compare the measurements made by these three methods. 88 cases (111 carotid arteries) were included in the study. Carotid CTA was performed by a 64 slice scanner (Toshiba, Aqullion 64).Two radiologists measured the degree of carotid stenosis by using NASCET, ECST and CC methods. Intraobserver and interobserver variability of each method was determined by intraclass correlation coefficient (ICC), Bland-Altman plots and kappa and linear weighted kappa statistics. The relation between the measurements was assessed by correlation coefficient (with linear and quadratic methods). Correlation coefficients showed that there is linear correlation between the measurements made by the three methods. The degree of stenosis measured with the NASCET method had the lowest value, while the corresponding values measured with the ECST and CC methods were close to each other. ICC and Bland-Altman plots showed high intra and inter observer agreement for NASCET, ECST and CC methods whereas kappa statistics showed moderate to substantial agreement. CC method had slightly higher agreement when compared with the other two methods. Intra and interobserver agreement is high for NASCET, ECST and CC methods however CC method has a slightly higher reproducibility. There is linear correlation between the measurements made by the three methods.

  17. Computer simulations to estimate organ doses from clinically validated cardiac, neuro, and pediatric protocols for multiple detector computed tomography scanners

    NASA Astrophysics Data System (ADS)

    Ghita, Monica

    Recent advances in Computed Tomography (CT) technology, particularly that of multiple detector CT (MDCT) scanning, have provided increased utilization and more diverse clinical applications including more advanced vascular and cardiac exams, perfusion imaging, and screening exams. Notwithstanding the benefits to the patient undergoing a CT study, the fundamental concern in radiation protection is the minimization of the radiation exposure delivered as well as the implementation of structures to prevent inappropriate ordering and clinical use of these advanced studies. This research work developed a computational methodology for routine clinical use to assess patient organ doses from MDCT scanners. To support the methodology, a computer code (DXS-Diagnostic X-ray Spectra) was developed to accurately and conveniently generate x-ray spectra in the diagnostic energy range (45-140 keV). The two accepted standard radiation transport calculation methods namely, deterministic and Monte Carlo, have been preliminarily investigated for their capability and readiness to support the proposed goal of the work. Thorough tests demonstrated that the lack of appropriate discrete photon interaction coefficients in the aforementioned diagnostic energy range impedes the applicability of the deterministic approach to routine clinical use; improvements in the multigroup treatment may make it more viable. Thus, the open source Monte Carlo code, MCNP5, was adapted to appropriately model an MDCT scan. For this, a new method, entirely based on routine clinical CT measurements, was developed and validated to generate an "equivalent source and filtration" model that obviates the need of proprietary information for a given CT scanner. Computer simulations employing the Monte Carlo methodology and UF's tomographic human phantoms were performed to assess, compare, and optimize pediatric, cardiac and neuro-imaging protocols for the new 320-slice scanner at Shands/UF based on dose considerations

  18. Cardiac Computed Tomography (Multidetector CT, or MDCT)

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Cardiac Computed Tomography (Multidetector CT, or MDCT) Updated:Sep 3,2015 ... facts MDCT is a very fast type of computed tomography (CT) scan. MDCT creates pictures of the healthy ...

  19. Applications of Computational Modeling in Cardiac Surgery

    PubMed Central

    Lee, Lik Chuan; Genet, Martin; Dang, Alan B.; Ge, Liang; Guccione, Julius M.; Ratcliffe, Mark B.

    2014-01-01

    Although computational modeling is common in many areas of science and engineering, only recently have advances in experimental techniques and medical imaging allowed this tool to be applied in cardiac surgery. Despite its infancy in cardiac surgery, computational modeling has been useful in calculating the effects of clinical devices and surgical procedures. In this review, we present several examples that demonstrate the capabilities of computational cardiac modeling in cardiac surgery. Specifically, we demonstrate its ability to simulate surgery, predict myofiber stress and pump function, and quantify changes to regional myocardial material properties. In addition, issues that would need to be resolved in order for computational modeling to play a greater role in cardiac surgery are discussed. PMID:24708036

  20. Clinically applicable gated cardiac computed tomography

    SciTech Connect

    Cipriano, P.R.; Nassi, M.; Brody, W.R.

    1983-03-01

    Several attempts have been made to improve cardiac images obtained with x-ray transmission computed tomography (CT) by stopping cardiac motion through electrocardiographic gating. These methods reconstruct images that correspond to time intervals of the cardiac cycle identified by electrocardiography using either a pulsed x-ray beam at a selected time in the cardiac cycle or selected measurements in retrospect from regularly pulsed measurements made over several cardiac cycles. Missing CT angles of view (line integrals) have been a major problem contributing to degradation of such gated cardiac CT images. A new method for CT reconstruction from an incomplete set of projection data is presented that can be used clinically with a standard fan-beam reconstruction algorithm to improve gated cardiac CT images.

  1. Image Quality and Radiation Dose for Prospectively Triggered Coronary CT Angiography: 128-Slice Single-Source CT versus First-Generation 64-Slice Dual-Source CT

    PubMed Central

    Gu, Jin; Shi, He-shui; Han, Ping; Yu, Jie; Ma, Gui-na; Wu, Sheng

    2016-01-01

    This study sought to compare the image quality and radiation dose of coronary computed tomography angiography (CCTA) from prospectively triggered 128-slice CT (128-MSCT) versus dual-source 64-slice CT (DSCT). The study was approved by the Medical Ethics Committee at Tongji Medical College of Huazhong University of Science and Technology. Eighty consecutive patients with stable heart rates lower than 70 bpm were enrolled. Forty patients were scanned with 128-MSCT, and the other 40 patients were scanned with DSCT. Two radiologists independently assessed the image quality in segments (diameter >1 mm) according to a three-point scale (1: excellent; 2: moderate; 3: insufficient). The CCTA radiation dose was calculated. Eighty patients with 526 segments in the 128-MSCT group and 544 segments in the DSCT group were evaluated. The image quality 1, 2 and 3 scores were 91.6%, 6.9% and 1.5%, respectively, for the 128-MSCT group and 97.6%, 1.7% and 0.7%, respectively, for the DSCT group, and there was a statistically significant inter-group difference (P ≤ 0.001). The effective doses were 3.0 mSv in the 128-MSCT group and 4.5 mSv in the DSCT group (P ≤ 0.001). Compared with DSCT, CCTA with prospectively triggered 128-MSCT had adequate image quality and a 33.3% lower radiation dose. PMID:27752040

  2. Optimization of the imaging quality of 64-slice CT acquisition protocol using Taguchi analysis: A phantom study.

    PubMed

    Pan, Lung Fa; Erdene, Erdenetsetseg; Chen, Chun Chi; Pan, Lung Kwang

    2015-01-01

    In this study, the phantom imaging quality of 64-slice CT acquisition protocol was quantitatively evaluated using Taguchi. The phantom acrylic line group was designed and assembled with multiple layers of solid water plate in order to imitate the adult abdomen, and scanned with Philips brilliance CT in order to simulate a clinical examination. According to the Taguchi L8(2(7)) orthogonal array, four major factors of the acquisition protocol were optimized, including (A) CT slice thickness, (B) the image reconstruction filter type, (C) the spiral CT pitch, and (D) the matrix size. The reconstructed line group phantom image was counted by four radiologists for three discrete rounds in order to obtain the averages and standard deviations of the line counts and the corresponding signal to noise ratios (S/N). The quantified S/N values were analyzed and the optimal combination of the four factor settings was determined to be comprised of (A) a 1-mm thickness, (B) a sharp filter type, (C) a 1.172 spiral CT pitch, and (D) a 1024×1024 matrix size. The dominant factors included the (A) filter type and the cross interaction between the filter type and CT slice thickness (A×B). The minor factors were determined to be (C) the spiral CT pitch and (D) the matrix size since neither was capable of yielding a 95% confidence level in the ANOVA test. PMID:26405931

  3. Assessment of cardiac function: magnetic resonance and computed tomography.

    PubMed

    Greenberg, S B

    2000-10-01

    A complete cardiac study requires both anatomic and physiologic evaluation. Cardiac function can be evaluated noninvasively by magnetic resonance imaging (MRI)or ultrafast computed tomography (CT). MRI allows for evaluation of cardiac function by cine gradient echo imaging of the ventricles and flow analysis across cardiac valves and the great vessels. Cine gradient echo imaging is useful for evaluation of cardiac wall motion, ventricular volumes and ventricular mass. Flow analysis allows for measurement of velocity and flow during the cardiac cycle that reflects cardiac function. Ultrafast CT allows for measurement of cardiac indices similar to that provided by gradient echo imaging of the ventricles.

  4. Is 3-Tesla Gd-EOB-DTPA-Enhanced MRI with Diffusion-Weighted Imaging Superior to 64-Slice Contrast-Enhanced CT for the Diagnosis of Hepatocellular Carcinoma?

    PubMed Central

    Maiwald, Bettina; Lobsien, Donald; Kahn, Thomas; Stumpp, Patrick

    2014-01-01

    Objectives To compare 64-slice contrast-enhanced computed tomography (CT) with 3-Tesla magnetic resonance imaging (MRI) using Gd-EOB-DTPA for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the utility of diffusion-weighted imaging (DWI) in this setting. Methods 3-phase-liver-CT was performed in fifty patients (42 male, 8 female) with suspected or proven HCC. The patients were subjected to a 3-Tesla-MRI-examination with Gd-EOB-DTPA and diffusion weighted imaging (DWI) at b-values of 0, 50 and 400 s/mm2. The apparent diffusion coefficient (ADC)-value was determined for each lesion detected in DWI. The histopathological report after resection or biopsy of a lesion served as the gold standard, and a surrogate of follow-up or complementary imaging techniques in combination with clinical and paraclinical parameters was used in unresected lesions. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated for each technique. Results MRI detected slightly more lesions that were considered suspicious for HCC per patient compared to CT (2.7 versus 2.3, respectively). ADC-measurements in HCC showed notably heterogeneous values with a median of 1.2±0.5×10−3 mm2/s (range from 0.07±0.1 to 3.0±0.1×10−3 mm2/s). MRI showed similar diagnostic accuracy, sensitivity, and positive and negative predictive values compared to CT (AUC 0.837, sensitivity 92%, PPV 80% and NPV 90% for MRI vs. AUC 0.798, sensitivity 85%, PPV 79% and NPV 82% for CT; not significant). Specificity was 75% for both techniques. Conclusions Our study did not show a statistically significant difference in detection in detection of HCC between MRI and CT. Gd-EOB-DTPA-enhanced MRI tended to detect more lesions per patient compared to contrast-enhanced CT; therefore, we would recommend this modality as the first-choice imaging method for the detection of HCC and therapeutic decisions. However, contrast-enhanced CT was not inferior in our study, so

  5. Computer Generated Cardiac Model For Nuclear Medicine

    NASA Astrophysics Data System (ADS)

    Hills, John F.; Miller, Tom R.

    1981-07-01

    A computer generated mathematical model of a thallium-201 myocardial image is described which is based on realistic geometric and physiological assumptions. The left ventricle is represented by an ellipsoid truncated by aortic and mitral valve planes. Initially, an image of a motionless left ventricle is calculated with the location, size, and relative activity of perfusion defects selected by the designer. The calculation includes corrections for photon attenuation by overlying structures and the relative distribution of activity within the tissues. Motion of the ventricular walls is simulated either by a weighted sum of images at different stages in the cardiac cycle or by a blurring function whose width varies with position. Camera and collimator blurring are estimated by the MTF of the system measured at a representative depth in a phantom. Statistical noise is added using a Poisson random number generator. The usefulness of this model is due to two factors: the a priori characterization of location and extent of perfusion defects and the strong visual similarity of the images to actual clinical studies. These properties should permit systematic evaluation of image processing algorithms using this model. The principles employed in developing this cardiac image model can readily be applied to the simulation of other nuclear medicine studies and to other medical imaging modalities including computed tomography, ultrasound, and digital radiography.

  6. Three-dimensional cardiac computational modelling: methods, features and applications.

    PubMed

    Lopez-Perez, Alejandro; Sebastian, Rafael; Ferrero, Jose M

    2015-01-01

    The combination of computational models and biophysical simulations can help to interpret an array of experimental data and contribute to the understanding, diagnosis and treatment of complex diseases such as cardiac arrhythmias. For this reason, three-dimensional (3D) cardiac computational modelling is currently a rising field of research. The advance of medical imaging technology over the last decades has allowed the evolution from generic to patient-specific 3D cardiac models that faithfully represent the anatomy and different cardiac features of a given alive subject. Here we analyse sixty representative 3D cardiac computational models developed and published during the last fifty years, describing their information sources, features, development methods and online availability. This paper also reviews the necessary components to build a 3D computational model of the heart aimed at biophysical simulation, paying especial attention to cardiac electrophysiology (EP), and the existing approaches to incorporate those components. We assess the challenges associated to the different steps of the building process, from the processing of raw clinical or biological data to the final application, including image segmentation, inclusion of substructures and meshing among others. We briefly outline the personalisation approaches that are currently available in 3D cardiac computational modelling. Finally, we present examples of several specific applications, mainly related to cardiac EP simulation and model-based image analysis, showing the potential usefulness of 3D cardiac computational modelling into clinical environments as a tool to aid in the prevention, diagnosis and treatment of cardiac diseases. PMID:25928297

  7. Comparison between coronary plaque 64-slice spiral CT characteristics and risk factors of coronary artery disease patients in Chinese Han population and Mongolian

    PubMed Central

    Bai, Zhigang; Yang, Xiaoguang; Han, Xiaodong; Dong, Peide; Liu, Aishi

    2013-01-01

    Objective : To compare the coronary atherosclerotic plaque 64-slice spiral CT characteristics and the risk factors of Han (in Inner Mongolia) and Mongolian coronary artery disease patients. Metho d s: The plaques of 126 Mongolian and 269 Han patients were analyzed by 64-slice spiral CT coronary angiography. Their gender, age, height, body mass, the history of hypertension, diabetes, smoking and family diseases, the levels of triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were compared. Results: The incidence of plaques (P <0.05), the proportion of plaques in the circumflex branch (P <0.05), the proportion of medium-severe lumen stenosis induced by plaques (P <0.05), and the proportion of obstructive plaque involved multi-branch (P <0.05) of the Mongolian patients were higher. The plaque compositions of the two groups did not differ significantly (P> 0.05). The body mass index of the Mongolian patients was higher (P <0.05). The hypertension, diabetes, smoking history, TG, TC, HDL-C and LDL-C of the two groups did not differ significantly (P> 0.05). Conclusion: The higher incidence of coronary atherosclerotic plaques and the more severe lesions of the Mongolian patients may be related to their higher body mass index. PMID:24353662

  8. [Cardiac magnetic resonance imaging and cardiac computed tomography in clinical practice].

    PubMed

    Barone-Rochette, G; Jankowski, A; Rodiere, M

    2014-11-01

    Technological advances have enabled the rapid development of cardiovascular imaging techniques. Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) have become diagnostic and prognostic tools for the management of patients in routine clinical practice. This review gives the main indications and describes the performance of both techniques.

  9. Variability of repeated coronary artery calcium measurements by 1.25-mm- and 2.5-mm-thickness images on prospective electrocardiograph-triggered 64-slice CT.

    PubMed

    Horiguchi, Jun; Matsuura, Noriaki; Yamamoto, Hideya; Hirai, Nobuhiko; Kiguchi, Masao; Fujioka, Chikako; Kitagawa, Toshiro; Kohno, Nobuoki; Ito, Katsuhide

    2008-02-01

    High reproducibility on coronary artery calcium scoring is a key requirement in monitoring the progression of coronary atherosclerosis. The purpose of this prospective study is to assess the reproducibility of 1.25-mm- and 2.5-mm-thickness images on prospective electrocardiograph-triggered 64-slice CT with respect to 2.5-mm-thickness images on spiral overlapping reconstruction. One hundred patients suspected of coronary artery disease were scanned twice repeatedly, both on prospective electrocardiograph-triggered step-and-shoot and retrospective electrocardiograph-gated spiral scans. Using 1.25-mm-thickness collimation, 1.25-mm- and 2.5-mm-thickness image sets on prospective scans and 2.5-mm-thickness image sets with 1.25-mm increment (overlapping) on retrospective scans were obtained. Coronary artery calcium scores, interscan variability and interobserver variability were evaluated. The mean interscan variability in coronary artery calcium measurement on 1.25-mm prospective/2.5-mm prospective/2.5-mm overlapping retrospective scans were Agatston: 10%/18%/12%, volume: 10%/12%/10% and mass: 8%/13%/11% for observer 1 and Agatston: 8%/14%/10%, volume: 7%/9%/10% and mass: 7%/10%/9% for observer 2, respectively. The mean interobserver variability was 5% to 14%. In conclusion, prospective electrocardiograph-triggered 64-slice CT using the 1.25-mm prospective scan shows the lowest variability. The 2.5-mm prospective scan on volume or mass scoring shows variability of around 10%, comparable to 2.5-mm-thickness spiral overlapping reconstruction images.

  10. A computer model of engineered cardiac monolayers.

    PubMed

    Kim, Jong M; Bursac, Nenad; Henriquez, Craig S

    2010-05-19

    Engineered monolayers created using microabrasion and micropatterning methods have provided a simplified in vitro system to study the effects of anisotropy and fiber direction on electrical propagation. Interpreting the behavior in these culture systems has often been performed using classical computer models with continuous properties. However, such models do not account for the effects of random cell shapes, cell orientations, and cleft spaces inherent in these monolayers on the resulting wavefront conduction. This work presents a novel methodology for modeling a monolayer of cardiac tissue in which the factors governing cell shape, cell-to-cell coupling, and degree of cleft space are not constant but rather are treated as spatially random with assigned distributions. This modeling approach makes it possible to simulate wavefront propagation in a manner analogous to performing experiments on engineered monolayer tissues. Simulated results are compared to previously published measured data from monolayers used to investigate the role of cellular architecture on conduction velocities and anisotropy ratios. We also present an estimate for obtaining the electrical properties from these networks and demonstrate how variations in the discrete cellular architecture affect the macroscopic conductivities. The simulations support the common assumption that under normal ranges of coupling strength, tissues with relatively uniform distributions of cell shapes and connectivity can be represented using continuous models with conductivities derived from random discrete cellular architecture using either global or local estimates. The results also reveal that in the presence of abrupt changes in cell orientation, local estimates of tissue properties predict smoother changes in conductivity that may not adequately predict the discrete nature of propagation at the transition sites. PMID:20441739

  11. Evaluation of organ doses and specific k effective dose of 64-slice CT thorax examination using an adult anthropomorphic phantom

    NASA Astrophysics Data System (ADS)

    Hashim, S.; Karim, M. K. A.; Bakar, K. A.; Sabarudin, A.; Chin, A. W.; Saripan, M. I.; Bradley, D. A.

    2016-09-01

    The magnitude of radiation dose in computed tomography (CT) depends on the scan acquisition parameters, investigated herein using an anthropomorphic phantom (RANDO®) and thermoluminescence dosimeters (TLD). Specific interest was in the organ doses resulting from CT thorax examination, the specific k coefficient for effective dose estimation for particular protocols also being determined. For measurement of doses representing five main organs (thyroid, lung, liver, esophagus and skin), TLD-100 (LiF:Mg, Ti) were inserted into selected holes in a phantom slab. Five CT thorax protocols were investigated, one routine (R1) and four that were modified protocols (R2 to R5). Organ doses were ranked from greatest to least, found to lie in the order: thyroid>skin>lung>liver>breast. The greatest dose, for thyroid at 25 mGy, was that in use of R1 while the lowest, at 8.8 mGy, was in breast tissue using R3. Effective dose (E) was estimated using three standard methods: the International Commission on Radiological Protection (ICRP)-103 recommendation (E103), the computational phantom CT-EXPO (E(CTEXPO)) method, and the dose-length product (DLP) based approach. E103 k factors were constant for all protocols, ~8% less than that of the universal k factor. Due to inconsistency in tube potential and pitch factor the k factors from CTEXPO were found to vary between 0.015 and 0.010 for protocols R3 and R5. With considerable variation between scan acquisition parameters and organ doses, optimization of practice is necessary in order to reduce patient organ dose.

  12. Computational approaches to understand cardiac electrophysiology and arrhythmias

    PubMed Central

    Roberts, Byron N.; Yang, Pei-Chi; Behrens, Steven B.; Moreno, Jonathan D.

    2012-01-01

    Cardiac rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. These impulses spread throughout the cardiac muscle to manifest as electrical waves in the whole heart. Regularity of electrical waves is critically important since they signal the heart muscle to contract, driving the primary function of the heart to act as a pump and deliver blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. For more than 50 years, mathematically based models of cardiac electrical activity have been used to improve understanding of basic mechanisms of normal and abnormal cardiac electrical function. Computer-based modeling approaches to understand cardiac activity are uniquely helpful because they allow for distillation of complex emergent behaviors into the key contributing components underlying them. Here we review the latest advances and novel concepts in the field as they relate to understanding the complex interplay between electrical, mechanical, structural, and genetic mechanisms during arrhythmia development at the level of ion channels, cells, and tissues. We also discuss the latest computational approaches to guiding arrhythmia therapy. PMID:22886409

  13. Computational modeling of cardiac hemodynamics: Current status and future outlook

    NASA Astrophysics Data System (ADS)

    Mittal, Rajat; Seo, Jung Hee; Vedula, Vijay; Choi, Young J.; Liu, Hang; Huang, H. Howie; Jain, Saurabh; Younes, Laurent; Abraham, Theodore; George, Richard T.

    2016-01-01

    The proliferation of four-dimensional imaging technologies, increasing computational speeds, improved simulation algorithms, and the widespread availability of powerful computing platforms is enabling simulations of cardiac hemodynamics with unprecedented speed and fidelity. Since cardiovascular disease is intimately linked to cardiovascular hemodynamics, accurate assessment of the patient's hemodynamic state is critical for the diagnosis and treatment of heart disease. Unfortunately, while a variety of invasive and non-invasive approaches for measuring cardiac hemodynamics are in widespread use, they still only provide an incomplete picture of the hemodynamic state of a patient. In this context, computational modeling of cardiac hemodynamics presents as a powerful non-invasive modality that can fill this information gap, and significantly impact the diagnosis as well as the treatment of cardiac disease. This article reviews the current status of this field as well as the emerging trends and challenges in cardiovascular health, computing, modeling and simulation and that are expected to play a key role in its future development. Some recent advances in modeling and simulations of cardiac flow are described by using examples from our own work as well as the research of other groups.

  14. Influence of computer work under time pressure on cardiac activity.

    PubMed

    Shi, Ping; Hu, Sijung; Yu, Hongliu

    2015-03-01

    Computer users are often under stress when required to complete computer work within a required time. Work stress has repeatedly been associated with an increased risk for cardiovascular disease. The present study examined the effects of time pressure workload during computer tasks on cardiac activity in 20 healthy subjects. Heart rate, time domain and frequency domain indices of heart rate variability (HRV) and Poincaré plot parameters were compared among five computer tasks and two rest periods. Faster heart rate and decreased standard deviation of R-R interval were noted in response to computer tasks under time pressure. The Poincaré plot parameters showed significant differences between different levels of time pressure workload during computer tasks, and between computer tasks and the rest periods. In contrast, no significant differences were identified for the frequency domain indices of HRV. The results suggest that the quantitative Poincaré plot analysis used in this study was able to reveal the intrinsic nonlinear nature of the autonomically regulated cardiac rhythm. Specifically, heightened vagal tone occurred during the relaxation computer tasks without time pressure. In contrast, the stressful computer tasks with added time pressure stimulated cardiac sympathetic activity.

  15. The feasibility of a 64-slice MDCT for detection of the Adamkiewicz artery: comparison of the detection rate of intravenous injection CT angiography using a 64-slice MDCT versus intra-arterial and intravenous injection CT angiography using a 16-slice MDCT.

    PubMed

    Nishii, Tatsuya; Kono, Atsushi K; Negi, Noriyuki; Hashimura, Hiromi; Uotani, Kensuke; Okita, Yutaka; Sugimura, Kazuro

    2013-12-01

    Identification of the Adamkiewicz artery (AKA) using CT angiography (CTA) is crucial in patients with thoracic aortic aneurysm (TAA) or aortic dissection (AD). The purpose of this study was to compare the AKA detection rate of intravenous injection with a 64-slice MDCT (IV64) versus a 16-slice MDCT (IV16) as well as by CTA using intra-arterial injection with a 16-slice MDCT (IA16). A retrospective review of 160 consecutive patients who underwent CTA was performed. There were 108 TAA and 52 AD cases, 105 of whom were examined with IV64, 15 with IV16, and 40 with IA16. The AKA detectability for each imaging method was assessed, and the factors influencing the detectability were analyzed by multivariate analysis. The detection rates for IV64, IV16, and IA16 were 85.7, 60.0, and 80.0 %, respectively, with IV64 being more sensitive than IV16 (P = 0.025). The detection rate for AD patients was 66.7 % with IV64, which was similar to IV16 (57.1 %) and IA16 (66.8 %). On the other hand, the detection rate for TAA patients was 93.3 % with IV64, which was higher than IV16 (62.5 %, P = 0.021) and similar to IA16 (88.0 %). Multivariate analysis demonstrated the independent factors for AKA detectability were TAA versus AD (P = 0.005, Odds ratio = 3.98) and IV64 versus IV16 (P = 0.037, Odds ratio = 4.03). The detection rate was higher for IV64 than for IV16, especially for TAA patients, while the rate was similar between IV64 and invasive IA16. A 64-slice MDCT thus provides a less invasive visualization of the AKA.

  16. Cardiac computed tomographic angiography and the primary care physician.

    PubMed

    Mikolich, J Ronald

    2012-05-01

    Through advancements in computer processing speed and storage capacity, new cardiac imaging modalities have become clinically feasible and useful. Cardiac computed tomographic angiography, a new diagnostic imaging modality, is capable of assessing coronary artery disease and left ventricular function on a par with invasive coronary arteriography in selected patients who meet appropriate use criteria. This imaging modality is of clinical value in the assessment of patients with chest pain who have an intermediate risk of coronary atherosclerosis. The purpose of the present report is to educate primary care physicians about the basic principles of advanced cardiac imaging techniques and to convey a useful strategy for their appropriate use in the current environment of medical economics.

  17. [Update on cardiac imaging techniques. Echocardiography, cardiac magnetic resonance and multidetector computed tomography].

    PubMed

    de Vinuesa, Pastora Gallego García; del Castillo, Sonia Velasco; Torres, Río Aguilar; Bardera, Juan C Paré

    2008-02-01

    This review of progress in cardiac imaging techniques summarizes the most significant development reported in the last year on different echocardiographic techniques and their application in a range of settings, from the treatment of heart failure to their use in intraoperative monitoring and guiding interventional procedures. Large sections are devoted to recent developments in three-dimensional imaging and, because of its clinical importance, to magnetic resonance imaging. Finally, there is a comprehensive update on the use of multidetector computed tomography in cardiology.

  18. Images as drivers of progress in cardiac computational modelling

    PubMed Central

    Lamata, Pablo; Casero, Ramón; Carapella, Valentina; Niederer, Steve A.; Bishop, Martin J.; Schneider, Jürgen E.; Kohl, Peter; Grau, Vicente

    2014-01-01

    Computational models have become a fundamental tool in cardiac research. Models are evolving to cover multiple scales and physical mechanisms. They are moving towards mechanistic descriptions of personalised structure and function, including effects of natural variability. These developments are underpinned to a large extent by advances in imaging technologies. This article reviews how novel imaging technologies, or the innovative use and extension of established ones, integrate with computational models and drive novel insights into cardiac biophysics. In terms of structural characterization, we discuss how imaging is allowing a wide range of scales to be considered, from cellular levels to whole organs. We analyse how the evolution from structural to functional imaging is opening new avenues for computational models, and in this respect we review methods for measurement of electrical activity, mechanics and flow. Finally, we consider ways in which combined imaging and modelling research is likely to continue advancing cardiac research, and identify some of the main challenges that remain to be solved. PMID:25117497

  19. Radiation dose at cardiac computed tomography: facts and fiction.

    PubMed

    Huda, Walter; Rowlett, W Taylor; Schoepf, U Joseph

    2010-08-01

    Cardiac computed tomography (CT) dosimetry makes use of two radiation parameters: a volume CT dose index (CTDI) and a dose length product (DLP). The volume CTDI quantifies the intensity of the radiation used to perform CT examinations, whereas DLP quantifies the amount of radiation used. CTDI metrics can be converted into patient dose metrics by using dose/CTDI conversion factors. In cardiac CT imaging, these need to take into account the x-ray tube voltage, scan length, and scan region, as well as patient size. Organ doses to patients in cardiac CT can be converted into cancer risks when patient demographic factors are taken into account. A risk analysis of patients undergoing cardiac CT angiography at our institution showed that a majority (62%) were males, with a median age of approximately 60 years and a median weight of approximately 90 kg. The median DLP was approximately 1100 mGy cm, corresponding to an effective dose of approximately 29 mSv in normal-sized patients. The average patient lifetime risk for a radiation-induced cancer was estimated to be 0.12%, with 85% of it attributed to lung cancer. Patients with an age and weight at the 10th percentile, who also received a DLP at the 90th percentile, would have cancer risk estimates approximately double the average value. Radiation risks are required to determine whether examinations are indicated, defined as examinations in which individual patient benefit exceeds corresponding patient risk. Understanding radiation risks in cardiac CT encourages operators to use the least amount of radiation to achieve satisfactory diagnostic performance. PMID:20711036

  20. Imaging techniques for cardiac strain and deformation: comparison of echocardiography, cardiac magnetic resonance and cardiac computed tomography.

    PubMed

    Tee, Michael; Noble, J Alison; Bluemke, David A

    2013-02-01

    Myocardial function assessment is essential for determining the health of the myocardium. Global assessment of myocardial function is widely performed (by estimating the ejection fraction), but many common cardiac diseases initially affect the myocardium on a regional, rather than global basis. Regional myocardial wall motion can be quantified using myocardial strain analysis (a normalized measure of deformation). Myocardial strain can be measured in terms of three normal strains (longitudinal strain, radial strain and circumferential) and six shear strains. Cardiac MRI (cMRI) is usually considered the reference standard for measurement of myocardial strain. The most common cMRI method, termed tagged cMRI, allows full, 3D assessment of regional strain. However, due to its complexity and lengthy times for analysis, tagged cMRI is not usually used outside of academic centers. Tagged cMRI is also primarily used only in research studies. Echocardiography combined with tissue Doppler imaging or a speckle tracking technique is now widely available in the clinical setting. Myocardial strain measurement by echocardiography shows reasonable agreement with cMRI. Limited standardization and differences between vendors represent current limitations of the technique. Cardiac computed tomography (CCT) is the newest and most rapidly growing modality for noninvasive imaging of the heart. While CCT studies are most commonly applied to assess the coronary arteries, CCT is easily adapted to provide functional information for both the left and right ventricles. New methods for CCT assessment of regional myocardial function are being developed. This review outlines the current literature on imaging techniques related to cardiac strain analysis and discusses the strengths and weaknesses of various methods for myocardial strain analysis.

  1. Cardiac PET/Computed Tomography Applications and Cardiovascular Outcome.

    PubMed

    Schindler, Thomas Hellmut

    2015-07-01

    Cardiac PET/computed tomography (CT) in conjunction with different blood flow tracers is increasingly applied for the assessment of myocardial perfusion and myocardial flow reserve (MFR) in the detection of coronary artery disease (CAD). The ability of PET/CT to noninvasively determine regional myocardial blood flow at rest and during vasomotor stress allows the calculation of the MFR, which carries important prognostic information in patients with subclinical forms of cardiomyopathy. The measured MFR optimizes the identification and characterization of the extent and severity of CAD burden, and contributes to the flow-limiting effect of single lesions in multivessel CAD. PMID:26099678

  2. Cardiac computed tomography in patients with acute chest pain.

    PubMed

    Nieman, Koen; Hoffmann, Udo

    2015-04-14

    The efficient and reliable evaluation of patients with acute chest pain is one of the most challenging tasks in the emergency department. Coronary computed tomography (CT) angiography may play a major role, since it permits ruling out coronary artery disease with high accuracy if performed with expertise in properly selected and prepared patients. Several randomized trials have established early cardiac CT as a viable safe and potentially more efficient alternative to functional testing in the evaluation of acute chest pain. Ongoing investigations explore whether advanced anatomic and functional assessments such as high-risk coronary plaque, resting myocardial perfusion, and left ventricular function, or the simulation of the fractional coronary flow reserve will add information to the anatomic assessment for stenosis, which would allow expanding the benefits of cardiac CT from triage to treatment decisions. Especially, the combination of high-sensitive troponins and coronary computed tomography angiography may play a valuable role in future strategies for the management of patients presenting with acute chest pain.

  3. Multislice computer tomography for detection of coronary artery disease.

    PubMed

    Ropers, Dieter

    2006-12-01

    Multislice computer tomography has undergone substantial technological progress during the past years. Current 64-slice scanners with gantry rotation speeds of as little as 330 ms, and particularly the recently introduced dual source CT equipped with two X-ray tubes, provide a temporal and spatial resolution that is sufficient to allow reliable imaging of cardiac morphology and coronary arteries. Especially the ability to noninvasively visualize the coronary arteries, including the assessment and quantification of calcifications, as well as the detection of luminal obstruction and atherosclerotic plaque, constitutes an attractive addition to currently available diagnostic tools for the work-up of patients with known or suspected coronary artery disease. Besides the evaluation of coronary artery calcium and atherosclerotic plaques, this review focuses on the contrast-enhanced CT visualization of the coronary vessels, including native coronary arteries, bypass grafts, and coronary stonts. Thereby detailed information concerning the scan protocol, clinical data, possible indications, and limitations using up-to-date 64-slice technology is provided. Finally, the overview includes design and initial image examples of dual source CT technology as the newest development in the field.

  4. Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging.

    PubMed

    Lembcke, Alexander; Hein, Patrick A; Dohmen, Pascal M; Klessen, Christian; Wiese, Till H; Hoffmann, Udo; Hamm, Bernd; Enzweiler, Christian N H

    2006-03-01

    Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure. PMID:16427236

  5. Computational modeling of muscular thin films for cardiac repair

    NASA Astrophysics Data System (ADS)

    Böl, Markus; Reese, Stefanie; Parker, Kevin Kit; Kuhl, Ellen

    2009-03-01

    Motivated by recent success in growing biohybrid material from engineered tissues on synthetic polymer films, we derive a computational simulation tool for muscular thin films in cardiac repair. In this model, the polydimethylsiloxane base layer is simulated in terms of microscopically motivated tetrahedral elements. Their behavior is characterized through a volumetric contribution and a chain contribution that explicitly accounts for the polymeric microstructure of networks of long chain molecules. Neonatal rat ventricular cardiomyocytes cultured on these polymeric films are modeled with actively contracting truss elements located on top of the sheet. The force stretch response of these trusses is motivated by the cardiomyocyte force generated during active contraction as suggested by the filament sliding theory. In contrast to existing phenomenological models, all material parameters of this novel model have a clear biophyisical interpretation. The predictive features of the model will be demonstrated through the simulation of muscular thin films. First, the set of parameters will be fitted for one particular experiment documented in the literature. This parameter set is then used to validate the model for various different experiments. Last, we give an outlook of how the proposed simulation tool could be used to virtually predict the response of multi-layered muscular thin films. These three-dimensional constructs show a tremendous regenerative potential in repair of damaged cardiac tissue. The ability to understand, tune and optimize their structural response is thus of great interest in cardiovascular tissue engineering.

  6. Design of a specialized computer for on-line monitoring of cardiac stroke volume

    NASA Technical Reports Server (NTRS)

    Webb, J. A., Jr.; Gebben, V. D.

    1972-01-01

    The design of a specialized analog computer for on-line determination of cardiac stroke volume by means of a modified version of the pressure pulse contour method is presented. The design consists of an analog circuit for computation and a timing circuit for detecting necessary events on the pressure waveform. Readouts of arterial pressures, systolic duration, heart rate, percent change in stroke volume, and percent change in cardiac output are provided for monitoring cardiac patients. Laboratory results showed that computational accuracy was within 3 percent, while animal experiments verified the operational capability of the computer. Patient safety considerations are also discussed.

  7. Human cardiac systems electrophysiology and arrhythmogenesis: iteration of experiment and computation.

    PubMed

    Holzem, Katherine M; Madden, Eli J; Efimov, Igor R

    2014-11-01

    Human cardiac electrophysiology (EP) is a unique system for computational modelling at multiple scales. Due to the complexity of the cardiac excitation sequence, coordinated activity must occur from the single channel to the entire myocardial syncytium. Thus, sophisticated computational algorithms have been developed to investigate cardiac EP at the level of ion channels, cardiomyocytes, multicellular tissues, and the whole heart. Although understanding of each functional level will ultimately be important to thoroughly understand mechanisms of physiology and disease, cardiac arrhythmias are expressly the product of cardiac tissue-containing enough cardiomyocytes to sustain a reentrant loop of activation. In addition, several properties of cardiac cellular EP, that are critical for arrhythmogenesis, are significantly altered by cell-to-cell coupling. However, relevant human cardiac EP data, upon which to develop or validate models at all scales, has been lacking. Thus, over several years, we have developed a paradigm for multiscale human heart physiology investigation and have recovered and studied over 300 human hearts. We have generated a rich experimental dataset, from which we better understand mechanisms of arrhythmia in human and can improve models of human cardiac EP. In addition, in collaboration with computational physiologists, we are developing a database for the deposition of human heart experimental data, including thorough experimental documentation. We anticipate that accessibility to this human heart dataset will further human EP computational investigations, as well as encourage greater data transparency within the field of cardiac EP.

  8. Human cardiac systems electrophysiology and arrhythmogenesis: iteration of experiment and computation

    PubMed Central

    Holzem, Katherine M.; Madden, Eli J.; Efimov, Igor R.

    2014-01-01

    Human cardiac electrophysiology (EP) is a unique system for computational modelling at multiple scales. Due to the complexity of the cardiac excitation sequence, coordinated activity must occur from the single channel to the entire myocardial syncytium. Thus, sophisticated computational algorithms have been developed to investigate cardiac EP at the level of ion channels, cardiomyocytes, multicellular tissues, and the whole heart. Although understanding of each functional level will ultimately be important to thoroughly understand mechanisms of physiology and disease, cardiac arrhythmias are expressly the product of cardiac tissue—containing enough cardiomyocytes to sustain a reentrant loop of activation. In addition, several properties of cardiac cellular EP, that are critical for arrhythmogenesis, are significantly altered by cell-to-cell coupling. However, relevant human cardiac EP data, upon which to develop or validate models at all scales, has been lacking. Thus, over several years, we have developed a paradigm for multiscale human heart physiology investigation and have recovered and studied over 300 human hearts. We have generated a rich experimental dataset, from which we better understand mechanisms of arrhythmia in human and can improve models of human cardiac EP. In addition, in collaboration with computational physiologists, we are developing a database for the deposition of human heart experimental data, including thorough experimental documentation. We anticipate that accessibility to this human heart dataset will further human EP computational investigations, as well as encourage greater data transparency within the field of cardiac EP. PMID:25362174

  9. Analysis of left atrial respiratory and cardiac motion for cardiac ablation therapy

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Holmes, D. R.; Johnson, S. B.; Lehmann, H. I.; Robb, R. A.; Packer, D. L.

    2015-03-01

    Cardiac ablation therapy is often guided by models built from preoperative computed tomography (CT) or magnetic resonance imaging (MRI) scans. One of the challenges in guiding a procedure from a preoperative model is properly synching the preoperative models with cardiac and respiratory motion through computational motion models. In this paper, we describe a methodology for evaluating cardiac and respiratory motion in the left atrium and pulmonary veins of a beating canine heart. Cardiac catheters were used to place metal clips within and near the pulmonary veins and left atrial appendage under fluoroscopic and ultrasound guidance and a contrast-enhanced, 64-slice multidetector CT scan was collected with the clips in place. Each clip was segmented from the CT scan at each of the five phases of the cardiac cycle at both end-inspiration and end-expiration. The centroid of each segmented clip was computed and used to evaluate both cardiac and respiratory motion of the left atrium. A total of three canine studies were completed, with 4 clips analyzed in the first study, 5 clips in the second study, and 2 clips in the third study. Mean respiratory displacement was 0.2+/-1.8 mm in the medial/lateral direction, 4.7+/-4.4 mm in the anterior/posterior direction (moving anterior on inspiration), and 9.0+/-5.0 mm superior/inferior (moving inferior with inspiration). At end inspiration, the mean left atrial cardiac motion at the clip locations was 1.5+/-1.3 mm in the medial/lateral direction, and 2.1+/-2.0 mm in the anterior/posterior and 1.3+/-1.2 mm superior/inferior directions. At end expiration, the mean left atrial cardiac motion at the clip locations was 2.0+/-1.5mm in the medial/lateral direction, 3.0+/-1.8mm in the anterior/posterior direction, and 1.5+/-1.5 mm in the superior/inferior directions.

  10. Evolution of Cardiac Biomodels from Computational to Therapeutics.

    PubMed

    Rathinam, Alwin Kumar; Mokhtar, Raja Amin Raja

    2016-01-01

    Biomodeling the human anatomy in exact structure and size is an exciting field of medical science. Utilizing medical data from various medical imaging topography, the data of an anatomical structure can be extracted and converted into a three-dimensional virtual biomodel; thereafter a physical biomodel can be generated utilizing rapid prototyping machines. Here, we have reviewed the utilization of this technology and have provided some guidelines to develop biomodels of cardiac structures. Cardiac biomodels provide insights for cardiothoracic surgeons, cardiologists, and patients alike. Additionally, the technology may have future usability for tissue engineering, robotic surgery, or routine hospital usage as a diagnostic and therapeutic tool for cardiovascular diseases (CVD). Given the broad areas of application of cardiac biomodels, attention should be given to further research and development of their potential. PMID:27585205

  11. Preliminary Experimental Results on Controlled Cardiac Computed Tomography: A Phantom Study

    PubMed Central

    Lu, Yang; Cai, Zhijun; Wang, Ge; Zhao, Jun; Bai, Er-Wei

    2010-01-01

    In this paper, we present the preliminary experimental results on controlled cardiac computed tomography (CT), which aims to reduce the motion artifacts by means of controlling the x-ray source rotation speed. An innovative cardiac phantom enables us to perform this experiment without modifying the scanner. It is the first experiment on the cardiac CT with speed controlled x-ray source. Experimental results demonstrate that the proposed method successfully separates the phantom images at different phases (improve the temporal resolution) though controlling the x-ray speed. PMID:19696470

  12. Evaluating the Effectiveness of an Interactive Multimedia Computer-based Patient Education Program in Cardiac Rehabilitation.

    ERIC Educational Resources Information Center

    Jenny, Ng Yuen Yee; Fai, Tam Sing

    2001-01-01

    A study compared 48 cardiac patients who used an interactive multimedia computer-assisted patient education program and 48 taught by tutorial. The computer-assisted instructional method resulted in significantly better knowledge about exercise and self-management of chronic diseases. (Contains 29 references.) (JOW)

  13. Characterization of cardiac quiescence from retrospective cardiac computed tomography using a correlation-based phase-to-phase deviation measure

    SciTech Connect

    Wick, Carson A.; McClellan, James H.; Arepalli, Chesnal D.; Auffermann, William F.; Henry, Travis S.; Khosa, Faisal; Coy, Adam M.; Tridandapani, Srini

    2015-02-15

    Purpose: Accurate knowledge of cardiac quiescence is crucial to the performance of many cardiac imaging modalities, including computed tomography coronary angiography (CTCA). To accurately quantify quiescence, a method for detecting the quiescent periods of the heart from retrospective cardiac computed tomography (CT) using a correlation-based, phase-to-phase deviation measure was developed. Methods: Retrospective cardiac CT data were obtained from 20 patients (11 male, 9 female, 33–74 yr) and the left main, left anterior descending, left circumflex, right coronary artery (RCA), and interventricular septum (IVS) were segmented for each phase using a semiautomated technique. Cardiac motion of individual coronary vessels as well as the IVS was calculated using phase-to-phase deviation. As an easily identifiable feature, the IVS was analyzed to assess how well it predicts vessel quiescence. Finally, the diagnostic quality of the reconstructed volumes from the quiescent phases determined using the deviation measure from the vessels in aggregate and the IVS was compared to that from quiescent phases calculated by the CT scanner. Three board-certified radiologists, fellowship-trained in cardiothoracic imaging, graded the diagnostic quality of the reconstructions using a Likert response format: 1 = excellent, 2 = good, 3 = adequate, 4 = nondiagnostic. Results: Systolic and diastolic quiescent periods were identified for each subject from the vessel motion calculated using the phase-to-phase deviation measure. The motion of the IVS was found to be similar to the aggregate vessel (AGG) motion. The diagnostic quality of the coronary vessels for the quiescent phases calculated from the aggregate vessel (P{sub AGG}) and IVS (P{sub IV} {sub S}) deviation signal using the proposed methods was comparable to the quiescent phases calculated by the CT scanner (P{sub CT}). The one exception was the RCA, which improved for P{sub AGG} for 18 of the 20 subjects when compared to P

  14. Functional Relevance of Coronary Artery Disease by Cardiac Magnetic Resonance and Cardiac Computed Tomography: Myocardial Perfusion and Fractional Flow Reserve

    PubMed Central

    Andreini, Daniele; Bertella, Erika; Mushtaq, Saima; Guaricci, Andrea Igoren; Pepi, Mauro

    2015-01-01

    Coronary artery disease (CAD) is one of the leading causes of morbidity and mortality and it is responsible for an increasing resource burden. The identification of patients at high risk for adverse events is crucial to select those who will receive the greatest benefit from revascularization. To this aim, several non-invasive functional imaging modalities are usually used as gatekeeper to invasive coronary angiography, but the diagnostic yield of elective invasive coronary angiography remains unfortunately low. Stress myocardial perfusion imaging by cardiac magnetic resonance (stress-CMR) has emerged as an accurate technique for diagnosis and prognostic stratification of the patients with known or suspected CAD thanks to high spatial and temporal resolution, absence of ionizing radiation, and the multiparametric value including the assessment of cardiac anatomy, function, and viability. On the other side, cardiac computed tomography (CCT) has emerged as unique technique providing coronary arteries anatomy and more recently, due to the introduction of stress-CCT and noninvasive fractional flow reserve (FFR-CT), functional relevance of CAD in a single shot scan. The current review evaluates the technical aspects and clinical experience of stress-CMR and CCT in the evaluation of functional relevance of CAD discussing the strength and weakness of each approach. PMID:25692133

  15. Computer Modelling for Better Diagnosis and Therapy of Patients by Cardiac Resynchronisation Therapy.

    PubMed

    Pluijmert, Marieke; Lumens, Joost; Potse, Mark; Delhaas, Tammo; Auricchio, Angelo; Prinzen, Frits W

    2015-05-01

    Mathematical or computer models have become increasingly popular in biomedical science. Although they are a simplification of reality, computer models are able to link a multitude of processes to each other. In the fields of cardiac physiology and cardiology, models can be used to describe the combined activity of all ion channels (electrical models) or contraction-related processes (mechanical models) in potentially millions of cardiac cells. Electromechanical models go one step further by coupling electrical and mechanical processes and incorporating mechano-electrical feedback. The field of cardiac computer modelling is making rapid progress due to advances in research and the ever-increasing calculation power of computers. Computer models have helped to provide better understanding of disease mechanisms and treatment. The ultimate goal will be to create patient-specific models using diagnostic measurements from the individual patient. This paper gives a brief overview of computer models in the field of cardiology and mentions some scientific achievements and clinical applications, especially in relation to cardiac resynchronisation therapy (CRT).

  16. Computer Modelling for Better Diagnosis and Therapy of Patients by Cardiac Resynchronisation Therapy

    PubMed Central

    Pluijmert, Marieke; Lumens, Joost; Potse, Mark; Delhaas, Tammo; Auricchio, Angelo; Prinzen, Frits W

    2015-01-01

    Mathematical or computer models have become increasingly popular in biomedical science. Although they are a simplification of reality, computer models are able to link a multitude of processes to each other. In the fields of cardiac physiology and cardiology, models can be used to describe the combined activity of all ion channels (electrical models) or contraction-related processes (mechanical models) in potentially millions of cardiac cells. Electromechanical models go one step further by coupling electrical and mechanical processes and incorporating mechano-electrical feedback. The field of cardiac computer modelling is making rapid progress due to advances in research and the ever-increasing calculation power of computers. Computer models have helped to provide better understanding of disease mechanisms and treatment. The ultimate goal will be to create patient-specific models using diagnostic measurements from the individual patient. This paper gives a brief overview of computer models in the field of cardiology and mentions some scientific achievements and clinical applications, especially in relation to cardiac resynchronisation therapy (CRT). PMID:26835103

  17. Ubiquitous Computing for Remote Cardiac Patient Monitoring: A Survey

    PubMed Central

    Kumar, Sunil; Kambhatla, Kashyap; Hu, Fei; Lifson, Mark; Xiao, Yang

    2008-01-01

    New wireless technologies, such as wireless LAN and sensor networks, for telecardiology purposes give new possibilities for monitoring vital parameters with wearable biomedical sensors, and give patients the freedom to be mobile and still be under continuous monitoring and thereby better quality of patient care. This paper will detail the architecture and quality-of-service (QoS) characteristics in integrated wireless telecardiology platforms. It will also discuss the current promising hardware/software platforms for wireless cardiac monitoring. The design methodology and challenges are provided for realistic implementation. PMID:18604301

  18. Conversion of cardiac performance data in analog form for digital computer entry

    NASA Technical Reports Server (NTRS)

    Miller, R. L.

    1972-01-01

    A system is presented which will reduce analog cardiac performance data and convert the results to digital form for direct entry into a commercial time-shared computer. Circuits are discussed which perform the measurement and digital conversion of instantaneous systolic and diastolic parameters from the analog blood pressure waveform. Digital averaging over a selected number of heart cycles is performed on these measurements, as well as those of flow and heart rate. The determination of average cardiac output and peripheral resistance, including trends, is the end result after processing by digital computer.

  19. Computational modeling of cardiac dual calcium-voltage optical mapping.

    PubMed

    Walton, Richard D; Bernus, Olivier

    2009-01-01

    Optical imaging allows mapping the complex spatiotemporal dynamics of transmembrane potential and intracellular calcium in cardiac tissue. Several studies have shown that the epi-fluorescent optical action potential contains contributions from the sub-epicardium, owing to scattering of photons in tissue. Hybrid electro-optical models have allowed careful quantification of these scattering effects and have lead to a better interpretation of the optical action potential. However, until now, these effects have not been investigated for optically recorded calcium transients. Here, we develop a hybrid model of cardiac dual calcium-voltage epi-fluorescence mapping. This model allows simulating both optical action potentials and optical calcium transients and investigating the effects of photon scattering on their synthesis. We find that optical calcium transients contain contributions from sub-epicardial layers up to 0.8 mm below the epicardium. These lead to significant differences in rise time and activation times between the optically acquired calcium signal and the epicardial intracellular calcium concentration. As has been the case with optically recording action potentials, these results should be taken into account in the interpretation of experimental optical measurements of intracellular calcium.

  20. Strategies for reduction of radiation dose in cardiac multislice CT.

    PubMed

    Paul, Jean-François; Abada, Hicham T

    2007-08-01

    Because cardiac computed tomography (CT) (mainly coronary CT angiography) is a very promising technique, used more and more for coronary artery evaluation, the benefits and risks of this new low-invasive technique must be balanced. Radiation dose is a major concern for coronary CT angiography, especially in case of repeated examinations or in particular subgroups of patients (for example young female patients). Radiation dose to patient tends to increase from 16- to 64-slice CT. Radiation exposure in ECG-gated acquisitions may reach up to 40 mSv; considerable differences are attributable to the performance of CT machines, to technical dose-sparing tools, but also to radiological habits. Setting radiation dose at the lowest level possible should be a constant goal for the radiologist. Current technological tools are detailed in regard to their efficiency. Optimisation is necessary, by a judicious use of technological tools and also by individual adaptation of kV or mAs. This paper reviews the different current strategies for radiation dose reduction, keeping image quality constant. Data from the literature are discussed, and future technological developments are considered in regards to radiation dose reduction. The particular case of paediatric patients with congenital heart disease is also addressed.

  1. Advanced computer techniques for inverse modeling of electric current in cardiac tissue

    SciTech Connect

    Hutchinson, S.A.; Romero, L.A.; Diegert, C.F.

    1996-08-01

    For many years, ECG`s and vector cardiograms have been the tools of choice for non-invasive diagnosis of cardiac conduction problems, such as found in reentrant tachycardia or Wolff-Parkinson-White (WPW) syndrome. Through skillful analysis of these skin-surface measurements of cardiac generated electric currents, a physician can deduce the general location of heart conduction irregularities. Using a combination of high-fidelity geometry modeling, advanced mathematical algorithms and massively parallel computing, Sandia`s approach would provide much more accurate information and thus allow the physician to pinpoint the source of an arrhythmia or abnormal conduction pathway.

  2. Catheter-Malposition-Induced Cardiac Tamponade via Contrast Media Leakage During Computed Tomography Study

    SciTech Connect

    Liang, C.-D. Ko, S.-F.; Huang, C.-F.; Chien, S.J.; Tiao, M.M.

    2005-12-15

    We present a rare case of a central venous catheter-malposition-induced life-threatening cardiac tamponade as a result of computed tomography (CT) with contrast enhancement in an infant with a ventricular septal defect and pulmonary atresia after a modified Blalock-Taussig shunt. The diagnosis was confirmed by chest radiographs and CT study with catheter perforation through the right atrial wall and extravasation of the contrast medium into the pericardium, leading to cardiac tamponade and subsequent circulatory collapse. Two hours after successful cardiopulmonary resuscitation, the patient gradually resumed normal hemodynamic status.

  3. Computational Chemical Imaging for Cardiovascular Pathology: Chemical Microscopic Imaging Accurately Determines Cardiac Transplant Rejection

    PubMed Central

    Tiwari, Saumya; Reddy, Vijaya B.; Bhargava, Rohit; Raman, Jaishankar

    2015-01-01

    Rejection is a common problem after cardiac transplants leading to significant number of adverse events and deaths, particularly in the first year of transplantation. The gold standard to identify rejection is endomyocardial biopsy. This technique is complex, cumbersome and requires a lot of expertise in the correct interpretation of stained biopsy sections. Traditional histopathology cannot be used actively or quickly during cardiac interventions or surgery. Our objective was to develop a stain-less approach using an emerging technology, Fourier transform infrared (FT-IR) spectroscopic imaging to identify different components of cardiac tissue by their chemical and molecular basis aided by computer recognition, rather than by visual examination using optical microscopy. We studied this technique in assessment of cardiac transplant rejection to evaluate efficacy in an example of complex cardiovascular pathology. We recorded data from human cardiac transplant patients’ biopsies, used a Bayesian classification protocol and developed a visualization scheme to observe chemical differences without the need of stains or human supervision. Using receiver operating characteristic curves, we observed probabilities of detection greater than 95% for four out of five histological classes at 10% probability of false alarm at the cellular level while correctly identifying samples with the hallmarks of the immune response in all cases. The efficacy of manual examination can be significantly increased by observing the inherent biochemical changes in tissues, which enables us to achieve greater diagnostic confidence in an automated, label-free manner. We developed a computational pathology system that gives high contrast images and seems superior to traditional staining procedures. This study is a prelude to the development of real time in situ imaging systems, which can assist interventionists and surgeons actively during procedures. PMID:25932912

  4. Analysis of Pulmonary Vein Antrums Motion with Cardiac Contraction Using Dual-Source Computed Tomography

    PubMed Central

    de Guise, Jacques; Vu, Toni; Chartrand-Lefebvre, Carl; Blais, Danis; Lebeau, Martin; Nguyen, Nhu-Tram; Roberge, David

    2016-01-01

    Purpose: The purpose of the study was to determine the extent of displacement of the pulmonary vein antrums resulting from the intrinsic motion of the heart using 4D cardiac dual-source computed tomography (DSCT). Methods: Ten consecutive female patients were enrolled in this prospective planning study. In breath-hold, a contrast-injected cardiac 4-dimensional (4D) computed tomography (CT) synchronized to the electrocardiogram was obtained using a prospective sequential acquisition method including the extreme phases of systole and diastole. Right and left atrial fibrillation target volumes (CTVR and CTVL) were defined, with each target volume containing the antral regions of the superior and inferior pulmonary veins. Four points of interest were used as surrogates for the right superior and inferior pulmonary vein antrum (RSPVA and RIPVA) and the left superior and inferior pulmonary vein antrum (LSPVA and LIPVA). On our 4D post-processing workstation (MIM Maestro™, MIM Software Inc.), maximum displacement of each point of interest from diastole to systole was measured in the mediolateral (ML), anteroposterior (AP), and superoinferior (SI) directions. Results: Median age of the enrolled patients was 60 years (range, 56-71 years). Within the CTVR, the mean displacements of the superior and inferior surrogates were 3 mm vs. 1 mm (p=0.002), 2 mm vs. 0 mm (p= 0.001), and 3 mm vs. 0 mm (p=0.00001), in the ML, AP, and SI directions, respectively. On the left, mean absolute displacements of the LSPVA vs. LIPVA were similar at 4 mm vs. 1 mm (p=0.0008), 2 mm vs. 0 mm (p= 0.001), and 3 mm vs. 1 mm (p=0.00001) in the ML, AP, and SI directions. Conclusion: When isolated from breathing, cardiac contraction is associated with minimal inferior pulmonary veins motion and modest (1-6 mm) motion of the superior veins. Target deformation was thus of a magnitude similar or greater than target motion, limiting the potential gains of cardiac tracking. Optimal strategies for cardiac

  5. Petascale computation performance of lightweight multiscale cardiac models using hybrid programming models.

    PubMed

    Pope, Bernard J; Fitch, Blake G; Pitman, Michael C; Rice, John J; Reumann, Matthias

    2011-01-01

    Future multiscale and multiphysics models must use the power of high performance computing (HPC) systems to enable research into human disease, translational medical science, and treatment. Previously we showed that computationally efficient multiscale models will require the use of sophisticated hybrid programming models, mixing distributed message passing processes (e.g. the message passing interface (MPI)) with multithreading (e.g. OpenMP, POSIX pthreads). The objective of this work is to compare the performance of such hybrid programming models when applied to the simulation of a lightweight multiscale cardiac model. Our results show that the hybrid models do not perform favourably when compared to an implementation using only MPI which is in contrast to our results using complex physiological models. Thus, with regards to lightweight multiscale cardiac models, the user may not need to increase programming complexity by using a hybrid programming approach. However, considering that model complexity will increase as well as the HPC system size in both node count and number of cores per node, it is still foreseeable that we will achieve faster than real time multiscale cardiac simulations on these systems using hybrid programming models.

  6. Prognostic capabilities of coronary computed tomographic angiography before non-cardiac surgery: prospective cohort study

    PubMed Central

    Chan, Matthew; Butler, Craig; Chow, Benjamin; Tandon, Vikas; Nagele, Peter; Mitha, Ayesha; Mrkobrada, Marko; Szczeklik, Wojciech; Faridah, Yang; Biccard, Bruce; Stewart, Lori K; Heels-Ansdell, Diane; Devereaux, P J

    2015-01-01

    Objectives To determine if coronary computed tomographic angiography enhances prediction of perioperative risk in patients before non-cardiac surgery and to assess the preoperative coronary anatomy in patients who experience a myocardial infarction after non-cardiac surgery. Design Prospective cohort study. Setting 12 centers in eight countries. Participants 955 patients with, or at risk of, atherosclerotic disease who underwent non-cardiac surgery. Interventions Coronary computed tomographic angiography was performed preoperatively; clinicians were blinded to the results unless left main disease was suspected. Results were classified as normal, non-obstructive (<50% stenosis), obstructive (one or two vessels with ≥50% stenosis), or extensive obstructive (≥50% stenosis in two vessels including the proximal left anterior descending artery, three vessels, or left main). Main outcome measure Composite of cardiovascular death and non-fatal myocardial infarction within 30 days after surgery (primary outcome). This was the dependent variable in Cox regression. The independent variables were scores on the revised cardiac risk index and findings on coronary computed tomographic angiography. Results The primary outcome occurred in 74 patients (8%). The model that included both scores on the revised cardiac risk index and findings on coronary computed tomographic angiography showed that coronary computed tomographic angiography provided independent prognostic information (P=0.014; C index=0.66). The adjusted hazard ratios were 1.51 (95% confidence interval 0.45 to 5.10) for non-obstructive disease; 2.05 (0.62 to 6.74) for obstructive disease; and 3.76 (1.12 to 12.62) for extensive obstructive disease. For the model with coronary computed tomographic angiography compared with the model based on the revised cardiac risk index alone, with 30 day risk categories of <5%, 5-15%, and >15% for the primary outcome, the results of risk reclassification indicate that in a sample of

  7. Cardiac Magnetic Resonance and Computed Tomography in Hypertrophic Cardiomyopathy: an Update

    PubMed Central

    de Oliveira, Diogo Costa Leandro; Assunção, Fernanda Boldrini; dos Santos, Alair Agusto Sarmet Moreira Damas; Nacif, Marcelo Souto

    2016-01-01

    Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease and represents the main cause of sudden death in young patients. Cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) are noninvasive imaging methods with high sensitivity and specificity, useful for the establishment of diagnosis and prognosis of HCM, and for the screening of patients with subclinical phenotypes. The improvement of image analysis by CMR and CCT offers the potential to promote interventions aiming at stopping the natural course of the disease. This study aims to describe the role of RCM and CCT in the diagnosis and prognosis of HCM, and how these methods can be used in the management of these patients. PMID:27305111

  8. Cardiac findings on non-gated chest computed tomography: A clinical and pictorial review.

    PubMed

    Kanza, Rene Epunza; Allard, Christian; Berube, Michel

    2016-02-01

    The use of chest computed tomography (CT) as an imaging test for the evaluation of thoracic pathology has significantly increased during the last four decades. Although cardiopulmonary diseases often overlap in their clinical manifestation, radiologists tend to overlook the heart while interpreting routine chest CT. Recent advances in CT technology have led to significant reduction of heart motion artefacts and now allow for the identification of several cardiac findings on chest CT even without electrocardiogram (ECG) gating. These observations range from simple curiosity to both benign and malignant discoveries, to life-threatening discoveries. We here present a clinical and radiologic review of common and less common cardiac findings discovered on non-gated chest CT in order to draw the attention of radiologists and referring physicians to these possibilities.

  9. Cardiac magnetic resonance imaging and computed tomography in ischemic cardiomyopathy: an update*

    PubMed Central

    Assunção, Fernanda Boldrini; de Oliveira, Diogo Costa Leandro; Souza, Vitor Frauches; Nacif, Marcelo Souto

    2016-01-01

    Ischemic cardiomyopathy is one of the major health problems worldwide, representing a significant part of mortality in the general population nowadays. Cardiac magnetic resonance imaging (CMRI) and cardiac computed tomography (CCT) are noninvasive imaging methods that serve as useful tools in the diagnosis of coronary artery disease and may also help in screening individuals with risk factors for developing this illness. Technological developments of CMRI and CCT have contributed to the rise of several clinical indications of these imaging methods complementarily to other investigation methods, particularly in cases where they are inconclusive. In terms of accuracy, CMRI and CCT are similar to the other imaging methods, with few absolute contraindications and minimal risks of adverse side-effects. This fact strengthens these methods as powerful and safe tools in the management of patients. The present study is aimed at describing the role played by CMRI and CCT in the diagnosis of ischemic cardiomyopathies. PMID:26929458

  10. Cardiac magnetic resonance imaging and computed tomography in ischemic cardiomyopathy: an update.

    PubMed

    Assunção, Fernanda Boldrini; de Oliveira, Diogo Costa Leandro; Souza, Vitor Frauches; Nacif, Marcelo Souto

    2016-01-01

    Ischemic cardiomyopathy is one of the major health problems worldwide, representing a significant part of mortality in the general population nowadays. Cardiac magnetic resonance imaging (CMRI) and cardiac computed tomography (CCT) are noninvasive imaging methods that serve as useful tools in the diagnosis of coronary artery disease and may also help in screening individuals with risk factors for developing this illness. Technological developments of CMRI and CCT have contributed to the rise of several clinical indications of these imaging methods complementarily to other investigation methods, particularly in cases where they are inconclusive. In terms of accuracy, CMRI and CCT are similar to the other imaging methods, with few absolute contraindications and minimal risks of adverse side-effects. This fact strengthens these methods as powerful and safe tools in the management of patients. The present study is aimed at describing the role played by CMRI and CCT in the diagnosis of ischemic cardiomyopathies. PMID:26929458

  11. Cardiac Magnetic Resonance and Computed Tomography in Hypertrophic Cardiomyopathy: an Update.

    PubMed

    Oliveira, Diogo Costa Leandro de; Assunção, Fernanda Boldrini; Santos, Alair Agusto Sarmet Moreira Damas Dos; Nacif, Marcelo Souto

    2016-08-01

    Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease and represents the main cause of sudden death in young patients. Cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) are noninvasive imaging methods with high sensitivity and specificity, useful for the establishment of diagnosis and prognosis of HCM, and for the screening of patients with subclinical phenotypes. The improvement of image analysis by CMR and CCT offers the potential to promote interventions aiming at stopping the natural course of the disease. This study aims to describe the role of RCM and CCT in the diagnosis and prognosis of HCM, and how these methods can be used in the management of these patients. PMID:27305111

  12. Cardiac magnetic resonance imaging and computed tomography in ischemic cardiomyopathy: an update.

    PubMed

    Assunção, Fernanda Boldrini; de Oliveira, Diogo Costa Leandro; Souza, Vitor Frauches; Nacif, Marcelo Souto

    2016-01-01

    Ischemic cardiomyopathy is one of the major health problems worldwide, representing a significant part of mortality in the general population nowadays. Cardiac magnetic resonance imaging (CMRI) and cardiac computed tomography (CCT) are noninvasive imaging methods that serve as useful tools in the diagnosis of coronary artery disease and may also help in screening individuals with risk factors for developing this illness. Technological developments of CMRI and CCT have contributed to the rise of several clinical indications of these imaging methods complementarily to other investigation methods, particularly in cases where they are inconclusive. In terms of accuracy, CMRI and CCT are similar to the other imaging methods, with few absolute contraindications and minimal risks of adverse side-effects. This fact strengthens these methods as powerful and safe tools in the management of patients. The present study is aimed at describing the role played by CMRI and CCT in the diagnosis of ischemic cardiomyopathies.

  13. Cardiac findings on non-gated chest computed tomography: A clinical and pictorial review.

    PubMed

    Kanza, Rene Epunza; Allard, Christian; Berube, Michel

    2016-02-01

    The use of chest computed tomography (CT) as an imaging test for the evaluation of thoracic pathology has significantly increased during the last four decades. Although cardiopulmonary diseases often overlap in their clinical manifestation, radiologists tend to overlook the heart while interpreting routine chest CT. Recent advances in CT technology have led to significant reduction of heart motion artefacts and now allow for the identification of several cardiac findings on chest CT even without electrocardiogram (ECG) gating. These observations range from simple curiosity to both benign and malignant discoveries, to life-threatening discoveries. We here present a clinical and radiologic review of common and less common cardiac findings discovered on non-gated chest CT in order to draw the attention of radiologists and referring physicians to these possibilities. PMID:26781150

  14. Prevalence of extracardiac findings in the evaluation of ischemic heart disease by multidetector computed tomography

    PubMed Central

    Cho, Jeong-Hwan; Park, Jong-Seon; Shin, Dong-Gu; Kim, Young-Jo; Lee, Sang-Hee; Choi, Yoon-Jung; Cho, Ihn-Ho

    2013-01-01

    Objective Multidector computed tomography (MDCT) is now commonly used for the evaluation of coronary artery disease. Because MDCT images include many non-cardiac organs and the patient population evaluated is highly susceptible to extracardiac diseases, this study was designed to evaluate the prevalence of extracardiac findings in the MDCT evaluation of ischemic heart disease. Methods From March 2007 to March 2008, a total of six-hundred twenty patients, who underwent 64-slice MDCT evaluations for chest pain, or dyspnea, were enrolled in this study. Cardiac and non-cardiac findings were comprehensively evaluated by a radiologist. Results Enrolled patients included 306 men (49.4%), with a mean age of 66 years. Significant coronary artery stenosis was found in 41.6% of the patients. A total of 158 extracardiac findings were observed in 110 (17.7%) patients. Commonly involved extracardiac organs were lung (36.7%), hepatobiliary system (21.5%), thyroid (19.6%), kidney (10.8%), spine (9.7%) and breast (0.6%). Of those 110 patients, 50 (45.5%) patients underwent further diagnostic investigations. Malignant disease was detected in three (2.7%) patients (lung cancer, pancreatic cancer, and thyroid cancer). Conclusions Extracardiac findings are frequently present and should be a concern in the MDCT evaluation of chest pain syndrome. PMID:24133511

  15. Multi-Detector Computed Tomography Angiography for Coronary Artery Disease

    PubMed Central

    2005-01-01

    groups: Group 1 included 9 studies that focused on the detection of CAD in symptomatic patients, and Group 2 included 4 studies that examined the use of 16-slice CT angiography to detect disease progression after cardiac interventions. The 2 abstracts on 64-slice CT angiography were presented separately, but were not critically appraised due to the lack of information provided in the abstracts. 16-Slice Computed Tomography Angiography The STARD initiative to evaluate the reporting quality of studies that focus on diagnostic tests was used. Overall the studies were relatively small (fewer than 100 people), and only about one-half recruited consecutive patients. Most studies reported inclusion criteria, but 5 did not report exclusion criteria. In these 5, the patients were highly selected; therefore, how representative they are of the general population of people with suspicion if CAD or those with disease progression after cardiac intervention is questionable. In most studies, patients were either already taking, or were given, β-blockers to reduce their heart rates to improve image quality sufficiently. Only 6 of the 13 studies reported interobserver reliability quantitatively. The studies typically assessed the quality of the images obtained from 16-slice CT angiography, excluded those of poor quality, and compared the rest with the gold standard, coronary angiography. This practice necessarily inflated the diagnostic accuracy measures. Only 3 studies reported confidence intervals around their measures. Evaluation of the studies in Group 1 reported variable sensitivity, from just over 60% to 96%, but a more stable specificity, at more than 95%. The false positive rate ranged from 5% to 8%, but the false negative rate was at best under 10% and at worst about 30%. This means that up to one-third of patients who have disease may be missed. These patients may therefore progress to a more severe level of disease and require more invasive procedures. The calculated positive

  16. Does preoperative computed tomography reduce the risks associated with re-do cardiac surgery?

    PubMed

    Khan, Nouman U; Yonan, Nizar

    2009-07-01

    A best evidence topic was written according to the structured protocol. The question addressed was whether preoperative computed tomography (CT) scan reduces the risk associated with re-do cardiac surgery. A Medline search revealed 412 papers, of which seven were deemed relevant to the topic. We conclude that preoperative CT angiography using ECG-gated multi-detector scan enables excellent anatomical details of heart, aorta and previous grafts, and highlights high-risk cases due to adherent grafts or ventricle or aortic atherosclerosis. This allows for better risk stratification and change of surgical strategy to reduce the potential risk in patients coming for re-do cardiac surgery. According to published reports, high-risk CT-scan findings in these patients caused clinicians to cancel surgery in up to 13% of cases, while preventive surgical strategies including non-midline approach, peripheral vascular exposure or establishing cardiopulmonary bypass prior to re-sternotomy have been reported in over two-thirds of patients with significant reduction in the operative risk. The risk of damage to vital structures, including previous grafts, heart or larger vessels is generally reported fewer than 10%, with evidence of significantly lower incidence of intra-operative injuries in patients who had prior CT-scans compared to those who did not. Hence, adequate preoperative imaging using ECG-gated multi-slice CT is essential for optimum planning of re-do cardiac surgery. PMID:19339275

  17. Mechano-chemical Interactions in Cardiac Sarcomere Contraction: A Computational Modeling Study

    PubMed Central

    Lumens, Joost; Arts, Theo; Delhaas, Tammo

    2016-01-01

    We developed a model of cardiac sarcomere contraction to study the calcium-tension relationship in cardiac muscle. Calcium mediates cardiac contraction through its interactions with troponin (Tn) and subsequently tropomyosin molecules. Experimental studies have shown that a slight increase in intracellular calcium concentration leads to a rapid increase in sarcomeric tension. Though it is widely accepted that the rapid increase is not possible without the concept of cooperativity, the mechanism is debated. We use the hypothesis that there exists a base level of cooperativity intrinsic to the thin filament that is boosted by mechanical tension, i.e. a high level of mechanical tension in the thin filament impedes the unbinding of calcium from Tn. To test these hypotheses, we developed a computational model in which a set of three parameters and inputs of calcium concentration and sarcomere length result in output tension. Tension as simulated appeared in good agreement with experimentally measured tension. Our results support the hypothesis that high tension in the thin filament impedes Tn deactivation by increasing the energy required to detach calcium from the Tn. Given this hypothesis, the model predicted that the areas with highest tension, i.e. closest to the Z-disk end of the single overlap region, show the largest concentration of active Tn’s. PMID:27716775

  18. ECG-gated emission computed tomography of the cardiac blood pool

    SciTech Connect

    Moore, M.L.; Murphy, P.H.; Burdine, J.A.

    1980-01-01

    ECG-gated cross-sectional images of the cardiac blood pool were produced using a specially constructed emission computed tomographic scanner. A pair of large-field-of-view cameras were mounted in opposition in a gantry that rotates 360/sup 0/ about the patient. The coordinates of each detected event, the output of a physiological synchronizer, and the position of the camera heads were input to a dedicated minicomputer which was used to produce the images. Display as a movie permitted evaluation of regional and global wall motion in cross section without the disadvantages of superimposed blood pools as obtained in nontomographic views.

  19. Radiation Dose to the Thyroid and Gonads in Patients Undergoing Cardiac CT Angiography

    PubMed Central

    Behroozi, Hamid; Davoodi, Mohammad; Aghasi, Shahriar

    2015-01-01

    Background: The present data show a global increase in the rate of cardiovascular disease. Cardiac CT angiography has developed as a fast and non-invasive cardiac imaging modality following the introduction of multi-slice computed tomogaraphy. Objectives: The aim of this study was to measure the radiation dose to the thyroid and pelvis regions in patients undergoing cardiac CT angiography using the Care Dose 4D method of 64-slice scanner. Patients and Methods: Eighty-one patients (41 males and 40 females) who were diagnosed with suspected coronary artery disease and were referred to Golestan Hospital, Imaging Department were recruited. Inclusion criteria were based on the protocol of multi-slice CT coronary angiography. The radiation dose to the thyroid and pelvis regions was measured using thermo luminescent dosimeters (TLDs). Results: The mean radiation dose to the thyroid in male and female subjects was 0.32 mSv and 0.41 mSv, respectively (P = 0.032) (total mean, 0.36 mSv). The mean radiation dose to the pelvis in male and female subjects was 81 μSv and 112 μSv, respectively (P = 0.026) (total mean, 96.5 μSv), Conclusions: The total mean radiation dose to the thyroid and gonads was 0.36 mSv, and 96.5 μSv, respectively for the subjects. These values were high for one organ in a single study. Gender can affect the radiation dose to the thyroid and gonads. This can be attributed to the anatomical characteristic differences of the male and female subjects. PMID:26060556

  20. Threshold adjusted calcium scoring using CT is less susceptible to cardiac motion and more accurate.

    PubMed

    Groen, J M; Dijkstra, H; Greuter, M J W; Oudkerk, M

    2009-02-01

    The purpose of this paper is to investigate calcium scoring on computed tomography (CT) using an adjusted threshold depending on the maximum Hounsfield value within the calcification (HU(peak)). The volume of 19 calcifications was retrospectively determined on 64-slice multidetector CT and dual source CT (DSCT) at different thresholds and the threshold associated with the physical volume was determined. In addition, approximately 10 000 computer simulations were done simulating the same process for calcifications with mixed density. Using these data a relation between the HU(peak) and the threshold could be established. Hereafter, this relation was assessed by scanning six calcifications in a phantom at 40-110 beats per minute using DSCT. The influence of motion was determined and the measured calcium scores were compared to the physical volumes and mass. A positive linear correlation was found between the scoring threshold and the HU(peak) of the calcifications both for the phantom measurements as for the computer simulations. Using this relation the individual threshold for each calcification could be calculated. Calcium scores of the moving calcifications determined with an adjusted threshold were approximately 30% less susceptible to cardiac motion compared to standard calcium scoring. Furthermore, these scores approximated the physical volume and mass at least 10% better than the standard calcium scores. The threshold in calcium scoring should be adjusted for each individual calcification based on the HU(peak) of the calcification. Calcium scoring using an adjusted threshold is less susceptible to cardiac motion and more accurate compared to the physical values. PMID:19291982

  1. Moving domain computational fluid dynamics to interface with an embryonic model of cardiac morphogenesis.

    PubMed

    Lee, Juhyun; Moghadam, Mahdi Esmaily; Kung, Ethan; Cao, Hung; Beebe, Tyler; Miller, Yury; Roman, Beth L; Lien, Ching-Ling; Chi, Neil C; Marsden, Alison L; Hsiai, Tzung K

    2013-01-01

    Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP) (y1) transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development. The CFD simulations were validated with particle image velocimetry (PIV) across the atrioventricular (AV) canal, revealing an increase in both velocities and heart rates, but a decrease in the duration of atrial systole from early to later stages. At 20-30 hours post fertilization (hpf), simulation results revealed bidirectional WSS across the AV canal in the heart tube in response to peristaltic motion of the wall. At 40-50 hpf, the tube structure undergoes cardiac looping, accompanied by a nearly 3-fold increase in WSS magnitude. At 110-120 hpf, distinct AV valve, atrium, ventricle, and bulbus arteriosus form, accompanied by incremental increases in both WSS magnitude and ∇P, but a decrease in bi-directional flow. Laminar flow develops across the AV canal at 20-30 hpf, and persists at 110-120 hpf. Reynolds numbers at the AV canal increase from 0.07±0.03 at 20-30 hpf to 0.23±0.07 at 110-120 hpf (p< 0.05, n=6), whereas Womersley numbers remain relatively unchanged from 0.11 to 0.13. Our moving domain simulations highlights hemodynamic changes in relation to cardiac morphogenesis; thereby, providing a 2-D quantitative approach to complement imaging analysis.

  2. Moving Domain Computational Fluid Dynamics to Interface with an Embryonic Model of Cardiac Morphogenesis

    PubMed Central

    Lee, Juhyun; Moghadam, Mahdi Esmaily; Kung, Ethan; Cao, Hung; Beebe, Tyler; Miller, Yury; Roman, Beth L.; Lien, Ching-Ling; Chi, Neil C.; Marsden, Alison L.; Hsiai, Tzung K.

    2013-01-01

    Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP)y1 transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development. The CFD simulations were validated with particle image velocimetry (PIV) across the atrioventricular (AV) canal, revealing an increase in both velocities and heart rates, but a decrease in the duration of atrial systole from early to later stages. At 20-30 hours post fertilization (hpf), simulation results revealed bidirectional WSS across the AV canal in the heart tube in response to peristaltic motion of the wall. At 40-50 hpf, the tube structure undergoes cardiac looping, accompanied by a nearly 3-fold increase in WSS magnitude. At 110-120 hpf, distinct AV valve, atrium, ventricle, and bulbus arteriosus form, accompanied by incremental increases in both WSS magnitude and ∇P, but a decrease in bi-directional flow. Laminar flow develops across the AV canal at 20-30 hpf, and persists at 110-120 hpf. Reynolds numbers at the AV canal increase from 0.07±0.03 at 20-30 hpf to 0.23±0.07 at 110-120 hpf (p< 0.05, n=6), whereas Womersley numbers remain relatively unchanged from 0.11 to 0.13. Our moving domain simulations highlights hemodynamic changes in relation to cardiac morphogenesis; thereby, providing a 2-D quantitative approach to complement imaging analysis. PMID:24009714

  3. Improved image quality and computation reduction in 4-D reconstruction of cardiac-gated SPECT images.

    PubMed

    Narayanan, M V; King, M A; Wernick, M N; Byrne, C L; Soares, E J; Pretorius, P H

    2000-05-01

    Spatiotemporal reconstruction of cardiac-gated SPECT images permits us to obtain valuable information related to cardiac function. However, the task of reconstructing this four-dimensional (4-D) data set is computation intensive. Typically, these studies are reconstructed frame-by-frame: a nonoptimal approach because temporal correlations in the signal are not accounted for. In this work, we show that the compression and signal decorrelation properties of the Karhunen-Loève (KL) transform may be used to greatly simplify the spatiotemporal reconstruction problem. The gated projections are first KL transformed in the temporal direction. This results in a sequence of KL-transformed projection images for which the signal components are uncorrelated along the time axis. As a result, the 4-D reconstruction task is simplified to a series of three-dimensional (3-D) reconstructions in the KL domain. The reconstructed KL components are subsequently inverse KL transformed to obtain the entire spatiotemporal reconstruction set. Our simulation and clinical results indicate that KL processing provides image sequences that are less noisy than are conventional frame-by-frame reconstructions. Additionally, by discarding high-order KL components that are dominated by noise, we can achieve savings in computation time because fewer reconstructions are needed in comparison to conventional frame-by-frame reconstructions.

  4. Morphological and Functional Evaluation of Quadricuspid Aortic Valves Using Cardiac Computed Tomography

    PubMed Central

    Song, Inyoung; Park, Jung Ah; Choi, Bo Hwa; Shin, Je Kyoun; Chee, Hyun Keun; Kim, Jun Seok

    2016-01-01

    Objective The aim of this study was to identify the morphological and functional characteristics of quadricuspid aortic valves (QAV) on cardiac computed tomography (CCT). Materials and Methods We retrospectively enrolled 11 patients with QAV. All patients underwent CCT and transthoracic echocardiography (TTE), and 7 patients underwent cardiovascular magnetic resonance (CMR). The presence and classification of QAV assessed by CCT was compared with that of TTE and intraoperative findings. The regurgitant orifice area (ROA) measured by CCT was compared with severity of aortic regurgitation (AR) by TTE and the regurgitant fraction (RF) by CMR. Results All of the patients had AR; 9 had pure AR, 1 had combined aortic stenosis and regurgitation, and 1 had combined subaortic stenosis and regurgitation. Two patients had a subaortic fibrotic membrane and 1 of them showed a subaortic stenosis. One QAV was misdiagnosed as tricuspid aortic valve on TTE. In accordance with the Hurwitz and Robert's classification, consensus was reached on the QAV classification between the CCT and TTE findings in 7 of 10 patients. The patients were classified as type A (n = 1), type B (n = 3), type C (n = 1), type D (n = 4), and type F (n = 2) on CCT. A very high correlation existed between ROA by CCT and RF by CMR (r = 0.99) but a good correlation existed between ROA by CCT and regurgitant severity by TTE (r = 0.62). Conclusion Cardiac computed tomography provides comprehensive anatomical and functional information about the QAV. PMID:27390538

  5. Development and clinical study of mobile 12-lead electrocardiography based on cloud computing for cardiac emergency.

    PubMed

    Fujita, Hideo; Uchimura, Yuji; Waki, Kayo; Omae, Koji; Takeuchi, Ichiro; Ohe, Kazuhiko

    2013-01-01

    To improve emergency services for accurate diagnosis of cardiac emergency, we developed a low-cost new mobile electrocardiography system "Cloud Cardiology®" based upon cloud computing for prehospital diagnosis. This comprises a compact 12-lead ECG unit equipped with Bluetooth and Android Smartphone with an application for transmission. Cloud server enables us to share ECG simultaneously inside and outside the hospital. We evaluated the clinical effectiveness by conducting a clinical trial with historical comparison to evaluate this system in a rapid response car in the real emergency service settings. We found that this system has an ability to shorten the onset to balloon time of patients with acute myocardial infarction, resulting in better clinical outcome. Here we propose that cloud-computing based simultaneous data sharing could be powerful solution for emergency service for cardiology, along with its significant clinical outcome. PMID:23920851

  6. Development and clinical study of mobile 12-lead electrocardiography based on cloud computing for cardiac emergency.

    PubMed

    Fujita, Hideo; Uchimura, Yuji; Waki, Kayo; Omae, Koji; Takeuchi, Ichiro; Ohe, Kazuhiko

    2013-01-01

    To improve emergency services for accurate diagnosis of cardiac emergency, we developed a low-cost new mobile electrocardiography system "Cloud Cardiology®" based upon cloud computing for prehospital diagnosis. This comprises a compact 12-lead ECG unit equipped with Bluetooth and Android Smartphone with an application for transmission. Cloud server enables us to share ECG simultaneously inside and outside the hospital. We evaluated the clinical effectiveness by conducting a clinical trial with historical comparison to evaluate this system in a rapid response car in the real emergency service settings. We found that this system has an ability to shorten the onset to balloon time of patients with acute myocardial infarction, resulting in better clinical outcome. Here we propose that cloud-computing based simultaneous data sharing could be powerful solution for emergency service for cardiology, along with its significant clinical outcome.

  7. Application of Micro-Computed Tomography with Iodine Staining to Cardiac Imaging, Segmentation and Computational Model Development

    PubMed Central

    Aslanidi, OV; Nikolaidou, T; Zhao, J; Smaill, BH; Gilbert, SH; Holden, AV; Lowe, T; Withers, PJ; Jarvis, JC; Stephenson, RS; Hart, G; Hancox, JC; Boyett, MR; Zhang, H

    2012-01-01

    Micro-computed tomography (micro-CT) has been widely used to generate high-resolution 3D tissue images from small animals non-destructively, especially for mineralized skeletal tissues. However, its application to the analysis of soft cardiovascular tissues has been limited by poor inter-tissue contrast. Recent ex vivo studies have shown that contrast between muscular and connective tissue in micro-CT images can be enhanced by staining with iodine. In the present study, we apply this novel technique for imaging of cardiovascular structures in canine hearts. We optimize the method to obtain high resolution X-ray micro-CT images of the canine atria and its distinctive regions - including the Bachmann’s bundle, atrioventricular node, pulmonary arteries and veins - with clear inter-tissue contrast. The imaging results are used to reconstruct and segment the detailed 3D geometry of the atria. Structure tensor analysis shows that the arrangement of atrial fibres can also be characterised using the enhanced micro-CT images, as iodine preferentially accumulates within the muscular fibres rather than in connective tissues. This novel technique can be particularly useful in non-destructive imaging of 3D cardiac architectures from large animals and humans, due to the combination of relatively high speed (~1 hour/scan of a large canine heart) and high voxel resolution (36 μm) provided. In summary, contrast micro-CT facilitates fast and non-destructive imaging and segmenting of detailed 3D cardiovascular geometries, as well as measuring fibre orientation, which are crucial in constructing biophysically detailed computational cardiac models. PMID:22829390

  8. The 100 most-cited original articles in cardiac computed tomography: A bibliometric analysis.

    PubMed

    O'Keeffe, Michael E; Hanna, Tarek N; Holmes, Davis; Marais, Olivia; Mohammed, Mohammed F; Clark, Sheldon; McLaughlin, Patrick; Nicolaou, Savvas; Khosa, Faisal

    2016-01-01

    Bibliometric analysis is the application of statistical methods to analyze quantitative data about scientific publications. It can evaluate research performance, author productivity, and manuscript impact. To the best of our knowledge, no bibliometric analysis has focused on cardiac computed tomography (CT). The purpose of this paper was to compile a list of the 100 most-cited articles related to cardiac CT literature using Scopus and Web of Science (WOS). A list of the 100 most-cited articles was compiled by order of citation frequency, as well a list of the top 10 most-cited guideline and review articles and the 20 most-cited articles of the years 2014-2015. The database of 100 most-cited articles was analyzed to identify characteristics of highly cited publications. For each manuscript, the number of authors, study design, size of patient cohort and departmental affiliations were cataloged. The 100 most-cited articles were published from 1990 to 2012, with the majority (53) published between 2005 and 2009. The total number of citations varied from 3354 to 196, and the number of citations per year varied from 9.5 to 129.0 with a median and mean of 30.9 and 38.7, respectively. The majority of publications had a study patients sample size of 200 patients or less. The USA and Germany were the nations with the highest number of frequently cited publications. This bibliometric analysis provides insights on the most-cited articles published on the subject of cardiac CT and calcium volume, thus helping to characterize the field and guide future research.

  9. A computational framework for the statistical analysis of cardiac diffusion tensors: application to a small database of canine hearts.

    PubMed

    Peyrat, Jean-Marc; Sermesant, Maxime; Pennec, Xavier; Delingette, Hervé; Xu, Chenyang; McVeigh, Elliot R; Ayache, Nicholas

    2007-11-01

    We propose a unified computational framework to build a statistical atlas of the cardiac fiber architecture from diffusion tensor magnetic resonance images (DT-MRIs). We apply this framework to a small database of nine ex vivo canine hearts. An average cardiac fiber architecture and a measure of its variability are computed using most recent advances in diffusion tensor statistics. This statistical analysis confirms the already established good stability of the fiber orientations and a higher variability of the laminar sheet orientations within a given species. The statistical comparison between the canine atlas and a standard human cardiac DT-MRI shows a better stability of the fiber orientations than their laminar sheet orientations between the two species. The proposed computational framework can be applied to larger databases of cardiac DT-MRIs from various species to better establish intraspecies and interspecies statistics on the anatomical structure of cardiac fibers. This information will be useful to guide the adjustment of average fiber models onto specific patients from in vivo anatomical imaging modalities.

  10. Epicardial Adipose Tissue Is Associated with Plaque Burden and Composition and Provides Incremental Value for the Prediction of Cardiac Outcome. A Clinical Cardiac Computed Tomography Angiography Study

    PubMed Central

    Gitsioudis, Gitsios; Schmahl, Christina; Missiou, Anna; Voss, Andreas; Schüssler, Alena; Abdel-Aty, Hassan; Buss, Sebastian J.; Mueller, Dirk; Vembar, Mani; Bryant, Mark; Kauczor, Hans-Ulrich; Giannitsis, Evangelos; Katus, Hugo A.; Korosoglou, Grigorios

    2016-01-01

    Objectives We sought to investigate the association of epicardial adipose tissue (eCAT) volume with plaque burden, circulating biomarkers and cardiac outcomes in patients with intermediate risk for coronary artery disease (CAD). Methods and Results 177 consecutive outpatients at intermediate risk for CAD and completed biomarker analysis including high-sensitive Troponin T (hs-TnT) and hs-CRP underwent 256-slice cardiac computed tomography angiography (CCTA) between June 2008 and October 2011. Patients with lumen narrowing ≥50% exhibited significantly higher eCAT volume than patients without any CAD or lumen narrowing <50% (median (interquartile range, IQR): 108 (73–167) cm3 vs. 119 (82–196) cm3, p = 0.04). Multivariate regression analysis demonstrated an independent association eCAT volume with plaque burden by number of lesions (R2 = 0.22, rpartial = 0.29, p = 0.026) and CAD severity by lumen narrowing (R2 = 0.22, rpartial = 0.23, p = 0.038) after adjustment for age, diabetes mellitus, hyperlidipemia, body-mass-index (BMI), hs-CRP and hs-TnT. Univariate Cox proportional hazards regression analysis identified a significant association for both increased eCAT volume and maximal lumen narrowing with all cardiac events. Multivariate Cox proportional hazards regression analysis revealed an independent association of increased eCAT volume with all cardiac events after adjustment for age, >3 risk factors, presence of CAD, hs-CRP and hs-TnT. Conclusion Epicardial adipose tissue volume is independently associated with plaque burden and maximum luminal narrowing by CCTA and may serve as an independent predictor for cardiac outcomes in patients at intermediate risk for CAD. PMID:27187590

  11. Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

    PubMed Central

    Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

    2015-01-01

    Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

  12. Assessment of cardiac single-photon emission computed tomography performance using a scanning linear observer

    SciTech Connect

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

    2013-01-15

    Purpose: Single-photon emission computed tomography (SPECT) is widely used to detect myocardial ischemia and myocardial infarction. It is important to assess and compare different SPECT system designs in order to achieve the highest detectability of cardiac defects. Methods: Whitaker et al.'s study ['Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,' Opt. Express 16(11), 8150-8173 (2008)] on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than with reconstruction data. Thus, this observer model assesses the overall hardware performance independent of any reconstruction algorithm. In addition, the computation time of image quality studies is significantly reduced. In this study, three systems based on the design of the GE cadmium zinc telluride-based dedicated cardiac SPECT camera Discovery 530c were assessed. This design, which is officially named the Alcyone Technology: Discovery NM 530c, was commercialized in August, 2009. The three systems, GE27, GE19, and GE13, contain 27, 19, and 13 detectors, respectively. Clinically, a human heart can be virtually segmented into three coronary artery territories: the left-anterior descending artery, left-circumflex artery, and right coronary artery. One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can accurately predict in which territory the defect exists [http://www.asnc.org/media/PDFs/PPReporting081511.pdf, Guideline from American Society of Nuclear Cardiology]. A good estimation of the extent of the defect from the projection images is also very helpful for determining the seriousness of the myocardial ischemia. In this study, both the location and extent of defects were estimated by the SLO, and the system performance was assessed by localization

  13. Computational biomarker pipeline from discovery to clinical implementation: plasma proteomic biomarkers for cardiac transplantation.

    PubMed

    Cohen Freue, Gabriela V; Meredith, Anna; Smith, Derek; Bergman, Axel; Sasaki, Mayu; Lam, Karen K Y; Hollander, Zsuzsanna; Opushneva, Nina; Takhar, Mandeep; Lin, David; Wilson-McManus, Janet; Balshaw, Robert; Keown, Paul A; Borchers, Christoph H; McManus, Bruce; Ng, Raymond T; McMaster, W Robert

    2013-04-01

    Recent technical advances in the field of quantitative proteomics have stimulated a large number of biomarker discovery studies of various diseases, providing avenues for new treatments and diagnostics. However, inherent challenges have limited the successful translation of candidate biomarkers into clinical use, thus highlighting the need for a robust analytical methodology to transition from biomarker discovery to clinical implementation. We have developed an end-to-end computational proteomic pipeline for biomarkers studies. At the discovery stage, the pipeline emphasizes different aspects of experimental design, appropriate statistical methodologies, and quality assessment of results. At the validation stage, the pipeline focuses on the migration of the results to a platform appropriate for external validation, and the development of a classifier score based on corroborated protein biomarkers. At the last stage towards clinical implementation, the main aims are to develop and validate an assay suitable for clinical deployment, and to calibrate the biomarker classifier using the developed assay. The proposed pipeline was applied to a biomarker study in cardiac transplantation aimed at developing a minimally invasive clinical test to monitor acute rejection. Starting with an untargeted screening of the human plasma proteome, five candidate biomarker proteins were identified. Rejection-regulated proteins reflect cellular and humoral immune responses, acute phase inflammatory pathways, and lipid metabolism biological processes. A multiplex multiple reaction monitoring mass-spectrometry (MRM-MS) assay was developed for the five candidate biomarkers and validated by enzyme-linked immune-sorbent (ELISA) and immunonephelometric assays (INA). A classifier score based on corroborated proteins demonstrated that the developed MRM-MS assay provides an appropriate methodology for an external validation, which is still in progress. Plasma proteomic biomarkers of acute cardiac

  14. Assessment of the Radiation Effects of Cardiac Computed Tomographic Angiography Using Protein and Genetic Biomarkers

    PubMed Central

    Nguyen, Patricia K.; Lee, Won Hee; Li, Yong Fuga; Hong, Wan Xing; Hu, Shijun; Chan, Charles; Liang, Grace; Nguyen, Ivy; Ong, Sang-Ging; Churko, Jared; Wang, Jia; Altman, Russ B.; Fleischmann, Dominik; Wu, Joseph C.

    2016-01-01

    Objectives To evaluate whether radiation exposure from cardiac computed tomographic angiography is associated with DNA damage and whether damage leads to programmed cell death and activation of genes involved in apoptosis and DNA repair. Background Exposure to radiation from medical imaging has become a public health concern, but whether it causes significant cell damage remains unclear. Methods We conducted a prospective cohort study in 67 patients undergoing cardiac computed tomographic angiography (CTA) between January 2012 and December 2013 in two US medical centers. Median blood radiation exposure was estimated using phantom dosimetry. Biomarkers of DNA damage and apoptosis were measured by flow cytometry, whole genome sequencing, and single cell polymerase chain reaction. Results The median DLP was 1535.3 mGy·cm (969.7 – 2674.0 mGy·cm). The median radiation dose to the blood was 29.8 milliSieverts (18.8 – 48.8 mSv). Median DNA damage increased 3.39% (1.29 – 8.04%, P<0.0001) post-radiation. Median apoptosis increased 3.1-fold (1.4 – 5.1-fold, P<0.0001) post-radiation. Whole genome sequencing revealed changes in the expression of 39 transcription factors involved in the regulation of apoptosis, cell cycle, and DNA repair. Genes involved in mediating apoptosis and DNA repair were significantly changed post-radiation, including DDB2 [1.9-fold (1.5 – 3.0-fold), P<0.001], XRCC4 [3.0-fold (1.1 – 5.4-fold), P=0.005], and BAX [1.6-fold (0.9 – 2.6-fold), P<0.001]. Exposure to radiation was associated with DNA damage [OR: 1.8 (1.2 – 2.6), P=0.003]. DNA damage was associated with apoptosis [OR: 1.9 (1.2 – 5.1), P<0.0001] and gene activation [OR: 2.8 (1.2 – 6.2), P=0.002]. Conclusions Patients exposed to radiation from cardiac CTA had evidence of DNA damage, which was associated with programmed cell death and activation of genes involved in apoptosis and DNA repair. PMID:26210695

  15. Personalised computational cardiology: Patient-specific modelling in cardiac mechanics and biomaterial injection therapies for myocardial infarction

    PubMed Central

    Sack, Kevin L.; Davies, Neil H.; Guccione, Julius M.

    2016-01-01

    Predictive computational modelling in biomedical research offers the potential to integrate diverse data, uncover biological mechanisms that are not easily accessible through experimental methods and expose gaps in knowledge requiring further research. Recent developments in computing and diagnostic technologies have initiated the advancement of computational models in terms of complexity and specificity. Consequently, computational modelling can increasingly be utilised as enabling and complementing modality in the clinic—with medical decisions and interventions being personalised. Myocardial infarction and heart failure are amongst the leading causes of death globally despite optimal modern treatment. The development of novel MI therapies is challenging and may be greatly facilitated through predictive modelling. Here, we review the advances in patient-specific modelling of cardiac mechanics, distinguishing specificity in cardiac geometry, myofibre architecture and mechanical tissue properties. Thereafter, the focus narrows to the mechanics of the infarcted heart and treatment of myocardial infarction with particular attention on intramyocardial biomaterial delivery. PMID:26833320

  16. Nonrigid registration-based coronary artery motion correction for cardiac computed tomography

    SciTech Connect

    Bhagalia, Roshni; Pack, Jed D.; Miller, James V.; Iatrou, Maria

    2012-07-15

    Purpose: X-ray computed tomography angiography (CTA) is the modality of choice to noninvasively monitor and diagnose heart disease with coronary artery health and stenosis detection being of particular interest. Reliable, clinically relevant coronary artery imaging mandates high spatiotemporal resolution. However, advances in intrinsic scanner spatial resolution (CT scanners are available which combine nearly 900 detector columns with focal spot oversampling) can be tempered by motion blurring, particularly in patients with unstable heartbeats. As a result, recently numerous methods have been devised to improve coronary CTA imaging. Solutions involving hardware, multisector algorithms, or {beta}-blockers are limited by cost, oversimplifying assumptions about cardiac motion, and populations showing contraindications to drugs, respectively. This work introduces an inexpensive algorithmic solution that retrospectively improves the temporal resolution of coronary CTA without significantly affecting spatial resolution. Methods: Given the goal of ruling out coronary stenosis, the method focuses on 'deblurring' the coronary arteries. The approach makes no assumptions about cardiac motion, can be used on exams acquired at high heart rates (even over 75 beats/min), and draws on a fast and accurate three-dimensional (3D) nonrigid bidirectional labeled point matching approach to estimate the trajectories of the coronary arteries during image acquisition. Motion compensation is achieved by employing a 3D warping of a series of partial reconstructions based on the estimated motion fields. Each of these partial reconstructions is created from data acquired over a short time interval. For brevity, the algorithm 'Subphasic Warp and Add' (SWA) reconstruction. Results: The performance of the new motion estimation-compensation approach was evaluated by a systematic observer study conducted using nine human cardiac CTA exams acquired over a range of average heart rates between 68 and

  17. Computational estimation of tricarboxylic acid cycle fluxes using noisy NMR data from cardiac biopsies

    PubMed Central

    2013-01-01

    Background The aerobic energy metabolism of cardiac muscle cells is of major importance for the contractile function of the heart. Because energy metabolism is very heterogeneously distributed in heart tissue, especially during coronary disease, a method to quantify metabolic fluxes in small tissue samples is desirable. Taking tissue biopsies after infusion of substrates labeled with stable carbon isotopes makes this possible in animal experiments. However, the appreciable noise level in NMR spectra of extracted tissue samples makes computational estimation of metabolic fluxes challenging and a good method to define confidence regions was not yet available. Results Here we present a computational analysis method for nuclear magnetic resonance (NMR) measurements of tricarboxylic acid (TCA) cycle metabolites. The method was validated using measurements on extracts of single tissue biopsies taken from porcine heart in vivo. Isotopic enrichment of glutamate was measured by NMR spectroscopy in tissue samples taken at a single time point after the timed infusion of 13C labeled substrates for the TCA cycle. The NMR intensities for glutamate were analyzed with a computational model describing carbon transitions in the TCA cycle and carbon exchange with amino acids. The model dynamics depended on five flux parameters, which were optimized to fit the NMR measurements. To determine confidence regions for the estimated fluxes, we used the Metropolis-Hastings algorithm for Markov chain Monte Carlo (MCMC) sampling to generate extensive ensembles of feasible flux combinations that describe the data within measurement precision limits. To validate our method, we compared myocardial oxygen consumption calculated from the TCA cycle flux with in vivo blood gas measurements for 38 hearts under several experimental conditions, e.g. during coronary artery narrowing. Conclusions Despite the appreciable NMR noise level, the oxygen consumption in the tissue samples, estimated from the NMR

  18. Simulation study of respiratory-induced errors in cardiac positron emission tomography/computed tomography

    SciTech Connect

    Fitzpatrick, Gianna M.; Wells, R. Glenn

    2006-08-15

    Heart disease is a leading killer in Canada and positron emission tomography (PET) provides clinicians with in vivo metabolic information for diagnosing heart disease. Transmission data are usually acquired with {sup 68}Ge, although the advent of PET/CT scanners has made computed tomography (CT) an alternative option. The fast data acquisition of CT compared to PET may cause potential misregistration problems, leading to inaccurate attenuation correction (AC). Using Monte Carlo simulations and an anthropomorphic dynamic computer phantom, this study determines the magnitude and location of respiratory-induced errors in radioactivity uptake measured in cardiac PET/CT. A homogeneous tracer distribution in the heart was considered. The AC was based on (1) a time-averaged attenuation map (2) CT maps from a single phase of the respiratory cycle, and (3) CT maps phase matched to the emission data. Circumferential profiles of the heart uptake were compared and differences of up to 24% were found between the single-phase CT-AC method and the true phantom values. Simulation results were supported by a PET/CT canine study which showed differences of up to 10% in the heart uptake in the lung-heart boundary region when comparing {sup 68}Ge- to CT-based AC with the CT map acquired at end inhalation.

  19. Computer-assisted continuous infusions of fentanyl during cardiac anesthesia: comparison with a manual method.

    PubMed

    Alvis, J M; Reves, J G; Govier, A V; Menkhaus, P G; Henling, C E; Spain, J A; Bradley, E

    1985-07-01

    The design and implementation of a computer-assisted continuous infusion (CACI) system to rapidly attain and maintain a constant plasma fentanyl concentration (PFC), as well as a CACI system that allowed the anesthesiologist to change the plasma level of fentanyl during cardiac anesthesia, were developed. In 30 patients (three groups of 10 patients each) these two automated methods of fentanyl infusion were compared with a manual fentanyl administration method. There was excellent agreement in the measured/predicted PFC ratios with the CACI stable fentanyl level system (ratio = 0.99, n = 91) and in the CACI variable fentanyl level system (ratio = 1.08, n = 79). The stable fentanyl level group of patients received significantly more (P less than 0.05) fentanyl than did the other groups. The CACI variable fentanyl level group of patients had greater hemodynamic stability, required significantly (P less than 0.05) fewer adjuvant drug interventions and experienced significantly (P less than 0.05) fewer hypotensive and hypertensive episodes than the manual, bolus fentanyl (control) group. These data show that a computer-assisted automated infusion of fentanyl is safe and as good as manual methods. CACI has greater potential as a new method of intravenous anesthesia administration. PMID:3874568

  20. Decoding Hemodynamics of Large Vessels via Dispersion of Contrast Agent in Cardiac Computed Tomography

    NASA Astrophysics Data System (ADS)

    Eslami, Parastou; Seo, Jung-Hee; Abd, Thura T.; George, Richard; Lardo, Albert C.; Chen, Marcus Y.; Mittal, Rajat

    2015-11-01

    Computed tomography angiography (CTA) has emerged as a powerful tool for the assessment of coronary artery disease and other cardiac conditions. Continuous improvements in the spatial and temporal resolution of CT scanners are revealing details regarding the spatially and temporally varying contrast concentration in the vasculature, that were not evident before. These contrast dispersion patterns offer the possibility of extracting useful information about the hemodynamics from the scans. In the current presentation, we will describe experimental studies carried out with CT compatible phantoms of coronary vessels that provide insights into the effect of imaging artifacts on the observed intracoronary contrast gradients. In addition, we will describe a series of computational fluid dynamics studies that explore the dispersion of contrast through the ascending-descending aorta with particular focus on the effect of the aortic curvature on the dispersion patterns. PE is supported by the NIH Graduate Partnership Program. RM and ACL pending patents in CTA based flow diagnostics and have other significant financial interests in these technologies.

  1. The Impact of Cardiac Motion on Aortic Valve Flow Used in Computational Simulations of the Thoracic Aorta.

    PubMed

    Wendell, David C; Samyn, Margaret M; Cava, Joseph R; Krolikowski, Mary M; LaDisa, John F

    2016-09-01

    Advancements in image-based computational modeling are producing increasingly more realistic representations of vasculature and hemodynamics, but so far have not compensated for cardiac motion when imposing inflow boundary conditions. The effect of cardiac motion on aortic flow is important when assessing sequelae in this region including coarctation of the aorta (CoA) or regurgitant fraction. The objective of this investigation was to develop a method to assess and correct for the influence of cardiac motion on blood flow measurements through the aortic valve (AoV) and to determine its impact on patient-specific local hemodynamics quantified by computational fluid dynamics (CFD). A motion-compensated inflow waveform was imposed into the CFD model of a patient with repaired CoA that accounted for the distance traveled by the basal plane during the cardiac cycle. Time-averaged wall shear stress (TAWSS) and turbulent kinetic energy (TKE) values were compared with CFD results of the same patient using the original waveform. Cardiac motion resulted in underestimation of flow during systole and overestimation during diastole. Influences of inflow waveforms on TAWSS were greatest along the outer wall of the ascending aorta (AscAo) (∼30 dyn/cm2). Differences in TAWSS were more pronounced than those from the model creation or mesh dependence aspects of CFD. TKE was slightly higher for the motion-compensated waveform throughout the aortic arch. These results suggest that accounting for cardiac motion when quantifying blood flow through the AoV can lead to different conclusions for hemodynamic indices, which may be important if these results are ultimately used to predict patient outcomes. PMID:27367143

  2. Computational modeling of inhibition of voltage-gated Ca channels: identification of different effects on uterine and cardiac action potentials

    PubMed Central

    Tong, Wing-Chiu; Ghouri, Iffath; Taggart, Michael J.

    2014-01-01

    The uterus and heart share the important physiological feature whereby contractile activation of the muscle tissue is regulated by the generation of periodic, spontaneous electrical action potentials (APs). Preterm birth arising from premature uterine contractions is a major complication of pregnancy and there remains a need to pursue avenues of research that facilitate the use of drugs, tocolytics, to limit these inappropriate contractions without deleterious actions on cardiac electrical excitation. A novel approach is to make use of mathematical models of uterine and cardiac APs, which incorporate many ionic currents contributing to the AP forms, and test the cell-specific responses to interventions. We have used three such models—of uterine smooth muscle cells (USMC), cardiac sinoatrial node cells (SAN), and ventricular cells—to investigate the relative effects of reducing two important voltage-gated Ca currents—the L-type (ICaL) and T-type (ICaT) Ca currents. Reduction of ICaL (10%) alone, or ICaT (40%) alone, blunted USMC APs with little effect on ventricular APs and only mild effects on SAN activity. Larger reductions in either current further attenuated the USMC APs but with also greater effects on SAN APs. Encouragingly, a combination of ICaL and ICaT reduction did blunt USMC APs as intended with little detriment to APs of either cardiac cell type. Subsequent overlapping maps of ICaL and ICaT inhibition profiles from each model revealed a range of combined reductions of ICaL and ICaT over which an appreciable diminution of USMC APs could be achieved with no deleterious action on cardiac SAN or ventricular APs. This novel approach illustrates the potential for computational biology to inform us of possible uterine and cardiac cell-specific mechanisms. Incorporating such computational approaches in future studies directed at designing new, or repurposing existing, tocolytics will be beneficial for establishing a desired uterine specificity of action

  3. An Interactive Computer Session to Initiate Physical Activity in Sedentary Cardiac Patients: Randomized Controlled Trial

    PubMed Central

    Smith-Ray, Renae L; Dzewaltowski, David A; Glasgow, Russell E; Lee, Rebecca E; Thomas, Deborah SK; Xu, Stanley; Estabrooks, Paul A

    2015-01-01

    Background Physical activity (PA) improves many facets of health. Despite this, the majority of American adults are insufficiently active. Adults who visit a physician complaining of chest pain and related cardiovascular symptoms are often referred for further testing. However, when this testing does not reveal an underlying disease or pathology, patients typically receive no additional standard care services. A PA intervention delivered within the clinic setting may be an effective strategy for improving the health of this population at a time when they may be motivated to take preventive action. Objective Our aim was to determine the effectiveness of a tailored, computer-based, interactive personal action planning session to initiate PA among a group of sedentary cardiac patients following exercise treadmill testing (ETT). Methods This study was part of a larger 2x2 randomized controlled trial to determine the impact of environmental and social-cognitive intervention approaches on the initiation and maintenance of weekly PA for patients post ETT. Participants who were referred to an ETT center but had a negative-test (ie, stress tests results indicated no apparent cardiac issues) were randomized to one of four treatment arms: (1) increased environmental accessibility to PA resources via the provision of a free voucher to a fitness facility in close proximity to their home or workplace (ENV), (2) a tailored social cognitive intervention (SC) using a “5 As”-based (ask, advise, assess, assist, and arrange) personal action planning tool, (3) combined intervention of both ENV and SC approaches (COMBO), or (4) a matched contact nutrition control (CON). Each intervention was delivered using a computer-based interactive session. A general linear model for repeated measures was conducted with change in PA behavior from baseline to 1-month post interactive computer session as the primary outcome. Results Sedentary participants (n=452; 34.7% participation rate) without

  4. Thermal dilution measurement of cardiac output in dogs using an analog computer.

    PubMed

    Hendriks, F F; Schipperheyn, J J; Quanjer, P H

    1978-01-01

    Thermal dilution cardiac output determinations in dogs were compared to simultaneously performed Fick oxygen measurements. The purpose of this study was to validate in dog experiments a method for thermal dilution measurement which employs a double-thermistor catheter combined with an automatic computer as described by Olsson et al. Dilution and injectate temperature are entered directly into the calculation. The method does not employ logarithmic extrapolation, integration of the dilution signal being terminated when a preset cut-off level is reached. Errors due to recirculation, thermal capacitance of the right heart and heat exchange with the catheter's dead space require the use of an empirically derived correction factor, which in dogs was found to be significantly different from the factor used for human thermal dilution curves. With the appropriate cut-off level and correction factor a good agreement was found between the results of the thermal dilution and the Fick method. The regression equation for 47 experiments was found to be COtd = 0.95 COFick + 0.08; the correlation coefficient was 0.94. PMID:728031

  5. Evaluation of static and dynamic perfusion cardiac computed tomography for quantitation and classification tasks.

    PubMed

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2016-04-01

    Cardiac computed tomography (CT) acquisitions for perfusion assessment can be performed in a dynamic or static mode. Either method may be used for a variety of clinical tasks, including (1) stratifying patients into categories of ischemia and (2) using a quantitative myocardial blood flow (MBF) estimate to evaluate disease severity. In this simulation study, we compare method performance on these classification and quantification tasks for matched radiation dose levels and for different flow states, patient sizes, and injected contrast levels. Under conditions simulated, the dynamic method has low bias in MBF estimates (0 to [Formula: see text]) compared to linearly interpreted static assessment (0.45 to [Formula: see text]), making it more suitable for quantitative estimation. At matched radiation dose levels, receiver operating characteristic analysis demonstrated that the static method, with its high bias but generally lower variance, had superior performance ([Formula: see text]) in stratifying patients, especially for larger patients and lower contrast doses [area under the curve [Formula: see text] to 96 versus 0.86]. We also demonstrate that static assessment with a correctly tuned exponential relationship between the apparent CT number and MBF has superior quantification performance to static assessment with a linear relationship and to dynamic assessment. However, tuning the exponential relationship to the patient and scan characteristics will likely prove challenging. This study demonstrates that the selection and optimization of static or dynamic acquisition modes should depend on the specific clinical task.

  6. Resistance reconstructed estimation of total peripheral resistance from computationally derived cardiac output - biomed 2013.

    PubMed

    Hill, Labarron K; Sollers Iii, John J; Thayer, Julian F

    2013-01-01

    Efficient functioning of the peripheral vasculature is an essential component in healthy cardiovascular regulation. Alterations in this functioning have been linked to the etiology and pathophysiological course of cardiovascular disease (CVD), especially hypertension. Given its significant role in the maintenance of both healthy and pathological blood pressure, total peripheral resistance (TPR), an index of the vasoconstrictive and elastic properties of the peripheral vasculature, has received much attention in this regard. However, obtaining a reliable estimate of TPR remains a complex and costly endeavor, primarily due to the necessity for sophisticated instrumentation as well as associated limitations in deriving cardiac output (CO). We have previously described a simple estimation method for CO using only arterial blood pressure and heart rate (Hill et al, 2012). In the present study we extend this technique to the estimation of TPR using beat-to-beat blood pressure data from the same sample of 67 young (mean age = 20.04± 2.8), healthy men (n = 30) and women (n = 37). Estimated TPR (TPRest) was calculated from the computationally-derived estimate of CO and mean arterial pressure (MAP). Correlation between TPR obtained via the validated Model-Flow technique and TPRest was moderate (r =.73, p <. 000) and stronger in men (r =.78, p <. 000) compared to women (r =.66, p <. 001). These data further suggest that reconstructed measures of hemodynamic functioning may be validly and adequately estimated from limited data sources.

  7. A computational model-based validation of Guyton's analysis of cardiac output and venous return curves

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Cohen, R. J.; Mark, R. G.

    2002-01-01

    Guyton developed a popular approach for understanding the factors responsible for cardiac output (CO) regulation in which 1) the heart-lung unit and systemic circulation are independently characterized via CO and venous return (VR) curves, and 2) average CO and right atrial pressure (RAP) of the intact circulation are predicted by graphically intersecting the curves. However, this approach is virtually impossible to verify experimentally. We theoretically evaluated the approach with respect to a nonlinear, computational model of the pulsatile heart and circulation. We developed two sets of open circulation models to generate CO and VR curves, differing by the manner in which average RAP was varied. One set applied constant RAPs, while the other set applied pulsatile RAPs. Accurate prediction of intact, average CO and RAP was achieved only by intersecting the CO and VR curves generated with pulsatile RAPs because of the pulsatility and nonlinearity (e.g., systemic venous collapse) of the intact model. The CO and VR curves generated with pulsatile RAPs were also practically independent. This theoretical study therefore supports the validity of Guyton's graphical analysis.

  8. Anatomical reconstructions of the human cardiac venous system using contrast-computed tomography of perfusion-fixed specimens.

    PubMed

    Spencer, Julianne; Fitch, Emily; Iaizzo, Paul A

    2013-01-01

    A detailed understanding of the complexity and relative variability within the human cardiac venous system is crucial for the development of cardiac devices that require access to these vessels. For example, cardiac venous anatomy is known to be one of the key limitations for the proper delivery of cardiac resynchronization therapy (CRT)(1) Therefore, the development of a database of anatomical parameters for human cardiac venous systems can aid in the design of CRT delivery devices to overcome such a limitation. In this research project, the anatomical parameters were obtained from 3D reconstructions of the venous system using contrast-computed tomography (CT) imaging and modeling software (Materialise, Leuven, Belgium). The following parameters were assessed for each vein: arc length, tortuousity, branching angle, distance to the coronary sinus ostium, and vessel diameter. CRT is a potential treatment for patients with electromechanical dyssynchrony. Approximately 10-20% of heart failure patients may benefit from CRT(2). Electromechanical dyssynchrony implies that parts of the myocardium activate and contract earlier or later than the normal conduction pathway of the heart. In CRT, dyssynchronous areas of the myocardium are treated with electrical stimulation. CRT pacing typically involves pacing leads that stimulate the right atrium (RA), right ventricle (RV), and left ventricle (LV) to produce more resynchronized rhythms. The LV lead is typically implanted within a cardiac vein, with the aim to overlay it within the site of latest myocardial activation. We believe that the models obtained and the analyses thereof will promote the anatomical education for patients, students, clinicians, and medical device designers. The methodologies employed here can also be utilized to study other anatomical features of our human heart specimens, such as the coronary arteries. To further encourage the educational value of this research, we have shared the venous models on our

  9. Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence.

    PubMed

    Gimeno-Blanes, Francisco J; Blanco-Velasco, Manuel; Barquero-Pérez, Óscar; García-Alberola, Arcadi; Rojo-Álvarez, José L

    2016-01-01

    Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG) analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indices, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indices in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indices which are tackled from the aforementioned viewpoints, namely, heart rate turbulence (HRT), heart rate variability (HRV), and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future. PMID:27014083

  10. Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence.

    PubMed

    Gimeno-Blanes, Francisco J; Blanco-Velasco, Manuel; Barquero-Pérez, Óscar; García-Alberola, Arcadi; Rojo-Álvarez, José L

    2016-01-01

    Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG) analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indices, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indices in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indices which are tackled from the aforementioned viewpoints, namely, heart rate turbulence (HRT), heart rate variability (HRV), and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future.

  11. Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence

    PubMed Central

    Gimeno-Blanes, Francisco J.; Blanco-Velasco, Manuel; Barquero-Pérez, Óscar; García-Alberola, Arcadi; Rojo-Álvarez, José L.

    2016-01-01

    Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG) analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indices, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indices in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indices which are tackled from the aforementioned viewpoints, namely, heart rate turbulence (HRT), heart rate variability (HRV), and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future. PMID:27014083

  12. Organ dose measurements from multiple-detector computed tomography using a commercial dosimetry system and tomographic, physical phantoms

    NASA Astrophysics Data System (ADS)

    Lavoie, Lindsey K.

    The technology of computed tomography (CT) imaging has soared over the last decade with the use of multi-detector CT (MDCT) scanners that are capable of performing studies in a matter of seconds. While the diagnostic information obtained from MDCT imaging is extremely valuable, it is important to ensure that the radiation doses resulting from these studies are at acceptably safe levels. This research project focused on the measurement of organ doses resulting from modern MDCT scanners. A commercially-available dosimetry system was used to measure organ doses. Small dosimeters made of optically-stimulated luminescent (OSL) material were analyzed with a portable OSL reader. Detailed verification of this system was performed. Characteristics studied include energy, scatter, and angular responses; dose linearity, ability to erase the exposed dose and ability to reuse dosimeters multiple times. The results of this verification process were positive. While small correction factors needed to be applied to the dose reported by the OSL reader, these factors were small and expected. Physical, tomographic pediatric and adult phantoms were used to measure organ doses. These phantoms were developed from CT images and are composed of tissue-equivalent materials. Because the adult phantom is comprised of numerous segments, dosimeters were placed in the phantom at several organ locations, and doses to select organs were measured using three clinical protocols: pediatric craniosynostosis, adult brain perfusion and adult cardiac CT angiography (CTA). A wide-beam, 320-slice, volumetric CT scanner and a 64-slice, MDCT scanner were used for organ dose measurements. Doses ranged from 1 to 26 mGy for the pediatric protocol, 1 to 1241 mGy for the brain perfusion protocol, and 2-100 mGy for the cardiac protocol. In most cases, the doses measured on the 64-slice scanner were higher than those on the 320-slice scanner. A methodology to measure organ doses with OSL dosimeters received from CT

  13. The relative role of patient physiology and device optimisation in cardiac resynchronisation therapy: A computational modelling study.

    PubMed

    Crozier, Andrew; Blazevic, Bojan; Lamata, Pablo; Plank, Gernot; Ginks, Matthew; Duckett, Simon; Sohal, Manav; Shetty, Anoop; Rinaldi, Christopher A; Razavi, Reza; Smith, Nicolas P; Niederer, Steven A

    2016-07-01

    Cardiac resynchronisation therapy (CRT) is an established treatment for heart failure, however the effective selection of patients and optimisation of therapy remain controversial. While extensive research is ongoing, it remains unclear whether improvements in patient selection or therapy planning offers a greater opportunity for the improvement of clinical outcomes. This computational study investigates the impact of both physiological conditions that guide patient selection and the optimisation of pacing lead placement on CRT outcomes. A multi-scale biophysical model of cardiac electromechanics was developed and personalised to patient data in three patients. These models were separated into components representing cardiac anatomy, pacing lead location, myocardial conductivity and stiffness, afterload, active contraction and conduction block for each individual, and recombined to generate a cohort of 648 virtual patients. The effect of these components on the change in total activation time of the ventricles (ΔTAT) and acute haemodynamic response (AHR) was analysed. The pacing site location was found to have the largest effect on ΔTAT and AHR. Secondary effects on ΔTAT and AHR were found for functional conduction block and cardiac anatomy. The simulation results highlight a need for a greater emphasis on therapy optimisation in order to achieve the best outcomes for patients.

  14. Dynamic single photon emission computed tomography—basic principles and cardiac applications

    PubMed Central

    Gullberg, Grant T; Reutter, Bryan W; Sitek, Arkadiusz; Maltz, Jonathan S; Budinger, Thomas F

    2011-01-01

    The very nature of nuclear medicine, the visual representation of injected radiopharmaceuticals, implies imaging of dynamic processes such as the uptake and wash-out of radiotracers from body organs. For years, nuclear medicine has been touted as the modality of choice for evaluating function in health and disease. This evaluation is greatly enhanced using single photon emission computed tomography (SPECT), which permits three-dimensional (3D) visualization of tracer distributions in the body. However, to fully realize the potential of the technique requires the imaging of in vivo dynamic processes of flow and metabolism. Tissue motion and deformation must also be addressed. Absolute quantification of these dynamic processes in the body has the potential to improve diagnosis. This paper presents a review of advancements toward the realization of the potential of dynamic SPECT imaging and a brief history of the development of the instrumentation. A major portion of the paper is devoted to the review of special data processing methods that have been developed for extracting kinetics from dynamic cardiac SPECT data acquired using rotating detector heads that move as radiopharmaceuticals exchange between biological compartments. Recent developments in multi-resolution spatiotemporal methods enable one to estimate kinetic parameters of compartment models of dynamic processes using data acquired from a single camera head with slow gantry rotation. The estimation of kinetic parameters directly from projection measurements improves bias and variance over the conventional method of first reconstructing 3D dynamic images, generating time–activity curves from selected regions of interest and then estimating the kinetic parameters from the generated time–activity curves. Although the potential applications of SPECT for imaging dynamic processes have not been fully realized in the clinic, it is hoped that this review illuminates the potential of SPECT for dynamic imaging

  15. Cardiac catheterization

    MedlinePlus

    Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization; CAD - cardiac catheterization; Coronary artery disease - cardiac catheterization; Heart valve - cardiac catheterization; Heart failure - ...

  16. Myocardial Blood Flow Quantification for Evaluation of Coronary Artery Disease by Positron Emission Tomography, Cardiac Magnetic Resonance Imaging, and Computed Tomography

    PubMed Central

    Waller, Alfonso H.; Blankstein, Ron; Kwong, Raymond Y.; Di Carli, Marcelo F.

    2014-01-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging and computed tomography, and its emerging clinical applications. PMID:24718671

  17. Practical considerations for optimizing cardiac computed tomography protocols for comprehensive acquisition prior to transcatheter aortic valve replacement.

    PubMed

    Khalique, Omar K; Pulerwitz, Todd C; Halliburton, Sandra S; Kodali, Susheel K; Hahn, Rebecca T; Nazif, Tamim M; Vahl, Torsten P; George, Isaac; Leon, Martin B; D'Souza, Belinda; Einstein, Andrew J

    2016-01-01

    Transcatheter aortic valve replacement (TAVR) is performed frequently in patients with severe, symptomatic aortic stenosis who are at high risk or inoperable for open surgical aortic valve replacement. Computed tomography angiography (CTA) has become the gold standard imaging modality for pre-TAVR cardiac anatomic and vascular access assessment. Traditionally, cardiac CTA has been most frequently used for assessment of coronary artery stenosis, and scanning protocols have generally been tailored for this purpose. Pre-TAVR CTA has different goals than coronary CTA and the high prevalence of chronic kidney disease in the TAVR patient population creates a particular need to optimize protocols for a reduction in iodinated contrast volume. This document reviews details which allow the physician to tailor CTA examinations to maximize image quality and minimize harm, while factoring in multiple patient and scanner variables which must be considered in customizing a pre-TAVR protocol.

  18. Computational Modeling of Open-Irrigated Electrodes for Radiofrequency Cardiac Ablation Including Blood Motion-Saline Flow Interaction.

    PubMed

    González-Suárez, Ana; Berjano, Enrique; Guerra, Jose M; Gerardo-Giorda, Luca

    2016-01-01

    Radiofrequency catheter ablation (RFCA) is a routine treatment for cardiac arrhythmias. During RFCA, the electrode-tissue interface temperature should be kept below 80 °C to avoid thrombus formation. Open-irrigated electrodes facilitate power delivery while keeping low temperatures around the catheter. No computational model of an open-irrigated electrode in endocardial RFCA accounting for both the saline irrigation flow and the blood motion in the cardiac chamber has been proposed yet. We present the first computational model including both effects at once. The model has been validated against existing experimental results. Computational results showed that the surface lesion width and blood temperature are affected by both the electrode design and the irrigation flow rate. Smaller surface lesion widths and blood temperatures are obtained with higher irrigation flow rate, while the lesion depth is not affected by changing the irrigation flow rate. Larger lesions are obtained with increasing power and the electrode-tissue contact. Also, larger lesions are obtained when electrode is placed horizontally. Overall, the computational findings are in close agreement with previous experimental results providing an excellent tool for future catheter research.

  19. Computational Modeling of Open-Irrigated Electrodes for Radiofrequency Cardiac Ablation Including Blood Motion-Saline Flow Interaction

    PubMed Central

    González-Suárez, Ana; Berjano, Enrique; Guerra, Jose M.; Gerardo-Giorda, Luca

    2016-01-01

    Radiofrequency catheter ablation (RFCA) is a routine treatment for cardiac arrhythmias. During RFCA, the electrode-tissue interface temperature should be kept below 80°C to avoid thrombus formation. Open-irrigated electrodes facilitate power delivery while keeping low temperatures around the catheter. No computational model of an open-irrigated electrode in endocardial RFCA accounting for both the saline irrigation flow and the blood motion in the cardiac chamber has been proposed yet. We present the first computational model including both effects at once. The model has been validated against existing experimental results. Computational results showed that the surface lesion width and blood temperature are affected by both the electrode design and the irrigation flow rate. Smaller surface lesion widths and blood temperatures are obtained with higher irrigation flow rate, while the lesion depth is not affected by changing the irrigation flow rate. Larger lesions are obtained with increasing power and the electrode-tissue contact. Also, larger lesions are obtained when electrode is placed horizontally. Overall, the computational findings are in close agreement with previous experimental results providing an excellent tool for future catheter research. PMID:26938638

  20. Computational Modeling of Open-Irrigated Electrodes for Radiofrequency Cardiac Ablation Including Blood Motion-Saline Flow Interaction.

    PubMed

    González-Suárez, Ana; Berjano, Enrique; Guerra, Jose M; Gerardo-Giorda, Luca

    2016-01-01

    Radiofrequency catheter ablation (RFCA) is a routine treatment for cardiac arrhythmias. During RFCA, the electrode-tissue interface temperature should be kept below 80 °C to avoid thrombus formation. Open-irrigated electrodes facilitate power delivery while keeping low temperatures around the catheter. No computational model of an open-irrigated electrode in endocardial RFCA accounting for both the saline irrigation flow and the blood motion in the cardiac chamber has been proposed yet. We present the first computational model including both effects at once. The model has been validated against existing experimental results. Computational results showed that the surface lesion width and blood temperature are affected by both the electrode design and the irrigation flow rate. Smaller surface lesion widths and blood temperatures are obtained with higher irrigation flow rate, while the lesion depth is not affected by changing the irrigation flow rate. Larger lesions are obtained with increasing power and the electrode-tissue contact. Also, larger lesions are obtained when electrode is placed horizontally. Overall, the computational findings are in close agreement with previous experimental results providing an excellent tool for future catheter research. PMID:26938638

  1. High frequency stimulation of cardiac myocytes: a theoretical and computational study.

    PubMed

    Weinberg, Seth H

    2014-12-01

    High-frequency stimulation (HFS) has recently been identified as a novel approach for terminating life-threatening cardiac arrhythmias. HFS elevates myocyte membrane potential and blocks electrical conduction for the duration of the stimulus. However, low amplitude HFS can induce rapidly firing action potentials, which may reinitiate an arrhythmia. The cellular level mechanisms underlying HFS-induced electrical activity are not well understood. Using a multiscale method, we show that a minimal myocyte model qualitatively reproduces the influence of HFS on cardiac electrical activity. Theoretical analysis and simulations suggest that persistent activation and de-inactivation of ionic currents, in particular a fast inward window current, underlie HFS-induced action potentials and membrane potential elevation, providing hypotheses for future experiments. We derive analytical expressions to describe how HFS modifies ionic current amplitude and gating dynamics. We show how fast inward current parameters influence the parameter regimes for HFS-induced electrical activity, demonstrating how the efficacy of HFS as a therapy for terminating arrhythmias may depend on the presence of pathological conditions or pharmacological treatments. Finally, we demonstrate that HFS terminates cardiac arrhythmias in a one-dimensional ring of cardiac tissue. In this study, we demonstrate a novel approach to characterize the influence of HFS on ionic current gating dynamics, provide new insight into HFS of the myocardium, and suggest mechanisms underlying HFS-induced electrical activity.

  2. High frequency stimulation of cardiac myocytes: A theoretical and computational study

    NASA Astrophysics Data System (ADS)

    Weinberg, Seth H.

    2014-12-01

    High-frequency stimulation (HFS) has recently been identified as a novel approach for terminating life-threatening cardiac arrhythmias. HFS elevates myocyte membrane potential and blocks electrical conduction for the duration of the stimulus. However, low amplitude HFS can induce rapidly firing action potentials, which may reinitiate an arrhythmia. The cellular level mechanisms underlying HFS-induced electrical activity are not well understood. Using a multiscale method, we show that a minimal myocyte model qualitatively reproduces the influence of HFS on cardiac electrical activity. Theoretical analysis and simulations suggest that persistent activation and de-inactivation of ionic currents, in particular a fast inward window current, underlie HFS-induced action potentials and membrane potential elevation, providing hypotheses for future experiments. We derive analytical expressions to describe how HFS modifies ionic current amplitude and gating dynamics. We show how fast inward current parameters influence the parameter regimes for HFS-induced electrical activity, demonstrating how the efficacy of HFS as a therapy for terminating arrhythmias may depend on the presence of pathological conditions or pharmacological treatments. Finally, we demonstrate that HFS terminates cardiac arrhythmias in a one-dimensional ring of cardiac tissue. In this study, we demonstrate a novel approach to characterize the influence of HFS on ionic current gating dynamics, provide new insight into HFS of the myocardium, and suggest mechanisms underlying HFS-induced electrical activity.

  3. Little impact of tsunami-stricken nuclear accident on awareness of radiation dose of cardiac computed tomography: A questionnaire study

    PubMed Central

    2013-01-01

    Background With the increased use of cardiac computed tomography (CT), radiation dose remains a major issue, although physicians are trying to reduce the substantial risks associated with use of this diagnostic tool. This study was performed to investigate recognition of the level of radiation exposure from cardiac CT and the differences in the level of awareness of radiation before and after the Fukushima nuclear plant accident. Methods We asked 30 physicians who were undergoing training in internal medicine to determine the equivalent doses of radiation for common radiological examinations when a normal chest X-ray is accepted as one unit; questions about the absolute radiation dose of cardiac CT data were also asked. Results According to the results, 86.6% of respondents believed the exposure to be 1 mSv at most, and 93.3% thought that the exposure was less than that of 100 chest X-rays. This finding indicates that their perceptions were far lower than the actual amounts. Even after the occurrence of such a large nuclear disaster in Fukushima, there were no significant differences in the same subjects’ overall awareness of radiation amounts. Conclusions Even after such a major social issue as the Fukushima nuclear accident, the level of awareness of the accurate radiation amount used in 64-channel multidetector CT (MDCT) by clinical physicians who order this test was not satisfactory. Thus, there is a need for the development of effective continuing education programs to improve awareness of radiation from ionizing radiation devices, including cardiac CT, and emphasis on risk-benefit evaluation based on accurate knowledge during medical training. PMID:23631688

  4. The Incremental Prognostic Value of Cardiac Computed Tomography in Comparison with Single-Photon Emission Computed Tomography in Patients with Suspected Coronary Artery Disease

    PubMed Central

    Lee, Heesun; Yoon, Yeonyee E.; Park, Jun-Bean; Kim, Hack-Lyoung; Park, Hyo Eun; Lee, Seung-Pyo; Kim, Hyung-Kwan; Choi, Su-Yeon; Kim, Yong-Jin; Cho, Goo-Yeong; Zo, Joo-Hee; Sohn, Dae-Won

    2016-01-01

    Background Coronary computed tomographic angiography (CCTA) facilitates comprehensive evaluation of coronary artery disease (CAD), including plaque characterization, and can provide additive diagnostic value to single-photon emission computed tomography (SPECT). However, data regarding the incremental prognostic value of CCTA to SPECT remain sparse. We evaluated the independent and incremental prognostic value of CCTA, as compared with clinical risk factors and SPECT. Materials and methods A total of 1,077 patients with suspected CAD who underwent both SPECT and cardiac CT between 2004 and 2012 were enrolled retrospectively. Presence of reversible or fixed perfusion defect (PD) and summed stress score were evaluated on SPECT. Presence, extent of coronary atherosclerosis and diameter stenosis (DS) were evaluated on CCTA. Plaque composition was categorized as non-calcified, mixed, or calcified according to the volume of calcified component (>130 Hounsfield Units). Patients were followed up for the occurrence of adverse cardiac events including cardiac death, non-fatal myocardial infarction, unstable angina, and late revascularization (>90 days after imaging studies). Results During follow-up (median 23 months), adverse cardiac events were observed in 71 patients (6.6%). When adjusted for clinical risk factors and SPECT findings, the presence of any coronary plaque, any plaque in ≥3 segments, coronary artery calcium score (CACS) ≥400, a plaque ≥50% DS, presence of non-calcified plaque (NCP) or mixed plaque (MP), and NCP/MP in ≥2 segments were independent predictors of adverse cardiac events; however, the presence of calcified plaque (CP) was not. Conventional CCTA findings, including CACS ≥400 and a plaque ≥50% DS, demonstrated incremental prognostic value over clinical risk factors and SPECT (χ² 54.19 to 101.03; p <0.001). Addition of NCP/MP in ≥2 segments resulted in further significantly improved prediction (χ² 101.03 to 113.29; p <0

  5. Feasibility study to demonstrate cardiac imaging using fast kVp switching dual-energy computed tomography: phantom study

    NASA Astrophysics Data System (ADS)

    Madhav, Priti; Imai, Yasuhiro; Narayanan, Suresh; Dutta, Sandeep; Chandra, Naveen; Hsieh, Jiang

    2012-03-01

    Dual-energy computed tomography is a novel imaging tool that has the potential to reduce beam hardening artifacts and enhance material separation over conventional imaging techniques. Dual-energy acquisitions can be performed by using a fast kVp technology to switch between acquiring adjacent projections at two distinct x-ray spectra (80 and 140 kVp). These datasets can be used to further compute material density and monochromatic images for better material separation and beam hardening reduction by virtue of the projection domain process. The purpose of this study was to evaluate the feasibility of using dual-energy in cardiac imaging for myocardial perfusion detection and coronary artery lumen visualization. Data was acquired on a heart phantom, which consisted of the chambers and aorta filled with Iodine density solution (500 HU @ 120 kVp), a defect region between the aorta and chamber (40 HU @ 120 kVp), two Iodinefilled vessels (400 HU @ 120 kVp) of different diameters with high attenuation (hydroxyapatite) plaques (HAP), and with a 30-cm water equivalent body ring around the phantom. Prospective ECG-gated single-energy and prospective ECG-gated dual-energy imaging was performed. Results showed that the generated monochromatic images had minimal beam hardening artifacts which improved the accuracy and detection of the myocardial defect region. Material density images were useful in differentiating and quantifying the actual size of the plaque and coronary artery lumen. Overall, this study shows that dual-energy cardiac imaging will be a valuable tool for cardiac applications.

  6. Construction of a computational anatomical model of the peripheral cardiac conduction system.

    PubMed

    Sebastian, Rafael; Zimmerman, Viviana; Romero, Daniel; Frangi, Alejandro F

    2011-12-01

    A methodology is presented here for automatic construction of a ventricular model of the cardiac conduction system (CCS), which is currently a missing block in many multiscale cardiac electromechanic models. It includes the His bundle, left bundle branches, and the peripheral CCS. The algorithm is fundamentally an enhancement of a rule-based method known as the Lindenmayer systems (L-systems). The generative procedure has been divided into three consecutive independent stages, which subsequently build the CCS from proximal to distal sections. Each stage is governed by a set of user parameters together with anatomical and physiological constrains to direct the generation process and adhere to the structural observations derived from histology studies. Several parameters are defined using statistical distributions to introduce stochastic variability in the models. The CCS built with this approach can generate electrical activation sequences with physiological characteristics.

  7. Towards an atrio-ventricular delay optimization assessed by a computer model for cardiac resynchronization therapy

    NASA Astrophysics Data System (ADS)

    Ojeda, David; Le Rolle, Virginie; Tse Ve Koon, Kevin; Thebault, Christophe; Donal, Erwan; Hernández, Alfredo I.

    2013-11-01

    In this paper, lumped-parameter models of the cardiovascular system, the cardiac electrical conduction system and a pacemaker are coupled to generate mitral ow pro les for di erent atrio-ventricular delay (AVD) con gurations, in the context of cardiac resynchronization therapy (CRT). First, we perform a local sensitivity analysis of left ventricular and left atrial parameters on mitral ow characteristics, namely E and A wave amplitude, mitral ow duration, and mitral ow time integral. Additionally, a global sensitivity analysis over all model parameters is presented to screen for the most relevant parameters that a ect the same mitral ow characteristics. Results provide insight on the in uence of left ventricle and atrium in uence on mitral ow pro les. This information will be useful for future parameter estimation of the model that could reproduce the mitral ow pro les and cardiovascular hemodynamics of patients undergoing AVD optimization during CRT.

  8. Cardiac Multidetector Computed Tomography: Basic Physics of Image Acquisition and Clinical Applications

    PubMed Central

    Bardo, Dianna M.E; Brown, Paul

    2008-01-01

    Cardiac MDCT is here to stay. And, it is more than just imaging coronary arteries. Understanding the differences in and the benefits of one CT scanner from another will help you to optimize the capabilities of the scanner, but requires a basic understanding of the MDCT imaging physics. This review provides key information needed to understand the differences in the types of MDCT scanners, from 64 – 320 detectors, flat panels, single and dual source configurations, step and shoot prospective and retrospective gating, and how each factor influences radiation dose, spatial and temporal resolution, and image noise. PMID:19936200

  9. Comparison of effective doses between computed tomography cardiac angiography and conventional angiography at Pantai Hospital, Kuala Lumpur

    NASA Astrophysics Data System (ADS)

    Mohamed, Faizal; Moin, F. H. A.

    2013-05-01

    This research studies two types of cardiac angiography procedures, namely Computed Tomography Cardiac Angiography (CTCA) and Conventional Angiography (CA). The following research was executed to estimate the difference of mean effective doses that the patients received through both procedures. The mean dose-length-product (DLP) from CTCA and mean dose-area-product (DAP) from CA were utilized in calculating the effective doses. The result shows that the mean effective dose for CTCA and CA are 1.71±0.59 mSv and 53.25±14.22 mSv respectively. This proves that the mean effective dose received by patients undergoing CA is higher than patients undergoing CTCA. According to t-test, both procedures differ significantly, with a difference amounting to p<0.0001. The increases of the effective dose that the patients received through CA procedure were influenced by exposure time, the coronary anatomical condition, the operator's experience, and the operation methods.

  10. Automatic computation of left ventricular volume changes over a cardiac cycle from echocardiography images by nonlinear dimensionality reduction.

    PubMed

    Alizadeh Sani, Zahra; Shalbaf, Ahmad; Behnam, Hamid; Shalbaf, Reza

    2015-02-01

    Curve of left ventricular (LV) volume changes throughout the cardiac cycle is a fundamental parameter for clinical evaluation of various cardiovascular diseases. Currently, this evaluation is often performed manually which is tedious and time consuming and suffers from significant interobserver and intraobserver variability. This paper introduces a new automatic method, based on nonlinear dimensionality reduction (NLDR) for extracting the curve of the LV volume changes over a cardiac cycle from two-dimensional (2-D) echocardiography images. Isometric feature mapping (Isomap) is one of the most popular NLDR algorithms. In this study, a modified version of Isomap algorithm, where image to image distance metric is computed using nonrigid registration, is applied on 2-D echocardiography images of one cycle of heart. Using this approach, the nonlinear information of these images is embedded in a 2-D manifold and each image is characterized by a symbol on the constructed manifold. This new representation visualizes the relationship between these images based on LV volume changes and allows extracting the curve of the LV volume changes automatically. Our method in comparison to the traditional segmentation algorithms does not need any LV myocardial segmentation and tracking, particularly difficult in the echocardiography images. Moreover, a large data set under various diseases for training is not required. The results obtained by our method are quantitatively evaluated to those obtained manually by the highly experienced echocardiographer on ten healthy volunteers and six patients which depict the usefulness of the presented method.

  11. Cardiac computed tomography radiation dose reduction using interior reconstruction algorithm with the aorta and vertebra as known information.

    PubMed

    Bharkhada, Deepak; Yu, Hengyong; Ge, Shuping; Carr, J Jeffrey; Wang, Ge

    2009-01-01

    High x-ray radiation dose is a major public concern with the increasing use of multidetector computed tomography (CT) for diagnosis of cardiovascular diseases. This issue must be effectively addressed by dose-reduction techniques. Recently, our group proved that an internal region of interest (ROI) can be exactly reconstructed solely from localized projections if a small subregion within the ROI is known. In this article, we propose to use attenuation values of the blood in aorta and vertebral bone to serve as the known information for localized cardiac CT. First, we describe a novel interior tomography approach that backprojects differential fan-beam or parallel-beam projections to obtain the Hilbert transform and then reconstructs the original image in an ROI using the iterative projection onto convex sets algorithm. Then, we develop a numerical phantom based on clinical cardiac CT images for simulations. Our results demonstrate that it is feasible to use practical prior information and exactly reconstruct cardiovascular structures only from projection data along x-ray paths through the ROI.

  12. An improved spatial tracking algorithm applied to coronary veins into Cardiac Multi-Slice Computed Tomography volume

    PubMed Central

    Garcia, Marie-Paule; Toumoulin, Christine; Garreau, Mireille; Kulik, Carine; Boulmier, Dominique; Leclercq, Christophe

    2008-01-01

    This paper describes an enhanced vessel tracking algorithm. The method specifity relies on the coronary venous tree extraction through Cardiac Multi-Slice Computed Tomography (MSCT). Indeed, contrast inhomogeneities are a major issue in the data sets that necessit a robust tracking procedure. The method is based on an existing moment-based algorithm designed for coronary arteries into MSCT volume. In order to extract the whole path of interest, improvements concerning progression strategy are proposed. Furthermore, the original procedure is combinated with an automatic recentring method based on ray casting. This enhanced method has been tested on three data sets. According to the first results, the method appears robust to curvatures, contrast inhomogeneities and low contrast blood veins. PMID:19163593

  13. Experimental and computational studies on complex spiral waves in 2-D cardiac substrates

    NASA Astrophysics Data System (ADS)

    Bursac, Nenad

    2005-03-01

    A variety of chemical and biological nonlinear excitable media including heart tissue can support stable, self-organized waves of activity in a form of rotating single-arm spirals. In the heart tissue, stable single-arm spirals can underlie highly periodic activity such as monomorphic ventricular tachycardia (VT), while unstable spirals that continuously form and break up are shown to underlie aperiodic and lethal heart activity, namely fibrillation. Although fast pacing from a point in the heart is commonly used to terminate VT, it can occasionally yield a transient or stable acceleration of tachicardia rate and/or fibrillation. In this study we tested the effect of rapid point pacing on sustained spiral waves in the uniformly anisotropic cultures of cardiac myocytes. In 15/79 cultures, rapid pacing induced a stable formation of multiple bound spiral waves (a complex spiral) and acceleration of overall excitation rate in the tissue, as assessed by pseudo ECG (pECG). The level of rate acceleration correlated with the number of rotating waves. Further rapid point pacing decelerated, terminated, or further accelerated the complex spiral activity via a change in the number of coexisting rotating waves. The dynamic restitution analysis revealed no alternans in action potential duration in any of the cultures. Stable formation of complex spirals was accomplished only in the cultures that showed relatively broad and steep impulse wavelength and conduction velocity restitutions. A necessary condition for rate acceleration in a medium with monotonic restitution is that the rate of rotation of a single spiral wave is significantly lower than maximum sustainable rate of excitation in the medium. Preliminary data in a homogeneous medium using 3-variable Fenton-Karma (FK) based model of cardiac tissue suggest that decrease of fast inward current (excitability) can shift the spiral rate away from the break point on the restitution curve, enabling a necessary condition for rate

  14. Modeling Cardiac Electrophysiology at the Organ Level in the Peta FLOPS Computing Age

    SciTech Connect

    Mitchell, Lawrence; Bishop, Martin; Hoetzl, Elena; Neic, Aurel; Liebmann, Manfred; Haase, Gundolf; Plank, Gernot

    2010-09-30

    Despite a steep increase in available compute power, in-silico experimentation with highly detailed models of the heart remains to be challenging due to the high computational cost involved. It is hoped that next generation high performance computing (HPC) resources lead to significant reductions in execution times to leverage a new class of in-silico applications. However, performance gains with these new platforms can only be achieved by engaging a much larger number of compute cores, necessitating strongly scalable numerical techniques. So far strong scalability has been demonstrated only for a moderate number of cores, orders of magnitude below the range required to achieve the desired performance boost.In this study, strong scalability of currently used techniques to solve the bidomain equations is investigated. Benchmark results suggest that scalability is limited to 512-4096 cores within the range of relevant problem sizes even when systems are carefully load-balanced and advanced IO strategies are employed.

  15. A novel approach for the automated segmentation and volume quantification of cardiac fats on computed tomography.

    PubMed

    Rodrigues, É O; Morais, F F C; Morais, N A O S; Conci, L S; Neto, L V; Conci, A

    2016-01-01

    The deposits of fat on the surroundings of the heart are correlated to several health risk factors such as atherosclerosis, carotid stiffness, coronary artery calcification, atrial fibrillation and many others. These deposits vary unrelated to obesity, which reinforces its direct segmentation for further quantification. However, manual segmentation of these fats has not been widely deployed in clinical practice due to the required human workload and consequential high cost of physicians and technicians. In this work, we propose a unified method for an autonomous segmentation and quantification of two types of cardiac fats. The segmented fats are termed epicardial and mediastinal, and stand apart from each other by the pericardium. Much effort was devoted to achieve minimal user intervention. The proposed methodology mainly comprises registration and classification algorithms to perform the desired segmentation. We compare the performance of several classification algorithms on this task, including neural networks, probabilistic models and decision tree algorithms. Experimental results of the proposed methodology have shown that the mean accuracy regarding both epicardial and mediastinal fats is 98.5% (99.5% if the features are normalized), with a mean true positive rate of 98.0%. In average, the Dice similarity index was equal to 97.6%. PMID:26474835

  16. Pred-hERG: A Novel web-Accessible Computational Tool for Predicting Cardiac Toxicity.

    PubMed

    Braga, Rodolpho C; Alves, Vinicius M; Silva, Meryck F B; Muratov, Eugene; Fourches, Denis; Lião, Luciano M; Tropsha, Alexander; Andrade, Carolina H

    2015-10-01

    The blockage of the hERG K(+) channels is closely associated with lethal cardiac arrhythmia. The notorious ligand promiscuity of this channel earmarked hERG as one of the most important antitargets to be considered in early stages of drug development process. Herein we report on the development of an innovative and freely accessible web server for early identification of putative hERG blockers and non-blockers in chemical libraries. We have collected the largest publicly available curated hERG dataset of 5,984 compounds. We succeed in developing robust and externally predictive binary (CCR≈0.8) and multiclass models (accuracy≈0.7). These models are available as a web-service freely available for public at http://labmol.farmacia.ufg.br/predherg/. Three following outcomes are available for the users: prediction by binary model, prediction by multi-class model, and the probability maps of atomic contribution. The Pred-hERG will be continuously updated and upgraded as new information became available. PMID:27490970

  17. Pred-hERG: A Novel web-Accessible Computational Tool for Predicting Cardiac Toxicity.

    PubMed

    Braga, Rodolpho C; Alves, Vinicius M; Silva, Meryck F B; Muratov, Eugene; Fourches, Denis; Lião, Luciano M; Tropsha, Alexander; Andrade, Carolina H

    2015-10-01

    The blockage of the hERG K(+) channels is closely associated with lethal cardiac arrhythmia. The notorious ligand promiscuity of this channel earmarked hERG as one of the most important antitargets to be considered in early stages of drug development process. Herein we report on the development of an innovative and freely accessible web server for early identification of putative hERG blockers and non-blockers in chemical libraries. We have collected the largest publicly available curated hERG dataset of 5,984 compounds. We succeed in developing robust and externally predictive binary (CCR≈0.8) and multiclass models (accuracy≈0.7). These models are available as a web-service freely available for public at http://labmol.farmacia.ufg.br/predherg/. Three following outcomes are available for the users: prediction by binary model, prediction by multi-class model, and the probability maps of atomic contribution. The Pred-hERG will be continuously updated and upgraded as new information became available.

  18. Effect of regional differences in cardiac cellular electrophysiology on the stability of ventricular arrhythmias: a computational study

    NASA Astrophysics Data System (ADS)

    Clayton, Richard H.; Holden, Arun V.

    2003-01-01

    Re-entry is an important mechanism of cardiac arrhythmias. During re-entry a wave of electrical activation repeatedly propagates into recovered tissue, rotating around a rod-like filament. Breakdown of a single re-entrant wave into multiple waves is believed to underlie the transition from ventricular tachycardia to ventricular fibrillation. Several mechanisms of breakup have been identified including the effect of anisotropic conduction in the ventricular wall. Cells in the inner and outer layers of the ventricular wall have different action potential durations (APD), and support re-entrant waves with different periods. The aim of this study was to use a computational approach to study twisting and breakdown in a transmural re-entrant wave spanning these regions, and examine the relative role of this effect and anisotropic conduction. We used a simplified model of action potential conduction in the ventricular wall that we modified so that it supported stable re-entry in an anisotropic model with uniform APD. We first examined the effect of regional differences on breakdown in an isotropic model with transmural differences in APD, and found that twisting of the re-entrant filament resulted in buckling and breakdown during the second cycle of re-entry. We found that breakdown was amplified in the anisotropic model, resulting in complex activation in the region of longest APD. This study shows that regional differences in cardiac electrophysiology are a potentially important mechanism for destabilizing re-entry and may act synergistically with other mechanisms to mediate the transition from ventricular tachycardia to ventricular fibrillation.

  19. Cardiac magnetic resonance and computed tomography angiography for clinical imaging of stable coronary artery disease. Diagnostic classification and risk stratification

    PubMed Central

    Korosoglou, Grigorios; Giusca, Sorin; Gitsioudis, Gitsios; Erbel, Christian; Katus, Hugo A.

    2014-01-01

    Despite advances in the pharmacologic and interventional treatment of coronary artery disease (CAD), atherosclerosis remains the leading cause of death in Western societies. X-ray coronary angiography has been the modality of choice for diagnosing the presence and extent of CAD. However, this technique is invasive and provides limited information on the composition of atherosclerotic plaque. Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) have emerged as promising non-invasive techniques for the clinical imaging of CAD. Hereby, CCTA allows for visualization of coronary calcification, lumen narrowing and atherosclerotic plaque composition. In this regard, data from the CONFIRM Registry recently demonstrated that both atherosclerotic plaque burden and lumen narrowing exhibit incremental value for the prediction of future cardiac events. However, due to technical limitations with CCTA, resulting in false positive or negative results in the presence of severe calcification or motion artifacts, this technique cannot entirely replace invasive angiography at the present time. CMR on the other hand, provides accurate assessment of the myocardial function due to its high spatial and temporal resolution and intrinsic blood-to-tissue contrast. Hereby, regional wall motion and perfusion abnormalities, during dobutamine or vasodilator stress, precede the development of ST-segment depression and anginal symptoms enabling the detection of functionally significant CAD. While CT generally offers better spatial resolution, the versatility of CMR can provide information on myocardial function, perfusion, and viability, all without ionizing radiation for the patients. Technical developments with these 2 non-invasive imaging tools and their current implementation in the clinical imaging of CAD will be presented and discussed herein. PMID:25147526

  20. A computer module for the continuous monitoring of cardiac output in the operating theatre and the ICU.

    PubMed

    Wesseling, K H; Purschke, R; Smith, N T; Wüst, H J; de Wit, B; Weber, H A

    1976-01-01

    A new pulse contour method to determine stroke volume and cardiac output continuously in patients on a beat-to-beat basis from the aortic pressure wave has been implemented in the form of a simple, inexpensive, fully automatic computing module for a commercially available patients monitoring system (Philips Medical Systems). Its reliability has been tested and shown in a computer analog, in experimental studies in 10 dogs (not reported here), in 22 hemodynamic studies on 20 young healthy volunteers and during 41 days in 20 postsurgical patients in the ICU, the most important result being that erros figures (15 and 19% respectively in the two human studies) are of the same order as when two standard methods, Fick and dye dilution are compared. The clinical studies have further indicated the easy applicability of the module 1 degree in the monitoring of critically ill patients in ICU's, 2 degrees as a monitor of the systemic circulation during anesthesia, and 3 degrees as a tool for studying the hemodynamic effects of pharmacological agents. The instrument consitutes no burden to the patients and has, several times during the course of the evaluation, provided an early warning of a deteriorating hemodynamic status of the patient to the physician.

  1. Toward an integrative computational model of the Guinea pig cardiac myocyte.

    PubMed

    Gauthier, Laura Doyle; Greenstein, Joseph L; Winslow, Raimond L

    2012-01-01

    The local control theory of excitation-contraction (EC) coupling asserts that regulation of calcium (Ca(2+)) release occurs at the nanodomain level, where openings of single L-type Ca(2+) channels (LCCs) trigger openings of small clusters of ryanodine receptors (RyRs) co-localized within the dyad. A consequence of local control is that the whole-cell Ca(2+) transient is a smooth continuous function of influx of Ca(2+) through LCCs. While this so-called graded release property has been known for some time, its functional importance to the integrated behavior of the cardiac ventricular myocyte has not been fully appreciated. We previously formulated a biophysically based model, in which LCCs and RyRs interact via a coarse-grained representation of the dyadic space. The model captures key features of local control using a low-dimensional system of ordinary differential equations. Voltage-dependent gain and graded Ca(2+) release are emergent properties of this model by virtue of the fact that model formulation is closely based on the sub-cellular basis of local control. In this current work, we have incorporated this graded release model into a prior model of guinea pig ventricular myocyte electrophysiology, metabolism, and isometric force production. The resulting integrative model predicts the experimentally observed causal relationship between action potential (AP) shape and timing of Ca(2+) and force transients, a relationship that is not explained by models lacking the graded release property. Model results suggest that even relatively subtle changes in AP morphology that may result, for example, from remodeling of membrane transporter expression in disease or spatial variation in cell properties, may have major impact on the temporal waveform of Ca(2+) transients, thus influencing tissue level electromechanical function. PMID:22783206

  2. Toward an Integrative Computational Model of the Guinea Pig Cardiac Myocyte

    PubMed Central

    Gauthier, Laura Doyle; Greenstein, Joseph L.; Winslow, Raimond L.

    2012-01-01

    The local control theory of excitation-contraction (EC) coupling asserts that regulation of calcium (Ca2+) release occurs at the nanodomain level, where openings of single L-type Ca2+ channels (LCCs) trigger openings of small clusters of ryanodine receptors (RyRs) co-localized within the dyad. A consequence of local control is that the whole-cell Ca2+ transient is a smooth continuous function of influx of Ca2+ through LCCs. While this so-called graded release property has been known for some time, its functional importance to the integrated behavior of the cardiac ventricular myocyte has not been fully appreciated. We previously formulated a biophysically based model, in which LCCs and RyRs interact via a coarse-grained representation of the dyadic space. The model captures key features of local control using a low-dimensional system of ordinary differential equations. Voltage-dependent gain and graded Ca2+ release are emergent properties of this model by virtue of the fact that model formulation is closely based on the sub-cellular basis of local control. In this current work, we have incorporated this graded release model into a prior model of guinea pig ventricular myocyte electrophysiology, metabolism, and isometric force production. The resulting integrative model predicts the experimentally observed causal relationship between action potential (AP) shape and timing of Ca2+ and force transients, a relationship that is not explained by models lacking the graded release property. Model results suggest that even relatively subtle changes in AP morphology that may result, for example, from remodeling of membrane transporter expression in disease or spatial variation in cell properties, may have major impact on the temporal waveform of Ca2+ transients, thus influencing tissue level electromechanical function. PMID:22783206

  3. Cardiac Rehabilitation

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Cardiac Rehabilitation? Cardiac rehabilitation (rehab) is a medically supervised program ... be designed to meet your needs. The Cardiac Rehabilitation Team Cardiac rehab involves a long-term commitment ...

  4. Step-and-shoot data acquisition and reconstruction for cardiac x-ray computed tomography

    SciTech Connect

    Hsieh Jiang; Londt, John; Vass, Melissa; Li, Jay; Tang Xiangyang; Okerlund, Darin

    2006-11-15

    Coronary artery imaging with x-ray computed tomography (CT) is one of the most recent advancements in CT clinical applications. Although existing ''state-of-the-art'' clinical protocols today utilize helical data acquisition, it suffers from the lack of ability to handle irregular heart rate and relatively high x-ray dose to patients. In this paper, we propose a step-and-shoot data acquisition protocol that significantly overcomes these shortcomings. The key to the proposed protocol is the large volume coverage (40 mm) enabled by the cone beam CT scanner, which allows the coverage of the entire heart in 3 to 4 steps. In addition, we propose a gated complementary reconstruction algorithm that overcomes the longitudinal truncation problem resulting from the cone beam geometry. Computer simulations, phantom experiments, and clinical studies were conducted to validate our approach.

  5. Step-and-shoot data acquisition and reconstruction for cardiac x-ray computed tomography.

    PubMed

    Hsieh, Jiang; Londt, John; Vass, Melissa; Li, Jay; Tang, Xiangyang; Okerlund, Darin

    2006-11-01

    Coronary artery imaging with x-ray computed tomography (CT) is one of the most recent advancements in CT clinical applications. Although existing "state-of-the-art" clinical protocols today utilize helical data acquisition, it suffers from the lack of ability to handle irregular heart rate and relatively high x-ray dose to patients. In this paper, we propose a step-and-shoot data acquisition protocol that significantly overcomes these shortcomings. The key to the proposed protocol is the large volume coverage (40 mm) enabled by the cone beam CT scanner, which allows the coverage of the entire heart in 3 to 4 steps. In addition, we propose a gated complementary reconstruction algorithm that overcomes the longitudinal truncation problem resulting from the cone beam geometry. Computer simulations, phantom experiments, and clinical studies were conducted to validate our approach.

  6. Calcium and IP3 dynamics in cardiac myocytes: experimental and computational perspectives and approaches.

    PubMed

    Hohendanner, Felix; McCulloch, Andrew D; Blatter, Lothar A; Michailova, Anushka P

    2014-01-01

    lays in quantitative differences of local [Ca(2+)] in the nuclear and cytosolic compartment. In this review, we discuss the state of knowledge regarding the origin and the physiological implications of nuclear Ca(2+) transients in different cardiac cell types (adult atrial and ventricular myocytes) as well as experimental and mathematical approaches to study Ca(2+) and IP3 signaling in the cytosol and nucleus. In particular, we focus on the concept that highly localized Ca(2+) signals are required to translocate and activate Ca(2+)-dependent transcription factors (e.g., nuclear factor of activated T-cells, NFAT; histone deacetylase, HDAC) through phosphorylation/dephosphorylation processes. PMID:24639654

  7. Identification of Cardiac and Aortic Injuries in Trauma with Multi-detector Computed Tomography

    PubMed Central

    Shergill, Arvind K; Maraj, Tishan; Barszczyk, Mark S; Cheung, Helen; Singh, Navneet; Zavodni, Anna E

    2015-01-01

    Blunt and penetrating cardiovascular (CV) injuries are associated with a high morbidity and mortality. Rapid detection of these injuries in trauma is critical for patient survival. The advent of multi-detector computed tomography (MDCT) has led to increased detection of CV injuries during rapid comprehensive scanning of stabilized major trauma patients. MDCT has the ability to acquire images with a higher temporal and spatial resolution, as well as the capability to create multiplanar reformats. This pictorial review illustrates several common and life-threatening traumatic CV injuries from a regional trauma center. PMID:26430541

  8. Comparison of cardiac output of the left and right side of the heart by ultrafast computed tomography

    SciTech Connect

    Wolfkiel, C.J.; Ferguson, J.L.; Law, W.R.; Chomka, E.V.; Brundage, B.H.

    1986-03-05

    Ultrafast computed tomography (CT) evaluation of cardiac output (CO) can be determined using indicator dilution theory. The concentration of an iodinated contrast agent injected into a vein of a subject can be measured as a function of time by serial EKG, gated CT imaging. The contrast density of the blood pool measured by CT defines the indicator concentration. CT CO is proportional to the area under a time density curve from a region of the blood pool. Proper subject position and scanning timing allows CT to measure CO in the pulmonary (PA) artery and the aorta (AO) with the same contrast bolus. Three anesthetized dogs were multiply scanned following simultaneous injections of contrast and radioactive tracer microspheres. Microsphere CO was determined by reference withdrawal method. Multiple thermodilution CO measurements were made just prior and after each CT CO procedure. 24 comparisons were made of thermodilution, microsphere and CT CO measured in the PA (right sided CO (RSCO)) and the AO (left sided CO (LSCO)). CT CO was calculated as the ratio of the volume of contrast injected to the time density curve area corrected for the relation of contrast density to CT number. RSCO agreed very closely to LSCO (r = .99, p < .001; y = 1.0x +/- .32). RSCO correlated to thermodilution (r = .96, p < .001; y = 1.2x +/- 1.3) and microsphere CO (r = .93, p < .001; y = .69x +/- 1.3). These data show that CT CO measurements can be made in the PA and AO with equal accuracy.

  9. Right ventricular free wall pacing improves cardiac pump function in severe pulmonary arterial hypertension: a computer simulation analysis.

    PubMed

    Lumens, Joost; Arts, Theo; Broers, Bernard; Boomars, Karin A; van Paassen, Pieter; Prinzen, Frits W; Delhaas, Tammo

    2009-12-01

    In pulmonary arterial hypertension (PAH), duration of myofiber shortening is prolonged in the right ventricular (RV) free wall (RVfw) compared with that in the interventricular septum and left ventricular free wall. This interventricular mechanical asynchrony eventually leads to right heart failure. We investigated by computer simulation whether, in PAH, early RVfw pacing may improve interventricular mechanical synchrony and, hence, cardiac pump function. A mathematical model of the human heart and circulation was used to simulate left ventricular and RV pump mechanics and myofiber mechanics. First, we simulated cardiovascular mechanics of a healthy adult at rest. Size and mass of heart and blood vessels were adapted so that mechanical tissue load was normalized. Second, compensated PAH was simulated by increasing mean pulmonary artery pressure to 32 mmHg while applying load adaptation. Third, decompensated PAH was simulated by increasing mean pulmonary artery pressure further to 79 mmHg without further adaptation. Finally, early RVfw pacing was simulated in severely decompensated PAH. Time courses of circumferential strain in the ventricular walls as simulated were similar to the ones measured in healthy subjects (uniform strain patterns) and in PAH patients (prolonged RVfw shortening). When simulating pacing in decompensated PAH, RV pump function was best upon 40-ms RVfw preexcitation, as evidenced by maximal decrease of RV end-diastolic volume, reduced RVfw myofiber work, and most homogeneous distribution of workload over the ventricular walls. Thus our simulations indicate that, in decompensated PAH, RVfw pacing may improve RV pump function and may homogenize workload over the ventricular walls.

  10. In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

    PubMed Central

    van Deel, Elza; Ridwan, Yanto; van Vliet, J. Nicole; Belenkov, Sasha; Essers, Jeroen

    2016-01-01

    The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD). PMID:26967592

  11. In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography.

    PubMed

    van Deel, Elza; Ridwan, Yanto; van Vliet, J Nicole; Belenkov, Sasha; Essers, Jeroen

    2016-01-01

    The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD). PMID:26967592

  12. The influence of novel CT reconstruction technique and ECG-gated technique on image quality and patient dose of cardiac computed tomography.

    PubMed

    Dyakov, I; Stoinova, V; Groudeva, V; Vassileva, J

    2015-07-01

    The aim of the present study was to compare image quality and patient dose in cardiac computed tomography angiography (CTA) in terms of volume computed tomography dose index (CTDI vol), dose length product (DLP) and effective dose, when changing from filtered back projection (FBP) to adaptive iterative dose reduction (AIDR) reconstruction techniques. Further aim was to implement prospective electrocardiogram (ECG) gating for patient dose reduction. The study was performed with Aquilion ONE 320-row CT of Toshiba Medical Systems. Analysis of cardiac CT protocols was performed before and after integration of the new software. The AIDR technique showed more than 50 % reduction in CTDIvol values and 57 % in effective dose. The subjective evaluation of clinical images confirmed the adequate image quality acquired by the AIDR technique. The preliminary results indicated significant dose reduction when using prospective ECG gating by keeping the adequate diagnostic quality of clinical images. PMID:25836680

  13. Propagation of Electrical Excitation in a Ring of Cardiac Cells: A Computer Simulation Study

    NASA Technical Reports Server (NTRS)

    Kogan, B. Y.; Karplus, W. J.; Karpoukhin, M. G.; Roizen, I. M.; Chudin, E.; Qu, Z.

    1996-01-01

    The propagation of electrical excitation in a ring of cells described by the Noble, Beeler-Reuter (BR), Luo-Rudy I (LR I), and third-order simplified (TOS) mathematical models is studied using computer simulation. For each of the models it is shown that after transition from steady-state circulation to quasi-periodicity achieved by shortening the ring length (RL), the action potential duration (APD) restitution curve becomes a double-valued function and is located below the original ( that of an isolated cell) APD restitution curve. The distributions of APD and diastolic interval (DI) along a ring for the entire range of RL corresponding to quasi-periodic oscillations remain periodic with the period slightly different from two RLs. The 'S' shape of the original APD restitution curve determines the appearance of the second steady-state circulation region for short RLs. For all the models and the wide variety of their original APD restitution curves, no transition from quasi-periodicity to chaos was observed.

  14. Genome-wide Computational Analysis Reveals Cardiomyocyte-specific Transcriptional Cis-regulatory Motifs That Enable Efficient Cardiac Gene Therapy

    PubMed Central

    Rincon, Melvin Y; Sarcar, Shilpita; Danso-Abeam, Dina; Keyaerts, Marleen; Matrai, Janka; Samara-Kuko, Ermira; Acosta-Sanchez, Abel; Athanasopoulos, Takis; Dickson, George; Lahoutte, Tony; De Bleser, Pieter; VandenDriessche, Thierry; Chuah, Marinee K

    2015-01-01

    Gene therapy is a promising emerging therapeutic modality for the treatment of cardiovascular diseases and hereditary diseases that afflict the heart. Hence, there is a need to develop robust cardiac-specific expression modules that allow for stable expression of the gene of interest in cardiomyocytes. We therefore explored a new approach based on a genome-wide bioinformatics strategy that revealed novel cardiac-specific cis-acting regulatory modules (CS-CRMs). These transcriptional modules contained evolutionary-conserved clusters of putative transcription factor binding sites that correspond to a “molecular signature” associated with robust gene expression in the heart. We then validated these CS-CRMs in vivo using an adeno-associated viral vector serotype 9 that drives a reporter gene from a quintessential cardiac-specific α-myosin heavy chain promoter. Most de novo designed CS-CRMs resulted in a >10-fold increase in cardiac gene expression. The most robust CRMs enhanced cardiac-specific transcription 70- to 100-fold. Expression was sustained and restricted to cardiomyocytes. We then combined the most potent CS-CRM4 with a synthetic heart and muscle-specific promoter (SPc5-12) and obtained a significant 20-fold increase in cardiac gene expression compared to the cytomegalovirus promoter. This study underscores the potential of rational vector design to improve the robustness of cardiac gene therapy. PMID:25195597

  15. Genome-wide computational analysis reveals cardiomyocyte-specific transcriptional Cis-regulatory motifs that enable efficient cardiac gene therapy.

    PubMed

    Rincon, Melvin Y; Sarcar, Shilpita; Danso-Abeam, Dina; Keyaerts, Marleen; Matrai, Janka; Samara-Kuko, Ermira; Acosta-Sanchez, Abel; Athanasopoulos, Takis; Dickson, George; Lahoutte, Tony; De Bleser, Pieter; VandenDriessche, Thierry; Chuah, Marinee K

    2015-01-01

    Gene therapy is a promising emerging therapeutic modality for the treatment of cardiovascular diseases and hereditary diseases that afflict the heart. Hence, there is a need to develop robust cardiac-specific expression modules that allow for stable expression of the gene of interest in cardiomyocytes. We therefore explored a new approach based on a genome-wide bioinformatics strategy that revealed novel cardiac-specific cis-acting regulatory modules (CS-CRMs). These transcriptional modules contained evolutionary-conserved clusters of putative transcription factor binding sites that correspond to a "molecular signature" associated with robust gene expression in the heart. We then validated these CS-CRMs in vivo using an adeno-associated viral vector serotype 9 that drives a reporter gene from a quintessential cardiac-specific α-myosin heavy chain promoter. Most de novo designed CS-CRMs resulted in a >10-fold increase in cardiac gene expression. The most robust CRMs enhanced cardiac-specific transcription 70- to 100-fold. Expression was sustained and restricted to cardiomyocytes. We then combined the most potent CS-CRM4 with a synthetic heart and muscle-specific promoter (SPc5-12) and obtained a significant 20-fold increase in cardiac gene expression compared to the cytomegalovirus promoter. This study underscores the potential of rational vector design to improve the robustness of cardiac gene therapy.

  16. Noninvasive Three-dimensional Cardiac Activation Imaging from Body Surface Potential Maps: A Computational and Experimental Study on a Rabbit Model

    PubMed Central

    Han, Chengzong; Liu, Zhongming; Zhang, Xin; Pogwizd, Steven; He, Bin

    2009-01-01

    Three-dimensional (3-D) cardiac activation imaging (3-DCAI) is a recently developed technique that aims at imaging the activation sequence throughout the 3-D volume of myocardium. 3-DCAI entails the modeling and estimation of the cardiac equivalent current density (ECD) distribution from which the local activation time within myocardium is determined as the time point with the peak amplitude of local ECD estimates. In this paper, we report, for the first time, an experimental study of the performance and applicability of 3-DCAI as judged by measured 3-D cardiac activation sequence using 3-D intra-cardiac mapping, in a group of 4 healthy rabbits during ventricular pacing. During the experiments, the body surface potentials and the intramural bipolar electrical recordings were simultaneously measured in a closed-chest condition to allow for a rigorous evaluation of the noninvasive 3-DCAI algorithm using the intra-cardiac mapping. The ventricular activation sequence non-invasively imaged from the body surface measurements by using 3-DCAI was generally in agreement with that obtained from the invasive intra-cardiac recordings. The overall difference between them, quantified as the root mean square (RMS) error, was 7.42±0.61 ms, and the normalized difference, quantified as the relative error (RE), was 0.24±0.03. The distance from the reconstructed site of initial activation to the actual pacing site, defined as the localization error (LE), was 5.47±1.57 mm. In addition, computer simulations were conducted to provide additional assessment of the performance of the 3-DCAI algorithm using a realistic-geometry rabbit heart-torso model. Averaged over 9 pacing sites, the RE and LE were 0.20±0.07 and 4.56±1.12 mm, respectively, for single-pacing, when 20 μV Gaussian white noise was added to the body surface potentials at 53 body surface locations. Averaged over 8 pairs of dual pacing, the RE was 0.25±0.06 for 20 μV additive noise. The present results obtained through

  17. Marketing cardiac CT programs.

    PubMed

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

  18. Computer-assisted diagnosis for chronic heart failure by the analysis of their cardiac reserve and heart sound characteristics.

    PubMed

    Zheng, Yineng; Guo, Xingming; Qin, Jian; Xiao, Shouzhong

    2015-12-01

    An innovative computer-assisted diagnosis system for chronic heart failure (CHF) was proposed in this study, based on cardiac reserve (CR) indexes extraction, heart sound hybrid characteristics extraction and intelligent diagnosis model definition. Firstly, the modified wavelet packet-based denoising method was applied to data pre-processing. Then, the CR indexes such as the ratio of diastolic to systolic duration (D/S) and the amplitude ratio of the first to second heart sound (S1/S2) were extracted. The feature set consisting of the heart sound characteristics such as multifractal spectrum parameters, the frequency corresponding to the maximum peak of the normalized PSD curve (fPSDmax) and adaptive sub-band energy fraction (sub_EF) were calculated based on multifractal detrended fluctuation analysis (MF-DFA), maximum entropy spectra estimation (MESE) and empirical mode decomposition (EMD). Statistical methods such as t-test and receiver operating characteristic (ROC) curve analysis were performed to analyze the difference of each parameter between the healthy and CHF patients. Finally, least square support vector machine (LS-SVM) was employed for the implementation of intelligent diagnosis. The result indicates the achieved diagnostic accuracy, sensitivity and specificity of the proposed system are 95.39%, 96.59% and 93.75% for the detection of CHF, respectively. The selected cutoff values of the diagnosis features are D/S=1.59, S1/S2=1.31, Δα=1.34 and fPSDmax=22.49, determined by ROC curve analysis. This study suggests the proposed methodology could provide a technical clue for the CHF point-of-care system design and be a supplement for CHF diagnosis. PMID:26387633

  19. Cardiac rehabilitation

    MedlinePlus

    ... Coronary artery disease - cardiac rehab; Angina - cardiac rehab; Heart failure - cardiac rehab ... have had: Heart attack Coronary heart disease (CHD) Heart failure Angina (chest pain) Heart or heart valve surgery ...

  20. The Cardiac Atlas Project—an imaging database for computational modeling and statistical atlases of the heart

    PubMed Central

    Fonseca, Carissa G.; Backhaus, Michael; Bluemke, David A.; Britten, Randall D.; Chung, Jae Do; Cowan, Brett R.; Dinov, Ivo D.; Finn, J. Paul; Hunter, Peter J.; Kadish, Alan H.; Lee, Daniel C.; Lima, Joao A. C.; Medrano−Gracia, Pau; Shivkumar, Kalyanam; Suinesiaputra, Avan; Tao, Wenchao; Young, Alistair A.

    2011-01-01

    Motivation: Integrative mathematical and statistical models of cardiac anatomy and physiology can play a vital role in understanding cardiac disease phenotype and planning therapeutic strategies. However, the accuracy and predictive power of such models is dependent upon the breadth and depth of noninvasive imaging datasets. The Cardiac Atlas Project (CAP) has established a large-scale database of cardiac imaging examinations and associated clinical data in order to develop a shareable, web-accessible, structural and functional atlas of the normal and pathological heart for clinical, research and educational purposes. A goal of CAP is to facilitate collaborative statistical analysis of regional heart shape and wall motion and characterize cardiac function among and within population groups. Results: Three main open-source software components were developed: (i) a database with web-interface; (ii) a modeling client for 3D + time visualization and parametric description of shape and motion; and (iii) open data formats for semantic characterization of models and annotations. The database was implemented using a three-tier architecture utilizing MySQL, JBoss and Dcm4chee, in compliance with the DICOM standard to provide compatibility with existing clinical networks and devices. Parts of Dcm4chee were extended to access image specific attributes as search parameters. To date, approximately 3000 de-identified cardiac imaging examinations are available in the database. All software components developed by the CAP are open source and are freely available under the Mozilla Public License Version 1.1 (http://www.mozilla.org/MPL/MPL-1.1.txt). Availability: http://www.cardiacatlas.org Contact: a.young@auckland.ac.nz Supplementary information: Supplementary data are available at Bioinformatics online. PMID:21737439

  1. Temporal resolution improvement using PICCS in MDCT cardiac imaging.

    PubMed

    Chen, Guang-Hong; Tang, Jie; Hsieh, Jiang

    2009-06-01

    The current paradigm for temporal resolution improvement is to add more source-detector units and/or increase the gantry rotation speed. The purpose of this article is to present an innovative alternative method to potentially improve temporal resolution by approximately a factor of 2 for all MDCT scanners without requiring hardware modification. The central enabling technology is a most recently developed image reconstruction method: Prior image constrained compressed sensing (PICCS). Using the method, cardiac CT images can be accurately reconstructed using the projection data acquired in an angular range of about 120 degrees, which is roughly 50% of the standard short-scan angular range (approximately 240 degrees for an MDCT scanner). As a result, the temporal resolution of MDCT cardiac imaging can be universally improved by approximately a factor of 2. In order to validate the proposed method, two in vivo animal experiments were conducted using a state-of-the-art 64-slice CT scanner (GE Healthcare, Waukesha, WI) at different gantry rotation times and different heart rates. One animal was scanned at heart rate of 83 beats per minute (bpm) using 400 ms gantry rotation time and the second animal was scanned at 94 bpm using 350 ms gantry rotation time, respectively. Cardiac coronary CT imaging can be successfully performed at high heart rates using a single-source MDCT scanner and projection data from a single heart beat with gantry rotation times of 400 and 350 ms. Using the proposed PICCS method, the temporal resolution of cardiac CT imaging can be effectively improved by approximately a factor of 2 without modifying any scanner hardware. This potentially provides a new method for single-source MDCT scanners to achieve reliable coronary CT imaging for patients at higher heart rates than the current heart rate limit of 70 bpm without using the well-known multisegment FBP reconstruction algorithm. This method also enables dual-source MDCT scanner to achieve higher

  2. Quantitative Analysis of Intraventricular Dyssynchrony Using Wall Thickness by Multidetector Computed Tomography

    PubMed Central

    Truong, Quynh A.; Singh, Jagmeet P.; Cannon, Christopher P.; Sarwar, Ammar; Nasir, Khurram; Auricchio, Angelo; Faletra, Francesco F.; Sorgente, Antonio; Conca, Cristina; Moccetti, Tiziano; Handschumacher, Mark; Brady, Thomas J.; Hoffmann, Udo

    2009-01-01

    OBJECTIVES We sought to determine the feasibility of cardiac computed tomography (CT) to detect significant differences in the extent of left ventricular dyssynchrony in heart failure (HF) patients with wide QRS, HF patients with narrow QRS, and age-matched controls. BACKGROUND The degree of mechanical dyssynchrony has been suggested as a predictor of response to cardiac resynchronization therapy. There have been no published reports of dyssynchrony assessment with the use of CT. METHODS Thirty-eight subjects underwent electrocardiogram-gated contrast-enhanced 64-slice multidetector CT. The left ventricular endocardial and epicardial boundaries were delineated from short-axis images reconstructed at 10% phase increments of the cardiac cycle. Global and segmental CT dyssynchrony metrics that used changes in wall thickness, wall motion, and volume over time were assessed for reproducibility. We defined a global metric using changes in wall thickness as the dyssynchrony index (DI). RESULTS The DI was the most reproducible metric (interobserver and intraobserver intraclass correlation coefficients ≥0.94, p < 0.0001) and was used to determine differences between the 3 groups: HF-wide QRS group (ejection fraction [EF] 22 ± 8%, QRS 163 ± 28 ms), HF-narrow QRS (EF 26 ± 7%, QRS 96 ± 11 ms), and age-matched control subjects (EF 64 ± 5%, QRS 87 ± 9 ms). Mean DI was significantly different between the 3 groups (HF-wide QRS: 152 ± 44 ms, HF-narrow QRS: 121 ± 58 ms, and control subjects: 65 ± 12 ms; p < 0.0001) and greater in the HF-wide QRS (p < 0.0001) and HF-narrow QRS (p = 0.005) groups compared with control subjects. We found that DI had a good correlation with 2-dimensional (r = 0.65, p = 0.012) and 3-dimensional (r = 0.68, p = 0.008) echocardiographic dyssynchrony. CONCLUSIONS Quantitative assessment of global CT-derived DI, based on changes in wall thickness over time, is highly reproducible and renders significant differences between subjects most likely to

  3. Computed tomography-guided in vivo cardiac orientation and correlation with ECG in individuals without structural heart disease and in age-matched obese and older individuals.

    PubMed

    Sathananthan, Gnalini; Aggarwal, Gunjan; Zahid, Simmi; Byth, Karen; Chik, William; Friedman, Daniel; Thiagalingam, Aravinda

    2015-05-01

    The cardiac axis in a structurally normal heart is influenced by a number of factors. We investigated the anatomical and electrical cardiac axes in middle-aged individuals without structural heart disease and compared this with age-matched obese and older individuals without structural heart disease. A retrospective study of controls included those between 30 and 60 years old with a normal body mass index (BMI), who were then compared with obese individuals between 30 and 60 years old and with individuals more than 60 years old with a normal BMI. The anatomical cardiac axis was determined along the long axis by cardiac computed tomography (CT) and correlated with the electrical cardiac axis on a surface electrocardiogram (ECG) in the frontal plane. A total of 124 patients were included. In the controls (n = 59), the mean CT axis was 38.1° ± 7.8° whilst the mean ECG axis was 51.8° ± 26.6°, Pearson r value 0.12 (P = 0.365). In the obese (n = 36), the mean CT axis was 25.1° ± 6.2° whilst the mean ECG axis was 20.1° ± 23.9°, Pearson r value 0.05 (P = 0.808). In the older group (n = 29), the mean CT axis was 34.4° ± 9.1° whilst the mean ECG axis was 34.4° ± 30.3°, Pearson r value 0.26 (P = 0.209). Obese individuals have a more leftward rotation of both axes than age-matched normals (P <0.0001), which could be secondary to elevation of the diaphragm. Older individuals have a more leftward rotation only of their electrical cardiac axis (P = 0.01), which could be a normal variant or reflect underlying conduction disturbances in this age group.

  4. Usefulness of Multidetector Row Computed Tomography for Predicting Cardiac Events in Asymptomatic Chronic Kidney Disease Patients at the Initiation of Renal Replacement Therapy

    PubMed Central

    Lee, Jung Eun; Lee, Yong Kyu; Choi, Eun Jeong; Nam, Ji Sun; Choi, Byoung Wook

    2013-01-01

    Background. The prevalence of coronary artery stenosis (CAS) at the initiation of renal replacement therapy (RRT) in chronic kidney disease (CKD) patients has not been fully elucidated. Although coronary angiography is the gold standard in diagnosing CAS its invasiveness and economic burden lead to searching for a noninvasive alternative method. In this study, we evaluated the prevalence of CAS by multidetector row computed tomography (MDCT) and related risk factor to articulate the usefulness of MDCT. Method. Seventy-four asymptomatic CKD patients who began dialysis were evaluated with echocardiography and MDCT. The patients were stratified into two groups according to CAS and coronary artery calcification score (CACS) by MDCT to detect silent CAS and evaluate its predictability for cardiac events. Results. CAS was seen in 24 (32.4%) of 74 asymptomatic CKD patients on MDCT. Both groups showed increasing frequencies of CAS with age (P < 0.01), presence of diabetes (P < 0.05), uric acid level (P < 0.01), and calcium score (P < 0.01). Multiple regression analysis revealed that age and uric acid level were independent risk factors for CAS and high CACS in asymptomatic CKD patients at the initiation of dialysis. Patients with both CAS and high CACS were presented with higher cardiac events rates compared to those without any of them. In Cox regression model, age and the presence of CAS and high CACS on MDCT were an independent risk factor for cardiac events in these patients. Conclusion. We showed that CAS was highly seen in asymptomatic CKD patients starting dialysis. Moreover, both high CACS and CAS on MDCT might predict cardiac events in these patients and MDCT can be a useful screening tool for evaluating coronary artery disease and predicting cardiovascular mortality noninvasively. PMID:24363626

  5. Biomechanics of Early Cardiac Development

    PubMed Central

    Goenezen, Sevan; Rennie, Monique Y.

    2012-01-01

    Biomechanics affect early cardiac development, from looping to the development of chambers and valves. Hemodynamic forces are essential for proper cardiac development, and their disruption leads to congenital heart defects. A wealth of information already exists on early cardiac adaptations to hemodynamic loading, and new technologies, including high resolution imaging modalities and computational modeling, are enabling a more thorough understanding of relationships between hemodynamics and cardiac development. Imaging and modeling approaches, used in combination with biological data on cell behavior and adaptation, are paving the road for new discoveries on links between biomechanics and biology and their effect on cardiac development and fetal programming. PMID:22760547

  6. Comparative cardiac imaging

    SciTech Connect

    Brundage, B.H.

    1990-01-01

    This book is designed to compare all major cardiac imaging techniques. All major imaging techniques - including conventional angiography, digital angiography, echocardiography and Doppler imaging, conventional radioisotope techniques, computed tomography, and magnetic resonance imaging - are covered in this text as they apply to the major cardiovascular disorders. There is brief coverage of positron emission tomography and an extensive presentation of ultrafast computed tomography.

  7. Data analysis in cardiac arrhythmias.

    PubMed

    Rodrigo, Miguel; Pedrón-Torecilla, Jorge; Hernández, Ismael; Liberos, Alejandro; Climent, Andreu M; Guillem, María S

    2015-01-01

    Cardiac arrhythmias are an increasingly present in developed countries and represent a major health and economic burden. The occurrence of cardiac arrhythmias is closely linked to the electrical function of the heart. Consequently, the analysis of the electrical signal generated by the heart tissue, either recorded invasively or noninvasively, provides valuable information for the study of cardiac arrhythmias. In this chapter, novel cardiac signal analysis techniques that allow the study and diagnosis of cardiac arrhythmias are described, with emphasis on cardiac mapping which allows for spatiotemporal analysis of cardiac signals.Cardiac mapping can serve as a diagnostic tool by recording cardiac signals either in close contact to the heart tissue or noninvasively from the body surface, and allows the identification of cardiac sites responsible of the development or maintenance of arrhythmias. Cardiac mapping can also be used for research in cardiac arrhythmias in order to understand their mechanisms. For this purpose, both synthetic signals generated by computer simulations and animal experimental models allow for more controlled physiological conditions and complete access to the organ.

  8. Cardiac arrest

    MedlinePlus

    ... Article.jsp. Accessed June 16, 2014. Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening ... PA: Elsevier Saunders; 2011:chap 63. Myerburg RJ, Castellanos A. Cardiac arrest and audden aardiac death. In: ...

  9. A new method for Fourier analysis in ECG-gated cardiac blood pool emission computed tomography (ECT)

    SciTech Connect

    Ito, T.; Maeda, H.; Takeda, K.; Nakagawa, T.; Yamaguchi, N.; Konishi, T.; Ichikawa, T.

    1984-01-01

    An integrated technique for Fourier analysis in multigated blood pool ECT study has been developed. Following the administration of 15-20 mCi of Tc-99m RBC, ECG-gated cardiac blood pool data were acquired using an ECT system with dual opposed gamma cameras. Fundamental studies for data acquisition showed that acquisition time of 10 sec. for each projection, 14 divisions of one cardiac cycle and angular interval of 6/sup 0/ (60 projections over 360/sup 0/) were reasonable for clinical purpose. Total acquisition time was about 5 minutes under these conditions. Data were processed as follows: 1) Transaxial (TA) tomographic images in every phase of cardiac cycle were reconstructed by convolution algorithm; 2) TA images were rotated to construct sagittal (SAG) and short axial (S-A) oblique-angle tomography which are respectively parallel and perpendicular to the long axis of either of the ventricles; 3) Images covering the portion other than the purposed ventricle were eliminated from the series of SAG images in every phase of the cycle; 4) Images in the same phase were summed to construct a series of SAG and S-A planar images; and 5) Fourier analysis was made to construct phase and amplitude images. The advantages of this method are that the phase and amplitude images from arbitrary directions can be obtained, that the region of interest can be selected on a three dimensional basis, eliminating the overlapping activity of the other ventricle or neighbouring tissues, that the diseased areas can be easily and accurately localized even in small inferior wall myocardial infarction and that patient study can be finished within 5 minutes.

  10. Relationship between left ventricular mass and coronary artery disease in young adults: a single-center study using cardiac computed tomography.

    PubMed

    Cho, Jae Yong; Sun, Joo Sung; Sur, Young Keun; Park, Jin Sun; Kang, Doo Kyoung

    2015-12-01

    We evaluated the relationship between coronary artery disease (CAD) and left ventricular mass (LVM) as measured by cardiac computed tomography (CT) in young adults ≤40 years of age. We retrospectively enrolled 490 consecutive individuals (383 males; mean age, 35.2 ± 4.4 years) who underwent cardiac CT. CAD was defined by the presence of any plaque detected by coronary CT angiography. Left ventricular (LV) function, including LVM, was automatically measured by a dedicated workstation. LVM and LVM index (LVMi) in patients with CT-detected CAD were compared to those of patients without CT-detected CAD. Logistic regression analysis was used to evaluate the relationship between cardiovascular risk factors and CAD. Fifty-five individuals had CT-detected CAD (11.2 %, 53 males). LVM measured by cardiac CT was 126.9 ± 30.0 g for males and 93.6 ± 20.9 g for females. LVM was higher (117.8 ± 30.8 vs. 133.6 ± 33.1 g, P < 0.001) in patients with CT-detected CAD compared with patients without CT-detected CAD. Obesity, hypertension, smoking, hypercholesterolemia, LVM and LVMi were predictors of CT-detected CAD. Body mass index (r = 0.237, P < 0.001) and systolic blood pressure (r = 0.281, P < 0.001) were positively correlated with LVM. In the multivariate analysis, LVM [odds ratio (OR) = 1.016] and LVMi (OR = 1.026) remained independent predictors of CAD. LVM and LVMi in patients with CT-detected CAD were higher than that of patients without CT-detected CAD. LVM and LVMi measured by cardiac CT were independent predictors of CAD.

  11. The association between a quantitative computed tomography (CT) measurement of cerebral edema and outcomes in post-cardiac arrest – a validation study

    PubMed Central

    Cristia, Cristal; Ho, Mai-Lan; Levy, Sean; Andersen, Lars W.; Perman, Sarah M.; Giberson, Tyler; Salciccoli, Justin; Saindon, Brian Z.; Cocchi, Michael N.; Donnino, Michael W.

    2014-01-01

    Aim Previous studies have examined the association between quantitative computed tomography (CT) measures of cerebral edema and patient outcomes. It has been reported that a calculated gray matter to white matter attenuation ratio (GWR) of < 1.2 indicates a near 100% non-survivable injury post-cardiac arrest. The objective of the current study was to validate whether a GWR < 1.2 reliably indicates poor survival post-cardiac arrest. We also sought to determine the inter-rater variability among reviewers, and examine the utility of a novel GWR measurement to facilitate easier practical use. Methods We performed a retrospective analysis of post-cardiac arrest patients admitted to a single center from 2008 to 2012. Inclusion criteria were age ≥ 18 years, non-traumatic arrest, and available CT imaging within 24 hours after ROSC. Three independent physician reviewers from different specialties measured CT attenuation of pre-specified gray and white matter areas for GWR calculations. Results Out of 171 consecutive patients, 90 met the study inclusion criteria. Thirteen patients were excluded for technical reasons and/or significant additional pathology, leaving 77 head CT scans for evaluation. Median age was 66 years and 63% were male. In-hospital mortality was 65% and 70% of patients received therapeutic hypothermia. For the validation measurement, the intra-class correlation coefficient was 0.70. In our dataset, a GWR below 1.2 did not accurately predict mortality or poor neurological outcome (sensitivity 0.56–0.62 and specificity 0.63–0.81). A score below 1.1 predicted a near 100% mortality but was not a sensitive metric (sensitivity 0.14–0.20 and specificity 0.96–1.00). Similar results were found for the exploratory model. Conclusion A GWR < 1.2 on CT imaging within 24 hours after cardiac arrest was moderately specific for poor neurologic outcome and mortality. Based on our data, a threshold GWR < 1.1 may be a safer cut-off to identify patients with low

  12. Coronary artery calcium score on low-dose computed tomography for lung cancer screening

    PubMed Central

    Arcadi, Teresa; Maffei, Erica; Sverzellati, Nicola; Mantini, Cesare; Guaricci, Andrea I; Tedeschi, Carlo; Martini, Chiara; La Grutta, Ludovico; Cademartiri, Filippo

    2014-01-01

    AIM: To evaluate the feasibility of coronary artery calcium score (CACS) on low-dose non-gated chest CT (ngCCT). METHODS: Sixty consecutive individuals (30 males; 73 ± 7 years) scheduled for risk stratification by means of unenhanced ECG-triggered cardiac computed tomography (gCCT) underwent additional unenhanced ngCCT. All CT scans were performed on a 64-slice CT scanner (Somatom Sensation 64 Cardiac, Siemens, Germany). CACS was calculated using conventional methods/scores (Volume, Mass, Agatston) as previously described in literature. The CACS value obtained were compared. The Mayo Clinic classification was used to stratify cardiovascular risk based on Agatston CACS. Differences and correlations between the two methods were compared. A P-value < 0.05 was considered significant. RESULTS: Mean CACS values were significantly higher for gCCT as compared to ngCCT (Volume: 418 ± 747 vs 332 ± 597; Mass: 89 ± 151 vs 78 ± 141; Agatston: 481 ± 854 vs 428 ± 776; P < 0.05). The correlation between the two values was always very high (Volume: r = 0.95; Mass: r = 0.97; Agatston: r = 0.98). Of the 6 patients with 0 Agatston score on gCCT, 2 (33%) showed an Agatston score > 0 in the ngCCT. Of the 3 patients with 1-10 Agatston score on gCCT, 1 (33%) showed an Agatston score of 0 in the ngCCT. Overall, 23 (38%) patients were reclassified in a different cardiovascular risk category, mostly (18/23; 78%) shifting to a lower risk in the ngCCT. The estimated radiation dose was significantly higher for gCCT (DLP 115.8 ± 50.7 vs 83.8 ± 16.3; Effective dose 1.6 ± 0.7 mSv vs 1.2 ± 0.2 mSv; P < 0.01). CONCLUSION: CACS assessment is feasible on ngCCT; the variability of CACS values and the associated re-stratification of patients in cardiovascular risk groups should be taken into account. PMID:24976939

  13. Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease

    PubMed Central

    2010-01-01

    Executive Summary In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities. After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website). The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.html Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Stress Echocardiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Stress Echocardiography with Contrast for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis 64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Cardiac

  14. Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization

    SciTech Connect

    Mory, Cyril; Auvray, Vincent; Zhang, Bo; Grass, Michael; Schäfer, Dirk; Chen, S. James; Carroll, John D.; Rit, Simon; Peyrin, Françoise; Douek, Philippe; Boussel, Loïc

    2014-02-15

    Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.

  15. Cardiac Sarcoidosis.

    PubMed

    Birnie, David; Ha, Andrew C T; Gula, Lorne J; Chakrabarti, Santabhanu; Beanlands, Rob S B; Nery, Pablo

    2015-12-01

    Studies suggest clinically manifest cardiac involvement occurs in 5% of patients with pulmonary/systemic sarcoidosis. The principal manifestations of cardiac sarcoidosis (CS) are conduction abnormalities, ventricular arrhythmias, and heart failure. Data indicate that an 20% to 25% of patients with pulmonary/systemic sarcoidosis have asymptomatic (clinically silent) cardiac involvement. An international guideline for the diagnosis and management of CS recommends that patients be screened for cardiac involvement. Most studies suggest a benign prognosis for patients with clinically silent CS. Immunosuppression therapy is advocated for clinically manifest CS. Device therapy, with implantable cardioverter defibrillators, is recommended for some patients.

  16. Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) imaging in the assessment of patients presenting with chest pain suspected for acute coronary syndrome

    PubMed Central

    De Filippo, Massimo; Capasso, Raffaella

    2016-01-01

    Acute chest pain is an important clinical challenge and a major reason for presentation to the emergency department. Although multiple imaging techniques are available to assess patients with suspected acute coronary syndrome (ACS), considerable interest has been focused on the use of non-invasive imaging options as coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR). According to several recent evidences, CCTA has been shown to represent a useful tool to rapidly and accurately diagnose coronary artery disease (CAD) in patients with low to intermediate cardiovascular risk. CCTA examination has the unique ability to non-invasively depict the coronary anatomy, not only allowing visualization of the lumen of the arteries in order to detect severe stenosis or occlusion responsible of myocardial ischemia, but also allows the assessment of coronary artery wall by demonstrating the presence or absence of CAD. However, routine CCTA is not able to differentiate ischemic from non-ischemic chest pain in patients with known CAD and it does not provide any functional assessment of the heart. Conversely, CMR is considered the gold standard in the evaluation of morphology, function, viability and tissue characterization of the heart. CMR offers a wide range of tools for diagnosing myocardial infarction (MI) at least at the same time of the elevation of cardiac troponin values, differentiating infarct tissue and ischemic myocardium from normal myocardium or mimicking conditions, and distinguishing between new and old ischemic events. In high-risk patients, with acute and chronic manifestations of CAD, CMR may be preferable to CCTA, since it would allow detection, differential diagnosis, prognostic evaluation and management of MI. PMID:27500156

  17. Cardiac transplantation.

    PubMed

    Shanewise, Jack

    2004-12-01

    Cardiac transplantation is a proven, accepted mode of therapy for selected patients with end-stage heart failure, but the inadequate number of suitable donor hearts available ultimately limits its application. This chapter reviews adult cardiac transplantation, with an emphasis on the anesthetic considerations of the heart transplant operation itself.

  18. Cardiac metastases

    PubMed Central

    Bussani, R; De‐Giorgio, F; Abbate, A; Silvestri, F

    2007-01-01

    Tumours metastatic to the heart (cardiac metastases) are among the least known and highly debated issues in oncology, and few systematic studies are devoted to this topic. Although primary cardiac tumours are extremely uncommon (various postmortem studies report rates between 0.001% and 0.28%), secondary tumours are not, and at least in theory, the heart can be metastasised by any malignant neoplasm able to spread to distant sites. In general, cardiac metastases are considered to be rare; however, when sought for, the incidence seems to be not as low as expected, ranging from 2.3% and 18.3%. Although no malignant tumours are known that diffuse preferentially to the heart, some do involve the heart more often than others—for example, melanoma and mediastinal primary tumours. This paper attempts to review the pathophysiology of cardiac metastatic disease, epidemiology and clinical presentation of cardiac metastases, and pathological characterisation of the lesions. PMID:17098886

  19. Analysis of cardiac development in the turtle Emys orbicularis (Testudines: Emidydae) using 3-D computer modeling from histological sections.

    PubMed

    Bertens, Laura M F; Richardson, M K; Verbeek, F J

    2010-07-01

    In this article we present a 3-D modeling study of cardiac development in the European pond turtle, Emys orbicularis (of the reptilian order Testudines). The study is aimed at elucidating the embryonic development of the horizontal septum in the ventricle and underscoring the importance of 3-D reconstructions in studying morphogenesis. Turtles possess one common ventricle, partly divided into three cava by a vertical and a horizontal septum, of which the embryonic origins have so far not been described. We used serial sectioning and computerized high-resolution 3-D reconstructions of different developmental stages to create a chronological overview of cardiogenesis, in order to study this process. This has yielded a new understanding of the development of the horizontal septum and (directly related) the looping of the heart tube. This looping is found to be markedly different from that in the human heart, with the turtle having two clear bends in the part of the heart tube leaving the primitive ventricle, as opposed to one in humans. It is this particular looping that is responsible for the formation of the horizontal septum. In addition to our findings on the ventricular septation this study has also yielded new insights into the developmental origins of the pulmonary vein. The 3-D reconstructions were built using our platform TDR-3-D base and enabled us to study the developmental processes in specific parts of the turtle heart separately and in three dimensions, over time. The complete 3-D reconstructions have been made available to the reader via internet using our 3-D model browser application, which allows interactive viewing of the models. The browser application can be found on bio-imaging.liacs.nl/galleries/emysorbicularis/TurtleGallery.html, along with additional images of both models and histological sections and animation sequences of the models. By allowing the reader to view the material in such an interactive way, we hope to make optimal use of the

  20. Should computed tomography angiography supersede invasive coronary angiography for the evaluation of graft patency following coronary artery bypass graft surgery?

    PubMed

    Gabriel, Joseph; Klimach, Stefan; Lang, Peter; Hildick-Smith, David

    2015-08-01

    Invasive coronary angiography (ICA) has long been the established gold standard in assessing graft patency following coronary artery bypass graft (CABG). Over the past decade or so however, improvements in computed tomography angiography (CTA) technology have allowed its emergence as a useful clinical tool in graft assessment. The recent introduction of 64-slice and now 128-slice scanners into widespread distribution, and the development of 320-detector row technology allowing volumetric imaging of the entire heart at single points in time within one cardiac cycle, has increased the potential of CTA to supersede ICA in this capacity. This study sought to examine the evidence surrounding this potential. A best evidence topic was constructed according to a structured protocol. The enquiry: In [patients who have undergone coronary artery bypass graft surgery] is [computed tomography angiography or invasive coronary angiography] superior in terms of [graft patency assessment, stenosis detection, radiation exposure and complication rate]? Four hundred and twenty-four articles were identified from the search strategy. Four additional articles were identified from references of key articles. Seventeen articles selected as best evidence were tabulated. The reliability of CTA as a tool in the detection of graft patency and stenosis has continued to improve with each successive generation of multislice technology. The latest 64- and 128-slice CTA techniques are able to detect graft patency and stenosis with very high sensitivities and specificities comparable with ICA, while remaining non-invasive procedures associated with fewer complications (ICA carries a 0.08% risk of myocardial infarction and 0.7% risk of minor complications in clinically stable patients). Present limitations of the technology include the accurate visualization of distal anastomoses and clip artefacts. In addition, the capacity of diagnostic ICA to be combined simultaneously with percutaneous coronary

  1. Artificial intelligence in medicine and cardiac imaging: harnessing big data and advanced computing to provide personalized medical diagnosis and treatment.

    PubMed

    Dilsizian, Steven E; Siegel, Eliot L

    2014-01-01

    Although advances in information technology in the past decade have come in quantum leaps in nearly every aspect of our lives, they seem to be coming at a slower pace in the field of medicine. However, the implementation of electronic health records (EHR) in hospitals is increasing rapidly, accelerated by the meaningful use initiatives associated with the Center for Medicare & Medicaid Services EHR Incentive Programs. The transition to electronic medical records and availability of patient data has been associated with increases in the volume and complexity of patient information, as well as an increase in medical alerts, with resulting "alert fatigue" and increased expectations for rapid and accurate diagnosis and treatment. Unfortunately, these increased demands on health care providers create greater risk for diagnostic and therapeutic errors. In the near future, artificial intelligence (AI)/machine learning will likely assist physicians with differential diagnosis of disease, treatment options suggestions, and recommendations, and, in the case of medical imaging, with cues in image interpretation. Mining and advanced analysis of "big data" in health care provide the potential not only to perform "in silico" research but also to provide "real time" diagnostic and (potentially) therapeutic recommendations based on empirical data. "On demand" access to high-performance computing and large health care databases will support and sustain our ability to achieve personalized medicine. The IBM Jeopardy! Challenge, which pitted the best all-time human players against the Watson computer, captured the imagination of millions of people across the world and demonstrated the potential to apply AI approaches to a wide variety of subject matter, including medicine. The combination of AI, big data, and massively parallel computing offers the potential to create a revolutionary way of practicing evidence-based, personalized medicine.

  2. A multiscale computational model of spatially resolved calcium cycling in cardiac myocytes: from detailed cleft dynamics to the whole cell concentration profiles

    PubMed Central

    Vierheller, Janine; Neubert, Wilhelm; Falcke, Martin; Gilbert, Stephen H.; Chamakuri, Nagaiah

    2015-01-01

    Mathematical modeling of excitation-contraction coupling (ECC) in ventricular cardiac myocytes is a multiscale problem, and it is therefore difficult to develop spatially detailed simulation tools. ECC involves gradients on the length scale of 100 nm in dyadic spaces and concentration profiles along the 100 μm of the whole cell, as well as the sub-millisecond time scale of local concentration changes and the change of lumenal Ca2+ content within tens of seconds. Our concept for a multiscale mathematical model of Ca2+ -induced Ca2+ release (CICR) and whole cardiomyocyte electrophysiology incorporates stochastic simulation of individual LC- and RyR-channels, spatially detailed concentration dynamics in dyadic clefts, rabbit membrane potential dynamics, and a system of partial differential equations for myoplasmic and lumenal free Ca2+ and Ca2+-binding molecules in the bulk of the cell. We developed a novel computational approach to resolve the concentration gradients from dyadic space to cell level by using a quasistatic approximation within the dyad and finite element methods for integrating the partial differential equations. We show whole cell Ca2+-concentration profiles using three previously published RyR-channel Markov schemes. PMID:26441674

  3. Cardiac amyloidosis

    MedlinePlus

    ... the way electrical signals move through the heart (conduction system). This can lead to abnormal heartbeats ( arrhythmias ) ... due to medicine) Sick sinus syndrome Symptomatic cardiac conduction system disease (arrhythmias related to abnormal conduction of ...

  4. Cardiac Sarcoidosis

    MedlinePlus

    ... is Cardiac Sarcoidosis? Sarcoidosis is a poorly understood disease that commonly affects the lungs. It can also involve the lymph nodes, liver, spleen, eyes, skin, bones, salivary glands and heart. ...

  5. Diagnostic accuracy of late iodine enhancement on cardiac computed tomography with a denoise filter for the evaluation of myocardial infarction.

    PubMed

    Matsuda, Takuya; Kido, Teruhito; Itoh, Toshihide; Saeki, Hideyuki; Shigemi, Susumu; Watanabe, Kouki; Kido, Tomoyuki; Aono, Shoji; Yamamoto, Masaya; Matsuda, Takeshi; Mochizuki, Teruhito

    2015-12-01

    We evaluated the image quality and diagnostic performance of late iodine enhancement (LIE) in dual-source computed tomography (DSCT) with low kilo-voltage peak (kVp) images and a denoise filter for the detection of acute myocardial infarction (AMI) in comparison with late gadolinium enhancement (LGE) magnetic resonance imaging (MRI). The Hospital Ethics Committee approved the study protocol. Before discharge, 19 patients who received percutaneous coronary intervention after AMI underwent DSCT and 1.5 T MRI. Immediately after coronary computed tomography (CT) angiography, contrast medium was administered at a slow injection rate. LIE-CT scans were acquired via dual-energy CT and reconstructed as 100-, 140-kVp, and mixed images. An iterative three-dimensional edge-preserved smoothing filter was applied to the 100-kVp images to obtain denoised 100-kVp images. The mixed, 140-kVp, 100-kVp, and denoised 100-kVp images were assessed using contrast-to-noise ratio (CNR), and their diagnostic performance in comparison with MRI and infarcted volumes were evaluated. Three hundred four segments of 19 patients were evaluated. Fifty-three segments showed LGE in MRI. The median CNR of the mixed, 140-, 100-kVp and denoised 100-kVp images was 3.49, 1.21, 3.57, and 6.08, respectively. The median CNR was significantly higher in the denoised 100-kVp images than in the other three images (P < 0.05). The denoised 100-kVp images showed the highest diagnostic accuracy and sensitivity. The percentage of myocardium in the four CT image types was significantly correlated with the respective MRI findings. The use of a denoise filter with a low-kVp image can improve CNR, sensitivity, and accuracy in LIE-CT.

  6. Diagnostic accuracy of late iodine enhancement on cardiac computed tomography with a denoise filter for the evaluation of myocardial infarction.

    PubMed

    Matsuda, Takuya; Kido, Teruhito; Itoh, Toshihide; Saeki, Hideyuki; Shigemi, Susumu; Watanabe, Kouki; Kido, Tomoyuki; Aono, Shoji; Yamamoto, Masaya; Matsuda, Takeshi; Mochizuki, Teruhito

    2015-12-01

    We evaluated the image quality and diagnostic performance of late iodine enhancement (LIE) in dual-source computed tomography (DSCT) with low kilo-voltage peak (kVp) images and a denoise filter for the detection of acute myocardial infarction (AMI) in comparison with late gadolinium enhancement (LGE) magnetic resonance imaging (MRI). The Hospital Ethics Committee approved the study protocol. Before discharge, 19 patients who received percutaneous coronary intervention after AMI underwent DSCT and 1.5 T MRI. Immediately after coronary computed tomography (CT) angiography, contrast medium was administered at a slow injection rate. LIE-CT scans were acquired via dual-energy CT and reconstructed as 100-, 140-kVp, and mixed images. An iterative three-dimensional edge-preserved smoothing filter was applied to the 100-kVp images to obtain denoised 100-kVp images. The mixed, 140-kVp, 100-kVp, and denoised 100-kVp images were assessed using contrast-to-noise ratio (CNR), and their diagnostic performance in comparison with MRI and infarcted volumes were evaluated. Three hundred four segments of 19 patients were evaluated. Fifty-three segments showed LGE in MRI. The median CNR of the mixed, 140-, 100-kVp and denoised 100-kVp images was 3.49, 1.21, 3.57, and 6.08, respectively. The median CNR was significantly higher in the denoised 100-kVp images than in the other three images (P < 0.05). The denoised 100-kVp images showed the highest diagnostic accuracy and sensitivity. The percentage of myocardium in the four CT image types was significantly correlated with the respective MRI findings. The use of a denoise filter with a low-kVp image can improve CNR, sensitivity, and accuracy in LIE-CT. PMID:26202159

  7. Pulmonary Findings on Computed Tomography in Asymptomatic Total Joint Arthroplasty Patients.

    PubMed

    Vigdorchik, Jonathan M; Riesgo, Aldo M; Lincoln, Denis; Markel, David C

    2016-08-01

    An increase in the diagnosis of pulmonary embolus (PE) in the early postoperative period has been attributed to the use of multidetector 64-slice computed tomographic (CT) scans. It was suspected that this finding was the result of marrow or fat emboli that are commonly associated with arthroplasty rather than a true venous thromboembolic phenomenon. The purpose of this study was to determine the baseline pulmonary findings in asymptomatic patients after total joint arthroplasty (TJA). Over a 1-year period, an institutional review board-approved prospective study of 20 asymptomatic patients using a multidetector 64-slice CT scanner was performed. Overall, 15 TKAs and 5 total hip arthroplasties were included for analysis. All of the CT scans were negative for PE. There were no signs of microemboli or fat emboli on any scan. No patient went on to develop a PE at 2 years postoperatively. Despite the fact that emboli are created during TJA, if emboli are seen on a CT scan postoperatively, they should be assumed to be real events with clinical sequelae. If pulmonary symptoms develop postoperatively, they should not simply be assumed to be the result of fat or marrow embolism.

  8. Prevalence of coronary artery ectasia in older adults and the relationship with epicardial fat volume by cardiac computed tomography angiography

    PubMed Central

    Yang, Jun-Jie; Yang, Xia; Chen, Zhi-Ye; Wang, Qi; He, Bai; Du, Luo-Shan; Chen, Yun-Dai

    2013-01-01

    Objective Coronary artery ectasia (CAE) refers to abnormal dilation of coronary artery segments to 1.5 times of adjacent normal ones. Epicardial fat is associated with cardiovascular risk factors. The relationship between CAE and epicardial fat has not yet been investigated. This study aimed to assess the relationship between CAE and epicardial fat volume (EFV) in older people by dual-source computed tomography coronary angiography (CTCA). Methods We prospectively enrolled 1400 older adults who were scheduled for dual-source CTCA. Under reconstruction protocols, patients with abnormal segments 1.5 times larger than the adjacent segments were accepted as CAE. EFV was measured by semi-automated software. Traditional risk factors in CAE patients, as well as the extent of EFV, were analyzed and compared to non-CAE group. Results A total of 885 male and 515 female older patients were enrolled. CAE was identified by univariable analysis in 131 patients and significantly correlated to hypertension, smoking, hyperlipidemia, prior percutaneous coronary intervention and ascending aorta aneurysm. EFV was shown to be significantly higher in CAE patients than patients without ectasia. In multivariable analyses, EFV (P = 0.018), hypertension (P < 0.001) and hyperlipidemia (P < 0.001) were significantly correlated to CAE. There was a significant negative correlation between EFV and Markis classification. Conclusions CAE can be reliably recognized by dual-source CTCA. Epicardial fat might play a role in etiopathogenesis and progression of CAE, providing a new target for treating ectasia. PMID:23610568

  9. A quality improvement project for reducing cardiac computed tomography radiation dose in a community-based, multihospital setting.

    PubMed

    Winchester, David E; Chauffe, Ryan J; Liu, Tong; Badiye, Amit; Patel, Mrugesh; Bello, David

    2013-06-01

    Radiation associated with computed tomography coronary angiography (CTCA) is a persistent concern. Strategies for reducing radiation exposure have been described, primarily in academic settings. We developed a standard protocol for CTCA acquisition focused on radiation reduction strategies in a community-based, multihospital setting and hypothesized that the protocol would be effective at reducing radiation in this setting. The protocol included the use of body mass index based tube voltage adjustment and routine use of prospective electrocardiographic gating with either dose modulation or step-and-shoot acquisition. Data on radiation exposure were collected retrospectively and compared by nonparametric testing. Some hospitals failed to routinely record radiation exposure data; only 2 facilities had data available from both before and after the intervention for direct comparison. Data were acquired from 124 subjects, 41 from the standard of care group and 83 scanned under the new protocol. In hospital A, radiation was significantly reduced by 61% from 20.5 ± 4.6 millisieverts (mSv) to 7.9 ± 4.8 mSv (P < 0.001). Within the new protocol group for hospital A, radiation was lower with step-and-shoot (4.0 ± 1.5 mSv) as compared to dose modulation (10.2 ± 4.2 mSv, P < 0.001). In hospital B, which already employed step-and-shoot acquisition, radiation dose was reduced 16% from 9.3 ± 3.0 mSv to 7.9 ± 2.2 mSv (P < 0.017) by applying body mass index-based tube voltage adjustment alone. In conclusion, a minimal investment in institutional resources can result in a reduction in radiation exposure from CTCA, even in a community-based, multihospital setting. Some facilities do not routinely record radiation exposure data. PMID:23680808

  10. Transmural myocardial perfusion gradients in relation to coronary artery stenoses severity assessed by cardiac multidetector computed tomography.

    PubMed

    Linde, Jesper James; Kühl, Jørgen Tobias; Hove, Jens Dahlgaard; Sørgaard, Mathias; Kelbæk, Henning; Nielsen, Walter Bjørn; Kofoed, Klaus Fuglsang

    2015-01-01

    To assess the relationship between epicardial coronary artery stenosis severity and the corresponding regional transmural perfusion at rest and during adenosine stress, using multidetector computed tomography (MDCT). We evaluated the relationship between the severity of coronary artery diameter stenosis assessed by MDCT angiography and semi-quantitative myocardial MDCT perfusion in 200 symptomatic patients. The perfusion index (PI = mean myocardial attenuation density/mean left ventricular lumen attenuation density) at rest and during adenosine stress, the myocardial perfusion reserve (MPR = stress - PI/rest - PI), and the transmural perfusion ratio (TPR = subendocardium/subepicardium) were calculated. A coronary artery stenosis ≥50 % was present in 49 patients (25 %). Rest-PI and rest-TPR values were similar in patients with and without a coronary artery stenosis ≥50 %, whereas stress-PI, stress-TPR and MPR were significantly reduced in patients with a stenosis ≥50 % (p < 0.001, p < 0.0001 and p = 0.02, respectively). Subendocardial PI was significantly higher than subepicardial PI at rest and during stress for patients without a significant stenosis, whereas this difference was blurred during stress in patients with ≥50 % stenosis. In a broad spectrum of stenosis severity groups, TPR at rest remained unchanged until the group of patients with total occlusions, whereas TPR during stress decreased progressively when a threshold of 50 % was superseded. In this study we establish the relationship between semi-quantitative perfusion measurements by MDCT and severity of coronary artery stenoses and find the transmural myocardial perfusion ratio to be a potential strong functional index of the hemodynamic significance of coronary artery atherosclerotic lesions.

  11. Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

    PubMed

    Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

    2016-02-01

    Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed.

  12. Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

    PubMed

    Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

    2016-02-01

    Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed. PMID:26774540

  13. [Cardiac amyloidosis].

    PubMed

    Hoyer, Caroline; Angermann, Christiane E; Knop, Stefan; Ertl, Georg; Störk, Stefan

    2008-03-15

    Amyloidoses are a heterogeneous group of multisystem disorders, which are characterized by an extracellular deposition of amyloid fibrils. Typically affected are the heart, liver, kidneys, and nervous system. More than half of the patients die due to cardiac involvement. Clinical signs of cardiac amyloidosis are edema of the lower limbs, hepatomegaly, ascites and elevated jugular vein pressure, frequently in combination with dyspnea. There can also be chest pain, probably due to microvessel disease. Dysfunction of the autonomous nervous system or arrhythmias may cause low blood pressure, dizziness, or recurrent syncope. The AL amyloidosis caused by the deposition of immunoglobulin light chains is the most common form. It can be performed by monoclonal gammopathy. The desirable treatment therapy consists of high-dose melphalan therapy twice followed by autologous stem cell transplantation. Due to the high peritransplantation mortality, selection of appropriate patients is mandatory. The ATTR amyloidosis is an autosomal dominant disorder caused by the amyloidogenic form of transthyretin, a plasmaprotein that is synthesized in the liver. Therefore, liver transplantation is the only curative therapy. The symptomatic treatment of cardiac amyloidosis is based on the current guidelines for chronic heart failure according to the patient's New York Heart Association (NYHA) state. Further types of amyloidosis with possible cardiac involvement comprise the senile systemic amyloidosis caused by the wild-type transthyretin, secondary amyloidosis after chronic systemic inflammation, and the beta(2)-microglobulin amyloidosis after long-term dialysis treatment. PMID:18344065

  14. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Inverse computation for cardiac sources using single current dipole and current multipole models

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Ma, Ping; Lu, Hong; Tang, Xue-Zheng; Hua, Ning; Tang, Fa-Kuan

    2009-12-01

    Two cardiac functional models are constructed in this paper. One is a single current model and the other is a current multipole model. Parameters denoting the properties of these two models are calculated by a least-square fit to the measurements using a simulated annealing algorithm. The measured signals are detected at 36 observation nodes by a superconducting quantum interference device (SQUID). By studying the trends of position, orientation and magnitude of the single current dipole model and the current multipole model in the QRS complex during one time span and comparing the reconstructed magnetocardiography (MCG) of these two cardiac models, we find that the current multipole model is a more appropriate model to represent cardiac electrophysiological activity.

  15. Cardiac dosimetric evaluation of deep inspiration breath-hold level variances using computed tomography scans generated from deformable image registration displacement vectors.

    PubMed

    Harry, Taylor; Rahn, Doug; Semenov, Denis; Gu, Xuejun; Yashar, Catheryn; Einck, John; Jiang, Steve; Cerviño, Laura

    2016-01-01

    There is a reduction in cardiac dose for left-sided breast radiotherapy during treatment with deep inspiration breath-hold (DIBH) when compared with treatment with free breathing (FB). Various levels of DIBH may occur for different treatment fractions. Dosimetric effects due to this and other motions are a major component of uncertainty in radiotherapy in this setting. Recent developments in deformable registration techniques allow displacement vectors between various temporal and spatial patient representations to be digitally quantified. We propose a method to evaluate the dosimetric effect to the heart from variable reproducibility of DIBH by using deformable registration to create new anatomical computed tomography (CT) scans. From deformable registration, 3-dimensional deformation vectors are generated with FB and DIBH. The obtained deformation vectors are scaled to 75%, 90%, and 110% and are applied to the reference image to create new CT scans at these inspirational levels. The scans are then imported into the treatment planning system and dose calculations are performed. The average mean dose to the heart was 2.5Gy (0.7 to 9.6Gy) at FB, 1.2Gy (0.6 to 3.8Gy, p < 0.001) at 75% inspiration, 1.1Gy (0.6 to 3.1Gy, p = 0.004) at 90% inspiration, 1.0Gy (0.6 to 3.0Gy) at 100% inspiration or DIBH, and 1.0Gy (0.6 to 2.8Gy, p = 0.019) at 110% inspiration. The average mean dose to the left anterior descending artery (LAD) was 19.9Gy (2.4 to 46.4Gy), 8.6Gy (2.0 to 43.8Gy, p < 0.001), 7.2Gy (1.9 to 40.1Gy, p = 0.035), 6.5Gy (1.8 to 34.7Gy), and 5.3Gy (1.5 to 31.5Gy, p < 0.001), correspondingly. This novel method enables numerous anatomical situations to be mimicked and quantifies the dosimetric effect they have on a treatment plan. PMID:26206154

  16. Comparison of accuracy of aortic root annulus assessment with cardiac magnetic resonance versus echocardiography and multidetector computed tomography in patients referred for transcatheter aortic valve implantation.

    PubMed

    Pontone, Gianluca; Andreini, Daniele; Bartorelli, Antonio L; Bertella, Erika; Mushtaq, Saima; Gripari, Paola; Loguercio, Monica; Cortinovis, Sarah; Baggiano, Andrea; Conte, Edoardo; Beltrama, Virginia; Annoni, Andrea; Formenti, Alberto; Tamborini, Gloria; Muratori, Manuela; Guaricci, Andrea; Alamanni, Francesco; Ballerini, Giovanni; Pepi, Mauro

    2013-12-01

    The evaluation of the aortic root in patients referred for transcatheter aortic valve implantation is crucial. The aim of the present study was to compare the accuracy of cardiac magnetic resonance (CMR) evaluation of the aortic annulus (AoA) with transthoracic and transesophageal echocardiography and multidetector computed tomography (MDCT) in patients referred for transcatheter aortic valve implantation. In 50 patients, maximum diameter, minimum diameter and AoA, length of the left coronary, right coronary, and noncoronary aortic leaflets, degree (grades 1 to 4) of aortic leaflet calcification, and distance between AoA and coronary artery ostia were assessed. AoA maximum diameter, minimum diameter, and area by CMR were 26.4 ± 2.8 mm, 20.6 ± 2.3 mm, 449.8 ± 86.2 mm(2), respectively. The length of left coronary, right coronary, and noncoronary leaflets by CMR were 13.9 ± 2.2, 13.3 ± 2.1, and 13.4 ± 1.8 mm, respectively, whereas the score of aortic leaflet calcifications was 2.9 ± 0.8. Finally, the distances between AoA and left main and right coronary artery ostia were 16.1 ± 2.8 and 16.1 ± 4.4 mm, respectively. Regarding AoA area, transthoracic and transesophageal echocardiography showed an underestimation (p <0.01), with a moderate agreement (r: 0.5 and 0.6, respectively, p <0.01) compared with CMR. No differences and excellent correlation were observed between CMR and MDCT for all parameters (r: 0.9, p <0.01), except for aortic leaflet calcifications that were underestimated by CMR. In conclusion, aortic root assessment with CMR including AoA size, aortic leaflet length, and coronary artery ostia height is accurate compared with MDCT. CMR may be a valid imaging alternative in patients unsuitable for MDCT. PMID:24045059

  17. Cardiac dosimetric evaluation of deep inspiration breath-hold level variances using computed tomography scans generated from deformable image registration displacement vectors.

    PubMed

    Harry, Taylor; Rahn, Doug; Semenov, Denis; Gu, Xuejun; Yashar, Catheryn; Einck, John; Jiang, Steve; Cerviño, Laura

    2016-01-01

    There is a reduction in cardiac dose for left-sided breast radiotherapy during treatment with deep inspiration breath-hold (DIBH) when compared with treatment with free breathing (FB). Various levels of DIBH may occur for different treatment fractions. Dosimetric effects due to this and other motions are a major component of uncertainty in radiotherapy in this setting. Recent developments in deformable registration techniques allow displacement vectors between various temporal and spatial patient representations to be digitally quantified. We propose a method to evaluate the dosimetric effect to the heart from variable reproducibility of DIBH by using deformable registration to create new anatomical computed tomography (CT) scans. From deformable registration, 3-dimensional deformation vectors are generated with FB and DIBH. The obtained deformation vectors are scaled to 75%, 90%, and 110% and are applied to the reference image to create new CT scans at these inspirational levels. The scans are then imported into the treatment planning system and dose calculations are performed. The average mean dose to the heart was 2.5Gy (0.7 to 9.6Gy) at FB, 1.2Gy (0.6 to 3.8Gy, p < 0.001) at 75% inspiration, 1.1Gy (0.6 to 3.1Gy, p = 0.004) at 90% inspiration, 1.0Gy (0.6 to 3.0Gy) at 100% inspiration or DIBH, and 1.0Gy (0.6 to 2.8Gy, p = 0.019) at 110% inspiration. The average mean dose to the left anterior descending artery (LAD) was 19.9Gy (2.4 to 46.4Gy), 8.6Gy (2.0 to 43.8Gy, p < 0.001), 7.2Gy (1.9 to 40.1Gy, p = 0.035), 6.5Gy (1.8 to 34.7Gy), and 5.3Gy (1.5 to 31.5Gy, p < 0.001), correspondingly. This novel method enables numerous anatomical situations to be mimicked and quantifies the dosimetric effect they have on a treatment plan.

  18. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  19. Cardiac Surgery

    PubMed Central

    Weisse, Allen B.

    2011-01-01

    Well into the first decades of the 20th century, medical opinion held that any surgical attempts to treat heart disease were not only misguided, but unethical. Despite such reservations, innovative surgeons showed that heart wounds could be successfully repaired. Then, extracardiac procedures were performed to correct patent ductus arteriosus, coarctation of the aorta, and tetralogy of Fallot. Direct surgery on the heart was accomplished with closed commissurotomy for mitral stenosis. The introduction of the heart-lung machine and cardiopulmonary bypass enabled the surgical treatment of other congenital and acquired heart diseases. Advances in aortic surgery paralleled these successes. The development of coronary artery bypass grafting greatly aided the treatment of coronary heart disease. Cardiac transplantation, attempts to use the total artificial heart, and the application of ventricular assist devices have brought us to the present day. Although progress in the field of cardiovascular surgery appears to have slowed when compared with the halcyon times of the past, substantial challenges still face cardiac surgeons. It can only be hoped that sufficient resources and incentive can carry the triumphs of the 20th century into the 21st. This review covers past developments and future opportunities in cardiac surgery. PMID:22163121

  20. Electrophysiological Cardiac Modeling: A Review.

    PubMed

    Beheshti, Mohammadali; Umapathy, Karthikeyan; Krishnan, Sridhar

    2016-01-01

    Cardiac electrophysiological modeling in conjunction with experimental and clinical findings has contributed to better understanding of electrophysiological phenomena in various species. As our knowledge on underlying electrical, mechanical, and chemical processes has improved over time, mathematical models of the cardiac electrophysiology have become more realistic and detailed. These models have provided a testbed for various hypotheses and conditions that may not be easy to implement experimentally. In addition to the limitations in experimentally validating various scenarios implemented by the models, one of the major obstacles for these models is computational complexity. However, the ever-increasing computational power of supercomputers facilitates the clinical application of cardiac electrophysiological models. The potential clinical applications include testing and predicting effects of pharmaceutical agents and performing patient-specific ablation and defibrillation. A review of studies involving these models and their major findings are provided.

  1. Electrophysiological Cardiac Modeling: A Review.

    PubMed

    Beheshti, Mohammadali; Umapathy, Karthikeyan; Krishnan, Sridhar

    2016-01-01

    Cardiac electrophysiological modeling in conjunction with experimental and clinical findings has contributed to better understanding of electrophysiological phenomena in various species. As our knowledge on underlying electrical, mechanical, and chemical processes has improved over time, mathematical models of the cardiac electrophysiology have become more realistic and detailed. These models have provided a testbed for various hypotheses and conditions that may not be easy to implement experimentally. In addition to the limitations in experimentally validating various scenarios implemented by the models, one of the major obstacles for these models is computational complexity. However, the ever-increasing computational power of supercomputers facilitates the clinical application of cardiac electrophysiological models. The potential clinical applications include testing and predicting effects of pharmaceutical agents and performing patient-specific ablation and defibrillation. A review of studies involving these models and their major findings are provided. PMID:27652454

  2. Cardiac MRI

    MedlinePlus

    ... a powerful magnetic field, radio waves and a computer to produce detailed pictures of the structures within ... powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, ...

  3. Cardiac conduction system

    MedlinePlus

    The cardiac conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals ... to contract. The main components of the cardiac conduction system are the SA node, AV node, bundle ...

  4. RELATION OF LEFT VENTRICULAR MASS AND CONCENTRIC REMODELING TO EXTENT OF CORONARY ARTERY DISEASE BY COMPUTED TOMOGRAPHY IN PATIENTS WITHOUT LEFT VENTRICULAR HYPERTROPHY: ROMICAT STUDY

    PubMed Central

    Truong, Quynh A.; Toepker, Michael; Mahabadi, Amir A.; Bamberg, Fabian; Rogers, Ian S.; Blankstein, Ron; Brady, Thomas J.; Nagurney, John T.; Hoffmann, Udo

    2010-01-01

    Objective Cardiac computed tomography (CT) allows for simultaneous assessment of left ventricular mass (LVM) and coronary artery disease (CAD). We aimed to determine whether LVM, LVM index (LVMi), and the left ventricular (LV) geometric pattern of concentric remodeling are associated with the extent of CAD in patients without left ventricular hypertrophy (LVH). Methods In 348 patients from the ROMICAT trial, 64-slice CT was performed and LVM measured at end-diastole. We used 3 LVM indexation criteria to obtain 3 cohorts: LVM indexed to body surface area by echocardiography (n=337) and CT criteria (n=325), and by height2.7 (n=326). The cohorts were subdivided into concentric remodeling and normal geometry. Extent of coronary plaque was classified based on a 17-segment model, treated as a continuous variable, and stratified into 3 groups: 0 segments, 1–4 segments, >4 segments. Results Patients with >4 segments of coronary plaque had higher LVM (Δ12.8–15.1g) and LVMi (Δ4.0–5.5g/m2 and Δ2.2g/m2.7) than those without CAD (all p≤0.03). After multivariable adjustment, LVM and LVMi remained independent predictors of extent of coronary plaque, with 0.27–0.29 segments more plaque per 20 g increase of LVM (all p=0.02), 0.32–0.34 segments more plaque per 10 g/m2 increase of LVMi (both p=0.02), and 0.80 segments more plaque per 10 g/m2.7 increase of LVMi (p=0.008). Concentric remodeling patients had 1.1–1.3 segments more plaque than those with normal geometry (all p≤0.05). Patients with >4 segments of plaque had 2-fold increase odds (all p≤0.05) of having concentric remodeling as compared to those without CAD. Conclusion Increased LVM, LVMi, and concentric remodeling are associated with a greater degree of coronary plaque burden in patients without LVH. These findings could provide an indication to intensify medical therapy in patients with subclinical CAD and hypertension. PMID:19696685

  5. Mechanical regulation of cardiac development

    PubMed Central

    Lindsey, Stephanie E.; Butcher, Jonathan T.; Yalcin, Huseyin C.

    2014-01-01

    Mechanical forces are essential contributors to and unavoidable components of cardiac formation, both inducing and orchestrating local and global molecular and cellular changes. Experimental animal studies have contributed substantially to understanding the mechanobiology of heart development. More recent integration of high-resolution imaging modalities with computational modeling has greatly improved our quantitative understanding of hemodynamic flow in heart development. Merging these latest experimental technologies with molecular and genetic signaling analysis will accelerate our understanding of the relationships integrating mechanical and biological signaling for proper cardiac formation. These advances will likely be essential for clinically translatable guidance for targeted interventions to rescue malforming hearts and/or reconfigure malformed circulations for optimal performance. This review summarizes our current understanding on the levels of mechanical signaling in the heart and their roles in orchestrating cardiac development. PMID:25191277

  6. Assessment of Mitral Valve Adaptation with Gated Cardiac Computed Tomography: Validation with Three-Dimensional Echocardiography and Mechanistic Insight to Functional Mitral Regurgitation

    PubMed Central

    Beaudoin, Jonathan; Thai, Wai-Ee; Wai, Bryan; Handschumacher, Mark D.; Levine, Robert A.; Truong, Quynh A.

    2013-01-01

    Background Mitral valve (MV) enlargement is a compensatory mechanism capable of preventing functional mitral regurgitation (FMR) in dilated ventricles. Total leaflet area and its relation with closure area measured by 3D-echocardiography have been related to FMR. Whether these parameters can be assessed with other imaging modalities is not known. Our objectives are to compare cardiac CT-based measurements of MV leaflets with 3D-echocardiography and determine the relationship of these metrics to the presence of FMR. Methods and Results We used two cohorts of patients who had cardiac CT to measure MV total leaflet, closure and annulus areas. In cohort 1 (26 patients), we validated these CT metrics to 3D-echocardiography. In cohort 2 (66 patients), we assessed the relation of MV size with the presence of FMR in three populations: heart failure with FMR, heart failure without FMR, and normal controls. Cardiac CT and 3D-echocardiography produced similar results for total leaflet (R2=0.97), closure (R2=0.89) and annulus areas (R2=0.84). MV size was largest in heart failure without FMR compared with controls and FMR patients (9.1±1.7 vs 7.5±1.0 vs 8.1±0.9 cm2/m2, p<0.01). FMR patients had reduced ratios of total leaflet:closure areas and total leaflet:annulus areas when compared to patients without FMR (p<0.01). Conclusions MV size measured by CT is comparable to 3D-echocardiography. MV enlargement in cardiomyopathy suggests leaflet adaptation. Patients with FMR have inadequate adaptation as reflected by decreased ratios of leaflet area and areas determined by ventricle size (annulus and closure areas). These measurements provide additional insight into the mechanism of FMR. PMID:23873402

  7. Imaging of cardiac sarcoidosis.

    PubMed

    Erthal, Fernanda; Juneau, Daniel; Lim, Siok P; Dwivedi, Girish; Nery, Pablo B; Birnie, David; Beanlands, Rob S

    2016-09-01

    Sarcoidosis is a multisystem inflammatory disease. Cardiac involvement is described in up to 50% of the cases. The disease spectrum is wide and cardiac manifestations ranges from being asymptomatic to heart failure, arrhythmias and sudden cardiac death. The diagnosis of cardiac sarcoidosis can be challenging due to its non-specific nature and the focal involvement of the heart. In this review, we discuss the utility of a stepwise approach with multimodality cardiac imaging in the diagnosis and management of CS. PMID:27225318

  8. Integrative modeling of the cardiac ventricular myocyte

    PubMed Central

    Winslow, Raimond L.; Cortassa, Sonia; O'Rourke, Brian; Hashambhoy, Yasmin L.; Rice, John Jeremy; Greenstein, Joseph L.

    2011-01-01

    Cardiac electrophysiology is a discipline with a rich 50-year history of experimental research coupled with integrative modeling which has enabled us to achieve a quantitative understanding of the relationships between molecular function and the integrated behavior of the cardiac myocyte in health and disease. In this paper, we review the development of integrative computational models of the cardiac myocyte. We begin with a historical overview of key cardiac cell models that helped shape the field. We then narrow our focus to models of the cardiac ventricular myocyte and describe these models in the context of their subcellular functional systems including dynamic models of voltage-gated ion channels, mitochondrial energy production, ATP-dependent and electrogenic membrane transporters, intracellular Ca dynamics, mechanical contraction, and regulatory signal transduction pathways. We describe key advances and limitations of the models as well as point to new directions for future modeling research. PMID:20865780

  9. CARDIAC MUSCLE

    PubMed Central

    Sommer, Joachim R.; Johnson, Edward A.

    1968-01-01

    With light and electron microscopy a comparison has been made of the morphology of ventricular (V) and Purkinje (P) fibers of the hearts of guinea pig, rabbit, cat, dog, goat, and sheep. The criteria, previously established for the rabbit heart, that V fibers are distinguished from P fibers by the respective presence and absence of transverse tubules is shown to be true for all animals studied. No evidence was found of a permanent connection between the sarcoplasmic reticulum and the extracellular space. The sarcoplasmic reticulum (SR) of V fibers formed couplings with the sarcolemma of a transverse tubule (interior coupling) and with the peripheral sarcolemma (peripheral coupling), whereas in P fibers the SR formed only peripheral couplings. The forms of the couplings were identical. The significance, with respect to excitation-contraction coupling, of the difference in the form of the couplings in cardiac versus skeletal muscle is discussed together with the electrophysiological implications of the differing geometries of bundles of P fibers from different animals. PMID:5645545

  10. Use of 100 kV versus 120 kV in cardiac dual source computed tomography: effect on radiation dose and image quality.

    PubMed

    Blankstein, Ron; Bolen, Michael A; Pale, Rodrigo; Murphy, Meagan K; Shah, Amar B; Bezerra, Hiram G; Sarwar, Ammar; Rogers, Ian S; Hoffmann, Udo; Abbara, Suhny; Cury, Ricardo C; Brady, Thomas J

    2011-04-01

    To evaluate the effective radiation dose and image quality resulting from use of 100 vs. 120 kV among patients referred for cardiac dual source CT exam (DSCT). Prospective data was collected on 294 consecutive patients referred for DSCT. For each scan, a physician specializing in cardiac CT chose all parameters including tube current and voltage, axial versus helical acquisition, and use of tube current modulation. Lower tube voltage was selected for thinner patients or when lower radiation was desired for younger patients, particularly females. For each study, image quality (IQ) was rated on a subjective IQ score and contrast (CNR) and signal-to-noise (SNR) ratios were calculated. Tube voltage of 100 kV was used for 77 (26%) exams while 120 kV was used for 217 (74%) exams. Use of 100 kV was more common in thinner patients (weight 166 lbs vs. 199 lbs, P < .001). The effective radiation dose for the 100 and 120 kV scans was 8.5 and 15.4 mSv respectively. Among scans utilizing 100 and 120 kV, there was no difference in exam indication, use of beta blockers, heart rate, scan length and use of radiation saving techniques such as prospective ECG triggering and tube current modulation. The IQ score was significantly higher for 100 kV scans. While 100 kV scans were found to have higher image noise then those utilizing 120 kV, the contrast-to-noise and signal-to-noise were significantly higher (SNR: 9.4 vs. 8.3, P = .02; CNR: 6.9 vs. 6.0, P = .02). In selected non-obese patients, use of low kV results in a substantial reduction of radiation dose and may result in improved image quality. These results suggest that low kV should be used more frequently in non-obese patients. PMID:20721630

  11. Physics of Cardiac Arrhythmogenesis

    NASA Astrophysics Data System (ADS)

    Karma, Alain

    2013-04-01

    A normal heartbeat is orchestrated by the stable propagation of an excitation wave that produces an orderly contraction. In contrast, wave turbulence in the ventricles, clinically known as ventricular fibrillation (VF), stops the heart from pumping and is lethal without prompt defibrillation. I review experimental, computational, and theoretical studies that have shed light on complex dynamical phenomena linked to the initiation, maintenance, and control of wave turbulence. I first discuss advances made to understand the precursor state to a reentrant arrhythmia where the refractory period of cardiac tissue becomes spatiotemporally disordered; this is known as an arrhythmogenic tissue substrate. I describe observed patterns of transmembrane voltage and intracellular calcium signaling that can contribute to this substrate, and symmetry breaking instabilities to explain their formation. I then survey mechanisms of wave turbulence and discuss novel methods that exploit electrical pacing stimuli to control precursor patterns and low-energy pulsed electric fields to control turbulence.

  12. Cardiac Physiology for Radiologists: Review of Relevant Physiology for Interpretation of Cardiac MR Imaging and CT.

    PubMed

    Sheth, Pooja J; Danton, Gary H; Siegel, Yoel; Kardon, Richard E; Infante, Juan C; Ghersin, Eduard; Fishman, Joel E

    2015-01-01

    Cardiac computed tomography (CT) and magnetic resonance (MR) imaging provide clinicians with important insights into cardiac physiology and pathology. However, not all radiologists understand the language and concepts of cardiac physiology that are used daily by cardiologists. This review article covers basic cardiac physiology as it relates to cardiac CT and MR imaging. Topics include a review of the cardiac cycle and left ventricular pressure-volume loops as they relate to different pathologic states, evaluation of cardiac function, and calculation of key parameters such as left ventricular volumes and the ejection fraction. The hemodynamics of cardiac shunts are covered, with an emphasis on factors important to cardiologists, including the ratio of pulmonary flow to systemic flow. Additionally, valvular physiologic function is reexamined, with a focus on understanding pressure gradients within the heart and also the changes associated with valvular pathologic conditions, including measurement of regurgitant fractions in patients with valvular insufficiency. Understanding these basic concepts will help radiologists tailor the reporting of cardiac studies to clinically relevant information.

  13. What Is Cardiac Rehabilitation?

    MedlinePlus

    ANSWERS by heart Treatments + Tests What Is Cardiac Rehabilitation? A cardiac rehabilitation (rehab) program takes place in a hospital or ... special help in making lifestyle changes. During your rehabilitation program you’ll… • Have a medical evaluation to ...

  14. Evaluation of a novel integrated sensor system for synchronous measurement of cardiac vibrations and cardiac potentials.

    PubMed

    Chuo, Yindar; Tavakolian, Kouhyar; Kaminska, Bozena

    2011-08-01

    The measurement of human body vibrations as a result of heart beating, simultaneously with cardiac potentials have been demonstrated in past studies to bring additional value to diagnostic cardiology through the detection of irregularities in the mechanical movement of the heart. The equipment currently available to the medical community is either large and bulky or difficult to synchronize. To address this problem, a novel integrated sensor system has been developed to record cardiac vibration and cardiac potential simultaneously and synchronously from a single compact site on the chest. The developed sensor system is lightweight, small in size, and suitable for mounting on active moving patients. The sensor is evaluated for its adequacy in measuring cardiac vibrations and potentials. In this evaluation, 45 independent signal recording are studied from 15 volunteers, and the morphology of the recorded signals are analyzed qualitatively (by visual inspection) and quantitatively (by computational methods) against larger devices used in established cardiac vibration studies (reference devices). It is found that the cardiac vibration signals acquired by the integrated sensor has 92.37% and 81.76% identically identifiable systolic and diastolic cardiac complexes, respectively, when compared to the cardiac vibration signals recorded simultaneously from the reference device. Further, the cardiac potential signals acquired by the integrated sensor show a high correlation coefficient of 0.8912 and a high estimated signal-to-noise-ratio of 22.00 dB when compared to the reference electrocardiograph (non-standard leads) acquired through a common clinical machine. The results suggest that the tiny, wearable, integrated sensor system that synchronously measures cardiac vibrations and cardiac potentials may be practical for use as an alternative or assistive cardiac diagnostic tool.

  15. Cardiac ion channels

    PubMed Central

    Priest, Birgit T; McDermott, Jeff S

    2015-01-01

    Ion channels are critical for all aspects of cardiac function, including rhythmicity and contractility. Consequently, ion channels are key targets for therapeutics aimed at cardiac pathophysiologies such as atrial fibrillation or angina. At the same time, off-target interactions of drugs with cardiac ion channels can be the cause of unwanted side effects. This manuscript aims to review the physiology and pharmacology of key cardiac ion channels. The intent is to highlight recent developments for therapeutic development, as well as elucidate potential mechanisms for drug-induced cardiac side effects, rather than present an in-depth review of each channel subtype. PMID:26556552

  16. Mathematical Models of Cardiac Pacemaking Function

    NASA Astrophysics Data System (ADS)

    Li, Pan; Lines, Glenn T.; Maleckar, Mary M.; Tveito, Aslak

    2013-10-01

    Over the past half century, there has been intense and fruitful interaction between experimental and computational investigations of cardiac function. This interaction has, for example, led to deep understanding of cardiac excitation-contraction coupling; how it works, as well as how it fails. However, many lines of inquiry remain unresolved, among them the initiation of each heartbeat. The sinoatrial node, a cluster of specialized pacemaking cells in the right atrium of the heart, spontaneously generates an electro-chemical wave that spreads through the atria and through the cardiac conduction system to the ventricles, initiating the contraction of cardiac muscle essential for pumping blood to the body. Despite the fundamental importance of this primary pacemaker, this process is still not fully understood, and ionic mechanisms underlying cardiac pacemaking function are currently under heated debate. Several mathematical models of sinoatrial node cell membrane electrophysiology have been constructed as based on different experimental data sets and hypotheses. As could be expected, these differing models offer diverse predictions about cardiac pacemaking activities. This paper aims to present the current state of debate over the origins of the pacemaking function of the sinoatrial node. Here, we will specifically review the state-of-the-art of cardiac pacemaker modeling, with a special emphasis on current discrepancies, limitations, and future challenges.

  17. Image reconstruction and image quality evaluation for a 64-slice CT scanner with z-flying focal spot

    SciTech Connect

    Flohr, T.G.; Stierstorfer, K.; Ulzheimer, S.; Bruder, H.; Primak, A.N.; McCollough, C.H.

    2005-08-15

    We present a theoretical overview and a performance evaluation of a novel z-sampling technique for multidetector row CT (MDCT), relying on a periodic motion of the focal spot in the longitudinal direction (z-flying focal spot) to double the number of simultaneously acquired slices. The z-flying focal spot technique has been implemented in a recently introduced MDCT scanner. Using 32x0.6 mm collimation, this scanner acquires 64 overlapping 0.6 mm slices per rotation in its spiral (helical) mode of operation, with the goal of improved longitudinal resolution and reduction of spiral artifacts. The longitudinal sampling distance at isocenter is 0.3 mm. We discuss in detail the impact of the z-flying focal spot technique on image reconstruction. We present measurements of spiral slice sensitivity profiles (SSPs) and of longitudinal resolution, both in the isocenter and off-center. We evaluate the pitch dependence of the image noise measured in a centered 20 cm water phantom. To investigate spiral image quality we present images of an anthropomorphic thorax phantom and patient scans. The full width at half maximum (FWHM) of the spiral SSPs shows only minor variations as a function of the pitch, measured values differ by less than 0.15 mm from the nominal values 0.6, 0.75, 1, 1.5, and 2 mm. The measured FWHM of the smallest slice ranges between 0.66 and 0.68 mm at isocenter, except for pitch 0.55 (0.72 mm). In a centered z-resolution phantom, bar patterns up to 15 lp/cm can be visualized independent of the pitch, corresponding to 0.33 mm longitudinal resolution. 100 mm off-center, bar patterns up to 14 lp/cm are visible, corresponding to an object size of 0.36 mm that can be resolved in the z direction. Image noise for constant effective mAs is almost independent of the pitch. Measured values show a variation of less than 7% as a function of the pitch, which demonstrates correct utilization of the applied radiation dose at any pitch. The product of image noise and square root of the slice width (FWHM of the respective SSP) is the same constant for all slices except 0.6 mm. For the thinnest slice, relative image noise is increased by 17%. Spiral windmill-type artifacts are effectively suppressed with the z-flying focal spot technique, which has the potential to maintain a low artifact level up to pitch 1.5, in this way increasing the maximum volume coverage speed that can be clinically used.

  18. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  19. Cardiac gated ventilation

    NASA Astrophysics Data System (ADS)

    Hanson, C. William, III; Hoffman, Eric A.

    1995-05-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

  20. Fast surface alignment for cardiac spatio-temporal modeling: application to Ischemic cardiac shape modeling

    NASA Astrophysics Data System (ADS)

    Huang, Heng; Shen, Li; Zhang, Rong; Makedon, Fillia; Hettleman, Bruce; Pearlman, Justin

    2006-03-01

    The visualization and comparison of local deformation from 3D image sequences is of critical importance in understanding the etiology of Ischemic cardiac disease. In this paper we describe a framework to combine our previous fast spherical harmonic surface alignment algorithm with a new local special surface reconstruction method to reconstruct the surface of LV with Ischaemic cardiac disease. Our new surface computational model allows people to extract the valuable ischemic tissues behavior from the dynamic shape. We have demonstrated our approaches by the experiments on cardiac MRI. A brief description of motivation is put forth, as well as an overview of the approaches and some initial results are described.

  1. Modeling the isolated cardiac myocyte.

    PubMed

    Puglisi, Jose L; Wang, Fei; Bers, Donald M

    2004-01-01

    Computer modeling of cardiac myocytes has flourished in recent years. Models have evolved from mathematical descriptions of ionic channels alone to more sophisticated formulations that include calcium transport mechanisms, ATP production and metabolic pathways. The increased complexity is fueled by the new data available in the field. The continuous production of experimental data has led to the evolution of increasingly refined descriptions of the phenomena by modelers. Integrating the numerous systems involved in cardiac myocyte homeostasis makes the use of computer models necessary due to the unreliability of intuitive approaches. However the complexity of the model should not imply a cumbersome operation of the program. As with any tool, computer models have to be easy to operate or their strength will be diminished and potential users will not benefit fully from them. The contribution of the computer modeler to their respective biological fields will be more successful and enduring if modelers devote sufficient time to implement their equations into a model with user-friendly characteristics. PMID:15142742

  2. Cardiac Innervation and Sudden Cardiac Death

    PubMed Central

    Fukuda, Keiichi; Kanazawa, Hideaki; Aizawa, Yoshiyasu; Ardell, Jeffrey L.; Shivkumar, Kalyanam

    2015-01-01

    Afferent and efferent cardiac neurotransmission via the cardiac nerves intricately modulates nearly all physiological functions of the heart (chronotropy, dromotropy, lusitropy and inotropy). Afferent information from the heart is transmitted to higher levels of the nervous system for processing (intrinsic cardiac nervous system, extracardiac-intrathoracic ganglia, spinal cord, brain stem and higher centers) which ultimately results in efferent cardiomotor neural impulses (via the sympathetic and parasympathetic nerves). This system forms interacting feedback loops that provide physiological stability for maintaining normal rhythm and life-sustaining circulation. This system also ensures that there is fine-tuned regulation of sympathetic-parasympathetic balance in the heart under normal and stressed states in the short (beat to beat), intermediate (minutes-hours) and long term (days-years). This important neurovisceral /autonomic nervous system also plays a major role in the pathophysiology and progression of heart disease, including heart failure and arrhythmias leading to sudden cardiac death (SCD). Transdifferentiation of neurons in heart failure, functional denervation, cardiac and extra-cardiac neural remodeling have also been identified and characterized during the progression of disease. Recent advances in understanding the cellular and molecular processes governing innervation and the functional control of the myocardium in health and disease provides a rational mechanistic basis for development of neuraxial therapies for preventing SCD and other arrhythmias. Advances in cellular, molecular, and bioengineering realms have underscored the emergence of this area as an important avenue of scientific inquiry and therapeutic intervention. PMID:26044253

  3. Digital retrospective motion-mode display and processing of electron beam cine-computed tomography and other cross-sectional cardiac imaging techniques

    NASA Astrophysics Data System (ADS)

    Reed, Judd E.; Rumberger, John A.; Buithieu, Jean; Behrenbeck, Thomas; Breen, Jerome F.; Sheedy, Patrick F., II

    1995-05-01

    Electron beam computed tomography is unparalleled in its ability to consistently produce high quality dynamic images of the human heart. Its use in quantification of left ventricular dynamics is well established in both clinical and research applications. However, the image analysis tools supplied with the scanners offer a limited number of analysis options. They are based on embedded computer systems which have not been significantly upgraded since the scanner was introduced over a decade ago in spite of the explosive improvements in available computer power which have occured during this period. To address these shortcomings, a workstation-based ventricular analysis system has been developed at our institution. This system, which has been in use for over five years, is based on current workstation technology and therefore has benefited from the periodic upgrades in processor performance available to these systems. The dynamic image segmentation component of this system is an interactively supervised, semi-automatic surface identification and tracking system. It characterizes the endocardial and epicardial surfaces of the left ventricle as two concentric 4D hyper-space polyhedrons. Each of these polyhedrons have nearly ten thousand vertices which are deposited into a relational database. The right ventricle is also processed in a similar manner. This database is queried by other custom components which extract ventricular function parameters such as regional ejection fraction and wall stress. The interactive tool which supervises dynamic image segmentation has been enhanced with a temporal domain display. The operator interactively chooses the spatial location of the endpoints of a line segment while the corresponding space/time image is displayed. These images, with content resembling M-Mode echocardiography, benefit form electron beam computed tomography's high spatial and contrast resolution. The segmented surfaces are displayed along with the imagery. These

  4. Numerical Investigation of Macroscopic Cardiac Mechanics.

    NASA Astrophysics Data System (ADS)

    Buxton, Gavin; Balazs, Anna

    2003-03-01

    In order to gain insight into the complex interactions between electrical excitation of the myocardial tissue, the mechanical contraction of the heart muscles and cardiac fluid dynamics, three computational techniques are successfully coupled. A Gerhardt-Schuster-Tyson Cellular Automata algorithm enables the excitation kinetics of myocardial tissue to be simulated in a computationally efficient manner. The cardiac excitation spreading is then coupled with a dynamic Born Lattice Spring Model which enables the contraction of the heart muscles and their subsequent relaxation to be modelled. The velocities at the inner surfaces of the heart can then be transferred to a Lattice Boltzmann simulation of blood flow within the cardiac chambers. The interactions (and complex feedback mechanisms) between electrical excitation, mechanical deformation, and fluid flow in the heart are explored through these three-dimensional models and the regular functionality of the whole heart is visualised.

  5. Imminent Cardiac Risk Assessment via Optical Intravascular Biochemical Analysis

    SciTech Connect

    Wetzel, D.; Wetzel, L; Wetzel, M; Lodder, R

    2009-01-01

    still the first line of defense. However, with the fidelity of 64-slice CT imaging, this technique has recently become an option when the patient presents with symptoms of reduced arterial flow. Single photon emission computerized tomography (SPECT) treadmill exercise testing is a standard non-invasive test for decreased perfusion of heart muscle, but is time consuming and not suited for emergent evaluation. Once the invasive clinical option of catherization is chosen, this provides the opportunity for intravascular ultrasound (IVUS) imaging. As the probe is pulled through the artery, the diameter at different parts is measurable, and monochrome contrast in the constricted area reveals the presence of tissue with a different ultrasonic response. Also, via an optical catheter with a fiber-optic conductor, the possibly of spectroscopic analysis of arterial walls is now a reality. In this case, the optical transducer is coupled to a near-infrared spectrometer. Revealing the arterial chemical health means that plaque vulnerability and imminent risk could be assessed by the physician. The classical emergency use of catherization involves a contrast agent and dynamic X-ray imaging to locate the constriction, determine its severity, and possibly perform angioplasty, and stent placement.

  6. Cardiac deformation recovery via incompressible transformation decomposition

    NASA Astrophysics Data System (ADS)

    Skrinjar, Oskar; Bistoque, Arnaud

    2005-04-01

    This paper presents a method for automated deformation recovery of the left and right ventricular wall from a time sequence of anatomical images of the heart. The deformation is recovered within the heart wall, i.e. it is not limited only to the epicardium and endocardium. Most of the suggested methods either ignore or approximately model incompressibility of the heart wall. This physical property of the cardiac muscle is mathematically guaranteed to be satisfied by the proposed method. A scheme for decomposition of a complex incompressible geometric transformation into simpler components and its application to cardiac deformation recovery is presented. A general case as well as an application specific solution is discussed. Furthermore, the manipulation of the constructed incompressible transformations, including the computation of the inverse transformation, is computationally inexpensive. The presented method is mathematically guaranteed to generate incompressible transformations which are experimentally shown to be a very good approximation of actual cardiac deformations. The transformation representation has a relatively small number of parameters which leads to a fast deformation recovery. The approach was tested on six sequences of two-dimensional short-axis cardiac MR images. The cardiac deformation was recovered with an average error of 1.1 pixel. The method is directly extendable to three dimensions and to the entire heart.

  7. Cardiac Involvement in Sarcoidosis: Evolving Concepts in Diagnosis and Treatment

    PubMed Central

    Lynch, Joseph P.; Hwang, Jennifer; Bradfield, Jason; Fishbein, Michael; Shivkumar, Kalyanam; Tung, Roderick

    2014-01-01

    Clinically evident sarcoidosis involving the heart has been noted in at least 2 to 7% of patients with sarcoidosis, but occult involvement is much higher (> 20%). Cardiac sarcoidosis is often not recognized antemortem, as sudden death may be the presenting feature. Cardiac involvement may occur at any point during the course of sarcoidosis and may occur in the absence of pulmonary or systemic involvement. Sarcoidosis can involve any part of the heart, with protean manifestations. Prognosis of cardiac sarcoidosis is related to extent and site(s) of involvement. Most deaths due to cardiac sarcoidosis are due to arrhythmias or conduction defects, but granulomatous infiltration of the myocardium may be lethal. The definitive diagnosis of isolated cardiac sarcoidosis is difficult. The yield of endomyocardial biopsies is low; treatment of cardiac sarcoidosis is often warranted even in the absence of histologic proof. Radionuclide scans are integral to the diagnosis. Currently, 18F-fluorodeoxyglucose positron emission tomography/computed tomography and gadolinium-enhanced magnetic resonance imaging scans are the key imaging modalities to diagnose cardiac sarcoidosis. The prognosis of cardiac sarcoidosis is variable, but mortality rates of untreated cardiac sarcoidosis are high. Although randomized therapeutic trials have not been done, corticosteroids (alone or combined with additional immunosuppressive medications) remain the mainstay of treatment. Because of the potential for sudden cardiac death, implantable cardioverter-defibrillators should be placed in any patient with cardiac sarcoidosis and serious ventricular arrhythmias or heart block, and should be considered for cardiomyopathy. Cardiac transplantation is a viable option for patients with end-stage cardiac sarcoidosis refractory to medical therapy. PMID:25007089

  8. Measurement of cardiac troponins.

    PubMed

    Collinson, P O; Boa, F G; Gaze, D C

    2001-09-01

    The cardiac troponins form part of the regulatory mechanism for muscle contraction. Specific cardiac isoforms of cardiac troponin T and cardiac troponin I exist and commercially available immunoassay systems have been developed for their measurement. A large number of clinical and analytical studies have been performed and the measurement of cardiac troponins is now considered the 'gold standard' biochemical test for diagnosis of myocardial damage. There have been advances in understanding the development and structure of troponins and their degradation following myocardial cell necrosis. This has contributed to the understanding of the problems with current assays. Greater clinical use has also highlighted areas of analytical and clinical confusion. The assays are reviewed based on manufacturers' information, current published material as well as the authors' in-house experience.

  9. Functional cardiac tissue engineering

    PubMed Central

    Liau, Brian; Zhang, Donghui; Bursac, Nenad

    2013-01-01

    Heart attack remains the leading cause of death in both men and women worldwide. Stem cell-based therapies, including the use of engineered cardiac tissues, have the potential to treat the massive cell loss and pathological remodeling resulting from heart attack. Specifically, embryonic and induced pluripotent stem cells are a promising source for generation of therapeutically relevant numbers of functional cardiomyocytes and engineering of cardiac tissues in vitro. This review will describe methodologies for successful differentiation of pluripotent stem cells towards the cardiovascular cell lineages as they pertain to the field of cardiac tissue engineering. The emphasis will be placed on comparing the functional maturation in engineered cardiac tissues and developing heart and on methods to quantify cardiac electrical and mechanical function at different spatial scales. PMID:22397609

  10. Cardiac Hegemony of Senescence

    PubMed Central

    Siddiqi, Sailay; Sussman, Mark A.

    2013-01-01

    Cardiac senescence and age-related disease development have gained general attention and recognition in the past decades due to increased accessibility and quality of health care. The advancement in global civilization is complementary to concerns regarding population aging and development of chronic degenerative diseases. Cardiac degeneration has been rigorously studied. The molecular mechanisms of cardiac senescence are on multiple cellular levels and hold a multilayer complexity level, thereby hampering development of unambiguous treatment protocols. In particular, the synergistic exchange of the senescence phenotype through a senescence secretome between myocytes and stem cells appears complicated and is of great future therapeutic value. The current review article will highlight hallmarks of senescence, cardiac myocyte and stem cell senescence, and the mutual exchange of senescent secretome. Future cardiac cell therapy approaches require a comprehensive understanding of myocardial senescence to improve therapeutic efficiency as well as efficacy. PMID:24349878

  11. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D

    2010-11-23

    The American College of Cardiology Foundation, along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research. PMID:20975004

  12. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D; Kramer, Christopher M; Berman, Daniel; Brown, Alan; Chaudhry, Farooq A; Cury, Ricardo C; Desai, Milind Y; Einstein, Andrew J; Gomes, Antoinette S; Harrington, Robert; Hoffmann, Udo; Khare, Rahul; Lesser, John; McGann, Christopher; Rosenberg, Alan; Schwartz, Robert; Shelton, Marc; Smetana, Gerald W; Smith, Sidney C

    2010-11-23

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research. PMID:21087721

  13. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D

    2010-01-01

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research. PMID:21232696

  14. Computational Cardiology: The Heart of the Matter

    PubMed Central

    Trayanova, Natalia A.

    2012-01-01

    This paper reviews the newest developments in computational cardiology. It focuses on the contribution of cardiac modeling to the development of new therapies as well as the advancement of existing ones for cardiac arrhythmias and pump dysfunction. Reviewed are cardiac modeling efforts aimed at advancing and optimizing existent therapies for cardiac disease (defibrillation, ablation of ventricular tachycardia, and cardiac resynchronization therapy) and at suggesting novel treatments, including novel molecular targets, as well as efforts to use cardiac models in stratification of patients likely to benefit from a given therapy, and the use of models in diagnostic procedures. PMID:23213566

  15. Role of breathing in cardiac performance: experimental and mathematical models

    NASA Astrophysics Data System (ADS)

    Tran, Binh Q.; Hoffman, Eric A.

    1999-05-01

    Due to the close proximity of the heart and lungs within a closed chest environment, we expect breathing to affect various cardiac performance parameters and hence cardiac output. We present an integrative approach to study heart-lung interactions, combining a mathematical formulation of the circulation system with imaging techniques using echo-planar magnetic resonance imaging (EPI) and dynamic x-ray CT (EBCT). We hypothesize that appropriate synchronization of mechanical ventilation to cardiac-cycle specific events can improve cardiac function, i.e. stroke volume (SV) and cardiac output (CO). Computational and experimental results support the notion that heart-lung interaction, leading to altered cardiac output associated with inspiration/expiration, is not directly associated with lung inflation/deflation and thus is felt to be more influenced by pleural pressure changes. The mathematical model of the circulation demonstrates the importance of cardiac-cycle specific timing of ventilation on cardiac function and matches with experimentally observed relationships found in animal models studied via EBCT and human studies using EPI. Results show that positive pressure mechanical ventilation timed to systolic events may increase SV and CO by up to 30%, mainly by increased filling of the ventricles during diastole. Similarly, negative pressure (spontaneous) respiration has its greatest effect on ventricular diastolic filling. Cardiac-gated mechanical ventilation may provide sufficient cardiac augmentation to warrant further investigation as a minimally-invasive technique for temporary cardiac assist. Through computational modeling and advanced imaging protocols, we were able to uniquely study heart-lung interactions within the intact milieu of the never-invaded thorax.

  16. Query cardiac pain.

    PubMed

    Todd, J W

    1983-08-01

    Query cardiac pain is a common problem, and immense efforts are made to solve it. No test can prove that a patient has not had a cardiac infarct, though in the recent past eminent authorities wrongly stated that a normal ECG supplied this proof. This history is by far the most important means of interpreting recurrent pain. Coronary arteriography is only useful in diagnosis when the pain is certainly due to myocardial ischaemia but it is uncertain whether this is caused by coronary artery disease or some other cardiac lesion. In practice, much pain is not diagnosed. This need be no cause for concern, and patients who in fact have had a small cardiac infarct gain rather than lose if wrongly reassured of its non-existence. The history of cardiology is a depressing catalogue of error. Bogus cardiac diseases have been diagnosed on an enormous scale, mainly because attention has been concentrated on the cardiac manifestations, while the patient was ignored. Much "excluding" is fatuous. Because treatment was derived from theory, treatment for patients who had had cardiac infarcts was disastrous. The great error at present is to overvalue technology.

  17. Diagnosis of traumatic cardiac contusion

    SciTech Connect

    Waxman, K.; Soliman, M.H.; Braunstein, P.; Formosa, P.; Cohen, A.J.; Matsuura, P.; Mason, G.R.

    1986-06-01

    Cardiac contusion following blunt chest trauma remains a diagnostic problem because of a lack of sensitive diagnostic tests. This study evaluated thallous chloride Tl 201 single-photon-emission computed tomography in a series of 48 patients following blunt chest trauma. Of the 48 patients, 23 had normal scans. None of these patients proved to have serious arrhythmias during three days of continuous monitoring. Of 25 patients with abnormal or ambiguous studies, five (20%) developed serious arrhythmias requiring therapy. Single-photon-emission computed tomography scanning thus was sensitive in indicating that group of patients at risk of serious arrhythmias, and may therefore prove to be a useful screening test to determine the need for hospitalization and arrhythmia monitoring following blunt chest trauma.

  18. Cardiac Arrest Resuscitation.

    PubMed

    Guyette, Francis X; Reynolds, Joshua C; Frisch, Adam

    2015-08-01

    Cardiac arrest is a dynamic disease that tests the multitasking and leadership abilities of emergency physicians. Providers must simultaneously manage the logistics of resuscitation while searching for the cause of cardiac arrest. The astute clinician will also realize that he or she is orchestrating only one portion of a larger series of events, each of which directly affects patient outcomes. Resuscitation science is rapidly evolving, and emergency providers must be familiar with the latest evidence and controversies surrounding resuscitative techniques. This article reviews evidence, discusses controversies, and offers strategies to provide quality cardiac arrest resuscitation.

  19. [Cardiac Rehabilitation 2015].

    PubMed

    Hoffmann, Andreas

    2015-11-25

    The goals of cardiac rehabilitation are (re-)conditioning and secondary prevention in patients with heart disease or an elevated cardiovascular risk profile. Rehabilitation is based on motivation through education, on adapted physical activity, instruction of relaxation techniques, psychological support and optimized medication. It is performed preferably in groups either in outpatient or inpatient settings. The Swiss working group on cardiac rehabilitation provides a network of institutions with regular quality auditing. Positive effects of rehabilitation programs on mortality and morbidity have been established by numerous studies. Although a majority of patients after cardiac surgery are being referred to rehabilitation, these services are notoriously underused after catheter procedures. PMID:26602848

  20. Cardiac nuclear imaging - Principles, instrumentation and pitfalls

    SciTech Connect

    Strauss, H.W.; Mckusick, K.A.; Bingham, J.B.

    1980-12-18

    Nuclear methods of cardiac imaging require a radiolabeled tracer, a collimator to assure interaction of photons from specific areas of the heart with the imaging device, equipment which converts gamma photon energy into an electrical signal which can be displayed, and a computer to record and quantify the data. Nuclear imaging is based on the averaging of many cardiac cycles, while nuclear probes supply information which can be analyzed only on a beat-by-beat basis imaging data can be reviewed visually and quantitatively. It is concluded that nuclear cardiac imaging can detect abnormal functions at rest or after interventions, and can be used both for outpatients and acutely ill persons in intensive care units.

  1. Considerations on an automatic computed tomography tube current modulation system.

    PubMed

    Moro, Luca; Panizza, Denis; D'Ambrosio, Daniela; Carne, Irene

    2013-10-01

    The scope of this study was to evaluate the effects on radiation output and image noise varying the acquisition parameters with an automatic tube current modulation (ATCM) system in computed tomography (CT). Chest CT examinations of an anthropomorphic phantom were acquired using a GE LightSpeed VCT 64-slice tomograph. Acquisitions were performed using different pitch, slice thickness and noise index (NI) values and varying the orientation of the scanned projection radiograph (SPR). The radiation output was determined by the CT dose index (CTDIvol). Image noise was evaluated measuring the standard deviation of CT numbers in several regions of interest. The radiation output was lower if the SPR was acquired in the anterior-posterior projection. The radiation dose with the posterior-anterior SPR was higher, because the divergence of the X-ray beam magnifies the anatomical structures closest to the tube, especially the spinal column, and this leads the ATCM system to estimate higher patient attenuation values and, therefore, to select higher tube current values. The NI was inversely proportional to the square root of the CTDIvol and, with fixed NI, the CTDIvol increased as the slice thickness decreased. This study suggests some important issues to use the GE ATCM system efficiently.

  2. Robust temporal alignment of multimodal cardiac sequences

    NASA Astrophysics Data System (ADS)

    Perissinotto, Andrea; Queirós, Sandro; Morais, Pedro; Baptista, Maria J.; Monaghan, Mark; Rodrigues, Nuno F.; D'hooge, Jan; Vilaça, João. L.; Barbosa, Daniel

    2015-03-01

    Given the dynamic nature of cardiac function, correct temporal alignment of pre-operative models and intraoperative images is crucial for augmented reality in cardiac image-guided interventions. As such, the current study focuses on the development of an image-based strategy for temporal alignment of multimodal cardiac imaging sequences, such as cine Magnetic Resonance Imaging (MRI) or 3D Ultrasound (US). First, we derive a robust, modality-independent signal from the image sequences, estimated by computing the normalized cross-correlation between each frame in the temporal sequence and the end-diastolic frame. This signal is a resembler for the left-ventricle (LV) volume curve over time, whose variation indicates different temporal landmarks of the cardiac cycle. We then perform the temporal alignment of these surrogate signals derived from MRI and US sequences of the same patient through Dynamic Time Warping (DTW), allowing to synchronize both sequences. The proposed framework was evaluated in 98 patients, which have undergone both 3D+t MRI and US scans. The end-systolic frame could be accurately estimated as the minimum of the image-derived surrogate signal, presenting a relative error of 1.6 +/- 1.9% and 4.0 +/- 4.2% for the MRI and US sequences, respectively, thus supporting its association with key temporal instants of the cardiac cycle. The use of DTW reduces the desynchronization of the cardiac events in MRI and US sequences, allowing to temporally align multimodal cardiac imaging sequences. Overall, a generic, fast and accurate method for temporal synchronization of MRI and US sequences of the same patient was introduced. This approach could be straightforwardly used for the correct temporal alignment of pre-operative MRI information and intra-operative US images.

  3. Neurologic complications of cardiac tumors.

    PubMed

    Roeltgen, David; Kidwell, Chelsea S

    2014-01-01

    Cardiac tumors are an uncommon cause for neurologic disease, but if undiagnosed can be associated with devastating neurologic consequences. Primary cardiac tumors, both benign and neoplastic, and metastatic tumors occur. Primary cardiac tumors are more likely to be associated with neurologic embolic complications. Metastatic cardiac tumors are more likely to be associated with valvular distraction, arrhythmia, diminished cardiac output and indirect neurological dysfunction. Primary and metastatic cardiac tumors may result in cerebral metastatic disease. Atrial myxoma, a benign primary cardiac tumor, is the most common cardiac tumor associated with neurologic disease, and most commonly causes cerebral embolization and stroke. The use of thrombolytic therapy for these strokes is controversial. Additionally, delayed manifestations, including aneurysm formation and intracranial hemorrhage, are possible. Aneurysm formation has been described as occurring after removal of the primary tumor. The availability of noninvasive cardiac imaging has significantly helped decrease the neurologic morbidity of cardiac tumors and has led to frequent successful intervention. PMID:24365298

  4. Molecular Basis of Cardiac Myxomas

    PubMed Central

    Singhal, Pooja; Luk, Adriana; Rao, Vivek; Butany, Jagdish

    2014-01-01

    Cardiac tumors are rare, and of these, primary cardiac tumors are even rarer. Metastatic cardiac tumors are about 100 times more common than the primary tumors. About 90% of primary cardiac tumors are benign, and of these the most common are cardiac myxomas. Approximately 12% of primary cardiac tumors are completely asymptomatic while others present with one or more signs and symptoms of the classical triad of hemodynamic changes due to intracardiac obstruction, embolism and nonspecific constitutional symptoms. Echocardiography is highly sensitive and specific in detecting cardiac tumors. Other helpful investigations are chest X-rays, magnetic resonance imaging and computerized tomography scan. Surgical excision is the treatment of choice for primary cardiac tumors and is usually associated with a good prognosis. This review article will focus on the general features of benign cardiac tumors with an emphasis on cardiac myxomas and their molecular basis. PMID:24447924

  5. Cardiac glycoside overdose

    MedlinePlus

    ... found in the leaves of the digitalis (foxglove) plant. This plant is the original source of this medicine. People ... Digitoxin (Crystodigin) Digoxin (Lanoxicaps, Lanoxin) Besides the foxglove plant, cardiac glycosides also occur naturally in plants such ...

  6. Neuroprotection during cardiac surgery.

    PubMed

    Grocott, Hilary P; Yoshitani, Kenji

    2007-01-01

    Cerebral injury following cardiac surgery continues to be a significant source of morbidity and mortality after cardiac surgery. A spectrum of injuries ranging from subtle neurocognitive dysfunction to fatal strokes are caused by a complex series of multifactorial mechanisms. Protecting the brain from these injuries has focused on intervening on each of the various etiologic factors. Although numerous studies have focused on a pharmacologic solution, more success has been found with nonpharmacologic strategies, including optimal temperature management and reducing emboli generation. PMID:17680190

  7. Ranolazine in Cardiac Arrhythmia.

    PubMed

    Saad, Marwan; Mahmoud, Ahmed; Elgendy, Islam Y; Richard Conti, C

    2016-03-01

    Ranolazine utilization in the management of refractory angina has been established by multiple randomized clinical studies. However, there is growing evidence showing an evolving role in the field of cardiac arrhythmias. Multiple experimental and clinical studies have evaluated the role of ranolazine in prevention and management of atrial fibrillation, with ongoing studies on its role in ventricular arrhythmias. In this review, we will discuss the pharmacological, experimental, and clinical evidence behind ranolazine use in the management of various cardiac arrhythmias.

  8. Cardiac rehabilitation in Germany.

    PubMed

    Karoff, Marthin; Held, Klaus; Bjarnason-Wehrens, Birna

    2007-02-01

    The purpose of this review is to give an overview of the rehabilitation measures provided for cardiac patients in Germany and to outline its legal basis and outcomes. In Germany the cardiac rehabilitation system is different from rehabilitation measures in other European countries. Cardiac rehabilitation in Germany since 1885 is based on specific laws and the regulations of insurance providers. Cardiac rehabilitation has predominantly been offered as an inpatient service, but has recently been complemented by outpatient services. A general agreement on the different indications for offering these two services has yet to be reached. Cardiac rehabilitation is mainly offered after an acute cardiac event and bypass surgery. It is also indicated in severe heart failure and special cases of percutaneous coronary intervention. Most patients are men (>65%) and the age at which events occur is increasing. The benefits obtained during the 3-4 weeks after an acute event, and confirmed in numerous studies, are often later lost under 'usual care' conditions. Many attempts have been made by rehabilitation institutions to improve this deficit by providing intensive aftercare. One instrument set up to achieve this is the nationwide institution currently comprising more than 6000 heart groups with approximately 120000 outpatients. After coronary artery bypass grafting or acute coronary syndrome cardiac rehabilitation can usually be started within 10 days. The multidisciplinary rehabilitation team consists of cardiologists, psychologists, exercise therapists, social workers, nutritionists and nurses. The positive effects of cardiac rehabilitation are also important economically, for example, for the improvement of secondary prevention and vocational integration. PMID:17301623

  9. Ranolazine in Cardiac Arrhythmia.

    PubMed

    Saad, Marwan; Mahmoud, Ahmed; Elgendy, Islam Y; Richard Conti, C

    2016-03-01

    Ranolazine utilization in the management of refractory angina has been established by multiple randomized clinical studies. However, there is growing evidence showing an evolving role in the field of cardiac arrhythmias. Multiple experimental and clinical studies have evaluated the role of ranolazine in prevention and management of atrial fibrillation, with ongoing studies on its role in ventricular arrhythmias. In this review, we will discuss the pharmacological, experimental, and clinical evidence behind ranolazine use in the management of various cardiac arrhythmias. PMID:26459200

  10. Cardiac Munchausen's syndrome.

    PubMed Central

    Dickinson, E J; Evans, T R

    1987-01-01

    Ten years' experience of cardiac Munchausen's syndrome in the Cardiac Care Unit of an Inner London teaching hospital is reported. Thirty-six admissions in this category were identified and analysed, and 4 typical cases are described. The common presenting complaints, recurring features and the relationship with other forms of Munchausen's syndrome are discussed, as are possible strategies available to deal with this clinical entity. PMID:3694601

  11. Cardiac imaging in adults

    SciTech Connect

    Jaffe, C.C.

    1987-01-01

    This book approaches adult cardiac disease from the correlative imaging perspective. It includes chest X-rays and angiographs, 2-dimensional echocardiograms with explanatory diagrams for clarity, plus details on digital radiology, nuclear medicine techniques, CT and MRI. It also covers the normal heart, valvular heart disease, myocardial disease, pericardial disease, bacterial endocarditis, aortic aneurysm, cardiac tumors, and congenital heart disease of the adult. It points out those aspects where one imaging technique has significant superiority.

  12. Cardiac Applications of Optogenetics

    PubMed Central

    Ambrosi, Christina M.; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-01-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics. PMID:25035999

  13. Trends in cardiac metastasis.

    PubMed

    Karwinski, B; Svendsen, E

    1989-11-01

    A review of 8571 autopsies disclosed 2833 patients with malignant tumours from 1975 to 1984 at the Department of Pathology, The Gade Institute. Cardiac metastases were found in 130 cases. An increase of cardiac involvement was shown in the autopsy material from 1.2% in 1975-1979 to 1.8% in 1980-1984. The same trend was seen if cardiac metastases were related to malignant tumours. Numerically, lung cancer accounted for most of the metastases seen, but the increase was made up by other tumours than lung cancer. especially malignant melanoma, mesothelioma, breast cancer and sarcomas. These tumours have a high frequency of heart metastases and the increased incidence of these cancers in the material explains the rise of cardiac metastases. Cardiac metastases increased with rising number of distant metastases. This study shows that mesotheliomas have the highest percentage of cardiac spread. The importance of autopsy for detecting metastatic spread in sites that are difficult to detect clinically is emphasized.

  14. Cardiac applications of optogenetics.

    PubMed

    Ambrosi, Christina M; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-08-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics.

  15. Direct Cardiac Reprogramming: Advances in Cardiac Regeneration

    PubMed Central

    Chen, Olivia; Qian, Li

    2015-01-01

    Heart disease is one of the lead causes of death worldwide. Many forms of heart disease, including myocardial infarction and pressure-loading cardiomyopathies, result in irreversible cardiomyocyte death. Activated fibroblasts respond to cardiac injury by forming scar tissue, but ultimately this response fails to restore cardiac function. Unfortunately, the human heart has little regenerative ability and long-term outcomes following acute coronary events often include chronic and end-stage heart failure. Building upon years of research aimed at restoring functional cardiomyocytes, recent advances have been made in the direct reprogramming of fibroblasts toward a cardiomyocyte cell fate both in vitro and in vivo. Several experiments show functional improvements in mouse models of myocardial infarction following in situ generation of cardiomyocyte-like cells from endogenous fibroblasts. Though many of these studies are in an early stage, this nascent technology holds promise for future applications in regenerative medicine. In this review, we discuss the history, progress, methods, challenges, and future directions of direct cardiac reprogramming. PMID:26176012

  16. Patient-specific models of cardiac biomechanics

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Adarsh; Villongco, Christopher T.; Chuang, Joyce; Frank, Lawrence R.; Nigam, Vishal; Belezzuoli, Ernest; Stark, Paul; Krummen, David E.; Narayan, Sanjiv; Omens, Jeffrey H.; McCulloch, Andrew D.; Kerckhoffs, Roy C. P.

    2013-07-01

    Patient-specific models of cardiac function have the potential to improve diagnosis and management of heart disease by integrating medical images with heterogeneous clinical measurements subject to constraints imposed by physical first principles and prior experimental knowledge. We describe new methods for creating three-dimensional patient-specific models of ventricular biomechanics in the failing heart. Three-dimensional bi-ventricular geometry is segmented from cardiac CT images at end-diastole from patients with heart failure. Human myofiber and sheet architecture is modeled using eigenvectors computed from diffusion tensor MR images from an isolated, fixed human organ-donor heart and transformed to the patient-specific geometric model using large deformation diffeomorphic mapping. Semi-automated methods were developed for optimizing the passive material properties while simultaneously computing the unloaded reference geometry of the ventricles for stress analysis. Material properties of active cardiac muscle contraction were optimized to match ventricular pressures measured by cardiac catheterization, and parameters of a lumped-parameter closed-loop model of the circulation were estimated with a circulatory adaptation algorithm making use of information derived from echocardiography. These components were then integrated to create a multi-scale model of the patient-specific heart. These methods were tested in five heart failure patients from the San Diego Veteran's Affairs Medical Center who gave informed consent. The simulation results showed good agreement with measured echocardiographic and global functional parameters such as ejection fraction and peak cavity pressures.

  17. Patient-Specific Models of Cardiac Biomechanics

    PubMed Central

    Krishnamurthy, Adarsh; Villongco, Christopher T; Chuang, Joyce; Frank, Lawrence R; Nigam, Vishal; Belezzuoli, Ernest; Stark, Paul; Krummen, David E; Narayan, Sanjiv; Omens, Jeffrey H.; Kerckhoffs, Roy CP

    2012-01-01

    Patient-specific models of cardiac function have the potential to improve diagnosis and management of heart disease by integrating medical images with heterogeneous clinical measurements subject to constraints imposed by physical first principles and prior experimental knowledge. We describe new methods for creating three-dimensional patient-specific models of ventricular biomechanics in the failing heart. Three-dimensional bi-ventricular geometry is segmented from cardiac CT images at end-diastole from patients with heart failure. Human myofiber and sheet architecture is modeled using eigenvectors computed from diffusion tensor MR images from an isolated, fixed human organ-donor heart and transformed to the patient-specific geometric model using large deformation diffeomorphic mapping. Semi-automated methods were developed for optimizing the passive material properties while simultaneously computing the unloaded reference geometry of the ventricles for stress analysis. Material properties of active cardiac muscle contraction were optimized to match ventricular pressures measured by cardiac catheterization, and parameters of a lumped-parameter closed-loop model of the circulation were estimated with a circulatory adaptation algorithm making use of information derived from echocardiography. These components were then integrated to create a multi-scale model of the patient-specific heart. These methods were tested in five heart failure patients from the San Diego Veteran’s Affairs Medical Center who gave informed consent. The simulation results showed good agreement with measured echocardiographic and global functional parameters such as ejection fraction and peak cavity pressures. PMID:23729839

  18. Engineering design of a cardiac myocyte

    NASA Astrophysics Data System (ADS)

    Adams, W. J.; Pong, T.; Geisse, N. A.; Sheehy, S. P.; Diop-Frimpong, B.; Parker, K. K.

    2007-04-01

    We describe a design algorithm to build a cardiac myocyte with specific spatial dimensions and physiological function. Using a computational model of a cardiac muscle cell, we modeled calcium (Ca2+) wave dynamics in a cardiac myocyte with controlled spatial dimensions. The modeled myocyte was replicated in vitro when primary neonate rat ventricular myocytes were cultured on micropatterned substrates. The myocytes remodel to conform to the two dimensional boundary conditions and assume the shape of the printed extracellular matrix island. Mechanical perturbation of the myocyte with an atomic force microscope results in calcium-induced calcium release from intracellular stores and the propagation of a Ca2+ wave, as indicated by high speed video microscopy using fluorescent indicators of intracellular Ca2+. Analysis and comparison of the measured wavefront dynamics with those simulated in the computer model reveal that the engineered myocyte behaves as predicted by the model. These results are important because they represent the use of computer modeling, computer-aided design, and physiological experiments to design and validate the performance of engineered cells. The ability to successfully engineer biological cells and tissues for assays or therapeutic implants will require design algorithms and tools for quality and regulatory assurance.

  19. [Psychosomatic aspects of cardiac arrhythmias].

    PubMed

    Siepmann, Martin; Kirch, Wilhelm

    2010-07-01

    Emotional stress facilitates the occurrence of cardiac arrhythmias including sudden cardiac death. The prevalence of anxiety and depression is increased in cardiac patients as compared to the normal population. The risk of cardiovascular mortality is enhanced in patients suffering from depression. Comorbid anxiety disorders worsen the course of cardiac arrhythmias. Disturbance of neurocardiac regulation with predominance of the sympathetic tone is hypothesized to be causative for this. The emotional reaction to cardiac arrhythmias is differing to a large extent between individuals. Emotional stress may result from coping with treatment of cardiac arrhythmias. Emotional stress and cardiac arrhythmias may influence each other in the sense of a vicious circle. Somatoform cardiac arrhythmias are predominantly of psychogenic origin. Instrumental measures and frequent contacts between physicians and patients may facilitate disease chronification. The present review is dealing with the multifaceted relationships between cardiac arrhythmias and emotional stress. The underlying mechanisms and corresponding treatment modalities are discussed.

  20. Living cardiac tissue slices: an organotypic pseudo two-dimensional model for cardiac biophysics research.

    PubMed

    Wang, Ken; Terrar, Derek; Gavaghan, David J; Mu-U-Min, Razik; Kohl, Peter; Bollensdorff, Christian

    2014-08-01

    for up to 50 min. After release of sustained stretch, AP duration (APD) and CaT duration reverted to shorter values. Living cardiac tissue slices are a promising experimental model for the study of cardiac mechano-electric interactions. The methodology described here can be refined to achieve more accurate control over stretch amplitude and timing (e.g. using a computer-controlled motorised stage, or by synchronising electrical and mechanical events) and through monitoring of regional tissue deformation (e.g. by adding motion tracking).

  1. Whole Heart Modeling: Applications to Cardiac Electrophysiology and Electromechanics

    PubMed Central

    Trayanova, Natalia A

    2010-01-01

    Rationale Recent developments in cardiac simulation have rendered the heart the most highly integrated example of a virtual organ. We are on the brink of a revolution in cardiac research–one in which computational modeling of proteins, cells, tissues and the organ allow to link genomic and proteomic information to the integrated organ behavior, in the quest to provide quantitative understanding of the functioning of the heart in health and disease. Objective The goal of this article is to assess the current state-of-the-art in whole-heart modeling and the plethora of its applications in cardiac research. Methods and Results General whole-heart modeling approaches are presented, and the applications of whole-heart models in cardiac electrophysiology and electromechanics research are reviewed. The article showcases the contributions that whole-heart modeling and simulation have made to our understanding of the functioning of the heart. A summary of the future developments envisioned for the field of cardiac simulation and modeling is also presented. Conclusions Biophysically-based computational modeling of the heart, applied to human heart physiology and the diagnosis and treatment of cardiac disease, has the potential to dramatically change twenty-first century cardiac research and the field of cardiology. PMID:21212393

  2. Cardiac cavernous hemangioma and multiple pulmonary cavernous hemangiomas.

    PubMed

    Yang, Lili; Dai, Jun; Xiao, Ying; Cheng, Henghui; Ruan, Qiurong

    2014-02-01

    We describe for the first time a rare coexistence of a cardiac cavernous hemangioma with multiple pulmonary cavernous hemangiomas. Computed tomography revealed bilateral pulmonary nodules, left pleural effusion, and pericardial effusion. Positron emission tomography showed a pericardial neoplasm. Pathologically, multiple large dilated vascular spaces, lined by a single layer of endothelial cells and filled with blood, were revealed in both the cardiac tumor and the pulmonary nodules. Immunohistochemical examination of the lining cells showed positivity for CD31, FLI1, FVIII, and CD34. Taken together, these findings led to the diagnosis of cardiac cavernous hemangioma and multiple pulmonary cavernous hemangiomas.

  3. Cardiac applications of PET.

    PubMed

    Sarikaya, Ismet

    2015-10-01

    Routine use of cardiac positron emission tomography (PET) applications has been increasing but has not replaced cardiac single-photon emission computerized tomography (SPECT) studies yet. The majority of cardiac PET tracers, with the exception of fluorine-18 fluorodeoxyglucose (18F-FDG), are not widely available, as they require either an onsite cyclotron or a costly generator for their production. 18F-FDG PET imaging has high sensitivity for the detection of hibernating/viable myocardium and has replaced Tl-201 SPECT imaging in centers equipped with a PET/CT camera. PET myocardial perfusion imaging with various tracers such as Rb-82, N-13 ammonia, and O-15 H2O has higher sensitivity and specificity than myocardial perfusion SPECT for the detection of coronary artery disease (CAD). In particular, quantitative PET measurements of myocardial perfusion help identify subclinical coronary stenosis, better define the extent and severity of CAD, and detect ischemia when there is balanced reduction in myocardial perfusion due to three-vessel or main stem CAD. Fusion images of PET perfusion and CT coronary artery calcium scoring or CT coronary angiography provide additional complementary information and improve the detection of CAD. PET studies with novel 18F-labeled perfusion tracers such as 18F-flurpiridaz and 18F-FBnTP have yielded high sensitivity and specificity in the diagnosis of CAD. These tracers are still being tested in humans, and, if approved for clinical use, they will be commercially and widely available. In addition to viability studies, 18F-FDG PET can also be utilized to detect inflammation/infection in various conditions such as endocarditis, sarcoidosis, and atherosclerosis. Some recent series have obtained encouraging results for the detection of endocarditis in patients with intracardiac devices and prosthetic valves. PET tracers for cardiac neuronal imaging, such as C-11 HED, help assess the severity of heart failure and post-transplant cardiac

  4. Cardiac involvement in hemochromatosis.

    PubMed

    Gulati, Vinay; Harikrishnan, Prakash; Palaniswamy, Chandrasekar; Aronow, Wilbert S; Jain, Diwakar; Frishman, William H

    2014-01-01

    Cardiac hemochromatosis or primary iron-overload cardiomyopathy is an important and potentially preventable cause of heart failure. This is initially characterized by diastolic dysfunction and arrhythmias and in later stages by dilated cardiomyopathy. Diagnosis of iron overload is established by elevated transferrin saturation (>55%) and elevated serum ferritin (>300 ng/mL). Genetic testing for mutations in the HFE (high iron) gene and other proteins, such as hemojuvelin, transferrin receptor, and ferroportin, should be performed if secondary causes of iron overload are ruled out. Patients should undergo comprehensive 2D and Doppler echocardiography to evaluate their systolic and diastolic function. Newer modalities like strain imaging and speckle-tracking echocardiography hold promise for earlier detection of cardiac involvement. Cardiac magnetic resonance imaging with measurement of T2* relaxation times can help quantify myocardial iron overload. In addition to its value in diagnosis of cardiac iron overload, response to iron reduction therapy can be assessed by serial imaging. Therapeutic phlebotomy and iron chelation are the cornerstones of therapy. The average survival is less than a year in untreated patients with severe cardiac impairment. However, if treated early and aggressively, the survival rate approaches that of the regular heart failure population.

  5. Cardiac varix in the right atrium

    PubMed Central

    Shiraishi, Manabu; Kimura, Chieri; Yamaguchi, Atsushi; Adachi, Hideo

    2012-01-01

    A 73-year old man underwent transthoracic and transoesophageal echocardiography and computed tomography, which revealed what appeared to be an asymptomatic primary mobile tumour located in the right atrium. During surgery, the mass was found to be associated with the right atrial septum and was subsequently resected. Histopathology of the mass revealed a cardiac varix with phleboliths. The patient had an uneventful postoperative course and no signs of recurrence at the 10-month follow-up. PMID:22314009

  6. [Preoperative cardiac assessment before non-cardiac surgery: cardiac risk stratification].

    PubMed

    Iglesias, J F; Sierro, C; Aebischer, N; Vogt, P; Eeckhout, E

    2010-06-01

    Perioperative cardiac events occurring in patients undergoing non-cardiac surgery are a common cause of morbidity and mortality. Current guidelines recommend an individualized approach to preoperative cardiac risk stratification prior to non-cardiac surgery, integrating risk factors both for the patient (active cardiac conditions, clinical risk factors, functional capacity) and for the planned surgery. Preoperative cardiac investigations are currently limited to high-risk patients in whom they may contribute to modify the perioperative management. A multidisciplinary approach to such patients, integrating the general practitioner, is recommended in order to define an individualized peri-operative strategy.

  7. Cardiac Imaging In Athletes.

    PubMed

    Khan, Asaad A; Safi, Lucy; Wood, Malissa

    2016-01-01

    Athletic heart syndrome refers to the physiological and morphological changes that occur in a human heart after repetitive strenuous physical exercise. Examples of exercise-induced changes in the heart include increases in heart cavity dimensions, augmentation of cardiac output, and increases in heart muscle mass. These cardiac adaptations vary based on the type of exercise performed and are often referred to as sport-specific cardiac remodeling. The hemodynamic effects of endurance and strength training exercise lead to these adaptations. Any abnormalities in chamber dilatation and left ventricular function usually normalize with cessation of exercise. Athletic heart syndrome is rare and should be differentiated from pathologic conditions such as hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia when assessing a patient for athletic heart syndrome. This paper describes specific adaptations that occur in athletic heart syndrome and tools to distinguish between healthy alterations versus underlying pathology. PMID:27486490

  8. Cardiac Imaging In Athletes

    PubMed Central

    Khan, Asaad A.; Safi, Lucy; Wood, Malissa

    2016-01-01

    Athletic heart syndrome refers to the physiological and morphological changes that occur in a human heart after repetitive strenuous physical exercise. Examples of exercise-induced changes in the heart include increases in heart cavity dimensions, augmentation of cardiac output, and increases in heart muscle mass. These cardiac adaptations vary based on the type of exercise performed and are often referred to as sport-specific cardiac remodeling. The hemodynamic effects of endurance and strength training exercise lead to these adaptations. Any abnormalities in chamber dilatation and left ventricular function usually normalize with cessation of exercise. Athletic heart syndrome is rare and should be differentiated from pathologic conditions such as hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia when assessing a patient for athletic heart syndrome. This paper describes specific adaptations that occur in athletic heart syndrome and tools to distinguish between healthy alterations versus underlying pathology. PMID:27486490

  9. Inter-individual variance and cardiac cycle dependency of aortic root dimensions and shape as assessed by ECG-gated multi-slice computed tomography in patients with severe aortic stenosis prior to transcatheter aortic valve implantation: is it crucial for correct sizing?

    PubMed

    Lehmkuhl, Lukas; Foldyna, Borek; Von Aspern, Konstantin; Lücke, Christian; Grothoff, Matthias; Nitzsche, Stefan; Kempfert, Jörg; Haensig, Martin; Rastan, Ardawan; Walther, Thomas; Mohr, Friedrich-Wilhelm; Gutberlet, Matthias

    2013-03-01

    To evaluate the inter-individual variance and the variability of the aortic root dimensions during the cardiac cycle by computed tomography (CT) in patients with severe aortic stenosis prior to transcatheter aortic valve implantation (TAVI). Fifty-six patients (m/w = 16/40, 81 ± 6.8 years), scheduled for a transapical aortic valve implantation with available preprocedural ECG-gated CT were retrospectively included. The evaluation included sizing of the aortic annulus and the aortic sinus, measurements of the coronary topography, aortic valve planimetry and scoring of calcification. The new defined aortic annulus sphericity ratio revealed a mostly elliptical shape with increasing diastolic deformation. The calculated effective diameter (ED), determined from the annulus' lumen area, turned out to be the parameter least affected from cardiac cycle changes while systolic and diastolic annulus dimensions and shape (diameter and area) differed significantly (p < 0.001). In about 70 % of the patients with relevant paravalvular leaks the finally implanted prosthesis was too small according to the CT based calculated ED. The ostial height of the coronaries showed a high variability with a critical minimum range <5 mm. The degree of the aortic calcification did not have an influence on the aortic annulus deformation during the cardiac cycle, but on the occurrence of paravalvular leaks. The aortic root anatomy demonstrated a high inter-individual variability and cardiac cycle dependency. These results must be strongly considered during the patient evaluation prior to TAVI to avoid complications. The systolic effective diameter, as measured by ECG-gated CT, represents an appropriate parameter for sizing the aortic annulus.

  10. Cardiac arrest in the skies.

    PubMed

    Charles, R A

    2011-08-01

    Cardiac arrest occurring on board aeroplanes is rare, but remains a common cause of inflight incidents. This review examines some of the management problems unique to inflight cardiac arrests, and emphasises the use of cardiopulmonary resuscitation and automated external defibrillators.

  11. [Cardiac failure in endocrine diseases].

    PubMed

    Hashizume, K

    1993-05-01

    Several endocrine diseases show the symptoms of cardiac failure. Among them, patients with acromegaly show a specific cardiomyopathy which results in a severe left-sided cardiac failure. Hypoparathyroidism also induces cardiac failure, which is resulted from hypocalcemia and low levels of serum parathyroid hormone. In the cases of hypothyroidism, the patients with myxedemal coma show a severe cardiac failure, which is characterized by disturbance of central nervous system, renal function, and cardiac function. In the patients with thyroid crisis (storm), the cardiac failure comes from the great reduction of cardiac output with dehydration. The reduction of circulation volume, observed in the patients with pheochromocytoma easily induces cardiac failure (shock) just after the removal of adrenal tumor. In patients with malignant carcinoid syndrome, right-sided ventricular failure which may be occurred through the actions of biogenic amines is observed. PMID:8331806

  12. Mechanisms of cardiac arrhythmias

    PubMed Central

    Tse, Gary

    2015-01-01

    Blood circulation is the result of the beating of the heart, which provides the mechanical force to pump oxygenated blood to, and deoxygenated blood away from, the peripheral tissues. This depends critically on the preceding electrical activation. Disruptions in the orderly pattern of this propagating cardiac excitation wave can lead to arrhythmias. Understanding of the mechanisms underlying their generation and maintenance requires knowledge of the ionic contributions to the cardiac action potential, which is discussed in the first part of this review. A brief outline of the different classification systems for arrhythmogenesis is then provided, followed by a detailed discussion for each mechanism in turn, highlighting recent advances in this area. PMID:27092186

  13. Perioperative management of cardiac disease.

    PubMed

    Aresti, N A; Malik, A A; Ihsan, K M; Aftab, S M E; Khan, W S

    2014-01-01

    Pre-existing cardiac disease contributes significantly to morbidity and mortality amongst patients undergoing non cardiac surgery. Patients with pre-existing cardiac disease or with risk factors for it, have as much as a 3.9% risk of suffering a major perioperative cardiac event (Lee et al 1999, Devereaux 2005). Furthermore, the incidence of perioperative myocardial infarction (MI) is increased 10 to 50 fold in patients with previous coronary events (Jassal 2008).

  14. Ubiquitous health monitoring and real-time cardiac arrhythmias detection: a case study.

    PubMed

    Li, Jian; Zhou, Haiying; Zuo, Decheng; Hou, Kun-Mean; De Vaulx, Christophe

    2014-01-01

    As the symptoms and signs of heart diseases that cause sudden cardiac death, cardiac arrhythmia has attracted great attention. Due to limitations in time and space, traditional approaches to cardiac arrhythmias detection fail to provide a real-time continuous monitoring and testing service applicable in different environmental conditions. Integrated with the latest technologies in ECG (electrocardiograph) analysis and medical care, the pervasive computing technology makes possible the ubiquitous cardiac care services, and thus brings about new technical challenges, especially in the formation of cardiac care architecture and realization of the real-time automatic ECG detection algorithm dedicated to care devices. In this paper, a ubiquitous cardiac care prototype system is presented with its architecture framework well elaborated. This prototype system has been tested and evaluated in all the clinical-/home-/outdoor-care modes with a satisfactory performance in providing real-time continuous cardiac arrhythmias monitoring service unlimitedly adaptable in time and space. PMID:24211993

  15. Ubiquitous health monitoring and real-time cardiac arrhythmias detection: a case study.

    PubMed

    Li, Jian; Zhou, Haiying; Zuo, Decheng; Hou, Kun-Mean; De Vaulx, Christophe

    2014-01-01

    As the symptoms and signs of heart diseases that cause sudden cardiac death, cardiac arrhythmia has attracted great attention. Due to limitations in time and space, traditional approaches to cardiac arrhythmias detection fail to provide a real-time continuous monitoring and testing service applicable in different environmental conditions. Integrated with the latest technologies in ECG (electrocardiograph) analysis and medical care, the pervasive computing technology makes possible the ubiquitous cardiac care services, and thus brings about new technical challenges, especially in the formation of cardiac care architecture and realization of the real-time automatic ECG detection algorithm dedicated to care devices. In this paper, a ubiquitous cardiac care prototype system is presented with its architecture framework well elaborated. This prototype system has been tested and evaluated in all the clinical-/home-/outdoor-care modes with a satisfactory performance in providing real-time continuous cardiac arrhythmias monitoring service unlimitedly adaptable in time and space.

  16. Penetrating Cardiac Injury: A Review

    PubMed Central

    Lateef Wani, Mohd; Ahangar, Ab Gani; Wani, Shadab Nabi; Irshad, Ifat; Ul-Hassan, Nayeem

    2012-01-01

    Cardiac injury presents a great challenge to the emergency resident because these injuries require urgent intervention to prevent death. Sometimes serious cardiac injury may manifest only subtle or occult symptoms or signs. As there is an epidemic of cardiac injuries in Kashmir valley due to problems of law and order, we herein present a review on management of such injuries. PMID:24829887

  17. Imaging techniques in cardiac resynchronization therapy

    PubMed Central

    Sá, Maria Isabel; de Roos, Albert; Westenberg, Jos J. M.

    2007-01-01

    Cardiac resynchronization therapy is a high cost therapeutic option with proven efficacy on improving symptoms of ventricular failure and for reducing both hospitalization and mortality. However, a significant number of patients do not respond to cardiac resynchronization therapy that is due to various reasons. Identification of the optimal pacing site is crucial to obtain the best therapeutic result that necessitates careful patient selection. Currently, using echocardiography for mechanical dyssynchrony assessment performs patient selection. Multi-Detector-Row Computed Tomography (MDCT) and Magnetic Resonance Imaging (MRI) are new imaging techniques that may assist the cardiologist in patient selection. These new imaging techniques have the potential to improve the success rate of cardiac resynchronization therapy, due to pre-interventional evaluation of the venous coronary anatomy, to evaluation of the presence of scar tissue, and to improved evaluation of mechanical dyssynchrony. In conclusion, clinical issues associated with heart failure in potential candidates for cardiac resynchronization therapy, and the information regarding this therapy that can be provided by the imaging techniques echocardiography, MDCT, and MRI, are reviewed. PMID:17503216

  18. Reconstruction of dynamic gated cardiac SPECT

    SciTech Connect

    Jin Mingwu; Yang Yongyi; King, Michael A.

    2006-11-15

    In this paper we propose an image reconstruction procedure which aims to unify gated single photon emission computed tomography (SPECT) and dynamic SPECT into a single method. We divide the cardiac cycle into a number of gate intervals as in gated SPECT, but treat the tracer distribution for each gate as a time-varying signal. By using both dynamic and motion-compensated temporal regularization, our reconstruction procedure will produce an image sequence that shows both cardiac motion and time-varying tracer distribution simultaneously. To demonstrate the proposed reconstruction method, we simulated gated cardiac perfusion imaging using the gated mathematical cardiac-torso (gMCAT) phantom with Tc99m-Teboroxime as the imaging agent. Our results show that the proposed method can produce more accurate reconstruction of gated dynamic images than independent reconstruction of individual gate frames with spatial smoothness alone. In particular, our results show that the former could improve the contrast to noise ratio of a simulated perfusion defect by as much as 100% when compared to the latter.

  19. Ultrasound imaging in teaching cardiac physiology.

    PubMed

    Johnson, Christopher D; Montgomery, Laura E A; Quinn, Joe G; Roe, Sean M; Stewart, Michael T; Tansey, Etain A

    2016-09-01

    This laboratory session provides hands-on experience for students to visualize the beating human heart with ultrasound imaging. Simple views are obtained from which students can directly measure important cardiac dimensions in systole and diastole. This allows students to derive, from first principles, important measures of cardiac function, such as stroke volume, ejection fraction, and cardiac output. By repeating the measurements from a subject after a brief exercise period, an increase in stroke volume and ejection fraction are easily demonstrable, potentially with or without an increase in left ventricular end-diastolic volume (which indicates preload). Thus, factors that affect cardiac performance can readily be discussed. This activity may be performed as a practical demonstration and visualized using an overhead projector or networked computers, concentrating on using the ultrasound images to teach basic physiological principles. This has proved to be highly popular with students, who reported a significant improvement in their understanding of Frank-Starling's law of the heart with ultrasound imaging. PMID:27445285

  20. Systems approaches in integrative cardiac biology: illustrations from cardiac heterocellular signalling studies.

    PubMed

    Nim, Hieu T; Boyd, Sarah E; Rosenthal, Nadia A

    2015-01-01

    Understanding the complexity of cardiac physiology requires system-level studies of multiple cardiac cell types. Frequently, however, the end result of published research lacks the detail of the collaborative and integrative experimental design process, and the underlying conceptual framework. We review the recent progress in systems modelling and omics analysis of the heterocellular heart environment through complementary forward and inverse approaches, illustrating these conceptual and experimental frameworks with case studies from our own research program. The forward approach begins by collecting curated information from the niche cardiac biology literature, and connecting the dots to form mechanistic network models that generate testable system-level predictions. The inverse approach starts from the vast pool of public omics data in recent cardiac biological research, and applies bioinformatics analysis to produce novel candidates for further investigation. We also discuss the possibility of combining these two approaches into a hybrid framework, together with the benefits and challenges. These interdisciplinary research frameworks illustrate the interplay between computational models, omics analysis, and wet lab experiments, which holds the key to making real progress in improving human cardiac wellbeing. PMID:25499442

  1. Cardiac Physiology of Pregnancy.

    PubMed

    May, Linda

    2015-07-01

    Although the physiology of the heart and vascular system has not changed, there are many things we have learned and are still learning today. Research related to heart adaptations during pregnancy has been performed since the 1930s. Since the mid-1950s, researchers began to look at changes in the maternal cardiovascular system during exercise while pregnant. Research related to exercise during pregnancy and offspring heart development began and has continued since the 1970s. We will review the normal female cardiovascular system adaptations to pregnancy in general. Additionally, topics related to maternal cardiac adaptations to pregnancy during acute exercise, as well as the chronic conditioning response from exercise training will be explored. Since physical activity during pregnancy influences fetal development, the fetal cardiac development will be discussed in regards to acute and chronic maternal exercise. Similarly, the influence of various types of maternal exercise on acute and chronic fetal heart responses will be described. Briefly, the topics related to how and if there is maternal-fetal synchrony will be explained. Lastly, the developmental changes of the fetal cardiovascular system that persist after birth will be explored. Overall, the article will discuss maternal cardiac physiology related to changes with normal pregnancy, and exercise during pregnancy, as well as fetal cardiac physiology related to changes with normal development, and exercise during pregnancy as well as developmental changes in offspring after birth.

  2. The cardiac malpositions.

    PubMed

    Perloff, Joseph K

    2011-11-01

    Dextrocardia was known in the 17th century and was 1 of the first congenital malformations of the heart to be recognized. Fifty years elapsed before Matthew Baillie published his account of complete transposition in a human of the thoracic and abdominal viscera to the opposite side from what is natural. In 1858, Thomas Peacock stated that "the heart may be congenitally misplaced in various ways, occupying either an unusual position within the thorax, or being situated external to that cavity." In 1915, Maude Abbott described ectopia cordis, and Richard Paltauf's remarkable illustrations distinguished the various types of dextrocardia. In 1928, the first useful classification of the cardiac malpositions was proposed, and in 1966, Elliott et al's radiologic classification set the stage for clinical recognition. The first section of this review deals with the 3 basic cardiac malpositions in the presence of bilateral asymmetry. The second section deals with cardiac malpositions in the presence of bilateral left-sidedness or right-sidedness. Previous publications on cardiac malpositions are replete with an arcane vocabulary that confounds rather than clarifies. Even if the terms themselves are understood, inherent complexity weighs against clarity. This review was designed as a guided tour of an unfamiliar subject.

  3. Advanced Cardiac Life Support.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document contains materials for an advanced college course in cardiac life support developed for the State of Iowa. The course syllabus lists the course title, hours, number, description, prerequisites, learning activities, instructional units, required text, six references, evaluation criteria, course objectives by units, course…

  4. Ethical Issues in Cardiac Surgery

    PubMed Central

    Kavarana, Minoo N.; Sade, Robert M.

    2012-01-01

    While ethical behavior has always been part of cardiac surgical practice, ethical deliberation has only recently become an important component of cardiac surgical practice. Issues such as informed consent, conflict of interest, and professional self-regulation, among many others, have increasingly attracted the attention of cardiac surgeons. This review covers several broad topics of interest to cardiac surgeons and cardiologists, and treats several other topics more briefly. There is much uncertainty about what the future holds for cardiac surgical practice, research, and culture, and we discuss the background of ethical issues to serve as a platform for envisioning what is to come. PMID:22642634

  5. Multimodal Imaging after Sudden Cardiac Arrest in an 18-Year-Old Athlete

    PubMed Central

    Rehman, Mobeen Ur; Atalay, Michael K.; Broderick, Ryan J.

    2015-01-01

    We report the case of a previously healthy 18-year-old male athlete who twice presented with sudden cardiac arrest. Our use of electrocardiography, echocardiography, cardiac magnetic resonance, coronary angiography, coronary computed tomographic angiography, and nuclear stress testing enabled the diagnoses of apical hypertrophic cardiomyopathy and anomalous origin of the right coronary artery. We discuss the patient's treatment and note the useful role of multiple cardiovascular imaging methods in cases of sudden cardiac arrest. PMID:26664308

  6. Important advances in technology and unique applications to cardiovascular computed tomography.

    PubMed

    Chaikriangkrai, Kongkiat; Choi, Su Yeon; Nabi, Faisal; Chang, Su Min

    2014-01-01

    For the past decade, multidetector cardiac computed tomography and its main application, coronary computed tomography angiography, have been established as a noninvasive technique for anatomical assessment of coronary arteries. This new era of coronary artery evaluation by coronary computed tomography angiography has arisen from the rapid advancement in computed tomography technology, which has led to massive diagnostic and prognostic clinical studies in various patient populations. This article gives a brief overview of current multidetector cardiac computed tomography systems, developing cardiac computed tomography technologies in both hardware and software fields, innovative radiation exposure reduction measures, multidetector cardiac computed tomography functional studies, and their newer clinical applications beyond coronary computed tomography angiography. PMID:25574342

  7. Symmetry of cardiac function assessment.

    PubMed

    Bai, Xu-Fang; Ma, Amy X

    2016-09-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function.

  8. Symmetry of cardiac function assessment.

    PubMed

    Bai, Xu-Fang; Ma, Amy X

    2016-09-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function. PMID:27582768

  9. Symmetry of cardiac function assessment

    PubMed Central

    Bai, Xu-Fang; Ma, Amy X

    2016-01-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function. PMID:27582768

  10. System for the diagnosis and monitoring of coronary artery disease, acute coronary syndromes, cardiomyopathy and other cardiac conditions

    NASA Technical Reports Server (NTRS)

    Schlegel, Todd T. (Inventor); Arenare, Brian (Inventor)

    2008-01-01

    Cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed and stored in a useful form using a computer. The computer monitor displays various useful information, and in particular graphically displays various permutations of reduced amplitude zones and kurtosis that increase the rapidity and accuracy of cardiac diagnoses. New criteria for reduced amplitude zones are defined that enhance the sensitivity and specificity for detecting cardiac abnormalities.

  11. Effects of cardiac phase on diameter measurements from coronary cineangiograms

    NASA Technical Reports Server (NTRS)

    Selzer, Robert H.; Siebes, Maria; Lee, Paul L.; Hagerty, Cheryl; Azen, P.

    1989-01-01

    The measurement variability of end-diastolic frames is compared with frames taken from the other portions of the cardiac cycle. Two computer measurements, average diameter and minimum, are obtained for every frame of two complete cardiac cycles in angiograms of 20 subjects. Six schemes for sampling frames in various portions of the cardiac cycle are defined and the standard deviation is calculated for pairs of measurements from each scheme. The results suggest that the best strategy for frame selection is to use sequential frames in end-diastole. However, it is noted that if random samples are taken anywhere in the cardiac cycle instead of sequentially in end-diastole, the variability of two vessel edge measures changes from 4.9 percent to 6.3 percent, which is considered to be a small penalty.

  12. Bezoar-induced small bowel obstruction: Clinical characteristics and diagnostic value of multi-slice spiral computed tomography

    PubMed Central

    Wang, Pei-Yuan; Wang, Xia; Zhang, Lin; Li, Hai-Fei; Chen, Liang; Wang, Xu; Wang, Bin

    2015-01-01

    AIM: To determine the possible predisposing factors of bezoar-induced small bowel obstruction (BI-SBO) and to discuss the diagnostic value of multi-slice spiral computed tomography, particularly contrast-enhanced scanning, in this condition. METHODS: A total of 35 BI-SBO cases treated at our hospital from January 2007 to December 2013 were retrospectively analysed. Complete clinical and computed tomography (CT) data of the patients were available and confirmed by surgery. SBO was clinically diagnosed on the basis of clinical manifestations. Of the 35 patients, 18 underwent abdominal and pelvic CT planar scanning with GE 64-slice spiral CT and 17 underwent abdominal and pelvic CT planar scanning with GE 64-slice spiral CT combined with contrast-enhanced examination. Original images were processed using a GE ADW4.3 workstation to obtain MPR, CPR, MIP and CTA images. The images of all patients were evaluated by two abdominal imaging experts. The main analytical contents of planar scanning included intestinal bezoar conditions, changes in the intestinal wall and changes in peri-intestinal conditions. Vascular hyperaemia and arterial blood supply conditions at a specific obstruction site and the distal end of the obstruction site were evaluated through contrast-enhanced examination. RESULTS: The proportion of males to females among the 35 cases was 1:1.69 (13:22); median age was 63.3 years. The following cases were observed: 29 (82.8%) cases occurred in autumn and winter and showed a history of consuming high amounts of persimmon and hawthorn; 19 (54.3%) cases revealed a history of gastrointestinal surgery; 19 exhibited incomplete dentition, with missing partial or whole posterior teeth; 26 suffered from obstruction at the ileum. A total of 51 bezoars were found in these patients, of whom 16 (45.7%) had multiple bezoars. CT planar scanning of bezoars showed lumps with mottled gas inside the intestinal cavity. Furthermore, 9 cases of bezoars had envelopes and 11 cases

  13. Non-invasive Mapping of Cardiac Arrhythmias.

    PubMed

    Shah, Ashok; Hocini, Meleze; Haissaguerre, Michel; Jaïs, Pierre

    2015-08-01

    Since more than 100 years, 12-lead electrocardiography (ECG) is the standard-of-care tool, which involves measuring electrical potentials from limited sites on the body surface to diagnose cardiac disorder, its possible mechanism, and the likely site of origin. Several decades of research has led to the development of a 252-lead ECG and computed tomography (CT) scan-based three-dimensional electro-imaging modality to non-invasively map abnormal cardiac rhythms including fibrillation. These maps provide guidance towards ablative therapy and thereby help advance the management of complex heart rhythm disorders. Here, we describe the clinical experience obtained using non-invasive technique in mapping the electrical disorder and guide the catheter ablation of atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beats), and ventricular pre-excitation (Wolff-Parkinson-White syndrome).

  14. Cardiac nuclear medicine

    SciTech Connect

    Gerson, M.C.

    1987-01-01

    The book begins with a review of the radionuclide methods available for evaluating cardiac perfusion and function. The authors discuss planar and tomographic thallium myocardial imaging, first-pass and equilibrium radionuclide angiography, and imaging with infarct-avid tracers. Several common but more specialized procedures are then reviewed: nonogemetric measurement of left ventricular volume, phase (Fourier) analysis, stroke volume ratio, right ventricular function, and diastolic function. A separate chapter is devoted to drug interventions and in particular the use of radionuclide ventriculography to monitor doxorubicin toxicity and therapy of congestive heart failure. The subsequent chapters provide a comprehensive guide to test selection, accuracy, and results in acute myocardial infarction, in postmyocardial infarction, in chronic coronary artery disease, before and after medical or surgical revascularization, in valvular heart disease, in cardiomyopathies, and in cardiac trauma.

  15. Cardiac arrhythmias in pregnancy.

    PubMed

    Knotts, Robert J; Garan, Hasan

    2014-08-01

    As more women with repaired congenital heart disease survive to their reproductive years and many other women are delaying pregnancy until later in life, a rising concern is the risk of cardiac arrhythmias during pregnancy. Naturally occurring cardiovascular changes during pregnancy increase the likelihood that a recurrence of a previously experienced cardiac arrhythmia or a de novo arrhythmia will occur. Arrhythmias should be thoroughly investigated to determine if there is a reversible etiology, and risks/benefits of treatment options should be fully explored. We discuss the approach to working up and treating various arrhythmias during pregnancy with attention to fetal and maternal risks as well as treatment of fetal arrhythmias. Acute management in stable patients includes close monitoring and intravenous pharmacologic therapy, while DC cardioversion should be used to terminate arrhythmias in hemodynamically unstable patients. Long-term management may require continued oral antiarrhythmic therapy, with particular attention to fetal safety, to prevent complications associated with arrhythmias.

  16. Recovery after cardiac events.

    PubMed

    Davidson, D M; Maloney, C A

    1985-12-01

    This article describes an interdisciplinary program of cardiac rehabilitation that integrates physical therapy with medical, nursing, nutritional, and psychological assessment and treatment. Hospitalized patients recovering from myocardial infarction or cardiac surgery progress through a seven-level program of physical activity, education, and emotional support. These components of the program continue during their early home period and again are integrated during the active training period. In the active training period, patients participate in support groups and receive nutritional, exercise, and medical education and engage in one hour of exercise three times weekly. In all phases, considerable attention is given to the development of behavioral skills necessary for long-term adherence to healthy life style habits.

  17. The Role of Cardiac Side Population Cells in Cardiac Regeneration

    PubMed Central

    Yellamilli, Amritha; van Berlo, Jop H.

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies.

  18. The Role of Cardiac Side Population Cells in Cardiac Regeneration

    PubMed Central

    Yellamilli, Amritha; van Berlo, Jop H.

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies. PMID:27679798

  19. The Role of Cardiac Side Population Cells in Cardiac Regeneration.

    PubMed

    Yellamilli, Amritha; van Berlo, Jop H

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies.

  20. The Role of Cardiac Side Population Cells in Cardiac Regeneration.

    PubMed

    Yellamilli, Amritha; van Berlo, Jop H

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies. PMID:27679798

  1. Cardiac Signatures of Personality

    PubMed Central

    Koelsch, Stefan; Enge, Juliane; Jentschke, Sebastian

    2012-01-01

    Background There are well-established relations between personality and the heart, as evidenced by associations between negative emotions on the one hand, and coronary heart disease or chronic heart failure on the other. However, there are substantial gaps in our knowledge about relations between the heart and personality in healthy individuals. Here, we investigated whether amplitude patterns of the electrocardiogram (ECG) correlate with neurotisicm, extraversion, agreeableness, warmth, positive emotion, and tender-mindedness as measured with the Neuroticism-Extraversion-Openness (NEO) personality inventory. Specifically, we investigated (a) whether a cardiac amplitude measure that was previously reported to be related to flattened affectivity (referred to as values) would explain variance of NEO scores, and (b) whether correlations can be found between NEO scores and amplitudes of the ECG. Methodology/Principal Findings NEO scores and rest ECGs were obtained from 425 healthy individuals. Neuroticism and positive emotion significantly differed between individuals with high and low values. In addition, stepwise cross-validated regressions indicated correlations between ECG amplitudes and (a) agreeableness, as well as (b) positive emotion. Conclusions/Significance These results are the first to demonstrate that ECG amplitude patterns provide information about the personality of an individual as measured with NEO personality scales and facets. These findings open new perspectives for a more efficient personality assessment using cardiac measures, as well as for more efficient risk-stratification and pre-clinical diagnosis of individuals at risk for cardiac, affective and psychosomatic disorders. PMID:22363649

  2. Biomechanics of Cardiac Function

    PubMed Central

    Voorhees, Andrew P.; Han, Hai-Chao

    2015-01-01

    The heart pumps blood to maintain circulation and ensure the delivery of oxygenated blood to all the organs of the body. Mechanics play a critical role in governing and regulating heart function under both normal and pathological conditions. Biological processes and mechanical stress are coupled together in regulating myocyte function and extracellular matrix structure thus controlling heart function. Here we offer a brief introduction to the biomechanics of left ventricular function and then summarize recent progress in the study of the effects of mechanical stress on ventricular wall remodeling and cardiac function as well as the effects of wall mechanical properties on cardiac function in normal and dysfunctional hearts. Various mechanical models to determine wall stress and cardiac function in normal and diseased hearts with both systolic and diastolic dysfunction are discussed. The results of these studies have enhanced our understanding of the biomechanical mechanism in the development and remodeling of normal and dysfunctional hearts. Biomechanics provide a tool to understand the mechanism of left ventricular remodeling in diastolic and systolic dysfunction and guidance in designing and developing new treatments. PMID:26426462

  3. Cardiac outflow tract anomalies

    PubMed Central

    Neeb, Zachary; Lajiness, Jacquelyn D.; Bolanis, Esther; Conway, Simon J

    2014-01-01

    The mature outflow tract (OFT) is, in basic terms, a short conduit. It is a simple, although vital, connection situated between contracting muscular heart chambers and a vast embryonic vascular network. Unfortunately, it is also a focal point underlying many multifactorial congenital heart defects (CHDs). Through the use of various animal models combined with human genetic investigations, we are beginning to comprehend the molecular and cellular framework that controls OFT morphogenesis. Clear roles of neural crest cells (NCC) and second heart field (SHF) derivatives have been established during OFT formation and remodeling. The challenge now is to determine how the SHF and cardiac NCC interact, the complex reciprocal signaling that appears to be occurring at various stages of OFT morphogenesis, and finally how endocardial progenitors and primary heart field (PHF) communicate with both these colonizing extra-cardiac lineages. Although we are beginning to understand that this dance of progenitor populations is wonderfully intricate, the underlying pathogenesis and the spatiotemporal cell lineage interactions remain to be fully elucidated. What is now clear is that OFT alignment and septation are independent processes, invested via separate SHF and cardiac neural crest (CNC) lineages. This review will focus on our current understanding of the respective contributions of the SHF and CNC lineage during OFT development and pathogenesis. PMID:24014420

  4. Analysis of Ventricular Function by Computed Tomography

    PubMed Central

    Rizvi, Asim; Deaño, Roderick C.; Bachman, Daniel P.; Xiong, Guanglei; Min, James K.; Truong, Quynh A.

    2014-01-01

    The assessment of ventricular function, cardiac chamber dimensions and ventricular mass is fundamental for clinical diagnosis, risk assessment, therapeutic decisions, and prognosis in patients with cardiac disease. Although cardiac computed tomography (CT) is a noninvasive imaging technique often used for the assessment of coronary artery disease, it can also be utilized to obtain important data about left and right ventricular function and morphology. In this review, we will discuss the clinical indications for the use of cardiac CT for ventricular analysis, review the evidence on the assessment of ventricular function compared to existing imaging modalities such cardiac MRI and echocardiography, provide a typical cardiac CT protocol for image acquisition and post-processing for ventricular analysis, and provide step-by-step instructions to acquire multiplanar cardiac views for ventricular assessment from the standard axial, coronal, and sagittal planes. Furthermore, both qualitative and quantitative assessments of ventricular function as well as sample reporting are detailed. PMID:25576407

  5. Determination of cardiac size following space missions of different durations - The second manned Skylab mission

    NASA Technical Reports Server (NTRS)

    Nicogossian, A.; Hoffler, G. W.; Johnson, R. L.; Gowen, R. J.

    1976-01-01

    A simple method to estimate cardiac size from single frontal plane chest roentgenograms has been described. Pre- and postflight chest X-rays from Apollo 17, and Skylab 2 and 3 have been analyzed for changes in the cardiac silhouette size. The data obtained from the computed cardiothoracic areal ratios compared well with the clinical cardiothoracic diametral ratios (r = .86). Though an overall postflight decrease in cardiac size is evident, the mean difference was not statistically significant (n = 8). The individual decreases in the cardiac silhouette size postflight are thought to be due to decrements in intracardiac chamber volumes rather than in myocardial muscle mass.

  6. Determination of cardiac size following space missions of different durations: the second manned Skylab mission.

    PubMed

    Nicogossian, A; Hoffler, G W; Johnson, R L; Gowen, R J

    1976-04-01

    A simple method to estimate cardiac size from single frontal plane chest roentgenograms has been described. Pre- and postflight chest X-rays from Apollo 17, and Skylab 2 and 3 have been analyzed for changes in the cardiac silhouette size. The data obtained from the computed cardiothoracic areal ratios compared well with the clinical cardiothoracic diametral ratios (r = .86). Though an overall postflight decrease in cardiac size is evident, the mean difference was not statistically significant (n = 8). The individual decreases in the cardiac silhouette size postflight are thought to be due to decrements in intracardiac chamber volumes rather than in myocardial muscle mass.

  7. A non-invasive method for measuring cardiac output: the effect of Christmas lunch.

    PubMed

    Cowley, A J; Stainer, K; Murphy, D T; Murphy, J; Hampton, J R

    Cardiac output was measured in ten patients at routine cardiac catheterisation and three patients with severe heart failure by means of a carbon dioxide rebreathing technique with a computer-assisted mass spectrometer and compared with cardiac output measured by thermodilution. There was a close correlation (r = 0.96, p less than 0.01) between the two methods. Cardiac output measured by the carbon dioxide rebreathing technique increased after a typical Christmas lunch by a mean of 1.6 1/min in a group of healthy volunteers.

  8. An overview of cardiac morphogenesis.

    PubMed

    Schleich, Jean-Marc; Abdulla, Tariq; Summers, Ron; Houyel, Lucile

    2013-11-01

    Accurate knowledge of normal cardiac development is essential for properly understanding the morphogenesis of congenital cardiac malformations that represent the most common congenital anomaly in newborns. The heart is the first organ to function during embryonic development and is fully formed at 8 weeks of gestation. Recent studies stemming from molecular genetics have allowed specification of the role of cellular precursors in the field of heart development. In this article we review the different steps of heart development, focusing on the processes of alignment and septation. We also show, as often as possible, the links between abnormalities of cardiac development and the main congenital heart defects. The development of animal models has permitted the unraveling of many mechanisms that potentially lead to cardiac malformations. A next step towards a better knowledge of cardiac development could be multiscale cardiac modelling. PMID:24138816

  9. Cardiac Emergencies in Neurosurgical Patients

    PubMed Central

    Petropolis, Andrea; Cappellani, Ronald B.

    2015-01-01

    Perioperative safety concerns are a major area of interest in recent years. Severe cardiac perturbation such as cardiac arrest is one of the most dreaded complications in the intraoperative period; however, little is known about the management of these events in the patients undergoing elective neurosurgery. This special group needs further attention, as it is often neither feasible nor appropriate to apply conventional advanced cardiac life support algorithms in patients undergoing neurosurgery. Factors such as neurosurgical procedure and positioning can also have a significant effect on the occurrence of cardiac arrest. Therefore, the aim of this paper is to describe the various causes and management of cardiac emergencies with special reference to cardiac arrest during elective neurosurgical procedures, including discussion of position-related factors and resuscitative considerations in these situations. This will help to formulate possible guidelines for management of such events. PMID:25692145

  10. Sudden Cardiac Death in Athletes.

    PubMed

    Wasfy, Meagan M; Hutter, Adolph M; Weiner, Rory B

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  11. Sudden Cardiac Death in Athletes

    PubMed Central

    Wasfy, Meagan M.; Hutter, Adolph M.; Weiner, Rory B.

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  12. Cardiac size during prenatal development.

    PubMed

    Jordaan, H V

    1987-06-01

    In this study, the cardiac circumference as measured in a four-chamber view was analyzed to determine its relationship to three linear, sonar measurements--biparietal diameter, femoral length, and abdominal circumference--and two sonographically derived fetal parameters--gestational age and estimated fetal weight. The results showed that the cardiac circumference correlates significantly with these direct and derived variables. It is recommended that the magnitude of the cardiac circumference as a function of any or all of these variables be used as an index of organ size when assessing fetuses at risk for anomalous cardiac development.

  13. Registry of Unexplained Cardiac Arrest

    ClinicalTrials.gov

    2016-05-16

    Cardiac Arrest; Long QT Syndrome; Brugada Syndrome; Catecholaminergi Polymorphic Ventricular Tachycardia; Idiopathic VentricularFibrillation; Early Repolarization Syndrome; Arrhythmogenic Right Ventricular Cardiomyopathy

  14. Enhancer modeling uncovers transcriptional signatures of individual cardiac cell states in Drosophila

    PubMed Central

    Busser, Brian W.; Haimovich, Julian; Huang, Di; Ovcharenko, Ivan; Michelson, Alan M.

    2015-01-01

    Here we used discriminative training methods to uncover the chromatin, transcription factor (TF) binding and sequence features of enhancers underlying gene expression in individual cardiac cells. We used machine learning with TF motifs and ChIP data for a core set of cardiogenic TFs and histone modifications to classify Drosophila cell-type-specific cardiac enhancer activity. We show that the classifier models can be used to predict cardiac cell subtype cis-regulatory activities. Associating the predicted enhancers with an expression atlas of cardiac genes further uncovered clusters of genes with transcription and function limited to individual cardiac cell subtypes. Further, the cell-specific enhancer models revealed chromatin, TF binding and sequence features that distinguish enhancer activities in distinct subsets of heart cells. Collectively, our results show that computational modeling combined with empirical testing provides a powerful platform to uncover the enhancers, TF motifs and gene expression profiles which characterize individual cardiac cell fates. PMID:25609699

  15. Functions of Myosin Light Chain-2 (MYL2) In Cardiac Muscle and Disease

    PubMed Central

    Sheikh, Farah; Lyon, Robert C.; Chen, Ju

    2015-01-01

    Myosin light chain-2 (MYL2, also called MLC-2) is an ∼19 kDa sarcomeric protein that belongs to the EF-hand calcium binding protein superfamily and exists as three major isoforms encoded by three distinct genes in mammalian striated muscle. Each of the three different MLC-2 genes (MLC-2f; fast twitch skeletal isoform, MLC-2v; cardiac ventricular and slow twitch skeletal isoform, MLC-2a; cardiac atrial isoform) has a distinct developmental expression pattern in mammals. Genetic loss-of-function studies in mice demonstrated an essential role for cardiac isoforms of MLC-2, MLC-2v and MLC-2a, in cardiac contractile function during early embryogenesis. In the adult heart, MLC-2v function is regulated by phosphorylation, which displays a specific expression pattern (high in epicardium and low in endocardium) across the heart. These data along with new data from computational models, genetic mouse models, and human studies have revealed a direct role for MLC-2v phosphorylation in cross-bridge cycling kinetics, calcium-dependent cardiac muscle contraction, cardiac torsion, cardiac function and various cardiac diseases. This review focuses on the regulatory functions of MLC-2 in the embryonic and adult heart, with an emphasis on phosphorylation-driven actions of MLC-2v in adult cardiac muscle, which provide new insights into mechanisms regulating myosin cycling kinetics and human cardiac diseases. PMID:26074085

  16. Adaptive phase-coded reconstruction for cardiac CT

    NASA Astrophysics Data System (ADS)

    Hsieh, Jiang; Mayo, John; Acharya, Kishor; Pan, Tin-Su

    2000-04-01

    Cardiac imaging with conventional computed tomography (CT) has gained significant attention in recent years. New hardware development enables a CT scanner to rotate at a faster speed so that less cardiac motion is present in acquired projection data. Many new tomographic reconstruction techniques have also been developed to reduce the artifacts induced by the cardiac motion. Most of the algorithms make use of the projection data collected over several cardiac cycles to formulate a single projection data set. Because the data set is formed with samples collected roughly in the same phase of a cardiac cycle, the temporal resolution of the newly formed data set is significantly improved compared with projections collected continuously. In this paper, we present an adaptive phase- coded reconstruction scheme (APR) for cardiac CT. Unlike the previously proposed schemes where the projection sector size is identical, APR determines each sector size based on the tomographic reconstruction algorithm. The newly proposed scheme ensures that the temporal resolution of each sector is substantially equal. In addition, the scan speed is selected based on the measured EKG signal of the patient.

  17. UPDATE: CARDIAC XENOTRANSPLANTATION

    PubMed Central

    Ekser, Burcin; Cooper, David K.C.

    2009-01-01

    Purpose of review To review the latest development in cardiac xenotransplantation in small and large animal models and related in vitro studies. Recent findings With the recent introduction of α1,3-galactosyltransferase gene-knockout (GT-KO) pig organs for xenotransplantation, improved cardiac graft survival has been obtained. However, this experience has demonstrated the importance of pig antigens other than Galα1,3Gal (Gal) antigens (so-called nonGal antigens) as targets for primate anti-pig antibodies. Several in vitro studies have confirmed that, although the incidence and levels of anti-nonGal antibodies in non-human primates and humans are significantly less when compared with total anti-pig antibodies (i.e., anti-Gal + anti-nonGal), they can result in complement-mediated lysis of GT-KO pig cells. More recently, it has been demonstrated that regulatory T cells (Treg) suppress the cellular xenogeneic response, thus potentially preventing or reducing T cell-mediated rejection. The importance of thrombotic microangiopathy as a feature of the immune/inflammatory response and incompatibilities between the coagulation-anticoagulation systems of pig and primate are receiving increasing attention. Development of GT-KO pigs transgenic for one or more ‘anti-thrombotic’ genes, e.g., CD39 or tissue factor pathway inhibitor, may contribute to overcoming these problems. Summary Although GT-KO pigs have provided an advance over wild-type pigs as a source of Organs for transplantation into primates, further genetic modification of GT-KO pigs is required to overcome the remaining immune barriers before a clinical trial of cardiac xenotransplantation can be contemplated. PMID:19060538

  18. Cardiac phase: Amplitude analysis using macro programming

    SciTech Connect

    Logan, K.W.; Hickey, K.A.

    1981-11-01

    The analysis of EKG gated radionuclide cardiac imaging data with Fourier amplitude and phase images is becoming a valuable clinical technique, demonstrating location, size, and severity of regional ventricular abnormalities. Not all commercially available nuclear medicine computer systems offer software for phase and amplitude analysis; however, many systems do have the capability of linear image arithmetic using simple macro commands which can easily be sequenced into stored macro-strings or programs. Using simple but accurate series approximations for the Fourier operations, macro programs have been written for a Digital Equipment Corporation Gamma-11 system to obtain phase and amplitude images from routine gated cardiac studies. In addition, dynamic cine-mode presentation of the onset of mechanical systole is generated from the phase data, using only a second set of macro programs. This approach is easily adapted to different data acquisition protocols, and can be used on any system with macro commands for image arithmetic. Key words: Fourier analysis, cardiac cycle, gated blood pool imaging, amplitude image, phase image

  19. A system for seismocardiography-based identification of quiescent heart phases: implications for cardiac imaging.

    PubMed

    Wick, Carson A; Su, Jin-Jyh; McClellan, James H; Brand, Oliver; Bhatti, Pamela T; Buice, Ashley L; Stillman, Arthur E; Tang, Xiangyang; Tridandapani, Srini

    2012-09-01

    Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate. PMID:22581141

  20. A System for Seismocardiography-Based Identification of Quiescent Heart Phases: Implications for Cardiac Imaging

    PubMed Central

    Wick, Carson A.; Su, Jin-Jyh; McClellan, James H.; Brand, Oliver; Bhatti, Pamela T.; Buice, Ashley L.; Stillman, Arthur E.; Tang, Xiangyang; Tridandapani, Srini

    2013-01-01

    Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate. PMID:22581141

  1. The risks of inappropriateness in cardiac imaging.

    PubMed

    Picano, Eugenio

    2009-05-01

    The immense clinical and scientific benefits of cardiovascular imaging are well-established, but are also true that 30 to 50% of all examinations are partially or totally inappropriate. Marketing messages, high patient demand and defensive medicine, lead to the vicious circle of the so-called Ulysses syndrome. Mr. Ulysses, a typical middle-aged "worried-well" asymptomatic subject with an A-type coronary personality, a heavy (opium) smoker, leading a stressful life, would be advised to have a cardiological check-up after 10 years of war. After a long journey across imaging laboratories, he will have stress echo, myocardial perfusion scintigraphy, PET-CT, 64-slice CT, and adenosine-MRI performed, with a cumulative cost of >100 times a simple exercise-electrocardiography test and a cumulative radiation dose of >4,000 chest x-rays, with a cancer risk of 1 in 100. Ulysses is tired of useless examinations, exorbitant costs. unaffordable even by the richest society, and unacceptable risks. PMID:19543412

  2. The risks of inappropriateness in cardiac imaging.

    PubMed

    Picano, Eugenio

    2009-05-01

    The immense clinical and scientific benefits of cardiovascular imaging are well-established, but are also true that 30 to 50% of all examinations are partially or totally inappropriate. Marketing messages, high patient demand and defensive medicine, lead to the vicious circle of the so-called Ulysses syndrome. Mr. Ulysses, a typical middle-aged "worried-well" asymptomatic subject with an A-type coronary personality, a heavy (opium) smoker, leading a stressful life, would be advised to have a cardiological check-up after 10 years of war. After a long journey across imaging laboratories, he will have stress echo, myocardial perfusion scintigraphy, PET-CT, 64-slice CT, and adenosine-MRI performed, with a cumulative cost of >100 times a simple exercise-electrocardiography test and a cumulative radiation dose of >4,000 chest x-rays, with a cancer risk of 1 in 100. Ulysses is tired of useless examinations, exorbitant costs. unaffordable even by the richest society, and unacceptable risks.

  3. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  4. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Pacifico, Antonio (Inventor)

    1999-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiator having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may be used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  5. Health Instruction Packages: Cardiac Anatomy.

    ERIC Educational Resources Information Center

    Phillips, Gwen; And Others

    Text, illustrations, and exercises are utilized in these five learning modules to instruct nurses, students, and other health care professionals in cardiac anatomy and functions and in fundamental electrocardiographic techniques. The first module, "Cardiac Anatomy and Physiology: A Review" by Gwen Phillips, teaches the learner to draw and label…

  6. Redox Control of Cardiac Excitability

    PubMed Central

    Aggarwal, Nitin T.

    2013-01-01

    Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

  7. Psychological aspects of cardiac arrhythmia.

    PubMed

    Lynch, J J; Paskewitz, D A; Gimbel, K S; Thomas, S A

    1977-05-01

    A review of data from a wide spectrum of research studies suggests that psychological-emotional factors can significantly influence and alter the incidence of cardiac arrhythmia. While the existing data are, in many cases, difficult to interpret because of theoretical and methodological problems, sufficient evidence does exist to warrant a concerted investigation into the total involvement of psychological factors in cardiac arrhythmia.

  8. Ictal Cardiac Ryhthym Abnormalities

    PubMed Central

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic–clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  9. Ictal Cardiac Ryhthym Abnormalities.

    PubMed

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic-clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  10. Cardiac rehabilitation in Germany.

    PubMed

    Cantwell, J D

    1976-09-01

    The concept of cardiac reconditioning centers for the prevention and rehabilitation of coronary patients has been tremendously successful in Germany over the past 20 years. At least 40 such centers are located throughout the country. Physicians, nurses, and physical therapists work closely together in the various facets of the rehabilitation process. The financial backing for these facilities is primarily through governmental and regional insurance companies, whose officials are apparently convinced that in the long run supporting preventive measures is financially sound. Objective data supporting their convictions come from studies such as that of Brusis, who showed that such as that of 1,500 employees was diminished by nearly 70 percent during a two-year period after cardiac reconditioning, as compared to a similar time period before the rehabilitation experience. Subjective benefits, which are extremely difficult to quantitate in meaningful terms, were nonetheless expressed by nearly all the patients with whom I conversed. Perhaps they have experienced the same feelings that Mark Twain did when he observed that "all frets and worries and chafings sank to sleep in the presence of the benignant serenity of the Alps; the Great Spirit of the Mountains breathed his own peace upon their hurt minds and sore hearts and healed them." PMID:959329

  11. Interventional cardiac catheterization.

    PubMed

    Pihkala, J; Nykanen, D; Freedom, R M; Benson, L N

    1999-04-01

    Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart lesions. These procedures may be broadly grouped as dilations (e.g., septostomy, valvuloplasty, angioplasty, and endovascular stenting) or as closures (e.g., vascular embolization and device closure of defects). Balloon valvuloplasty has become the treatment of choice for patients in all age groups with simple valvar pulmonic stenosis and, although not curative, seems at least comparable to surgery for congenital aortic stenosis in newborns to young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Stents are useful in dilating lesions of which the intrinsic elasticity results in vessel recoil after balloon dilation alone. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although some devices remain investigational, they have been successfully used for closure of many arterial ducts and atrial and ventricular septal defects. In the therapy for patients with complex CHD, best results may be achieved by combining cardiac surgery with interventional catheterization. The cooperation among interventional cardiologists and cardiac surgeons was highlighted in a report of an algorithm to manage patients with tetralogy of Fallot or pulmonary atresia with diminutive pulmonary arteries, involving balloon dilation, coil embolization of collaterals, and intraoperative stent placement. In this setting, well-planned catheterization procedures have an important role in reducing the overall number of procedures that patients may require over a lifetime, with improved outcomes.

  12. Leadership in cardiac surgery.

    PubMed

    Rao, Christopher; Patel, Vanash; Ibrahim, Michael; Ahmed, Kamran; Wong, Kathie A; Darzi, Ara; von Segesser, Ludwig K; Athanasiou, Thanos

    2011-06-01

    Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importance.

  13. Decoding the Cardiac Message

    PubMed Central

    Dorn, Gerald W

    2012-01-01

    This review reflects and expands upon the contents of the author’s presentation at The Thomas W. Smith Memorial Lecture at AHA Scientific Sessions, 2011. “Decoding the cardiac message” refers to accumulating results from ongoing microRNA research that is altering longstanding concepts of the mechanisms for, and consequences of, messenger RNA (mRNA) regulation in the heart. First, I provide a brief historical perspective of the field of molecular genetics, touching upon seminal research that paved the way for modern molecular cardiovascular research and helped establish the foundation for current concepts of mRNA regulation in the heart. I follow with some interesting details about the specific research that led to the discovery and appreciation of microRNAs as highly conserved pivotal regulators of RNA expression and translation. Finally, I provide a personal viewpoint as to how agnostic genome-wide techniques for measuring microRNAs, their mRNA targets, and their protein products can be applied in an integrated multi-systems approach to uncover direct and indirect effects of microRNAs. Experimental designs integrating next-generation sequencing and global proteomics have the potential to address unanswered questions regarding microRNA-mRNA interactions in cardiac disease, how disease alters mRNA targeting by specific microRNAs, and how mutational and polymorphic nucleotide variation in microRNAs can affect end-organ function and stress-response. PMID:22383710

  14. The Cardiac Electrophysiology Web Lab.

    PubMed

    Cooper, Jonathan; Scharm, Martin; Mirams, Gary R

    2016-01-19

    Computational modeling of cardiac cellular electrophysiology has a long history, and many models are now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviors so that we can choose a model as a suitable basis for a new study or to characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models in a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models encoded in CellML, and a website (https://chaste.cs.ox.ac.uk/WebLab) provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyperkalemia. This resource is publicly available, open source, and free, and we invite the community to use it and become involved in future developments. Investigators interested in comparing competing hypotheses using models can make a more informed decision, and those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols.

  15. The Cardiac Electrophysiology Web Lab.

    PubMed

    Cooper, Jonathan; Scharm, Martin; Mirams, Gary R

    2016-01-19

    Computational modeling of cardiac cellular electrophysiology has a long history, and many models are now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviors so that we can choose a model as a suitable basis for a new study or to characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models in a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models encoded in CellML, and a website (https://chaste.cs.ox.ac.uk/WebLab) provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyperkalemia. This resource is publicly available, open source, and free, and we invite the community to use it and become involved in future developments. Investigators interested in comparing competing hypotheses using models can make a more informed decision, and those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols. PMID:26789753

  16. Cardiac Biomarkers and Acute Kidney Injury After Cardiac Surgery

    PubMed Central

    Bucholz, Emily M.; Whitlock, Richard P.; Zappitelli, Michael; Devarajan, Prasad; Eikelboom, John; Garg, Amit X.; Philbrook, Heather Thiessen; Devereaux, Philip J.; Krawczeski, Catherine D.; Kavsak, Peter; Shortt, Colleen

    2015-01-01

    OBJECTIVES: To examine the relationship of cardiac biomarkers with postoperative acute kidney injury (AKI) among pediatric patients undergoing cardiac surgery. METHODS: Data from TRIBE-AKI, a prospective study of children undergoing cardiac surgery, were used to examine the association of cardiac biomarkers (N-type pro–B-type natriuretic peptide, creatine kinase-MB [CK-MB], heart-type fatty acid binding protein [h-FABP], and troponins I and T) with the development of postoperative AKI. Cardiac biomarkers were collected before and 0 to 6 hours after surgery. AKI was defined as a ≥50% or 0.3 mg/dL increase in serum creatinine, within 7 days of surgery. RESULTS: Of the 106 patients included in this study, 55 (52%) developed AKI after cardiac surgery. Patients who developed AKI had higher median levels of pre- and postoperative cardiac biomarkers compared with patients without AKI (all P < .01). Preoperatively, higher levels of CK-MB and h-FABP were associated with increased odds of developing AKI (CK-MB: adjusted odds ratio 4.58, 95% confidence interval [CI] 1.56–13.41; h-FABP: adjusted odds ratio 2.76, 95% CI 1.27–6.03). When combined with clinical models, both preoperative CK-MB and h-FABP provided good discrimination (area under the curve 0.77, 95% CI 0.68–0.87, and 0.78, 95% CI 0.68–0.87, respectively) and improved reclassification indices. Cardiac biomarkers collected postoperatively did not significantly improve the prediction of AKI beyond clinical models. CONCLUSIONS: Preoperative CK-MB and h-FABP are associated with increased risk of postoperative AKI and provide good discrimination of patients who develop AKI. These biomarkers may be useful for risk stratifying patients undergoing cardiac surgery. PMID:25755241

  17. Overview of left ventricular outpouchings on cardiac magnetic resonance imaging

    PubMed Central

    Kumar, Sanjeev

    2015-01-01

    Left ventricular outpouchings commonly include aneurysm, pseudoaneurysm, and diverticulum and are now being increasingly detected on imaging. Distinction between these entities is of prime importance to guide proper management as outcomes for these entities differ substantially. Chest radiograph is usually nonspecific in their diagnosis. Echocardiography, multi-detector computed tomography evaluation and angiography are helpful in the diagnosis with their inherit limitations. Cardiac magnetic resonance imaging (MRI) is emerging as a very useful tool that allows simultaneous anatomical and functional evaluation along with tissue characterization, which has diagnostic, theraputic and prognostic implications. This article gives an overview of left ventricular outpouchings with special emphasis on their differentiation using cardiac MRI. PMID:26675616

  18. Direct cone-beam cardiac reconstruction algorithm with cardiac banding artifact correction

    SciTech Connect

    Taguchi, Katsuyuki; Chiang, Beshan S.; Hein, Ilmar A.

    2006-02-15

    Multislice helical computed tomography (CT) is a promising noninvasive technique for coronary artery imaging. Various factors can cause inconsistencies in cardiac CT data, which can result in degraded image quality. These inconsistencies may be the result of the patient physiology (e.g., heart rate variations), the nature of the data (e.g., cone-angle), or the reconstruction algorithm itself. An algorithm which provides the best temporal resolution for each slice, for example, often provides suboptimal image quality for the entire volume since the cardiac temporal resolution (TRc) changes from slice to slice. Such variations in TRc can generate strong banding artifacts in multi-planar reconstruction images or three-dimensional images. Discontinuous heart walls and coronary arteries may compromise the accuracy of the diagnosis. A {beta}-blocker is often used to reduce and stabilize patients' heart rate but cannot eliminate the variation. In order to obtain robust and optimal image quality, a software solution that increases the temporal resolution and decreases the effect of heart rate is highly desirable. This paper proposes an ECG-correlated direct cone-beam reconstruction algorithm (TCOT-EGR) with cardiac banding artifact correction (CBC) and disconnected projections redundancy compensation technique (DIRECT). First the theory and analytical model of the cardiac temporal resolution is outlined. Next, the performance of the proposed algorithms is evaluated by using computer simulations as well as patient data. It will be shown that the proposed algorithms enhance the robustness of the image quality against inconsistencies by guaranteeing smooth transition of heart cycles used in reconstruction.

  19. Functional imaging as an indicator of diagnostic information in cardiac magnetic-resonance images

    NASA Astrophysics Data System (ADS)

    Klingler, Joseph W.; Andrews, Lee T.; Begeman, Michael S.; Zeiss, Jacob; Leighton, Richard F.

    1990-08-01

    Magnetic Resonance (MR) images of the human heart provide three dimensional geometric information about the location of cardiac structures throughout the cardiac cycle. Analysis of this four dimensional data set allows detection of abnormal cardiac function related to the presence of coronary artery disease. To assist in this analysis, quantitative measurements of cardiac performance are made from the MR data including ejection fractions, regional wall motion and myocardial wall thickening. Analysis of cardiac performance provided by quantitative analysis of MR data can be aided by computer graphics presentation techniques. Two and three dimensional functional images are computed to indicate regions of abnormality based on the previous methods. The two dimensional images are created using color graphics overlays on the original MR image to represent performance. Polygon surface modeling techniques are used to represent data which is three dimensional, such as blood pool volumes. The surface of these images are color encoded by regional ejection fraction, wall motion or wall thickening. A functional image sequence is constructed at each phase of the cardiac cycle and displayed as a movie loop for review by the physician. Selection of a region on the functional image allows visual interpretation of the original MR images, graphical plots of cardiac function and tabular results. Color encoding is based on absolute measurements and comparison to standard normal templates of cardiac performance.

  20. Trends in Cardiac Pacemaker Batteries

    PubMed Central

    Mallela, Venkateswara Sarma; Ilankumaran, V; Rao, N.Srinivasa

    2004-01-01

    Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future. PMID:16943934

  1. Trends in cardiac pacemaker batteries.

    PubMed

    Mallela, Venkateswara Sarma; Ilankumaran, V; Rao, N Srinivasa

    2004-01-01

    Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future. PMID:16943934

  2. The Pathogenesis of Cardiac Fibrosis

    PubMed Central

    Kong, Ping; Christia, Panagiota; Frangogiannis, Nikolaos G

    2013-01-01

    Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. This review manuscript discusses the cellular effectors and molecular pathways implicated in the pathogenesis of cardiac fibrosis. Although activated myofibroblasts are the main effector cells in the fibrotic heart, monocytes/macrophages, lymphocytes, mast cells, vascular cells and cardiomyocytes may also contribute to the fibrotic response by secreting key fibrogenic mediators. Inflammatory cytokines and chemokines, reactive oxygen species, mast cell-derived proteases, endothelin-1, the renin/angiotensin/aldosterone system, matricellular proteins and growth factors (such as TGF-β and PDGF) are some of the best-studied mediators implicated in cardiac fibrosis. Both experimental and clinical evidence suggests that cardiac fibrotic alterations may be reversible. Understanding the mechanisms responsible for initiation, progression and resolution of cardiac fibrosis is crucial to design anti-fibrotic treatment strategies for patients with heart disease. PMID:23649149

  3. Cardiac action potential imaging

    NASA Astrophysics Data System (ADS)

    Tian, Qinghai; Lipp, Peter; Kaestner, Lars

    2013-06-01

    Action potentials in cardiac myocytes have durations in the order of magnitude of 100 milliseconds. In biomedical investigations the documentation of the occurrence of action potentials is often not sufficient, but a recording of the shape of an action potential allows a functional estimation of several molecular players. Therefore a temporal resolution of around 500 images per second is compulsory. In the past such measurements have been performed with photometric approaches limiting the measurement to one cell at a time. In contrast, imaging allows reading out several cells at a time with additional spatial information. Recent developments in camera technologies allow the acquisition with the required speed and sensitivity. We performed action potential imaging on isolated adult cardiomyocytes of guinea pigs utilizing the fluorescent membrane potential sensor di-8-ANEPPS and latest electron-multiplication CCD as well as scientific CMOS cameras of several manufacturers. Furthermore, we characterized the signal to noise ratio of action potential signals of varying sets of cameras, dye concentrations and objective lenses. We ensured that di-8-ANEPPS itself did not alter action potentials by avoiding concentrations above 5 μM. Based on these results we can conclude that imaging is a reliable method to read out action potentials. Compared to conventional current-clamp experiments, this optical approach allows a much higher throughput and due to its contact free concept leaving the cell to a much higher degree undisturbed. Action potential imaging based on isolated adult cardiomyocytes can be utilized in pharmacological cardiac safety screens bearing numerous advantages over approaches based on heterologous expression of hERG channels in cell lines.

  4. Verification of cardiac tissue electrophysiology simulators using an N-version benchmark

    PubMed Central

    Niederer, Steven A.; Kerfoot, Eric; Benson, Alan P.; Bernabeu, Miguel O.; Bernus, Olivier; Bradley, Chris; Cherry, Elizabeth M.; Clayton, Richard; Fenton, Flavio H.; Garny, Alan; Heidenreich, Elvio; Land, Sander; Maleckar, Mary; Pathmanathan, Pras; Plank, Gernot; Rodríguez, José F.; Roy, Ishani; Sachse, Frank B.; Seemann, Gunnar; Skavhaug, Ola; Smith, Nic P.

    2011-01-01

    Ongoing developments in cardiac modelling have resulted, in particular, in the development of advanced and increasingly complex computational frameworks for simulating cardiac tissue electrophysiology. The goal of these simulations is often to represent the detailed physiology and pathologies of the heart using codes that exploit the computational potential of high-performance computing architectures. These developments have rapidly progressed the simulation capacity of cardiac virtual physiological human style models; however, they have also made it increasingly challenging to verify that a given code provides a faithful representation of the purported governing equations and corresponding solution techniques. This study provides the first cardiac tissue electrophysiology simulation benchmark to allow these codes to be verified. The benchmark was successfully evaluated on 11 simulation platforms to generate a consensus gold-standard converged solution. The benchmark definition in combination with the gold-standard solution can now be used to verify new simulation codes and numerical methods in the future. PMID:21969679

  5. Biophotonic Modelling of Cardiac Optical Imaging.

    PubMed

    Bishop, Martin J; Plank, Gernot

    2015-01-01

    Computational models have been recently applied to simulate and better understand the nature of fluorescent photon scattering and optical signal distortion during cardiac optical imaging. The goal of such models is both to provide a useful post-processing tool to facilitate a more accurate and faithful comparison between computational simulations of electrical activity and experiments, as well as providing essential insight into the mechanisms underlying this distortion, suggesting ways in which it may be controlled or indeed utilised to maximise the information derived from the recorded fluorescent signal. Here, we present different modelling methodologies developed and used in the field to simulate both the explicit processes involved in optical signal synthesis and the resulting consequences of the effects of photon scattering within the myocardium upon the optically-detected signal. We focus our attentions to two main types of modelling approaches used to simulate light transport in cardiac tissue, specifically continuous (reaction-diffusion) and discrete stochastic (Monte Carlo) methods. For each method, we provide both a summary of the necessary methodological details of such models, in addition to brief reviews of relevant application studies which have sought to apply these methods to elucidate important information regarding experimentally-recorded optical signals under different circumstances.

  6. Multidivergent-beam stationary cardiac SPECT.

    PubMed

    Zeng, Gengsheng L; Stevens, Andrew M

    2009-07-01

    This article develops a stationary cardiac single photon emission computed tomography (SPECT) system using a novel multidivergent-beam collimator. This stationary SPECT system is inexpensive to build, small, and able to acquire true dynamic SPECT data. Stationary cardiac SPECT systems with multipinhole technology already exist. The proposed approach is to replace the multipinhole collimators with the originally designed multidivergent-beam collimators. The motivation for replacing the pinhole technology by divergent-beam technology is based on the following facts. The resolution/sensitivity trade-off for the pinhole is excellent (good resolution and good sensitivity) only in small object (e.g., small animal) imaging when it operates in the image magnifying mode. However, in large object (e.g., human) imaging, the resolution/sensitivity trade-off is poor (poor resolution and poor sensitivity) when the pinhole operates in the image reducing mode. In a stationary system, the number of angular views is limited; thus, image reduction is necessary to obtain more view angles. In this image reducing situation, divergent-beam collimation is able to provide better resolution and detection sensitivity than pinhole collimation. Computer simulations are carried out to verified the claims. PMID:19673185

  7. Solvers for the Cardiac Bidomain Equations

    PubMed Central

    Vigmond, E.J.; Weber dos Santos, R.; Prassl, A.J.; Deo, M.; Plank, G.

    2010-01-01

    The bidomain equations are widely used for the simulation of electrical activity in cardiac tissue. They are especially important for accurately modelling extracellular stimulation, as evidenced by their prediction of virtual electrode polarization before experimental verification. However, solution of the equations is computationally expensive due to the fine spatial and temporal discretization needed. This limits the size and duration of the problem which can be modeled. Regardless of the specific form into which they are cast, the computational bottleneck becomes the repeated solution of a large, linear system. The purpose of this review is to give an overview of the equations, and the methods by which they have been solved. Of particular note are recent developments in multigrid methods, which have proven to be the most efficient. PMID:17900668

  8. Cardiac Involvement in Ankylosing Spondylitis

    PubMed Central

    Ozkan, Yasemin

    2016-01-01

    Ankylosing spondylitis is one of the subgroup of diseases called “seronegative spondyloarthropathy”. Frequently, it affects the vertebral colon and sacroiliac joint primarily and affects the peripheral joints less often. This chronic, inflammatory and rheumatic disease can also affect the extraarticular regions of the body. The extraarticular affections can be ophthalmologic, cardiac, pulmonary or neurologic. The cardiac affection can be 2-10% in all patients. Cardiac complications such as left ventricular dysfunction, aortitis, aortic regurgitation, pericarditis and cardiomegaly are reviewed. PMID:27222669

  9. Acupuncture therapy related cardiac injury.

    PubMed

    Li, Xue-feng; Wang, Xian

    2013-12-01

    Cardiac injury is the most serious adverse event in acupuncture therapy. The causes include needling chest points near the heart, the cardiac enlargement and pericardial effusion that will enlarge the projected area on the body surface and make the proper depth of needling shorter, and the incorrect needling method of the points. Therefore, acupuncture practitioners must be familiar with the points of the heart projected area on the chest and the correct needling methods in order to reduce the risk of acupuncture therapy related cardiac injury.

  10. Videoscope-assisted cardiac surgery

    PubMed Central

    Chen, Robert Jeen-Chen

    2014-01-01

    Videoscope-assisted cardiac surgery (VACS) offers a minimally invasive platform for most cardiac operations such as coronary and valve procedures. It includes robotic and thoracoscopic approaches and each has strengths and weaknesses. The success depends on appropriate hardware setup, staff training, and troubleshooting efficiency. In our institution, we often use VACS for robotic left-internal-mammary-artery takedown, mitral valve repair, and various intra-cardiac operations such as tricuspid valve repair, combined Maze procedure, atrial septal defect repair, ventricular septal defect repair, etc. Hands-on reminders and updated references are provided for reader’s further understanding of the topic. PMID:24455172

  11. Dual gated nuclear cardiac images

    SciTech Connect

    Zubal, I.G.; Bennett, G.W.; Bizais, Y.; Brill, A.B.

    1984-02-01

    A data acquisition system has been developed to collect camera events simultaneously with continually digitized electrocardiograph signals and respiratory flow measurements. Software processing of the list mode data creates more precisely gated cardiac frames. Additionally, motion blur due to heart movement during breathing is reduced by selecting events within a specific respiratory phase. Thallium myocardium images of a healthy volunteer show increased definition. This technique of combined cardiac and respiratory gating has the potential of improving the detectability of small lesions, and the characterization of cardiac wall motion.

  12. Design and assessment of cardiac SPECT systems

    NASA Astrophysics Data System (ADS)

    Lee, Chih-Jie

    Single-photon emission computed tomography (SPECT) is a modality widely used to detect myocardial ischemia and myocardial infarction. Objectively assessing and comparing different SPECT systems is important so that the best detectability of cardiac defects can be achieved. Whitaker, Clarkson, and Barrett's study on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than reconstruction data. Thus, this observer model assesses overall hardware performance independent by any reconstruction algorithm. In addition, we will show that the run time of image-quality studies is significantly reduced. Several systems derived from the GE CZT-based dedicated cardiac SPECT camera Discovery 530c design, which is officially named the Alcyone Technology: Discovery NM 530c, were assessed using the performance of the SLO for the task of detecting cardiac defects and estimating the properties of the defects. Clinically, hearts can be virtually segmented into three coronary artery territories: left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA). One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can correctly predict in which territory the defect exists. A good estimation of the defect extent from the images is also very helpful for determining the seriousness of the myocardial ischemia. In this dissertation, both locations and extent of defects were estimated by the SLO, and system performance was assessed using localization receiver operating characteristic (LROC) / estimation receiver operating characteristic (EROC) curves. Area under LROC curve (AULC) / area under EROC curve (AUEC) and true positive fraction (TPF) at specific false positive fraction (FPF) can be treated as the gures of merit (FOMs). As the results will show, a

  13. Echocardiography as an indication of continuous-time cardiac quiescence

    NASA Astrophysics Data System (ADS)

    Wick, C. A.; Auffermann, W. F.; Shah, A. J.; Inan, O. T.; Bhatti, P. T.; Tridandapani, S.

    2016-07-01

    Cardiac computed tomography (CT) angiography using prospective gating requires that data be acquired during intervals of minimal cardiac motion to obtain diagnostic images of the coronary vessels free of motion artifacts. This work is intended to assess B-mode echocardiography as a continuous-time indication of these quiescent periods to determine if echocardiography can be used as a cost-efficient, non-ionizing modality to develop new prospective gating techniques for cardiac CT. These new prospective gating approaches will not be based on echocardiography itself but on CT-compatible modalities derived from the mechanics of the heart (e.g. seismocardiography and impedance cardiography), unlike the current standard electrocardiogram. To this end, echocardiography and retrospectively-gated CT data were obtained from ten patients with varied cardiac conditions. CT reconstructions were made throughout the cardiac cycle. Motion of the interventricular septum (IVS) was calculated from both echocardiography and CT reconstructions using correlation-based, deviation techniques. The IVS was chosen because it (1) is visible in echocardiography images, whereas the coronary vessels generally are not, and (2) has been shown to be a suitable indicator of cardiac quiescence. Quiescent phases were calculated as the minima of IVS motion and CT volumes were reconstructed for these phases. The diagnostic quality of the CT reconstructions from phases calculated from echocardiography and CT data was graded on a four-point Likert scale by a board-certified radiologist fellowship-trained in cardiothoracic radiology. Using a Wilcoxon signed-rank test, no significant difference in the diagnostic quality of the coronary vessels was found between CT volumes reconstructed from echocardiography- and CT-selected phases. Additionally, there was a correlation of 0.956 between the echocardiography- and CT-selected phases. This initial work suggests that B-mode echocardiography can be used as a

  14. Complete valvular heart apparatus model from 4D cardiac CT.

    PubMed

    Grbic, Sasa; Ionasec, Razvan; Vitanovski, Dime; Voigt, Ingmar; Wang, Yang; Georgescu, Bogdan; Navab, Nassir; Comaniciu, Dorin

    2012-07-01

    The cardiac valvular apparatus, composed of the aortic, mitral, pulmonary and tricuspid valves, is an essential part of the anatomical, functional and hemodynamic characteristics of the heart and the cardiovascular system as a whole. Valvular heart diseases often involve multiple dysfunctions and require joint assessment and therapy of the valves. In this paper, we propose a complete and modular patient-specific model of the cardiac valvular apparatus estimated from 4D cardiac CT data. A new constrained Multi-linear Shape Model (cMSM), conditioned by anatomical measurements, is introduced to represent the complex spatio-temporal variation of the heart valves. The cMSM is exploited within a learning-based framework to efficiently estimate the patient-specific valve parameters from cine images. Experiments on 64 4D cardiac CT studies demonstrate the performance and clinical potential of the proposed method. Our method enables automatic quantitative evaluation of the complete valvular apparatus based on non-invasive imaging techniques. In conjunction with existent patient-specific chamber models, the presented valvular model enables personalized computation modeling and realistic simulation of the entire cardiac system.

  15. CEnPiT: Helical cardiac CT reconstruction

    SciTech Connect

    Bontus, Claas; Koken, Peter; Koehler, Thomas; Grass, Michael

    2006-08-15

    Computer tomography (CT) scanners with an increasing number of detector rows offer the potential of shorter scanning times. Nevertheless, the reconstruction problem becomes more challenging, since cone beam artifacts are likely to enter. Here, we consider helical cardiac CT. We analyze how a relationship can be established between exact reconstruction algorithms and the demand to perform a cardiac gating. Utilizing the redundancies requires the consideration of all kinds of Radon planes. For the reconstruction algorithm proposed here, we separate the data into two parts. The first part contains contributions of Radon planes, which are measured with a large number of redundancies. The second part contains the remaining contributions. As it turns out, the second part contributes rather to the low-frequency contents of trans-axial slices. Therefore, we propose to perform a gated back-projection only for the first part, while the second part is back-projected in an ungated way. Data from the complete source trajectory are employed in the reconstruction process in contrary to conventional helical cardiac reconstruction methods. Moreover, all different types of Radon planes are taken into account in the reconstruction, though an ECG-dependent cardiac gating is applied. The reconstruction results, which we present for clinical and simulated data, demonstrate the high potential of CEnPiT for helical cardiac CT with large cone angle systems.

  16. Oral health, dental treatment, and cardiac valve surgery outcomes.

    PubMed

    Wu, Grace Hsiao; Manzon, Steve; Badovinac, Rachel; Woo, Sook-Bin

    2008-01-01

    The aim of this study was to determine whether not treating chronic dental infection during the admission for cardiac valve surgery would increase the morbidity and mortality of patients. Patients were divided into three groups: dentally unhealthy and untreated (Group A), dentally healthy not requiring treatment (Group B), and dentally unhealthy and treated (Group C). Hospital computer records and phone interviews were used to assess morbidity and mortality as assessed through the Social Security Death Index. Ninety-eight patient charts were reviewed. Patients in Group A (n = 47)were not at a significantly greater risk for developing infective endocarditis (IE) within 6 months of cardiac surgery compared to patients in Groups B (n = 17) and C (n = 34). Also, patients in Group A did not have a significantly higher rate of mortality compared to other groups (p= .09). The results suggest that there is no need to treat chronic oral infections in patients with compromised cardiac function within 24 to 48 hours prior to cardiac valve replacement surgery since this will not lower the risk of IE and death following cardiac valve surgery. Multicenter prospective case-controlled studies are needed to address this question definitively.

  17. Recent developments in cardiac pacing.

    PubMed

    Rodak, D J

    1995-10-01

    Indications for cardiac pacing continue to expand. Pacing to improve functional capacity, which is now common, relies on careful patient selection and technical improvements, such as complex software algorithms and diagnostic capabilities.

  18. Robot-Assisted Cardiac Surgery

    PubMed Central

    Watanabe, Go

    2015-01-01

    Recognition of the significant advantages of minimizing surgical trauma has resulted in the development of minimally invasive surgical procedures. Endoscopic surgery offers patients the benefits of minimally invasive surgery, and surgical robots have enhanced the ability and precision of surgeons. Consequently, technological advances have facilitated totally endoscopic robotic cardiac surgery, which has allowed surgeons to operate endoscopically rather than through a median sternotomy during cardiac surgery. Thus, repairs for structural heart conditions, including mitral valve plasty, atrial septal defect closure, multivessel minimally invasive direct coronary artery bypass grafting (MIDCAB), and totally endoscopic coronary artery bypass graft surgery (CABG), can be totally endoscopic. Robot-assisted cardiac surgery as minimally invasive cardiac surgery is reviewed. PMID:26134073

  19. Cardiac Rehabilitation: Then and Now.

    ERIC Educational Resources Information Center

    Wilson, Philip K.

    1988-01-01

    As more and more patients survive a coronary event, the need for cardiac rehabilitation will increase. The author reviews the history and current status of this field and predicts what lies ahead. (JD)

  20. Robot-assisted cardiac surgery.

    PubMed

    Ishikawa, Norihiko; Watanabe, Go

    2015-01-01

    Recognition of the significant advantages of minimizing surgical trauma has resulted in the development of minimally invasive surgical procedures. Endoscopic surgery offers patients the benefits of minimally invasive surgery, and surgical robots have enhanced the ability and precision of surgeons. Consequently, technological advances have facilitated totally endoscopic robotic cardiac surgery, which has allowed surgeons to operate endoscopically rather than through a median sternotomy during cardiac surgery. Thus, repairs for structural heart conditions, including mitral valve plasty, atrial septal defect closure, multivessel minimally invasive direct coronary artery bypass grafting (MIDCAB), and totally endoscopic coronary artery bypass graft surgery (CABG), can be totally endoscopic. Robot-assisted cardiac surgery as minimally invasive cardiac surgery is reviewed. PMID:26134073

  1. MedlinePlus: Cardiac Rehabilitation

    MedlinePlus

    ... available Research Clinical Trials Journal Articles Resources Reference Desk Find an Expert For You Patient Handouts Summary Cardiac rehabilitation (rehab) is a medically supervised program to help people who have A heart attack Angioplasty or ...

  2. Cardiac effects of noncardiac neoplasms

    SciTech Connect

    Schoen, F.J.; Berger, B.M.; Guerina, N.G.

    1984-11-01

    Clinically significant cardiovascular abnormalities may occur as secondary manifestations of noncardiac neoplasms. The principal cardiac effects of noncardiac tumors include the direct results of metastases to the heart or lungs, the indirect effects of circulating tumor products (causing nonbacterial thrombotic endocarditis, myeloma-associated amyloidosis, pheochromocytoma-associated cardiac hypertrophy and myofibrillar degeneration, and carcinoid heart disease), and the undesired cardiotoxicities of chemotherapy and radiotherapy. 89 references.

  3. Gene Transfer into Cardiac Myocytes

    PubMed Central

    Lang, Sarah E.; Westfall, Margaret V.

    2016-01-01

    Traditional methods for DNA transfection are often inefficient and toxic for terminally differentiated cells, such as cardiac myocytes. Vector-based gene transfer is an efficient approach for introducing exogenous cDNA into these types of primary cell cultures. In this chapter, separate protocols for adult rat cardiac myocyte isolation and gene transfer with recombinant adenovirus are provided and are routinely utilized for studying the effects of sarcomeric proteins on myofilament function. PMID:25836585

  4. Cardiac anatomy revisited

    PubMed Central

    Anderson, Robert H; Razavi, Reza; Taylor, Andrew M

    2004-01-01

    In tomorrow's world of clinical medicine, students will increasingly be confronted by anatomic displays reconstructed from tomographically derived images. These images all display the structure of the various organs in anatomical orientation, this being determined in time-honoured fashion by describing the individual in the ‘anatomical position’, standing upright and facing the observer. It follows from this approach that all adjectives used to describe the organs should be related to the three orthogonal planes of the body. Unfortunately, at present this convention is not followed for the heart, even though most students are taught that the so-called ‘right chambers’ are, in reality, in front of their ‘left’ counterparts. Rigorous analysis of the tomographic images already available, along with comparison with dissected hearts displayed in attitudinally correct orientation, calls into question this continuing tendency to describe the heart in terms of its own orthogonal axes, but with the organ positioned on its apex, so that the chambers can artefactually be visualized with the right atrium and right ventricle in right-sided position. Although adequate for describing functional aspects, such as ‘right-to-left’ shunting across intracardiac communications, this convention falls short when used to describe the position of the artery that supplies the diaphragmatic surface of the heart. Currently known as the ‘posterior descending artery’, in reality it is positioned inferiorly, and its blockage produces inferior myocardial infarction. In this review, we extend the concept of describing cardiac structure in attitudinally correct orientation, showing also how access to tomographic images clarifies many aspects of cardiac structure previously considered mysterious and arcane. We use images prepared using new techniques such as magnetic resonance imaging and computerized tomography, and compare them with dissection of the heart made in time

  5. Drosophila Models of Cardiac Disease

    PubMed Central

    Piazza, Nicole; Wessells, R.J.

    2013-01-01

    The fruit fly Drosophila melanogaster has emerged as a useful model for cardiac diseases, both developmental abnormalities and adult functional impairment. Using the tools of both classical and molecular genetics, the study of the developing fly heart has been instrumental in identifying the major signaling events of cardiac field formation, cardiomyocyte specification, and the formation of the functioning heart tube. The larval stage of fly cardiac development has become an important model system for testing isolated preparations of living hearts for the effects of biological and pharmacological compounds on cardiac activity. Meanwhile, the recent development of effective techniques to study adult cardiac performance in the fly has opened new uses for the Drosophila model system. The fly system is now being used to study long-term alterations in adult performance caused by factors such as diet, exercise, and normal aging. The fly is a unique and valuable system for the study of such complex, long-term interactions, as it is the only invertebrate genetic model system with a working heart developmentally homologous to the vertebrate heart. Thus, the fly model combines the advantages of invertebrate genetics (such as large populations, facile molecular genetic techniques, and short lifespan) with physiological measurement techniques that allow meaningful comparisons with data from vertebrate model systems. As such, the fly model is well situated to make important contributions to the understanding of complicated interactions between environmental factors and genetics in the long-term regulation of cardiac performance. PMID:21377627

  6. [Stem cells and cardiac regeneration].

    PubMed

    Perez Millan, Maria Ines; Lorenti, Alicia

    2006-01-01

    Stem cells are defined by virtue of their functional attributes: absence of tissue specific differentitated markers, capable of proliferation, able to self-maintain the population, able to produce a large number of differentiated, functional progeny, able to regenerate the tissue after injury. Cell therapy is an alternative for the treatment of several diseases, like cardiac diseases (cell cardiomyoplasty). A variety of stem cells could be used for cardiac repair: from cardiac and extracardiac sources. Each cell type has its own profile of advantages, limitations, and practicability issues in specific clinical settings. Differentiation of bone marrow stem cells to cardiomyocyte-like cells have been observed under different culture conditions. The presence of resident cardiac stem cell population capable of differentiation into cardiomyocyte or vascular lineage suggests that these cells could be used for cardiac tissue repair, and represent a great promise for clinical application. Stem cells mobilization by cytokines may also offer a strategy for cardiac regeneration. The use of stem cells (embryonic and adult) may hold the key to replacing cells lost in many devastating diseases. This potential benefit is a major focus for stem cell research.

  7. Cardiac Regeneration and Stem Cells.

    PubMed

    Zhang, Yiqiang; Mignone, John; MacLellan, W Robb

    2015-10-01

    After decades of believing the heart loses the ability to regenerate soon after birth, numerous studies are now reporting that the adult heart may indeed be capable of regeneration, although the magnitude of new cardiac myocyte formation varies greatly. While this debate has energized the field of cardiac regeneration and led to a dramatic increase in our understanding of cardiac growth and repair, it has left much confusion in the field as to the prospects of regenerating the heart. Studies applying modern techniques of genetic lineage tracing and carbon-14 dating have begun to establish limits on the amount of endogenous regeneration after cardiac injury, but the underlying cellular mechanisms of this regeneration remained unclear. These same studies have also revealed an astonishing capacity for cardiac repair early in life that is largely lost with adult differentiation and maturation. Regardless, this renewed focus on cardiac regeneration as a therapeutic goal holds great promise as a novel strategy to address the leading cause of death in the developed world.

  8. Global availability of cardiac rehabilitation.

    PubMed

    Turk-Adawi, Karam; Sarrafzadegan, Nizal; Grace, Sherry L

    2014-10-01

    Cardiovascular disease (CVD) is the most-prevalent noncommunicable disease and leading cause of death globally. Over 80% of deaths from CVD occur in low-income and middle-income countries (LMICs). To limit the socioeconomic impact of CVD, a comprehensive approach to health care is needed. Cardiac rehabilitation delivers a cost-effective and structured exercise, education, and risk reduction programme, which can reduce mortality by up to 25% in addition to improving a patient's functional capacity and lowering rehospitalization rates. Despite these benefits and recommendations in clinical practice guidelines, cardiac rehabilitation programmes are grossly under-used compared with revascularization or medical therapy for patients with CVD. Worldwide, only 38.8% of countries have cardiac rehabilitation programmes. Specifically, 68.0% of high-income and 23% of LMICs (8.3% for low-income and 28.2% for middle-income countries) offer cardiac rehabilitation programmes to patients with CVD. Cardiac rehabilitation density estimates range from one programme per 0.1 to 6.4 million inhabitants. Multilevel strategies to augment cardiac rehabilitation capacity and availability at national and international levels, such as supportive public health policies, systematic referral strategies, and alternative models of delivery are needed. PMID:25027487

  9. Cardiac Regeneration and Stem Cells

    PubMed Central

    Zhang, Yiqiang; Mignone, John; MacLellan, W. Robb

    2015-01-01

    After decades of believing the heart loses the ability to regenerate soon after birth, numerous studies are now reporting that the adult heart may indeed be capable of regeneration, although the magnitude of new cardiac myocyte formation varies greatly. While this debate has energized the field of cardiac regeneration and led to a dramatic increase in our understanding of cardiac growth and repair, it has left much confusion in the field as to the prospects of regenerating the heart. Studies applying modern techniques of genetic lineage tracing and carbon-14 dating have begun to establish limits on the amount of endogenous regeneration after cardiac injury, but the underlying cellular mechanisms of this regeneration remained unclear. These same studies have also revealed an astonishing capacity for cardiac repair early in life that is largely lost with adult differentiation and maturation. Regardless, this renewed focus on cardiac regeneration as a therapeutic goal holds great promise as a novel strategy to address the leading cause of death in the developed world. PMID:26269526

  10. Subtle alternating electrocardiographic morphology as an indicator of decreased cardiac electrical stability

    NASA Technical Reports Server (NTRS)

    Smith, J. M.; Blue, B.; Clancy, E.; Valeri, C. R.; Cohen, R. J.

    1985-01-01

    Observations from finite-element computer models, together with analytic developments based on percolation theory have suggested that subtle fluctuations of ECG morphology might serve as an indicator diminished cardiac electrical stability. With fixed-rate atrial pacing in canines, we have previously observed a pattern of alternation in T wave energy which correlated with cardiac electrical stability. We report here on a series of 20 canine experiments in which cardiac electrical stability (measured via Ventricular Fibrillation Threshold determination) was compared to a non-degenerate, multidimensional measurement of the degree of alternating activity present in the ECG complex morphology. The decrease in cardiac electrical stability brought on by both coronary artery occlusion and systemic hypothermia was consistently accompanied by subtle alternation in ECG morphology, with the absolute degree of alternating activity being significantly (negatively) correlated with cardiac electrical stability.

  11. Individual patient data meta-analysis for the clinical assessment of coronary computed tomography angiography: protocol of the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT)

    PubMed Central

    2013-01-01

    Background Coronary computed tomography angiography has become the foremost noninvasive imaging modality of the coronary arteries and is used as an alternative to the reference standard, conventional coronary angiography, for direct visualization and detection of coronary artery stenoses in patients with suspected coronary artery disease. Nevertheless, there is considerable debate regarding the optimal target population to maximize clinical performance and patient benefit. The most obvious indication for noninvasive coronary computed tomography angiography in patients with suspected coronary artery disease would be to reliably exclude significant stenosis and, thus, avoid unnecessary invasive conventional coronary angiography. To do this, a test should have, at clinically appropriate pretest likelihoods, minimal false-negative outcomes resulting in a high negative predictive value. However, little is known about the influence of patient characteristics on the clinical predictive values of coronary computed tomography angiography. Previous regular systematic reviews and meta-analyses had to rely on limited summary patient cohort data offered by primary studies. Performing an individual patient data meta-analysis will enable a much more detailed and powerful analysis and thus increase representativeness and generalizability of the results. The individual patient data meta-analysis is registered with the PROSPERO database (CoMe-CCT, CRD42012002780). Methods/Design The analysis will include individual patient data from published and unpublished prospective diagnostic accuracy studies comparing coronary computed tomography angiography with conventional coronary angiography. These studies will be identified performing a systematic search in several electronic databases. Corresponding authors will be contacted and asked to provide obligatory and additional data. Risk factors, previous test results and symptoms of individual patients will be used to estimate the pretest

  12. Cardiac Imaging System

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Although not available to all patients with narrowed arteries, balloon angioplasty has expanded dramatically since its introduction with an estimated further growth to 562,000 procedures in the U.S. alone by 1992. Growth has fueled demand for higher quality imaging systems that allow the cardiologist to be more accurate and increase the chances of a successful procedure. A major advance is the Digital Cardiac Imaging (DCI) System designed by Philips Medical Systems International, Best, The Netherlands and marketed in the U.S. by Philips Medical Systems North America Company. The key benefit is significantly improved real-time imaging and the ability to employ image enhancement techniques to bring out added details. Using a cordless control unit, the cardiologist can manipulate images to make immediate assessment, compare live x-ray and roadmap images by placing them side-by-side on monitor screens, or compare pre-procedure and post procedure conditions. The Philips DCI improves the cardiologist's precision by expanding the information available to him.

  13. The Implantable Cardiac Pacemaker

    PubMed Central

    Trimble, A. S.; Heimbecker, R. O.; Bigelow, W. G.

    1964-01-01

    The transistorized implanted pacemaker is proving to be an effective and reliable method for long-term pacing of the heart. All patients suffering from Stokes-Adams seizures were first given a trial period of conservative therapy, including isoproterenol (Isuprel), ephedrine, atropine and steroids. Twenty-four pacemaker implants were performed on 23 patients over a 21-month period. The preoperative insertion of a pacemaker cardiac catheter was a very valuable safety precaution. In this way the heart could be safely and reliably paced during the period of preoperative assessment and during the critical periods of anesthetic induction and thoracotomy. Infection did not occur, probably because of careful gas sterilization of the units. Various models of pacemakers are compared, and the reasons for two pacemaker failures are presented. There were two early deaths and one late death in the series. The relationship of progressive coronary disease to recent infarction is stressed. Patients having intermittent heart block frequently showed the picture of “competing pacemakers” postoperatively, but without deleterious effect. Twenty patients, between 54 and 88 years of age, are alive and well at the time of reporting, with excellent pacemaker response and no further Stokes-Adams attacks. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:14118681

  14. Exploring cardiac biophysical properties

    PubMed Central

    Mou, Younss Ait; Bollensdorff, Christian; Cazorla, Olivier; Magdi, Yacoub; de Tombe, Pieter P.

    2015-01-01

    The heart is subject to multiple sources of stress. To maintain its normal function, and successfully overcome these stresses, heart muscle is equipped with fine-tuned regulatory mechanisms. Some of these mechanisms are inherent within the myocardium itself and are known as intrinsic mechanisms. Over a century ago, Otto Frank and Ernest Starling described an intrinsic mechanism by which the heart, even ex vivo, regulates its function on a beat-to-beat basis. According to this phenomenon, the higher the ventricular filling is, the bigger the stroke volume. Thus, the Frank-Starling law establishes a direct relationship between the diastolic and systolic function of the heart. To observe this biophysical phenomenon and to investigate it, technologic development has been a pre-requisite to scientific knowledge. It allowed for example to observe, at the cellular level, a Frank-Starling like mechanism and has been termed: Length Dependent Activation (LDA). In this review, we summarize some experimental systems that have been developed and are currently still in use to investigate cardiac biophysical properties from the whole heart down to the single myofibril. As a scientific support, investigation of the Frank-Starling mechanism will be used as a case study. PMID:26779498

  15. [Pharmaca Induced Cardiac Injury].

    PubMed

    Haen, Ekkehard

    2016-01-01

    Many drugs influence vital functions via the sympathetic and the parasympathetic system. Besides that hypersensitivity reactions and reactions by chemical radicals that arise in drug metabolism may directly harm the heart muscle cell. Cardiac adverse drug reactions (ADR) result in disturbances of the heart rhythm, negative inotropic effects, direct damage to the heart muscle cell, and reduced perfusion of heart tissue. Their importance is often neglected because pharmacologically similar drugs are licensed for completely different indications. This is of particular interest if more drugs are prescribed in combination. Now these effects may add up to pharmacodynamic drug-drug-interactions. Data banks like PSIAConline (www.psiac.de), individualization of drug prescription by therapeutic drug monitoring (TDM) combined with a clinical pharmacological report (www.konbest.de), as well as drug information systems such as AGATE (www.amuep-agate.de) are today of help not just to recognize such drug risks, but also to find professional and evidence based solutions for it. PMID:26800070

  16. Cardiac achalasia in childhood

    PubMed Central

    Singh, Harjit; Sethi, R. S.; Gupta, H. L.; Khetarpal, S. K.

    1969-01-01

    Cardiac achalasia is a disorder not unknown in the paediatric age-group and may occur even in the neonatal period. This disorder should, therefore, be considered in all cases presenting with persistent vomiting, as well as in those with chronic respiratory disease in whom more common causes have been excluded. It is almost universally accepted that the disorder results from a disturbed function of ganglion cells in the distal oesophagus, as the disease has been reproduced in laboratory animals by denervation of the distal oesophagus. The exact pathogenesis of this degenerative change is not well understood. However, in at least some of the cases congenital absence of the ganglion cells may be responsible for this functional disturbance. This is inferred from the fact that the disease may be found in association with Hirschsprung disease, in which there is a congenital absence of ganglion cells in the terminal colon. Moreover, the occurrence of the disease in the neonatal period itself favours a congenital lesion. Surgery was preferred to other forms of treatment in the paediatric age-group in view of the reported equivocal response to mechanical dilatation and pre-disposition of children to respiratory complications. The results of surgery were satisfactory. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8 PMID:5790932

  17. Gender and cardiac surgery.

    PubMed

    Koch, Colleen Gorman; Nussmeier, Nancy A

    2003-09-01

    The increased operative mortality and morbidity of women compared with men undergoing CABG surgery results from multiple differences in presentation, preoperative risk profile, and surgical factors. Investigators have found consistently that women present with a different preoperative risk profile than do men. Women more commonly have factors associated with increased short- and long-term mortality, such as less frequent use of IMA grafts. Differences in study design and patient population may contribute to variability in short- and long-term mortality among the various studies. The lack of representation of women in older clinical trials has hindered our understanding of the management of CAD in women; this situation must be remedied in future studies, [95]. Known physiologic and anatomic differences must be evaluated for their effects on outcomes. Further studies are needed to evaluate gender-related differences in autonomic responses to acute coronary occlusion, complications related to cardiopulmonary bypass, susceptibility to abnormalities in coagulation, and other factors that might account for discrepant outcomes in men versus women undergoing CABG [96]. Beyond these factors, specific pharmacologic and therapeutic considerations, such as the role of estrogen replacement therapy, need to be clarified. As further knowledge accumulates, it is hoped that gender-specific risk factors can be mitigated and protective factors exploited, thereby improving the outcomes for all cardiac surgery patients.

  18. Cardiac cone-beam CT volume reconstruction using ART

    SciTech Connect

    Nielsen, T.; Manzke, R.; Proksa, R.; Grass, M.

    2005-04-01

    Modern computed tomography systems allow volume imaging of the heart. Up to now, approximately two-dimensional (2D) and 3D algorithms based on filtered backprojection are used for the reconstruction. These algorithms become more sensitive to artifacts when the cone angle of the x-ray beam increases as it is the current trend of computed tomography (CT) technology. In this paper, we investigate the potential of iterative reconstruction based on the algebraic reconstruction technique (ART) for helical cardiac cone-beam CT. Iterative reconstruction has the advantages that it takes the cone angle into account exactly and that it can be combined with retrospective cardiac gating fairly easily. We introduce a modified ART algorithm for cardiac CT reconstruction. We apply it to clinical cardiac data from a 16-slice CT scanner and compare the images to those obtained with a current analytical reconstruction method. In a second part, we investigate the potential of iterative reconstruction for a large area detector with 256 slices. For the clinical cases, iterative reconstruction produces excellent images of diagnostic quality. For the large area detector, iterative reconstruction produces images superior to analytical reconstruction in terms of cone-beam artifacts.

  19. Cell-Specific Cardiac Electrophysiology Models

    PubMed Central

    Groenendaal, Willemijn; Ortega, Francis A.; Kherlopian, Armen R.; Zygmunt, Andrew C.; Krogh-Madsen, Trine; Christini, David J.

    2015-01-01

    The traditional cardiac model-building paradigm involves constructing a composite model using data collected from many cells. Equations are derived for each relevant cellular component (e.g., ion channel, exchanger) independently. After the equations for all components are combined to form the composite model, a subset of parameters is tuned, often arbitrarily and by hand, until the model output matches a target objective, such as an action potential. Unfortunately, such models often fail to accurately simulate behavior that is dynamically dissimilar (e.g., arrhythmia) to the simple target objective to which the model was fit. In this study, we develop a new approach in which data are collected via a series of complex electrophysiology protocols from single cardiac myocytes and then used to tune model parameters via a parallel fitting method known as a genetic algorithm (GA). The dynamical complexity of the electrophysiological data, which can only be fit by an automated method such as a GA, leads to more accurately parameterized models that can simulate rich cardiac dynamics. The feasibility of the method is first validated computationally, after which it is used to develop models of isolated guinea pig ventricular myocytes that simulate the electrophysiological dynamics significantly better than does a standard guinea pig model. In addition to improving model fidelity generally, this approach can be used to generate a cell-specific model. By so doing, the approach may be useful in applications ranging from studying the implications of cell-to-cell variability to the prediction of intersubject differences in response to pharmacological treatment. PMID:25928268

  20. Intramuscular pressure-induced inhibition of cardiac contraction: implications for cardiac-locomotor synchronization.

    PubMed

    Niizeki, Kyuichi

    2005-03-01

    The synchronization of cardiac and locomotor rhythms has been suggested to enhance the efficiency of arterial delivery to active muscles during rhythmic exercise, but direct evidence showing such a functional role has not been provided. In this study, we tested the hypothesis that the heartbeat is coupled with intramuscular pressure (IMP) changes so as to time the delivery of blood through peripheral tissues when the IMP is lower. To this end, we developed a computer-controlled, dynamic, thigh cuff occlusion device that enables bilateral thigh cuffs to repeatedly inflate and deflate, one side after the other, to simulate rhythmic IMP changes during bipedal locomotion. Nine healthy subjects were examined, and three different occlusion pressures (50, 80, and 120 mmHg) were applied separately to the thigh cuffs of normal subjects while they were sitting. Alternate occlusions of the bilateral thigh cuffs administered at the frequency of the mean heart rate produced significant phase synchronization between the cardiac and cuff-occlusion rhythms when 120 mmHg pressure was applied. However, synchronization was not observed when the occlusion pressure was 50 or 80 mmHg. During synchronization, heartbeats were most likely to occur in phases that did not include overlap between the peak arterial flow velocity in the thigh and elevated cuff pressure. We believe that phase synchronization occurs so that the cardiac cycle is timed to deliver blood through the lower legs when IMP is not maximal. If this can be extrapolated to natural locomotion, synchronization between cardiac and locomotor activities may be associated with the improved perfusion of exercising muscles.

  1. Design and formulation of functional pluripotent stem cell-derived cardiac microtissues

    PubMed Central

    Thavandiran, Nimalan; Dubois, Nicole; Mikryukov, Alexander; Massé, Stéphane; Beca, Bogdan; Simmons, Craig A.; Deshpande, Vikram S.; McGarry, J. Patrick; Chen, Christopher S.; Nanthakumar, Kumaraswamy; Keller, Gordon M.; Radisic, Milica; Zandstra, Peter W.

    2013-01-01

    Access to robust and information-rich human cardiac tissue models would accelerate drug-based strategies for treating heart disease. Despite significant effort, the generation of high-fidelity adult-like human cardiac tissue analogs remains challenging. We used computational modeling of tissue contraction and assembly mechanics in conjunction with microfabricated constraints to guide the design of aligned and functional 3D human pluripotent stem cell (hPSC)-derived cardiac microtissues that we term cardiac microwires (CMWs). Miniaturization of the platform circumvented the need for tissue vascularization and enabled higher-throughput image-based analysis of CMW drug responsiveness. CMW tissue properties could be tuned using electromechanical stimuli and cell composition. Specifically, controlling self-assembly of 3D tissues in aligned collagen, and pacing with point stimulation electrodes, were found to promote cardiac maturation-associated gene expression and in vivo-like electrical signal propagation. Furthermore, screening a range of hPSC-derived cardiac cell ratios identified that 75% NKX2 Homeobox 5 (NKX2-5)+ cardiomyocytes and 25% Cluster of Differentiation 90 OR (CD90)+ nonmyocytes optimized tissue remodeling dynamics and yielded enhanced structural and functional properties. Finally, we demonstrate the utility of the optimized platform in a tachycardic model of arrhythmogenesis, an aspect of cardiac electrophysiology not previously recapitulated in 3D in vitro hPSC-derived cardiac microtissue models. The design criteria identified with our CMW platform should accelerate the development of predictive in vitro assays of human heart tissue function. PMID:24255110

  2. The cardiac torsion as a sensitive index of heart pathology: A model study.

    PubMed

    Cutrì, E; Serrani, M; Bagnoli, P; Fumero, R; Costantino, M L

    2015-03-01

    The torsional behaviour of the heart (i.e. the mutual rotation of the cardiac base and apex) was proved to be sensitive to alterations of some cardiovascular parameters, i.e. preload, afterload and contractility. Moreover, pathologies which affect the fibers architecture and cardiac geometry were proved to alter the cardiac torsion pattern. For these reasons, cardiac torsion represents a sensitive index of ventricular performance. The aim of this work is to provide further insight into physiological and pathological alterations of the cardiac torsion by means of computational analyses, combining a structural model of the two ventricles with simple lumped parameter models of both the systemic and the pulmonary circulations. Starting from diagnostic images, a 3D anatomy based geometry of the two ventricles was reconstructed. The myocytes orientation in the ventricles was assigned according to literature data and the myocardium was modelled as an anisotropic hyperelastic material. Both the active and the passive phases of the cardiac cycle were modelled, and different clinical conditions were simulated. The results in terms of alterations of the cardiac torsion in the presence of pathologies are in agreement with experimental literature data. The use of a computational approach allowed the investigation of the stresses and strains in the ventricular wall as well as of the global hemodynamic parameters in the presence of the considered pathologies. Furthermore, the model outcomes highlight how for specific pathological conditions, an altered torsional pattern of the ventricles can be present, encouraging the use of the ventricular torsion in the clinical practice.

  3. Automated segmentation of cardiac visceral fat in low-dose non-contrast chest CT images

    NASA Astrophysics Data System (ADS)

    Xie, Yiting; Liang, Mingzhu; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2015-03-01

    Cardiac visceral fat was segmented from low-dose non-contrast chest CT images using a fully automated method. Cardiac visceral fat is defined as the fatty tissues surrounding the heart region, enclosed by the lungs and posterior to the sternum. It is measured by constraining the heart region with an Anatomy Label Map that contains robust segmentations of the lungs and other major organs and estimating the fatty tissue within this region. The algorithm was evaluated on 124 low-dose and 223 standard-dose non-contrast chest CT scans from two public datasets. Based on visual inspection, 343 cases had good cardiac visceral fat segmentation. For quantitative evaluation, manual markings of cardiac visceral fat regions were made in 3 image slices for 45 low-dose scans and the Dice similarity coefficient (DSC) was computed. The automated algorithm achieved an average DSC of 0.93. Cardiac visceral fat volume (CVFV), heart region volume (HRV) and their ratio were computed for each case. The correlation between cardiac visceral fat measurement and coronary artery and aortic calcification was also evaluated. Results indicated the automated algorithm for measuring cardiac visceral fat volume may be an alternative method to the traditional manual assessment of thoracic region fat content in the assessment of cardiovascular disease risk.

  4. Cardiac pacing and aviation.

    PubMed

    Toff, W D; Edhag, O K; Camm, A J

    1992-12-01

    Certain applicants with stable disturbances of rhythm or conduction requiring cardiac pacing, in whom no other disqualifying condition is present, may be considered fit for medical certification restricted to multi-crew operations. The reliability of modern pacing systems appears adequate to permit restricted certification even in pacemaker dependent subjects except for certain models of pacemakers and leads known to be at increased risk of failure. These are to be avoided. There is little evidence to suggest that newer devices are any more reliable than their predecessors. Single and dual chamber systems appear to have similar reliability up to 4 years, after which time significant attrition of dual chamber devices occurs, principally due to battery depletion. All devices require increased scrutiny as they approach their end of life as predicted from longevity data and pacing characteristics. Unipolar and bipolar leads are of similar reliability, apart from a number of specific bipolar polyurethane leads which have been identified. Atrial leads, particularly those without active fixation, are less secure than ventricular leads and applicants who are dependent on atrial sensing or pacing should be denied certification. Bipolar leads are to be preferred due to the lower risk of myopotential and exogenous EMI. Sensor-driven adaptive-rate pacing systems using active sensors may have reduced longevity and require close scrutiny. Activity-sensing devices using piezoelectric crystal sensors may be subject to significant rate rises in rotary wing aircraft. The impracticality of restricted certification in helicopters will, in any event, preclude certification. Such devices would best be avoided in hovercraft (air cushioned vehicle) pilots. Only minor rate rises are likely in fixed-wing aircraft which are unlikely to be of significance. Anti-tachycardia devices and implanted defibrillators are inconsistent with any form of certification to fly. PMID:1493823

  5. Improving the stability of cardiac mechanical simulations.

    PubMed

    Land, Sander; Niederer, Steven A; Lamata, Pablo; Smith, Nicolas P

    2015-03-01

    In the field of cardiac modeling, the mechanical action of the heart is often simulated using finite element methods. These simulations are becoming increasingly challenging as the computational domain is customized to a patient's anatomy, within which large heterogeneous tension gradients are generated via biophysical cell models which drive simulations of the cardiac pump cycle. The convergence of nonlinear solvers in simulations of large deformation mechanics depends on many factors. When extreme stress or irregular deformations are modeled, commonly used numerical methods can often fail to find a solution, which can prevent investigation of interesting parameter variations or use of models in a clinical context with high standards for robustness. This paper outlines a novel numerical method that is straightforward to implement and which significantly improves the stability of these simulations. The method involves adding a compressibility penalty to the standard incompressible formulation of large deformation mechanics. We compare the method's performance when used with both a direct discretization of the equations for incompressible solid mechanics, as well as the formulation based on an isochoric/deviatoric split of the deformation gradient. The addition of this penalty decreases the tendency for solutions to deviate from the incompressibility constraint, and significantly improves the ability of the Newton solver to find a solution. Additionally, our method maintains the expected order of convergence under mesh refinement, has nearly identical solutions for the pressure-volume relations, and stabilizes the solver to allow challenging simulations of both diastolic and systolic function on personalized patient geometries. PMID:25474804

  6. Women's compliance with cardiac rehabilitation programs.

    PubMed

    Ginzel, A R

    1996-01-01

    As the incidence of cardiovascular disease in women increases, the process of cardiac rehabilitation in women is becoming increasingly important to nurses. Specifically, the issue of women's compliance with cardiac rehabilitation needs to be addressed by nurses. Most past and current research on cardiac rehabilitation and compliance with rehabilitation programs has been conducted on male subjects and cannot be accurately generalized to the female population. This article reviews current literature which addresses the issues of heart disease in women, cardiac rehabilitation and compliance in the general population, gender differences in cardiac rehabilitation, and compliance of women in cardiac rehabilitation. PMID:8657707

  7. A novel multimedia tool to improve bedside teaching of cardiac auscultation.

    PubMed

    Woywodt, A; Herrmann, A; Kielstein, J T; Haller, H; Haubitz, M; Purnhagen, H

    2004-06-01

    Training in cardiac auscultation is a core element of undergraduate teaching but recent studies have documented a remarkable decline in auscultatory skills. Therefore there is an interest in new ways to teach cardiac auscultation. In analogy to phonocardiography, an electronic system for simultaneous auscultation and visualisation of murmurs was sought. For this purpose, an electronic stethoscope was linked to a laptop computer and software created to visualise auscultatory findings. In a preliminary trial in undergraduate students, this approach greatly facilitated teaching. Amalgamating traditional phonocardiography with a multimedia approach, this system represents a novel tool for bedside teaching of cardiac auscultation.

  8. Direct Cardiac Reprogramming: From Developmental Biology to Cardiac Regeneration

    PubMed Central

    Qian, Li; Srivastava, Deepak

    2013-01-01

    Heart disease affects millions worldwide and is a progressive condition involving loss of cardiomyocytes. The human heart has limited endogenous regenerative capacity and is thus an important target for novel regenerative medicine approaches. While cell-based regenerative therapies hold promise, cellular reprogramming of endogenous cardiac fibroblasts, which represent more than half of the cells in the mammalian heart, may be an attractive alternative strategy for regenerating cardiac muscle. Recent advances leveraging years of developmental biology point to the feasibility of generating de novo cardiomyocyte-like cells from terminally differentiated non-myocytes in the heart in situ after ischemic damage. Here, we review the progress in cardiac reprogramming methods and consider the opportunities and challenges that lie ahead in refining this technology for regenerative medicine. PMID:24030021

  9. Finite Element Model of Cardiac Electrical Conduction.

    NASA Astrophysics Data System (ADS)

    Yin, John Zhihao

    1994-01-01

    In this thesis, we develop mathematical models to study electrical conduction of the heart. One important pattern of wave propagation of electrical excitation in the heart is reentry which is believed to be the underlying mechanism of some dangerous cardiac arhythmias such as ventricular tachycardia and ventricular fibrillation. We present in this thesis a new ionic channel model of the ventricular cardiac cell membrane to study the microscopic electrical properties of myocardium. We base our model on recent single channel experiment data and a simple physical diffusion model of the calcium channel. Our ionic channel model of myocardium has simpler differential equations and fewer parameters than previous models. Further more, our ionic channel model achieves better results in simulating the strength-interval curve when we connect the membrane patch model to form a one dimensional cardiac muscle strand. We go on to study a finite element model which uses multiple states and non-nearest neighbor interactions to include curvature and dispersion effects. We create a generalized lattice randomization to overcome the artifacts generated by the interaction between the local dynamics and the regularities of the square lattice. We show that the homogeneous model does not display spontaneous wavefront breakup in a reentrant wave propagation once the lattice artifacts have been smoothed out by lattice randomization with a randomization scale larger than the characteristic length of the interaction. We further develop a finite 3-D 3-state heart model which employs a probability interaction rule. This model is applied to the simulation of Body Surface Laplacian Mapping (BSLM) using a cylindrical volume conductor as the torso model. We show that BSLM has a higher spatial resolution than conventional mapping methods in revealing the underlying electrical activities of the heart. The results of these studies demonstrate that mathematical modeling and computer simulation are very

  10. Cardiac injury complicating traumatic asphyxia.

    PubMed

    Rosato, R M; Shapiro, M J; Keegan, M J; Connors, R H; Minor, C B

    1991-10-01

    During a 3-year period (1986-1989), 8 patients were seen at St. Louis University Medical Center exhibiting the stigmata of traumatic asphyxia. Fewer than 200 cases of traumatic asphyxia have been reported and there is only a single report of a cardiac injury. In this series, 3 of 8 (37.5%) patients were found to have an injury to the heart: two cardiac contusions and a ventricular rupture. Five patients were crushed in motor vehicle collisions, one by an elevator counterweight, and two patients by river barges. Injuries associated with these patients include pulmonary contusion, hemopneumothorax, traumatic pneumatocele, traumatic retinopathy, bone fractures, mental confusion, and liver contusion. There was one death in the series, a patient with rupture of the right ventricle and severe splenic and liver injuries. The cardiac status of the patients was evaluated by serial serum cardiac enzyme determinations, electrocardiograms, and echocardiography. This report illustrates the importance of complete cardiac evaluation in patients with traumatic asphyxia. PMID:1942148

  11. Cardiac complications in thalassemia major.

    PubMed

    Auger, Dominique; Pennell, Dudley J

    2016-03-01

    The myocardium is particularly susceptible to complications from iron loading in thalassemia major. In the first years of life, severe anemia leads to high-output cardiac failure and death if not treated. The necessary supportive blood transfusions create loading of iron that cannot be naturally excreted, and this iron accumulates within tissues, including the heart. Free unbound iron catalyzes the formation of toxic hydroxyl radicals, which damage cells and cause cardiac dysfunction. Significant cardiac siderosis may present by the age of 10 and may lead to acute clinical heart failure, which must be treated urgently. Atrial fibrillation is the most frequently encountered iron-related arrhythmia. Iron chelation is effective at removing iron from the myocardium, at the expense of side effects that hamper compliance to therapy. Monitoring of myocardial iron content is mandatory for clinical management of cardiac risk. T2* cardiac magnetic resonance measures myocardial iron and is the strongest biomarker for prediction of heart failure and arrhythmic events. It has been calibrated to human myocardial tissue iron concentration and is highly reproducible across all magnetic resonance scanner vendors. As survival and patient age increases, endothelial dysfunction and diabetes may become new factors in the cardiovascular health of thalassemia patients. Promising new imaging technology and therapies could ameliorate the long-term prognosis.

  12. Animal models of cardiac cachexia.

    PubMed

    Molinari, Francesca; Malara, Natalia; Mollace, Vincenzo; Rosano, Giuseppe; Ferraro, Elisabetta

    2016-09-15

    Cachexia is the loss of body weight associated with several chronic diseases including chronic heart failure (CHF). The cachectic condition is mainly due to loss of skeletal muscle mass and adipose tissue depletion. The majority of experimental in vivo studies on cachexia rely on animal models of cancer cachexia while a reliable and appropriate model for cardiac cachexia has not yet been established. A critical issue in generating a cardiac cachexia model is that genetic modifications or pharmacological treatments impairing the heart functionality and used to obtain the heart failure model might likely impair the skeletal muscle, this also being a striated muscle and sharing with the myocardium several molecular and physiological mechanisms. On the other hand, often, the induction of heart damage in the several existing models of heart failure does not necessarily lead to skeletal muscle loss and cachexia. Here we describe the main features of cardiac cachexia and illustrate some animal models proposed for cardiac cachexia studies; they include the genetic calsequestrin and Dahl salt-sensitive models, the monocrotaline model and the surgical models obtained by left anterior descending (LAD) ligation, transverse aortic constriction (TAC) and ascending aortic banding. The availability of a specific animal model for cardiac cachexia is a crucial issue since, besides the common aspects of cachexia in the different syndromes, each disease has some peculiarities in its etiology and pathophysiology leading to cachexia. Such peculiarities need to be unraveled in order to find new targets for effective therapies. PMID:27317993

  13. Animal models of cardiac cachexia.

    PubMed

    Molinari, Francesca; Malara, Natalia; Mollace, Vincenzo; Rosano, Giuseppe; Ferraro, Elisabetta

    2016-09-15

    Cachexia is the loss of body weight associated with several chronic diseases including chronic heart failure (CHF). The cachectic condition is mainly due to loss of skeletal muscle mass and adipose tissue depletion. The majority of experimental in vivo studies on cachexia rely on animal models of cancer cachexia while a reliable and appropriate model for cardiac cachexia has not yet been established. A critical issue in generating a cardiac cachexia model is that genetic modifications or pharmacological treatments impairing the heart functionality and used to obtain the heart failure model might likely impair the skeletal muscle, this also being a striated muscle and sharing with the myocardium several molecular and physiological mechanisms. On the other hand, often, the induction of heart damage in the several existing models of heart failure does not necessarily lead to skeletal muscle loss and cachexia. Here we describe the main features of cardiac cachexia and illustrate some animal models proposed for cardiac cachexia studies; they include the genetic calsequestrin and Dahl salt-sensitive models, the monocrotaline model and the surgical models obtained by left anterior descending (LAD) ligation, transverse aortic constriction (TAC) and ascending aortic banding. The availability of a specific animal model for cardiac cachexia is a crucial issue since, besides the common aspects of cachexia in the different syndromes, each disease has some peculiarities in its etiology and pathophysiology leading to cachexia. Such peculiarities need to be unraveled in order to find new targets for effective therapies.

  14. Neurological prognostication after cardiac arrest

    PubMed Central

    Sandroni, Claudio; Geocadin, Romergryko G.

    2016-01-01

    Purpose of review Prediction of neurological prognosis in patients who are comatose after successful resuscitation from cardiac arrest remains difficult. Previous guidelines recommended ocular reflexes, somatosensory evoked potentials and serum biomarkers for predicting poor outcome within 72h from cardiac arrest. However, these guidelines were based on patients not treated with targeted temperature management and did not appropriately address important biases in literature. Recent findings Recent evidence reviews detected important limitations in prognostication studies, such as low precision and, most importantly, lack of blinding, which may have caused a self-fulfilling prophecy and overestimated the specificity of index tests. Maintenance of targeted temperature using sedatives and muscle relaxants may interfere with clinical examination, making assessment of neurological status before 72 h or more after cardiac arrest unreliable. Summary No index predicts poor neurological outcome after cardiac arrest with absolute certainty. Prognostic evaluation should start not earlier than 72 h after ROSC and only after major confounders have been excluded so that reliable clinical examination can be made. Multimodality appears to be the most reasonable approach for prognostication after cardiac arrest. PMID:25922894

  15. MSCT labelling for pre-operative planning in cardiac resynchronization therapy

    PubMed Central

    Rioual, Kristell; Unanua, Edurne; Laguitton, Soizic; Garreau, Mireille; Boulmier, Dominique; Haigron, Pascal; Leclercq, Christophe; Coatrieux, Jean-Louis

    2005-01-01

    The objective of this paper is twofold: (i) to show how Multislice Computed Tomography (MSCT) data sets bring the information required for Cardiac Resynchronisation Therapy (CRT) planning; (ii) to demonstrate the feasibility of 3-D navigation into the veins where Left Ventricular leads have to be placed. The former has been achieved by exploring and labelling the cardiac structures of concern, the latter has been performed by using the concept of virtual navigation with high resolution surface detection and estimation algorithms. PMID:16005608

  16. Stochastic Aspects of Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Lerma, Claudia; Krogh-Madsen, Trine; Guevara, Michael; Glass, Leon

    2007-07-01

    Abnormal cardiac rhythms (cardiac arrhythmias) often display complex changes over time that can have a random or haphazard appearance. Mathematically, these changes can on occasion be identified with bifurcations in difference or differential equation models of the arrhythmias. One source for the variability of these rhythms is the fluctuating environment. However, in the neighborhood of bifurcation points, the fluctuations induced by the stochastic opening and closing of individual ion channels in the cell membrane, which results in membrane noise, may lead to randomness in the observed dynamics. To illustrate this, we consider the effects of stochastic properties of ion channels on the resetting of pacemaker oscillations and on the generation of early afterdepolarizations. The comparison of the statistical properties of long records showing arrhythmias with the predictions from theoretical models should help in the identification of different mechanisms underlying cardiac arrhythmias.

  17. Cardiac myofilaments: mechanics and regulation

    NASA Technical Reports Server (NTRS)

    de Tombe, Pieter P.; Bers, D. M. (Principal Investigator)

    2003-01-01

    The mechanical properties of the cardiac myofilament are an important determinant of pump function of the heart. This report is focused on the regulation of myofilament function in cardiac muscle. Calcium ions form the trigger that induces activation of the thin filament which, in turn, allows for cross-bridge formation, ATP hydrolysis, and force development. The structure and protein-protein interactions of the cardiac sarcomere that are responsible for these processes will be reviewed. The molecular mechanism that underlies myofilament activation is incompletely understood. Recent experimental approaches have been employed to unravel the mechanism and regulation of myofilament mechanics and energetics by activator calcium and sarcomere length, as well as contractile protein phosphorylation mediated by protein kinase A. Central to these studies is the question whether such factors impact on muscle function simply by altering thin filament activation state, or whether modulation of cross-bridge cycling also plays a part in the responses of muscle to these stimuli.

  18. Cardiac Regenerative Capacity and Mechanisms

    PubMed Central

    Kikuchi, Kazu; Poss, Kenneth D.

    2013-01-01

    The heart holds the monumental yet monotonous task of maintaining circulation. Although cardiac function is critical to other organs and to life itself, mammals are not equipped with significant natural capacity to replace heart muscle that has been lost by injury. This deficiency plays a role in leaving millions worldwide each year vulnerable to heart failure. By contrast, certain other vertebrate species like zebrafish are strikingly good at heart regeneration. A cellular and molecular understanding of endogenous regenerative mechanisms, combined with advances in methodology to transplant cells, together project a future in which cardiac muscle regeneration can be therapeutically stimulated in injured human hearts. This review will focus on what has been discovered recently about cardiac regenerative capacity and how natural mechanisms of heart regeneration in model systems are stimulated and maintained. PMID:23057748

  19. Cardiac output during human sleep.

    PubMed

    Miller, J C; Horvath, S M

    1976-10-01

    Impedance cardiogram and sleep EEG were recorded from four male and four female subjects, aged 21 to 22 years, during one night in the laboratory following one adaptation night. Cardiac output fell approximately 26% during the night as a consequence of diminished stroke volume, the lowest values of both occurring during the latter portion of the night, dominated by SREM (rapid-eye-movement stage). Intracycle comparisons between SREM and SWS (slow wave sleep) or between eye movement burst and non-burst SREM showed no significant differences in stroke volume or cardiac output. Pre-ejection period and systolic ejection period were measured and discussed. The non-coincidence of the nadir of metabolic activity, expressed as cardiac output, and the apex of slow-wave sleep activity supported the concept of slow-wave sleep as a period of physiological restoration.

  20. Multimodality treatment for cardiac angiosarcoma.

    PubMed

    Wang, Meng; Fu, Ganglan; Jiang, Huiqi; Zeng, Kuan; Hua, Ping

    2014-01-01

    Primary cardiac angiosarcoma is a rare and highly malignant condition. Besides performing complete surgical excision, it remains controversial as to whether survival can be improved with additional treatment. We herein describe a 30-year-old man with a right atrial angiosarcoma. He underwent two operations for the resection of the primary lesion, and the patient's metastatic lesions involved an intestinal segment. With chemotherapy, radiotherapy, and molecular targeted therapy, he survived for 33 months. The literature describing adjuvant therapy for cardiac angiosarcoma, which is mostly case reports, is also reviewed. In conclusion, the limited evidence suggests that multimodality treatment for cardiac angiosarcoma is a beacon of hope to improve the survival of such patients.

  1. [Risk management in cardiac anesthesia].

    PubMed

    Inada, Eiichi

    2008-05-01

    Cardiac anesthesia carries high risk because of the patient's cardiac and coexisting diseases and rapid and complex hemodynamic changes during surgery. We should be ready to treat hemodynamic changes which may rapidly deteriorate into a vicious cycle. Many potent drugs and life-support devices are used. The drugs should be properly labeled to avoid drug error. Prefilled drug syringes and ready-to-use bags are helpful to avoid mixture error. Syringe and infusion pumps should be properly set. All the infusion systems should be checked in a systematical way. Blood management including blood transfusion and coagulation is important. Heparin-induced thrombocytopenia (HIT) may cause thrombosis. Heparin and heparin-coated catheter should be avoided in patients with HIT. Causes of bleeding tendency should be sort out and treated accordingly. Protamine reactions including hypotension and pulmonary hypertension can be catastrophic. Lastly, intimate communication between surgeons, anesthesiologists, medical engineers, and nurses is essential to perform cardiac surgery safely.

  2. Sudden Cardiac Arrest in Pediatrics.

    PubMed

    Scheller, RoseAnn L; Johnson, Laurie; Lorts, Angela; Ryan, Thomas D

    2016-09-01

    Sudden cardiac arrest (SCA) in the pediatric population is a rare and potentially devastating occurrence. An understanding of the differential diagnosis for the etiology of the cardiac arrest allows for the most effective emergency care and provides the patient with the best possible outcome. Pediatric SCA can occur with or without prodromal symptoms and may occur during exercise or rest. The most common cause is arrhythmia secondary to an underlying channelopathy, cardiomyopathy, or myocarditis. After stabilization, evaluation should include electrocardiogram, chest radiograph, and echocardiogram. Management should focus on decreasing the potential for recurring arrhythmia, maintaining cardiac preload, and thoughtful medication use to prevent exacerbation of the underlying condition. The purpose of this review was to provide the emergency physician with a concise and current review of the incidence, differential diagnosis, and management of pediatric patients presenting with SCA. PMID:27585126

  3. MR and CT appearance of cardiac hemangioma

    SciTech Connect

    Kemp, J.L.; Kessler, R.M.; Raizada, V.; Williamson, M.R.

    1996-05-01

    We present a case of cardiac hemangioma in a symptomatic patient. MR and CT each have specific characteristics that should make one consider including or excluding this in the differential diagnosis of a cardiac tumor. 7 refs., 3 figs.

  4. Sudden Cardiac Arrest (SCA) Risk Assessment

    MedlinePlus

    ... Find a Specialist Share Twitter Facebook SCA Risk Assessment Sudden Cardiac Arrest (SCA) occurs abruptly and without ... of all ages and health conditions. Start Risk Assessment The Sudden Cardiac Arrest (SCA) Risk Assessment Tool ...

  5. [Cardiac arrhythmias: Diagnosis and management].

    PubMed

    Waldmann, V; Marijon, E

    2016-09-01

    Cardiac arrhythmias, with, on top of the list, atrial fibrillation, are frequent conditions and any physician might have to get involved at any stage of patient care (from diagnosis to treatment), without always having the opportunity to immediately refer to the cardiologist. The aim of this review is to present a summary of pathophysiology, clinical and electrocardiographic presentations, as well as diagnostic and therapeutic strategies for the main cardiac arrhythmias. Supra-ventricular tachycardias (atrial fibrillation and flutter, atrioventricular reciprocating tachycardias) and ventricular tachycardias will be consecutively presented and discussed.

  6. Cardiac 4D Ultrasound Imaging

    NASA Astrophysics Data System (ADS)

    D'hooge, Jan

    Volumetric cardiac ultrasound imaging has steadily evolved over the last 20 years from an electrocardiography (ECC) gated imaging technique to a true real-time imaging modality. Although the clinical use of echocardiography is still to a large extent based on conventional 2D ultrasound imaging it can be anticipated that the further developments in image quality, data visualization and interaction and image quantification of three-dimensional cardiac ultrasound will gradually make volumetric ultrasound the modality of choice. In this chapter, an overview is given of the technological developments that allow for volumetric imaging of the beating heart by ultrasound.

  7. Benign cardiac tumours, malignant arrhythmias

    PubMed Central

    Myers, Kimberley A; Wong, Kenny K; Tipple, Marion; Sanatani, Shubhayan

    2010-01-01

    Four cases of pediatric cardiac tumours (PCTs) associated with ventricular arrhythmias are reported. Sudden cardiac death attributable to the tumour occurred in two children. A third child received an implantable cardioverter defibrillator and the fourth had persistent ventricular arrhythmia despite medical therapy. Most PCTs are considered benign; however, the development of malignant arrhythmias may complicate the management of these tumours in some patients. The literature regarding the arrhythmogenic potential of PCTs and the use of implantable cardioverter defibrillators in these patients is reviewed. The series highlights the deficiency of prognostic information for this cohort. PMID:20151061

  8. Cardiac Metastasis from Invasive Thymoma Via the Superior Vena Cava: Cardiac MRI Findings

    SciTech Connect

    Dursun, Memduh Sarvar, Sadik; Cekrezi, Bledi; Kaba, Erkan; Bakir, Baris; Toker, Alper

    2008-07-15

    Cardiac tumors are rare, and metastatic deposits are more common than primary cardiac tumors. We present cardiac magnetic resonance imaging (MRI) findings of a 50-year-old woman with invasive thymoma. Cardiac MRI revealed a heterogeneous, lobulated anterior mediastinal mass invading the superior vena cava and extending to the right atrium. In cine images there was no invasion to the right atrial wall.

  9. [Cardiac output monitoring by impedance cardiography in cardiac surgery].

    PubMed

    Shimizu, H; Seki, S; Mizuguchi, A; Tsuchida, H; Watanabe, H; Namiki, A

    1990-04-01

    The cardiac output monitoring by impedance cardiography, NCCOM3, was evaluated in adult patients (n = 12) who were subjected to coronary artery bypass grafting. Values of cardiac output measured by impedance cardiography were compared to those by the thermodilution method. Changes of base impedance level used as an index of thoracic fluid volume were also investigated before and after cardiopulmonary bypass (CPB). Correlation coefficient (r) of the values obtained by thermodilution with impedance cardiography was 0.79 and the mean difference was 1.29 +/- 16.9 (SD)% during induction of anesthesia. During the operation, r was 0.83 and the mean difference was -14.6 +/- 18.7%. The measurement by impedance cardiography could be carried out through the operation except when electro-cautery was used. Base impedance level before CPB was significantly lower as compared with that after CPB. There was a negative correlation between the base impedance level and central venous pressure (CVP). No patients showed any signs suggesting lung edema and all the values of CVP, pulmonary artery pressure and blood gas analysis were within normal ranges. From the result of this study, it was concluded that cardiac output monitoring by impedance cardiography was useful in cardiac surgery, but further detailed examinations will be necessary on the relationship between the numerical values of base impedance and the clinical state of the patients. PMID:2362347

  10. Health Literacy Predicts Cardiac Knowledge Gains in Cardiac Rehabilitation Participants

    ERIC Educational Resources Information Center

    Mattson, Colleen C.; Rawson, Katherine; Hughes, Joel W.; Waechter, Donna; Rosneck, James

    2015-01-01

    Objective: Health literacy is increasingly recognised as a potentially important patient characteristic related to patient education efforts. We evaluated whether health literacy would predict gains in knowledge after completion of patient education in cardiac rehabilitation. Method: This was a re-post observational analysis study design based on…

  11. Cardiac torsion and electromagnetic fields: the cardiac bioinformation hypothesis.

    PubMed

    Burleson, Katharine O; Schwartz, Gary E

    2005-01-01

    Although in physiology the heart is often referred to as a simple piston pump, there are in fact two additional features that are integral to cardiac physiology and function. First, the heart as it contracts in systole, also rotates and produces torsion due to the structure of the myocardium. Second, the heart produces a significant electromagnetic field with each contraction due to the coordinated depolarization of myocytes producing a current flow. Unlike the electrocardiogram, the magnetic field is not limited to volume conduction and extends outside the body. The therapeutic potential for interaction of this cardioelectromagnetic field both within and outside the body is largely unexplored. It is our hypothesis that the heart functions as a generator of bioinformation that is central to normative functioning of body. The source of this bioinformation is based on: (1) vortex blood flow in the left ventricle; (2) a cardiac electromagnetic field and both; (3) heart sounds; and (4) pulse pressure which produce frequency and amplitude information. Thus, there is a multidimensional role for the heart in physiology and biopsychosocial dynamics. Recognition of these cardiac properties may result in significant implications for new therapies for cardiovascular disease based on increasing cardiac energy efficiency (coherence) and bioinformation from the cardioelectromagnetic field. Research studies to test this hypothesis are suggested.

  12. Cardiac tamponade: an unusual clinical presentation.

    PubMed

    Eakle, J F; Goodin, R R

    2001-02-01

    Pericardial effusion with cardiac tamponade is an unusual presentation of lymphoma, although cardiac involvement is often a late finding in widespread malignancy. Clinical identification can be difficult ante-mortem. New cardiac symptoms or classic findings of cardiac tamponade should prompt aggressive investigation. We present a case of B-cell lymphoma that initially presented as pericardial effusion with tamponade and discuss the characteristic physical findings and radiographic data that assist in diagnosis. PMID:11441582

  13. Cardiac image segmentation using spatiotemporal clustering

    NASA Astrophysics Data System (ADS)

    Galic, Sasa; Loncaric, Sven

    2001-07-01

    Image segmentation is an important and challenging problem in image analysis. Segmentation of moving objects in image sequences is even more difficult and computationally expensive. In this work we propose a technique for spatio- temporal segmentation of medical sequences based on K-mean clustering in the feature vector space. The motivation for spatio-temporalsegmentation approach comes from the fact that motion is a useful clue for object segmentation. Two- dimensional feature vector has been used for clustering in the feature space. In this paper we apply the proposed technique to segmentation of cardiac images. The first feature used in this particular application is image brightness, which reveals the structure of interest in the image. The second feature is the Euclidean norm of the optical flow vector. The third feature is the three- dimensional optical flow vector, which consists of computed motion in all three dimensions. The optical flow itself is computed using Horn-Schunck algorithm. The fourth feature is the mean brightness of the input image in a local neighborhood. By applying the clustering algorithm it is possible to detect moving object in the image sequence. The experiment has been conducted using a sequence of ECG-gated magnetic resonance (MR) images of a beating heart taken as in time so in the space.

  14. Cardiac transplantation in Becker muscular dystrophy.

    PubMed

    Quinlivan, R M; Dubowitz, V

    1992-01-01

    Becker muscular dystrophy is associated with abnormal cardiac features in about 75% of cases; up to one-third will develop ventricular dilatation leading to congestive cardiac failure. As this form of muscular dystrophy is relatively benign, failure to respond to medical treatment warrants assessment for cardiac transplantation.

  15. Telocytes in exercise-induced cardiac growth.

    PubMed

    Xiao, Junjie; Chen, Ping; Qu, Yi; Yu, Pujiao; Yao, Jianhua; Wang, Hongbao; Fu, Siyi; Bei, Yihua; Chen, Yan; Che, Lin; Xu, Jiahong

    2016-05-01

    Exercise can induce physiological cardiac growth, which is featured by enlarged cardiomyocyte cell size and formation of new cardiomyocytes. Telocytes (TCs) are a recently identified distinct interstitial cell type, existing in many tissues and organs including heart. TCs have been shown to form a tandem with cardiac stem/progenitor cells in cardiac stem cell niches, participating in cardiac regeneration and repair. Although exercise-induced cardiac growth has been confirmed as an important way to promote cardiac regeneration and repair, the response of cardiac TCs to exercise is still unclear. In this study, 4 weeks of swimming training was used to induce robust healthy cardiac growth. Exercise can induce an increase in cardiomyocyte cell size and formation of new cardiomyocytes as determined by Wheat Germ Lectin and EdU staining respectively. TCs were identified by three immunofluorescence stainings including double labelling for CD34/vimentin, CD34/platelet-derived growth factor (PDGF) receptor-α and CD34/PDGF receptor-β. We found that cardiac TCs were significantly increased in exercised heart, suggesting that TCs might help control the activity of cardiac stem/progenitor cells, cardiomyocytes or endothelial cells. Adding cardiac TCs might help promote cardiac regeneration and renewal. PMID:26987685

  16. Mathematics and the Heart: Understanding Cardiac Output

    ERIC Educational Resources Information Center

    Champanerkar, Jyoti

    2013-01-01

    This paper illustrates a biological application of the concepts of relative change and area under a curve, from mathematics. We study two biological measures "relative change in cardiac output" and "cardiac output", which are predictors of heart blockages and other related ailments. Cardiac output refers to the quantity of…

  17. Cardiac rate detection method based on the beam splitter prism

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Liu, Xiaohua; Liu, Ming; Zhao, Yuejin; Dong, Liquan; Zhao, Ruirui; Jin, Xiaoli; Zhao, Jingsheng

    2013-09-01

    A new cardiac rate measurement method is proposed. Through the beam splitter prism, the common-path optical system of transmitting and receiving signals is achieved. By the focusing effect of the lens, the small amplitude motion artifact is inhibited and the signal-to-noise is improved. The cardiac rate is obtained based on the PhotoPlethysmoGraphy (PPG). We use LED as the light source and use photoelectric diode as the receiving tube. The LED and the photoelectric diode are on the different sides of the beam splitter prism and they form the optical system. The signal processing and display unit is composed by the signal processing circuit, data acquisition device and computer. The light emitted by the modulated LED is collimated by the lens and irradiates the measurement target through the beam splitter prism. The light reflected by the target is focused on the receiving tube through the beam splitter prism and another lens. The signal received by the photoelectric diode is processed by the analog circuit and obtained by the data acquisition device. Through the filtering and Fast Fourier Transform, the cardiac rate is achieved. We get the real time cardiac rate by the moving average method. We experiment with 30 volunteers, containing different genders and different ages. We compare the signals captured by this method to a conventional PPG signal captured concurrently from a finger. The results of the experiments are all relatively agreeable and the biggest deviation value is about 2bmp.

  18. Tissue and Animal Models of Sudden Cardiac Death

    PubMed Central

    Sallam, Karim; Li, Yingxin; Sager, Philip T.; Houser, Steven R.; Wu, Joseph C.

    2015-01-01

    Sudden Cardiac Death (SCD) is a common cause of death in patients with structural heart disease, genetic mutations or acquired disorders affecting cardiac ion channels. A wide range of platforms exist to model and study disorders associated with SCD. Human clinical studies are cumbersome and are thwarted by the extent of investigation that can be performed on human subjects. Animal models are limited by their degree of homology to human cardiac electrophysiology including ion channel expression. Most commonly used cellular models are cellular transfection models, which are able to mimic the expression of a single ion channel offering incomplete insight into changes of the action potential profile. Induced pluripotent stem cell derived Cardiomyocytes (iPSC-CMs) resemble, but are not identical, to adult human cardiomyocytes, and provide a new platform for studying arrhythmic disorders leading to SCD. A variety of platforms exist to phenotype cellular models including conventional and automated patch clamp, multi-electrode array, and computational modeling. iPSC-CMs have been used to study Long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy and other hereditary cardiac disorders. Although iPSC-CMs are distinct from adult cardiomyocytes, they provide a robust platform to advance the science and clinical care of SCD. PMID:26044252

  19. Cardiac changes due to electronic control devices? A computer-based analysis of electrical effects at the human heart caused by an ECD pulse applied to the body's exterior.

    PubMed

    Kunz, Sebastian N; Aronshtam, Julia; Tränkler, Hans-Rolf; Kraus, Sybille; Graw, Matthias; Peschel, Oliver

    2014-05-01

    Electronic control devices (ECDs) deliver high-voltage, low-current energy pulses temporarily paralyzing a person. For the ECD-human interaction, we have developed a computer model using the SEMCAD program within which to simulate the electrical effects throughout the body resulting from the imposition of an ECD pulse at a particular point on the body surface. Our human body models were based on cross-sectional MRIs and CT scans, with the dielectric properties of the various tissues assigned based on previously published values. We simulated the application of a single ECD pulse and calculated the resulting electric field strength and current and charge densities at different body locations. The results were compared with corresponding values obtained by other researchers in similar simulations. Furthermore, we simulated an application of a pulse of 20-millisecond duration equal to the European household current of 50 Hz and to the ventricular fibrillation threshold. The resulting current level indicated at the heart muscle was 1/5 the level considered the threshold for triggering ventricular fibrillation. PMID:24712742

  20. Cardiac sarcoidosis: diagnosis and management.

    PubMed

    Dubrey, S W; Sharma, R; Underwood, R; Mittal, T

    2015-07-01

    Cardiac sarcoidosis is one of the most serious and unpredictable aspects of this disease state. Heart involvement frequently presents with arrhythmias or conduction disease, although myocardial infiltration resulting in congestive heart failure may also occur. The prognosis in cardiac sarcoidosis is highly variable, which relates to the heterogeneous nature of heart involvement and marked differences between racial groups. Electrocardiography and echocardiography often provide the first clue to the diagnosis, but advanced imaging studies using positron emission tomography and MRI, in combination with nuclear isotope perfusion scanning are now essential to the diagnosis and management of this condition. The identification of clinically occult cardiac sarcoidosis and the management of isolated and/or asymptomatic heart involvement remain both challenging and contentious. Corticosteroids remain the first treatment choice with the later substitution of immunosuppressive and steroid-sparing therapies. Heart transplantation is an unusual outcome, but when performed, the results are comparable or better than heart transplantation for other disease states. We review the epidemiology, developments in diagnostic techniques and the management of cardiac sarcoidosis.

  1. Primary Cardiac Solitary Fibrous Tumors

    PubMed Central

    2015-01-01

    Primary cardiac solitary fibrous tumors were reviewed. They are classified as pericardial tumors. Their incidences are very rare. Only 16 cases were reported in the literature. Basically, surgical treatments are performed. Their prognoses are generally good, although malignant cases are also reported. PMID:26156195

  2. Real time cardiac radionuclide imaging

    SciTech Connect

    Jarkewicz, G.G.

    1986-04-29

    A data acquisition system is described for use in radionuclide cardiac imaging of a patient having been administered a myocardium specific radionuclide, comprising: (a) means for monitoring the electrical activity of the heart; (b) first temporary storage means for accumulating respective pages of data corresponding to nuclear events during each cardiac cycle; (c) means, responsive to the means for monitoring, for determining the time duration of each successive cardiac cycle; (d) means for comparing each determined duration of a cardiac cycle with a preselected time duration range; (e) second temporary storage means; and (f) means for conditionally transferring pages of data from the first temporary storage means to the second temporary storage means if the measured duration associated with each page has predetermined correspondence with the preselected duration range, whereby pages of data having the predetermined correspondence may be collated into a quasi-real time study, while pages of data having different correspondence with the preselected time duration range are discarded from the study.

  3. Cardiac R-wave detector

    NASA Technical Reports Server (NTRS)

    Gebben, V. D.

    1968-01-01

    Cardiac R wave detector obtains the systolic contraction signal of the human heart and uses it as a reference signal for the heart-assist pump cycle. It processes the electrocardiac signal /QRS wave complex/ of the natural heart in a sequence of operations which essentially elimates all components from the input signal except the R wave.

  4. The cardiac patient in Ramadan

    PubMed Central

    Chamsi-Pasha, Majed; Chamsi-Pasha, Hassan

    2016-01-01

    Ramadan is one of the five fundamental pillars of Islam. During this month, the majority of the 1.6 billion Muslims worldwide observe an absolute fast from dawn to sunset without any drink or food. Our review shows that the impact of fasting during Ramadan on patients with stable cardiac disease is minimal and does not lead to any increase in acute events. Most patients with the stable cardiac disease can fast safely. Most of the drug doses and their regimen are easily manageable during this month and may need not to be changed. Ramadan fasting is a healthy nonpharmacological means for improving cardiovascular risk factors. Most of the Muslims, who suffer from chronic diseases, insist on fasting Ramadan despite being exempted by religion. The Holy Quran specifically exempts the sick from fasting. This is particularly relevant if fasting worsens one's illness or delays recovery. Patients with unstable angina, recent myocardial infarction, uncontrolled hypertension, decompensated heart failure, recent cardiac intervention or cardiac surgery or any debilitating diseases should avoid fasting. PMID:27144139

  5. Bifurcation theory and cardiac arrhythmias.

    PubMed

    Karagueuzian, Hrayr S; Stepanyan, Hayk; Mandel, William J

    2013-01-01

    In this paper we review two types of dynamic behaviors defined by the bifurcation theory that are found to be particularly useful in describing two forms of cardiac electrical instabilities that are of considerable importance in cardiac arrhythmogenesis. The first is action potential duration (APD) alternans with an underlying dynamics consistent with the period doubling bifurcation theory. This form of electrical instability could lead to spatially discordant APD alternans leading to wavebreak and reentrant form of tachyarrhythmias. Factors that modulate the APD alternans are discussed. The second form of bifurcation of importance to cardiac arrhythmogenesis is the Hopf-homoclinic bifurcation that adequately describes the dynamics of the onset of early afterdepolarization (EAD)-mediated triggered activity (Hopf) that may cause ventricular tachycardia and ventricular fibrillation (VT/VF respectively). The self-termination of the triggered activity is compatible with the homoclinic bifurcation. Ionic and intracellular calcium dynamics underlying these dynamics are discussed using available experimental and simulation data. The dynamic analysis provides novel insights into the mechanisms of VT/VF, a major cause of sudden cardiac death in the US.

  6. Device Assists Cardiac Chest Compression

    NASA Technical Reports Server (NTRS)

    Eichstadt, Frank T.

    1995-01-01

    Portable device facilitates effective and prolonged cardiac resuscitation by chest compression. Developed originally for use in absence of gravitation, also useful in terrestrial environments and situations (confined spaces, water rescue, medical transport) not conducive to standard manual cardiopulmonary resuscitation (CPR) techniques.

  7. The Cardiac Complications of Methamphetamines.

    PubMed

    Paratz, Elizabeth D; Cunningham, Neil J; MacIsaac, Andrew I

    2016-04-01

    Methamphetamines are increasingly popular drugs of abuse in Australia, and are rising in purity. The rising popularity and purity of methamphetamines has notably increased demands upon Australian medical services. Methamphetamines are sympathomimetic amines with a range of adverse effects upon multiple organ systems. Cardiovascular complications are the second leading cause of death in methamphetamine abusers, and there appears to be a high prevalence of cardiac pathology. Cardiovascular pathology frequently seen in methamphetamine abusers includes hypertension, aortic dissection, acute coronary syndromes, pulmonary arterial hypertension and methamphetamine-associated cardiomyopathy. The rising prevalence of methamphetamine abuse is likely to increase the burden of cardiovascular pathology in Australians. A National Parliamentary Enquiry was opened in March 2015 to address concerns regarding the medical and social impacts of methamphetamine abuse. From April 2015, a National 'Ice Taskforce' was also created in parallel. Reversal of cardiac pathology appears to be achievable with abstinence from methamphetamines and initiation of appropriate treatment. It is key to appreciate that the pathogenesis of methamphetamine-induced cardiac complications arises as a result of the specific toxic effects of methamphetamines. Clinical management is hence individualised; suggested management approaches for methamphetamine-induced cardiac complications are detailed within this article.

  8. Phenomics of Cardiac Chloride Channels

    PubMed Central

    Duan, Dayue Darrel

    2014-01-01

    Forward genetic studies have identified several chloride (Cl−) channel genes, including CFTR, ClC-2, ClC-3, CLCA, Bestrophin, and Ano1, in the heart. Recent reverse genetic studies using gene targeting and transgenic techniques to delineate the functional role of cardiac Cl− channels have shown that Cl− channels may contribute to cardiac arrhythmogenesis, myocardial hypertrophy and heart failure, and cardioprotection against ischemia reperfusion. The study of physiological or pathophysiological phenotypes of cardiac Cl− channels, however, is complicated by the compensatory changes in the animals in response to the targeted genetic manipulation. Alternatively, tissue-specific conditional or inducible knockout or knockin animal models may be more valuable in the phenotypic studies of specific Cl− channels by limiting the effect of compensation on the phenotype. The integrated function of Cl− channels may involve multiprotein complexes of the Cl− channel subproteome. Similar phenotypes can be attained from alternative protein pathways within cellular networks, which are influenced by genetic and environmental factors. The phenomics approach, which characterizes phenotypes as a whole phenome and systematically studies the molecular changes that give rise to particular phenotypes achieved by modifying the genotype under the scope of genome/proteome/phenome, may provide more complete understanding of the integrated function of each cardiac Cl− channel in the context of health and disease. PMID:23720326

  9. Cardiac arrest during dipyridamole imaging

    SciTech Connect

    Blumenthal, M.S.; McCauley, C.S.

    1988-05-01

    A case of cardiac arrest and subsequent acute myocardial infarction occurring during thallium-201 imaging with oral dipyridamole augmentation is presented. Previous reports emphasizing the safety of this procedure are briefly reviewed and a recommendation for close hemodynamic and arrhythmia monitoring during the study is made. Large doses of oral dipyridamole may be contraindicated in patients with unstable angina.

  10. Dermatoglyphic's in Congenital Cardiac Disease.

    PubMed

    Brijendra, Singh; Renu, Gupta; Dushyant, Agrawal; Rajneesh, Garg; Sunil, Katri

    2016-02-01

    Various dermatoglyphic parameters like finger print pattern, atd angle, absolute ridge count & ab, bc ,cd, and ad ridge counts were observed in 150 cases of congenital cardiac disease, comprising of 72 cases of Ventricular Septal Defects (VSD), 60 cases of Atrial Septal Defects (ASD), 9 cases of Coarctation of Aorta (COA) & 9 cases of Tetralogy of Fallot's (TOF). Same dermatoglyphic parameters were also studied in 300 controls and statistical comparison of cases and controls was done. In our study it was observed that the congenital cardiac disease cases exhibited preponderance of whorls (55.8%) with decrease in loop pattern (36.2%) as compared to those of controls and the difference was highly significant (P<0.001). The difference in the mean total finger ridge count (TFRC) of the controls and of the cases of Congenital Cardiac Diseases (CCD) was found to be highly significant (P<0.001), while the  mean atd angle in the cases of Congenital Cardiac Disease (CCD) was widen up and was statistically significant too. The mean ab, the mean bc ridge, the mean cd ridge and the mean ad ridge counts were also higher in the various type of CCD as compared to that controls and on statistical comparison, the difference was found to be highly significant.

  11. [Long-term cardiac rehabilitation].

    PubMed

    Tormo Alfonso, V

    1995-01-01

    Cardiac rehabilitation for life-time in a patient who has suffered coronary pathology is considered as appropriate. The reasons for such an opinion are given, as well as the two most indicated courses of action, being this rehabilitation at home and coronary clubs.

  12. MedlinePlus: Cardiac Arrest

    MedlinePlus

    ... Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine) Article: A Prospective Study of Sudden Cardiac Death ... Players MedlinePlus Connect for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  13. MR imaging of cardiac tumors.

    PubMed

    Sparrow, Patrick J; Kurian, John B; Jones, Tim R; Sivananthan, Mohan U

    2005-01-01

    Magnetic resonance (MR) imaging is an important tool in the evaluation of cardiac neoplasms. T1-weighted, T2-weighted, and gadolinium-enhanced sequences are used for anatomic definition and tissue characterization, whereas cine gradient-echo imaging is used to assess functional effects. Recent improvements in pulse sequences for cardiac MR imaging have led to superior image quality, with reduced motion artifact and improved signal-to-noise ratio and tissue contrast. Although there is some overlap in the MR imaging appearances of cardiac tumors, particularly of primary malignancies, differences in characteristic locations and features should allow confident differentiation between benign and malignant tumors. Indicators of malignancy at MR imaging are invasive behavior, involvement of the right side of the heart or the pericardium, tissue inhomogeneity, diameter greater than 5 cm, and enhancement after administration of gadolinium contrast material (as a result of higher tissue vascularity). Concomitant pericardial or pleural effusions are rare in benign processes but occur in about 50% of cases of malignant tumors. MR imaging offers improved resolution, a larger field of view, and superior soft-tissue contrast compared with those of echocardiography, suggesting that knowledge of the MR imaging features of cardiac neoplasms is important for accurate diagnosis and management. PMID:16160110

  14. Molecular Modeling of Cardiac Troponin

    NASA Astrophysics Data System (ADS)

    Manning, Edward P.

    The cardiac thin filament regulates interactions of actin and myosin, the force-generating elements of muscular contraction. Over the past several decades many details have been discovered regarding the structure and function of the cardiac thin filament and its components, including cardiac troponin (cTn). My hypothesis is that signal propagation occurs between distant ends of the cardiac troponin complex through calcium-dependent alterations in the dynamics of cTn and tropomyosin (Tm). I propose a model of the thin filament that encompasses known structures of cTn, Tm and actin to gain insight into cardiac troponin's allosteric regulation of thin filament dynamics. By performing molecular dynamics simulations of cTn in conjunction with overlapping Tm in two conditions, with and without calcium bound to site II of cardiac troponin C (cTnC), I found a combination of calcium-dependent changes in secondary structure and dynamics throughout the cTn-Tm complex. I then applied this model to investigate familial hypertrophic cardiomyopathy (FHC), a disease of the sarcomere that is one of the most commonly occurring genetic causes of heart disease. Approximately 15% of known FHC-related mutations are found in cardiac troponin T (cTnT), most of which are in or flank the alpha-helical N-tail domain TNT1. TNT1 directly interacts with overlapping Tm coiled coils. Using this model I identified effects of TNT1 mutations that propagate to the cTn core where site II of cTnC, the regulatory site of calcium binding in the thin filament, is located. Specifically, I found that mutations in TNT1 alter the flexibility of TNT1 and that the flexibility of TNT1 is inversely proportional to the cooperativity of calcium activation of the thin filament. Further, I identified a pathway of propagation of structural and dynamic changes linking TNT1 to site II of cTnC. Mutation-induced changes at site II cTnC alter calcium coordination which corresponds to biophysical measurements of calcium

  15. [Drowning versus cardiac ischemia: Cardiac arrest of an 11-year-old boy at a swimming lake].

    PubMed

    Födinger, A; Wöss, C; Semsroth, S; Stadlbauer, K H; Wenzel, V

    2015-11-01

    This report describes a case of sudden cardiac arrest and subsequent attempted cardiopulmonary resuscitation of an 11-year-old child on the shores of a swimming lake. Reports of eyewitnesses excluded the obviously suspected diagnosis of a drowning accident. The result of the autopsy was sudden cardiac death due to a congenital coronary anomaly (abnormal left coronary artery, ALCA). Favored by vigorous physical activity, this anomaly can lead to malignant arrhythmias because the ectopic coronary artery with its intramural course through the aortic wall is compressed during every systole. This pathology was not known to the boy or his family; in fact he liked sports but had suffered of a syncope once which was not followed up. Without a strong suspicion it is difficult to diagnose a coronary artery anomaly and it is often missed even in college athletes. Tragically, sudden cardiac arrest may be the first symptom of an undiagnosed abnormal coronary artery. Following syncope or chest pain during exercise with a normal electrocardiogram (ECG) cardiac imaging, such as computed tomography (CT) or angiography should be initiated in order to enable surgical repair of an abnormal coronary artery.

  16. Carney complex with biatrial cardiac myxoma.

    PubMed

    Havrankova, Eniko; Stenova, Emoke; Olejarova, Ingrid; Sollarova, Katarina; Kinova, Sona

    2014-01-01

    Cardiac myxomas make up approximately 50% of all benign cardiac tumors and represented 86% of all surgically treated cardiac tumors. Most of them originated from the left atrium, in some cases from both of atria. We report a case of male patient with biatrial myxomas and other extra-cardiac involvement: hypophyseal adenoma, enlargement of thyroid gland, tubular adenoma polyp of colon and bilateral large cell calcifying Sertoli cell tumor (LCCSCT) of testis. These findings led to the diagnosis of Carney's complex, which is a syndrome with multiple neoplasias, cardiac myxomas, lentigines, and endocrine abnormalities. A genetic test confirm this diagnosis. PMID:24088910

  17. Bioactive scaffolds for engineering vascularized cardiac tissues

    PubMed Central

    Chiu, Loraine; Radisic, Milica; Vunjak-Novakovic, Gordana

    2013-01-01

    Functional vascularization is a key requirement for the development and function of most tissues, and most critically cardiac muscle. Rapid and irreversible loss of cardiomyocytes during cardiac infarction directly results from the lack of blood supply. Contractile cardiac grafts, engineered using cardiovascular cells in conjunction with biomaterial scaffolds, are an actively studied method for cardiac repair. In this article, we focus on biomaterial scaffolds designed to mediate the development and maturation of vascular networks, by immobilized growth factors. The interactive effects of multiple vasculogenic factors are discussed in the context of cardiac tissue engineering. PMID:20857391

  18. Cardiac Function and Dysfunction in Sepsis.

    PubMed

    Fenton, Kimberly E; Parker, Margaret M

    2016-06-01

    Cardiac function and dysfunction are important in the clinical outcomes of sepsis and septic shock. Cardiac dysfunction is not a single entity, but is a broad spectrum of syndromes that result in biventricular cardiac dysfunction manifested by both systolic and diastolic dysfunction and is influenced by cardiac loading conditions (ie, preload and afterload). Elucidating the underlying pathophysiology has proved to be complex. This article emphasizes the underlying pathophysiology of cardiac dysfunction and explores recent evidence related to diagnosis, including the utility of biomarkers, the role of echocardiography, and management goals and treatment. PMID:27229645

  19. Cardiac image modelling: Breadth and depth in heart disease.

    PubMed

    Suinesiaputra, Avan; McCulloch, Andrew D; Nash, Martyn P; Pontre, Beau; Young, Alistair A

    2016-10-01

    With the advent of large-scale imaging studies and big health data, and the corresponding growth in analytics, machine learning and computational image analysis methods, there are now exciting opportunities for deepening our understanding of the mechanisms and characteristics of heart disease. Two emerging fields are computational analysis of cardiac remodelling (shape and motion changes due to disease) and computational analysis of physiology and mechanics to estimate biophysical properties from non-invasive imaging. Many large cohort studies now underway around the world have been specifically designed based on non-invasive imaging technologies in order to gain new information about the development of heart disease from asymptomatic to clinical manifestations. These give an unprecedented breadth to the quantification of population variation and disease development. Also, for the individual patient, it is now possible to determine biophysical properties of myocardial tissue in health and disease by interpreting detailed imaging data using computational modelling. For these population and patient-specific computational modelling methods to develop further, we need open benchmarks for algorithm comparison and validation, open sharing of data and algorithms, and demonstration of clinical efficacy in patient management and care. The combination of population and patient-specific modelling will give new insights into the mechanisms of cardiac disease, in particular the development of heart failure, congenital heart disease, myocardial infarction, contractile dysfunction and diastolic dysfunction.

  20. Fast automatic delineation of cardiac volume of interest in MSCT images

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Lessick, Jonathan; Lavi, Guy; Bulow, Thomas; Renisch, Steffen

    2004-05-01

    Computed Tomography Angiography (CTA) is an emerging modality for assessing cardiac anatomy. The delineation of the cardiac volume of interest (VOI) is a pre-processing step for subsequent visualization or image processing. It serves the suppression of anatomic structures being not in the primary focus of the cardiac application, such as sternum, ribs, spinal column, descending aorta and pulmonary vasculature. These structures obliterate standard visualizations such as direct volume renderings or maximum intensity projections. In addition, outcome and performance of post-processing steps such as ventricle suppression, coronary artery segmentation or the detection of short and long axes of the heart can be improved. The structures being part of the cardiac VOI (coronary arteries and veins, myocardium, ventricles and atria) differ tremendously in appearance. In addition, there is no clear image feature associated with the contour (or better cut-surface) distinguishing between cardiac VOI and surrounding tissue making the automatic delineation of the cardiac VOI a difficult task. The presented approach locates in a first step chest wall and descending aorta in all image slices giving a rough estimate of the location of the heart. In a second step, a Fourier based active contour approach delineates slice-wise the border of the cardiac VOI. The algorithm has been evaluated on 41 multi-slice CT data-sets including cases with coronary stents and venous and arterial bypasses. The typical processing time amounts to 5-10s on a 1GHz P3 PC.

  1. High-order finite element methods for cardiac monodomain simulations.

    PubMed

    Vincent, Kevin P; Gonzales, Matthew J; Gillette, Andrew K; Villongco, Christopher T; Pezzuto, Simone; Omens, Jeffrey H; Holst, Michael J; McCulloch, Andrew D

    2015-01-01

    Computational modeling of tissue-scale cardiac electrophysiology requires numerically converged solutions to avoid spurious artifacts. The steep gradients inherent to cardiac action potential propagation necessitate fine spatial scales and therefore a substantial computational burden. The use of high-order interpolation methods has previously been proposed for these simulations due to their theoretical convergence advantage. In this study, we compare the convergence behavior of linear Lagrange, cubic Hermite, and the newly proposed cubic Hermite-style serendipity interpolation methods for finite element simulations of the cardiac monodomain equation. The high-order methods reach converged solutions with fewer degrees of freedom and longer element edge lengths than traditional linear elements. Additionally, we propose a dimensionless number, the cell Thiele modulus, as a more useful metric for determining solution convergence than element size alone. Finally, we use the cell Thiele modulus to examine convergence criteria for obtaining clinically useful activation patterns for applications such as patient-specific modeling where the total activation time is known a priori. PMID:26300783

  2. High-order finite element methods for cardiac monodomain simulations

    PubMed Central

    Vincent, Kevin P.; Gonzales, Matthew J.; Gillette, Andrew K.; Villongco, Christopher T.; Pezzuto, Simone; Omens, Jeffrey H.; Holst, Michael J.; McCulloch, Andrew D.

    2015-01-01

    Computational modeling of tissue-scale cardiac electrophysiology requires numerically converged solutions to avoid spurious artifacts. The steep gradients inherent to cardiac action potential propagation necessitate fine spatial scales and therefore a substantial computational burden. The use of high-order interpolation methods has previously been proposed for these simulations due to their theoretical convergence advantage. In this study, we compare the convergence behavior of linear Lagrange, cubic Hermite, and the newly proposed cubic Hermite-style serendipity interpolation methods for finite element simulations of the cardiac monodomain equation. The high-order methods reach converged solutions with fewer degrees of freedom and longer element edge lengths than traditional linear elements. Additionally, we propose a dimensionless number, the cell Thiele modulus, as a more useful metric for determining solution convergence than element size alone. Finally, we use the cell Thiele modulus to examine convergence criteria for obtaining clinically useful activation patterns for applications such as patient-specific modeling where the total activation time is known a priori. PMID:26300783

  3. Computers as Teachers: Learning from Animations.

    ERIC Educational Resources Information Center

    Lilienfield, Lawrence S.; Broering, Naomi C.

    1994-01-01

    Describes the use of an interactive multimedia computer program in the study of cardiovascular physiology. Scores on tests given immediately after completion of a two-hour animation program on the Cardiac Cycle and Introduction to Electrocardiography were significantly higher than pretest scores. Students who used the computer program achieved…

  4. [Cardiac sarcoidosis: seven keypoints to remind in order to avoid misdiagnosis].

    PubMed

    Porretta, Alessandra Pia; Van der Gucht, Axel; Bisch, Laurence; Mitsakis, Periklis; Pomoni, Anastasia; Allenbach, Gilles; Lalonde, Marie Nicod; Schaefer, Niklaus; Buss, Guillaume; Prior, John O; Pruvot, Étienne

    2016-05-25

    Early diagnosis of cardiac sarcoidosis remains difficult in the absence of specific symptoms. The evolution and prognosis of the disease are strongly correlated to an early and appropriate treatment. The multi-modality assessment based on cardiac MRI and positron emission tomography associated with computed tomography (PET/CT) has significantly improved the detection of cardiac sarcoidosis over the last two decades. These approaches appear as useful and suitable imaging strategy for the early diagnosis, the assessment of the disease extent as well as the management and therapeutic follow-up. This article is a didactic review on cardiac sarcoidosis, with a special focus on recent diagnostic and therapeutic modalities, prognosis and interest of imaging techniques.

  5. Reversible cardiac conduction block and defibrillation with high-frequency electric field.

    PubMed

    Tandri, Harikrishna; Weinberg, Seth H; Chang, Kelly C; Zhu, Renjun; Trayanova, Natalia A; Tung, Leslie; Berger, Ronald D

    2011-09-28

    Electrical impulse propagation is an essential function in cardiac, skeletal muscle, and nervous tissue. Abnormalities in cardiac impulse propagation underlie lethal reentrant arrhythmias, including ventricular fibrillation. Temporary propagation block throughout the ventricular myocardium could possibly terminate these arrhythmias. Electrical stimulation has been applied to nervous tissue to cause reversible conduction block, but has not been explored sufficiently in cardiac tissue. We show that reversible propagation block can be achieved in cardiac tissue by holding myocardial cells in a refractory state for a designated period of time by applying a sustained sinusoidal high-frequency alternating current (HFAC); in doing so, reentrant arrhythmias are terminated. We demonstrate proof of concept using several models, including optically mapped monolayers of neonatal rat ventricular cardiomyocytes, Langendorff-perfused guinea pig and rabbit hearts, intact anesthetized adult rabbits, and computer simulations of whole-heart impulse propagation. HFAC may be an effective and potentially safer alternative to direct current application, currently used to treat ventricular fibrillation.

  6. Successful fibrinolytic and therapeutic hypothermic management of cardiac arrest following massive pulmonary embolism

    PubMed Central

    Ko, Eunsil; Lee, Jeong Hoon; Chae, Minjung Kathy; Lee, Tae Rim; Sim, Min Seob; Shin, Tae Gun; Cha, Won Chul; Jo, Ik Joon; Song, Keun Jeong; Rhee, Joong Eui; Jeong, Yeon Kwon

    2015-01-01

    Massive pulmonary embolism (MPE) with hemodynamic instability is a clinical condition with a poor prognosis and high mortality rates. There are no definitive treatment options for cardiac arrest due to MPE. A 52-year-old female presented at our emergency department with cardiac arrest, and a 62-year-old female presented after achieving return of spontaneous circulation of cardiac arrest from a local hospital, respectively. In each case, computed tomographic pulmonary angiography after return of spontaneous circulation demonstrated heavy burdens of pulmonary embolism in the pulmonary arteries. We immediately started therapeutic hypothermia and fibrinolytic therapy. They were transferred to the thoracic surgery and cardiology departments respectively, and then discharged with a cerebral performance categories scale score of 1. In summary, we report two cases of out-of-hospital cardiac arrest due to MPE in which fibrinolytic therapy was successfully combined with therapeutic hypothermia. PMID:27752597

  7. Reversible Cardiac Conduction Block and Defibrillation with High-Frequency Electric Field

    PubMed Central

    Tandri, Harikrishna; Weinberg, Seth H.; Chang, Kelly C.; Zhu, Renjun; Trayanova, Natalia A.; Tung, Leslie; Berger, Ronald D.

    2012-01-01

    Electrical impulse propagation is an essential function in cardiac, skeletal muscle, and nervous tissue. Abnormalities in cardiac impulse propagation underlie lethal reentrant arrhythmias, including ventricular fibrillation. Temporary propagation block throughout the ventricular myocardium could possibly terminate these arrhythmias. Electrical stimulation has been applied to nervous tissue to cause reversible conduction block, but has not been explored sufficiently in cardiac tissue. We show that reversible propagation block can be achieved in cardiac tissue by holding myocardial cells in a refractory state for a designated period of time by applying a sustained sinusoidal high-frequency alternating current (HFAC); in doing so, reentrant arrhythmias are terminated. We demonstrate proof of concept using several models, including optically mapped monolayers of neonatal rat ventricular cardiomyocytes, Langendorff-perfused guinea pig and rabbit hearts, intact anesthetized adult rabbits, and computer simulations of whole-heart impulse propagation. HFAC may be an effective and potentially safer alternative to direct current application, currently used to treat ventricular fibrillation. PMID:21957174

  8. Cardiac haemangioma with coronary-pulmonary artery fistula in one patient.

    PubMed

    Xu, Hongfei; Li, Weidong; Teng, Peng; Ni, Yiming

    2015-02-01

    Cardiac haemangioma and coronary-pulmonary artery fistula are both rare entities. We present the case of a 45-year-old symptomatic male patient with a rare cardiac cavernous haemangioma. During assessment, coronary-pulmonary artery fistula was diagnosed by computed tomographic angiography (CTA) of the coronary artery. As far as we know, this is the first case in which cardiac haemangioma has been found to co-exist with coronary-pulmonary artery fistula. Surgery remains the most effective form of therapy. Meanwhile, in patients with heart issues, CTA of the coronary artery has its particularly advantages that can reduce the risk of a second operation and missed diagnosis. We also performed an electronic search of the published literature in English on cases of cardiac haemangioma.

  9. Use of the single-breath method of estimating cardiac output during exercise-stress testing.

    NASA Technical Reports Server (NTRS)

    Buderer, M. C.; Rummel, J. A.; Sawin, C. F.; Mauldin, D. G.

    1973-01-01

    The single-breath cardiac output measurement technique of Kim et al. (1966) has been modified for use in obtaining cardiac output measurements during exercise-stress tests on Apollo astronauts. The modifications involve the use of a respiratory mass spectrometer for data acquisition and a digital computer program for data analysis. The variation of the modified method for triplicate steady-state cardiac output measurements was plus or minus 1 liter/min. The combined physiological and methodological variation seen during a set of three exercise tests on a series of subjects was 1 to 2.5 liter/min. Comparison of the modified method with the direct Fick technique showed that although the single-breath values were consistently low, the scatter of data was small and the correlation between the two methods was high. Possible reasons for the low single-breath cardiac output values are discussed.

  10. Spatiotemporal processing of gated cardiac SPECT images using deformable mesh modeling

    SciTech Connect

    Brankov, Jovan G.; Yang Yongyi; Wernick, Miles N.

    2005-09-15

    In this paper we present a spatiotemporal processing approach, based on deformable mesh modeling, for noise reduction in gated cardiac single-photon emission computed tomography images. Because of the partial volume effect (PVE), clinical cardiac-gated perfusion images exhibit a phenomenon known as brightening--the myocardium appears to become brighter as the heart wall thickens. Although brightening is an artifact, it serves as an important diagnostic feature for assessment of wall thickening in clinical practice. Our proposed processing algorithm aims to preserve this important diagnostic feature while reducing the noise level in the images. The proposed algorithm is based on the use of a deformable mesh for modeling the cardiac motion in a gated cardiac sequence, based on which the images are processed by smoothing along space-time trajectories of object points while taking into account the PVE. Our experiments demonstrate that the proposed algorithm can yield significantly more-accurate results than several existing methods.

  11. ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 appropriate use criteria for cardiac radionuclide imaging: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the American Society of Nuclear Cardiology, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the Society of Cardiovascular Computed Tomography, the Society for Cardiovascular Magnetic Resonance, and the Society of Nuclear Medicine.

    PubMed

    Hendel, Robert C; Berman, Daniel S; Di Carli, Marcelo F; Heidenreich, Paul A; Henkin, Robert E; Pellikka, Patricia A; Pohost, Gerald M; Williams, Kim A

    2009-06-01

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac radionuclide imaging (RNI) is frequently considered. This document is a revision of the original Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT MPI) Appropriateness Criteria, published 4 years earlier, written to reflect changes in test utilization and new clinical data, and to clarify RNI use where omissions or lack of clarity existed in the original criteria. This is in keeping with the commitment to revise and refine appropriate use criteria (AUC) on a frequent basis. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Sixty-seven clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of cardiac RNI for diagnosis and risk assessment in intermediate- and high-risk patients with coronary artery disease (CAD) was viewed favorably, while testing in low-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Additionally, use for perioperative testing was found to be inappropriate except for high selected groups of patients. It is anticipated that these results will have a significant impact on physician decision making, test performance, and reimbursement policy, and will help guide future research. PMID:19451357

  12. Stem cells in cardiac repair.

    PubMed

    Henning, Robert J

    2011-01-01

    Myocardial infarction is the leading cause of death among people in industrialized nations. Although the heart has some ability to regenerate after infarction, myocardial restoration is inadequate. Consequently, investigators are currently exploring the use of human embryonic stem cells (hESCs), skeletal myoblasts and adult bone marrow stem cells to limit infarct size. hESCs are pluripotent cells that can regenerate myocardium in infarcted hearts, attenuate heart remodeling and contribute to left ventricle (LV) systolic force development. Since hESCs can form heart teratomas, investigators are differentiating hESCs toward cardiac progenitor cells prior to transplantation into hearts. Large quantities of hESCs cardiac progenitor cells, however, must be generated, immune rejection must be prevented and grafts must survive over the long term to significantly improve myocardial performance. Transplanted autologous skeletal myoblasts can survive in infarcted myocardium in small numbers, proliferate, differentiate into skeletal myofibers and increase the LV ejection fraction. These cells, however, do not form electromechanical connections with host cardiomyocytes. Consequently, electrical re-entry can occur and cause cardiac arrhythmias. Autologous bone marrow mononuclear cells contain hematopoietic and mesenchymal stem cells. In several meta-analyses, patients with coronary disease who received autologous bone marrow cells by intracoronary injection show significant 3.7% (range: 1.9-5.4%) increases in LV ejection fraction, decreases in LV end-systolic volume of -4.8 ml (range: -1.4 to -8.2 ml) and reductions in infarct size of 5.5% (-1.9 to -9.1%), without experiencing arrhythmias. Bone marrow cells appear to release biologically active factors that limit myocardial damage. Unfortunately, bone marrow cells from patients with chronic diseases propagate poorly and can die prematurely. Substantial challenges must be addressed and resolved to advance the use of stem cells

  13. A multiresolution restoration method for cardiac SPECT

    NASA Astrophysics Data System (ADS)

    Franquiz, Juan Manuel

    Single-photon emission computed tomography (SPECT) is affected by photon attenuation and image blurring due to Compton scatter and geometric detector response. Attenuation correction is important to increase diagnostic accuracy of cardiac SPECT. However, in attenuation-corrected scans, scattered photons from radioactivity in the liver could produce a spillover of counts into the inferior myocardial wall. In the clinical setting, blurring effects could be compensated by restoration with Wiener and Metz filters. Inconveniences of these procedures are that the Wiener filter depends upon the power spectra of the object image and noise, which are unknown, while Metz parameters have to be optimized by trial and error. This research develops an alternative restoration procedure based on a multiresolution denoising and regularization algorithm. It was hypothesized that this representation leads to a more straightforward and automatic restoration than conventional filters. The main objective of the research was the development and assessment of the multiresolution algorithm for compensating the liver spillover artifact. The multiresolution algorithm decomposes original SPECT projections into a set of sub-band frequency images. This allows a simple denoising and regularization procedure by discarding high frequency channels and performing inversion only in low and intermediate frequencies. The method was assessed in bull's eye polar maps and short- axis attenuation-corrected reconstructions of a realistic cardiac-chest phantom with a custom-made liver insert and different 99mTc liver-to-heart activity ratios. Inferior myocardial defects were simulated in some experiments. The cardiac phantom in free air was considered as the gold standard reference. Quantitative analysis was performed by calculating contrast of short- axis slices and the normalized chi-square measure, defect size and mean and standard deviation of polar map counts. The performance of the multiresolution

  14. Risk stratification for major adverse cardiac events and ventricular tachyarrhythmias by cardiac MRI in patients with cardiac sarcoidosis

    PubMed Central

    Yasuda, Masakazu; Iwanaga, Yoshitaka; Kato, Takao; Izumi, Toshiaki; Inuzuka, Yasutaka; Nakamura, Takashi; Miyaji, Yuki; Kawamura, Takayuki; Ikeguchi, Shigeru; Inoko, Moriaki; Kurita, Takashi; Miyazaki, Shunichi

    2016-01-01

    Background The presence of myocardial fibrosis by cardiac MRI has prognostic value in cardiac sarcoidosis, and localisation may be equally relevant to clinical outcomes. Objective We aimed to analyse cardiac damage and function in detail and explore the relationship with clinical outcomes in patients with cardiac sarcoidosis using cardiac MRI. Methods We included 81 consecutive patients with cardiac sarcoidosis undergoing cardiac MR. Left ventricular mass and fibrosis mass were calculated, and localisation was analysed using a 17-segment model. Participants underwent follow-up through 2015, and the development of major adverse cardiac events including ventricular tachyarrhythmias was recorded. Results Increased left ventricular fibrosis mass was associated with increased prevalence of ventricular tachyarrhythmias (p<0.001). When localisation was defined as the sum of late gadolinium enhancement in the left ventricular basal anterior and basal anteroseptal areas, or the right ventricular area, it was associated with ventricular tachyarrhythmias (p<0.001). Kaplan-Meier analysis during a median follow-up of 22.1 months showed that both the mass and localisation groupings for fibrosis were significantly associated with major adverse cardiac events or ventricular tachyarrhythmias and that when combined, the risk stratification was better than for each variable alone (p<0.001, respectively). By Cox-proportional hazard risk analysis, the localisation grouping was an independent predictor for the both. Conclusions In patients with cardiac sarcoidosis, both fibrosis mass and its localisation to the basal anterior/anteroseptal left ventricle, or right ventricle was associated with the development of major adverse cardiac events or ventricular tachyarrhythmias. Cardiac MR with late gadolinium enhancement may be useful for improving risk stratification in patients with cardiac sarcoidosis. PMID:27547432

  15. Primary proteasome inhibition results in cardiac dysfunction

    PubMed Central

    Herrmann, Joerg; Wohlert, Christine; Saguner, Ardan M.; Flores, Ana; Nesbitt, Lisa L.; Chade, Alejandro; Lerman, Lilach O.; Lerman, Amir

    2013-01-01

    Aims The proteasome prevents the intracellular accumulation of proteins and its impairment can lead to structural and functional alterations, as noted for the coronary vasculature in a previous study. Utilizing the same model, this study was designed to test the hypothesis that chronic proteasome inhibition (PSI) also leads to structural and functional changes of the heart. Methods and results Female domestic pigs were randomized to a normal diet without (N) or with twice-weekly subcutaneous injections of the proteasome inhibitor MLN-273 (0.08 mg/kg, N + PSI, n = 5 each group). In vivo data on cardiac structure and function as well as myocardial perfusion and microvascular permeability response to adenosine and dobutamine were obtained by electron beam computed tomography after 11 weeks. Subsequent ex vivo myocardial analyses included immunoblotting, immunostaining, TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labelling), Masson trichrome, and Congo red staining. Compared with N, an increase in LV mass was observed in N + PSI (106.5 ± 16.4 g vs. 183.1 ± 24.2 g, P < 0.05). The early to late diastolic filling ratio was increased in N + PSI vs. N (3.5 ± 0.6 vs. 1.8 ± 0.1, P < 0.05). The EF tended to be lower (46 ± 12% and 53 ± 9%, respectively) and cardiac output was significantly lower in N + PSI than in N (2.9 ± 1.1 vs. 4.7 ± 1.1 L/min, P < 0.05). Tissue analyses demonstrated an accumulation of proteasome substrates, apoptosis, and fibrosis in the PSI group. Compared with N, the myocardial perfusion response was reduced and microvascular permeability was increased in N + PSI. Conclusion The current study demonstrates that chronic proeasome inhibition affects the cardiovascular system, leading to functional and structural alteration of the heart consistent with a hypertrophic–restrictive cardiomyopathy phenotype. PMID:23616520

  16. Non-rigid dual respiratory and cardiac motion correction methods after, during, and before image reconstruction for 4D cardiac PET

    NASA Astrophysics Data System (ADS)

    Feng, Tao; Wang, Jizhe; Fung, George; Tsui, Benjamin

    2016-01-01

    Respiratory motion (RM) and cardiac motion (CM) degrade the quality and resolution in cardiac PET scans. We have developed non-rigid motion estimation methods to estimate both RM and CM based on 4D cardiac gated PET data alone, and compensate the dual respiratory and cardiac (R&C) motions after (MCAR), during (MCDR), and before (MCBR) image reconstruction. In all three R&C motion correction methods, attenuation-activity mismatch effect was modeled by using transformed attenuation maps using the estimated RM. The difference of using activity preserving and non-activity preserving models in R&C correction was also studied. Realistic Monte Carlo simulated 4D cardiac PET data using the 4D XCAT phantom and accurate models of the scanner design parameters and performance characteristics at different noise levels were employed as the known truth and for method development and evaluation. Results from the simulation study suggested that all three dual R&C motion correction methods provide substantial improvement in the quality of 4D cardiac gated PET images as compared with no motion correction. Specifically, the MCDR method yields the best performance for all different noise levels compared with the MCAR and MCBR methods. While MCBR reduces computational time dramatically but the resultant 4D cardiac gated PET images has overall inferior image quality when compared to that from the MCAR and MCDR approaches in the ‘almost’ noise free case. Also, the MCBR method has better noise handling properties when compared with MCAR and provides better quantitative results in high noise cases. When the goal is to reduce scan time or patient radiation dose, MCDR and MCBR provide a good compromise between image quality and computational times.

  17. Non-rigid dual respiratory and cardiac motion correction methods after, during, and before image reconstruction for 4D cardiac PET.

    PubMed

    Feng, Tao; Wang, Jizhe; Fung, George; Tsui, Benjamin

    2016-01-01

    Respiratory motion (RM) and cardiac motion (CM) degrade the quality and resolution in cardiac PET scans. We have developed non-rigid motion estimation methods to estimate both RM and CM based on 4D cardiac gated PET data alone, and compensate the dual respiratory and cardiac (R&C) motions after (MCAR), during (MCDR), and before (MCBR) image reconstruction. In all three R&C motion correction methods, attenuation-activity mismatch effect was modeled by using transformed attenuation maps using the estimated RM. The difference of using activity preserving and non-activity preserving models in R&C correction was also studied. Realistic Monte Carlo simulated 4D cardiac PET data using the 4D XCAT phantom and accurate models of the scanner design parameters and performance characteristics at different noise levels were employed as the known truth and for method development and evaluation. Results from the simulation study suggested that all three dual R&C motion correction methods provide substantial improvement in the quality of 4D cardiac gated PET images as compared with no motion correction. Specifically, the MCDR method yields the best performance for all different noise levels compared with the MCAR and MCBR methods. While MCBR reduces computational time dramatically but the resultant 4D cardiac gated PET images has overall inferior image quality when compared to that from the MCAR and MCDR approaches in the 'almost' noise free case. Also, the MCBR method has better noise handling properties when compared with MCAR and provides better quantitative results in high noise cases. When the goal is to reduce scan time or patient radiation dose, MCDR and MCBR provide a good compromise between image quality and computational times.

  18. An integrated platform for image-guided cardiac resynchronization therapy

    NASA Astrophysics Data System (ADS)

    Ma, Ying Liang; Shetty, Anoop K.; Duckett, Simon; Etyngier, Patrick; Gijsbers, Geert; Bullens, Roland; Schaeffter, Tobias; Razavi, Reza; Rinaldi, Christopher A.; Rhode, Kawal S.

    2012-05-01

    Cardiac resynchronization therapy (CRT) is an effective procedure for patients with heart failure but 30% of patients do not respond. This may be due to sub-optimal placement of the left ventricular (LV) lead. It is hypothesized that the use of cardiac anatomy, myocardial scar distribution and dyssynchrony information, derived from cardiac magnetic resonance imaging (MRI), may improve outcome by guiding the physician for optimal LV lead positioning. Whole heart MR data can be processed to yield detailed anatomical models including the coronary veins. Cine MR data can be used to measure the motion of the LV to determine which regions are late-activating. Finally, delayed Gadolinium enhancement imaging can be used to detect regions of scarring. This paper presents a complete platform for the guidance of CRT using pre-procedural MR data combined with live x-ray fluoroscopy. The platform was used for 21 patients undergoing CRT in a standard catheterization laboratory. The patients underwent cardiac MRI prior to their procedure. For each patient, a MRI-derived cardiac model, showing the LV lead targets, was registered to x-ray fluoroscopy using multiple views of a catheter looped in the right atrium. Registration was maintained throughout the procedure by a combination of C-arm/x-ray table tracking and respiratory motion compensation. Validation of the registration between the three-dimensional (3D) roadmap and the 2D x-ray images was performed using balloon occlusion coronary venograms. A 2D registration error of 1.2 ± 0.7 mm was achieved. In addition, a novel navigation technique was developed, called Cardiac Unfold, where an entire cardiac chamber is unfolded from 3D to 2D along with all relevant anatomical and functional information and coupled to real-time device detection. This allowed more intuitive navigation as the entire 3D scene was displayed simultaneously on a 2D plot. The accuracy of the unfold navigation was assessed off-line using 13 patient data sets

  19. Changes in entrance surface dose in relation to the location of shielding material in chest computed tomography

    NASA Astrophysics Data System (ADS)

    Kang, Y. M.; Cho, J. H.; Kim, S. C.

    2015-07-01

    This study examined the effects of entrance surface dose (ESD) on the abdomen and pelvis of the patient when undergoing chest computed tomography (CT) procedure, and evaluated the effects of ESD reduction depending on the location of radiation shield. For CT scanner, the 64-slice multi-detector computed tomography was used. The alderson radiation therapy phantom and optically stimulated luminescence dosimeter (OSLD), which enabled measurement from low to high dose, were also used. For measurement of radiation dose, the slice number from 9 to 21 of the phantom was set as the test range, which included apex up to both costophrenic angles. A total of 10 OSLD nanoDots were attached for measurement of the front and rear ESD. Cyclic tests were performed using the low-dose chest CT and high-resolution CT (HRCT) protocol on the following set-ups: without shielding; shielding only on the front side; shielding only on the rear side; and shielding for both front and rear sides. According to the test results, ESD for both front and rear sides was higher in HRCT than low-dose CT when radiation shielding was not used. It was also determined that, compared to the set-up that did not use the radiation shield, locating the radiation shield on the front side was effective in reducing front ESD, while locating the radiation shield on the rear side reduced rear ESD level. Shielding both the front and rear sides resulted in ESD reduction. In conclusion, it was confirmed that shielding the front and rear sides was the most effective method to reduce the ESD effect caused by scatter ray during radiography.

  20. Proceedings of the cardiac PET summit meeting 12 may 2014: Cardiac PET and SPECT instrumentation.

    PubMed

    Garcia, Ernest V

    2015-06-01

    Advances in PET and SPECT and imaging hardware and software are vastly improving the noninvasive evaluation of myocardial perfusion and function. PET perfusion imaging has benefitted from the introduction of novel detectors that now allow true 3D imaging, and precise attenuation correction (AC). These developments have also resulted in perfusion images with higher spatial and contrast resolution that may be acquired in shorter protocols and/or with less patient radiation exposure than traditional PET or SPECT studies. Hybrid PET/CT cameras utilize transmission computed tomographic (CT) scans for AC, and offer the additional clinical advantages of evaluating coronary calcium and myocardial anatomy but at a higher cost than PET scanners that use (68)Ge radioactive line sources. As cardiac PET systems continue to improve, dedicated cardiac SPECT systems are also undergoing a profound change in their design. The scintillation camera general purpose design is being replaced with systems with multiple detectors focused on the heart yielding 5 to 10 times the sensitivity of conventional SPECT. As a result, shorter acquisition times and/or lower tracer doses produce higher quality SPECT images than were possible before. This article reviews these concepts and compares the attributes of PET and SPECT instrumentation. PMID:25824018

  1. Proceedings of the cardiac PET summit meeting 12 may 2014: Cardiac PET and SPECT instrumentation.

    PubMed

    Garcia, Ernest V

    2015-06-01

    Advances in PET and SPECT and imaging hardware and software are vastly improving the noninvasive evaluation of myocardial perfusion and function. PET perfusion imaging has benefitted from the introduction of novel detectors that now allow true 3D imaging, and precise attenuation correction (AC). These developments have also resulted in perfusion images with higher spatial and contrast resolution that may be acquired in shorter protocols and/or with less patient radiation exposure than traditional PET or SPECT studies. Hybrid PET/CT cameras utilize transmission computed tomographic (CT) scans for AC, and offer the additional clinical advantages of evaluating coronary calcium and myocardial anatomy but at a higher cost than PET scanners that use (68)Ge radioactive line sources. As cardiac PET systems continue to improve, dedicated cardiac SPECT systems are also undergoing a profound change in their design. The scintillation camera general purpose design is being replaced with systems with multiple detectors focused on the heart yielding 5 to 10 times the sensitivity of conventional SPECT. As a result, shorter acquisition times and/or lower tracer doses produce higher quality SPECT images than were possible before. This article reviews these concepts and compares the attributes of PET and SPECT instrumentation.

  2. [Primary Cardiac Angiosarcoma with Superior Vena Cava Syndrome].

    PubMed

    Shimada, Naohiro; Shiomi, Daisuke; Kaki, Nobuaki; Kiyama, Hiroshi

    2016-05-01

    Primary cardiac angiosarcoma is rare and its prognosis very poor. A 34-year-old woman complained of facial edema and dyspnea. Echocardiography, chest computed tomography scan and chest magnetic resonance imaging showed a huge tumor arising in the right atrium. Surgical excision of the tumor was performed for the purpose of relieving superior vena cava syndrome and making diagnosis of the tumor. The right atrial wall, including the tumor, was resected and reconstructed with Gore Tex patch under cardiopulmonary bypass. The tumor was diagnosed as angiosarcoma. Doxorubicin hydrochloride/ifosfamide were used to treat postoperative cardiac recurrence and lung metastasis. These drugs were effective to a certain degree, but she died of brain metastasis of the tumor in the 14th postoperative month. PMID:27220927

  3. Electrophysiological Modeling of Cardiac Ventricular Function: From Cell to Organ

    PubMed Central

    Winslow, R. L.; Scollan, D. F.; Holmes, A.; Yung, C. K.; Zhang, J.; Jafri, M. S.

    2005-01-01

    Three topics of importance to modeling the integrative function of the heart are reviewed. The first is modeling of the ventricular myocyte. Emphasis is placed on excitation-contraction coupling and intracellular Ca2+ handling, and the interpretation of experimental data regarding interval-force relationships. Second, data on use of diffusion tensor magnetic resonance (DTMR) imaging for measuring the anatomical structure of the cardiac ventricles are presented. A method for the semi-automated reconstruction of the ventricles using a combination of gradient recalled acquisition in the steady state (GRASS) and DTMR images is described. Third, we describe how these anatomically and biophysically based models of the cardiac ventricles can be implemented on parallel computers. PMID:11701509

  4. [Information system at Department of Cardiac Surgery Intensive Care Unit].

    PubMed

    Dokozić, Josipa

    2014-03-01

    This paper analyzes the aspects of using computer technology in nursing practice. Transfer and managing of data, information and knowledge in nursing is enabled by using modern technology and suitable applications. Cardio applications at the Intensive Care Unit of Department of Cardiac Surgery in Osijek enables nurses/technicians to gain insight into patient personal data, medical history, microbiological findings, interventions that have been made as well as those scheduled in the field of health care, all this by using a few simple connections. Nurses/technicians are those who enter patient data into his/her Electronic Health Record. There are multiple contributions of cardiac system. In comparison with previous paper-based managing of nursing documentation, this program has considerably facilitated and improved nursing practice.

  5. Towards a statistical atlas of cardiac fiber structure.

    PubMed

    Peyrat, Jean-Marc; Sermesant, Maxime; Pennec, Xavier; Delingette, Hervé; Xu, Chenyang; McVeigh, Elliot; Ayache, Nicholas

    2006-01-01

    We propose here a framework to build a statistical atlas of diffusion tensors of canine hearts. The anatomical images of seven hearts are first non-rigidly registered in the same reference frame and their associated diffusion tensors are then transformed with a method that preserves the cardiac laminar sheets. In this referential frame, the mean tensor and its covariance matrix are computed based on the Log-Euclidean framework. With this method, we can produce a smooth mean tensor field that is suited for fiber tracking algorithms or the electromechanical modeling of the heart. In addition, by examining the covariance matrix at each voxel it is possible to assess the variability of the cardiac fiber directions and of the orientations of laminar sheets. The results show a strong coherence of the diffusion tensors and the fiber orientations among a population of seven normal canine hearts.

  6. Cardiac Arrest in a Heart Transplant Patient Receiving Dexmedetomidine During Cardiac Catheterization.

    PubMed

    Schwartz, Lawrence Israel; Miyamoto, Shelley D; Stenquist, Scott; Twite, Mark David

    2016-06-01

    Dexmedetomidine is an α-2 agonist with a sedative and cardiopulmonary profile that makes it an attractive anesthetic in pediatric cardiac patients. Cardiac transplant patients may suffer from acute cellular rejection of the cardiac conduction system and, therefore, are at an increased risk of the electrophysiological effect of dexmedetomidine. We present such a patient who had a cardiac arrest while receiving dexmedetomidine during cardiac catheterization. Because acute cellular rejection of the cardiac conduction system is difficult to diagnose, dexmedetomidine should be used with caution in pediatric heart transplant patients. PMID:26721807

  7. Computers and clinical arrhythmias.

    PubMed

    Knoebel, S B; Lovelace, D E

    1983-02-01

    Cardiac arrhythmias are ubiquitous in normal and abnormal hearts. These disorders may be life-threatening or benign, symptomatic or unrecognized. Arrhythmias may be the precursor of sudden death, a cause or effect of cardiac failure, a clinical reflection of acute or chronic disorders, or a manifestation of extracardiac conditions. Progress is being made toward unraveling the diagnostic and therapeutic problems involved in arrhythmogenesis. Many of the advances would not be possible, however, without the availability of computer technology. To preserve the proper balance and purposeful progression of computer usage, engineers and physicians have been exhorted not to work independently in this field. Both should learn some of the other's trade. The two disciplines need to come together to solve important problems with computers in cardiology. The intent of this article was to acquaint the practicing cardiologist with some of the extant and envisioned computer applications and some of the problems with both. We conclude that computer-based database management systems are necessary for sorting out the clinical factors of relevance for arrhythmogenesis, but computer database management systems are beset with problems that will require sophisticated solutions. The technology for detecting arrhythmias on routine electrocardiograms is quite good but human over-reading is still required, and the rationale for computer application in this setting is questionable. Systems for qualitative, continuous monitoring and review of extended time ECG recordings are adequate with proper noise rejection algorithms and editing capabilities. The systems are limited presently for clinical application to the recognition of ectopic rhythms and significant pauses. Attention should now be turned to the clinical goals for detection and quantification of arrhythmias. We should be asking the following questions: How quantitative do systems need to be? Are computers required for the detection of

  8. Systems biology and cardiac arrhythmias

    PubMed Central

    Grace, Andrew A; Roden, Dan M

    2013-01-01

    During the past few years, the development of effective, empirical technologies for treatment of cardiac arrhythmias has exceeded the pace at which detailed knowledge of the underlying biology has accumulated. As a result, although some clinical arrhythmias can be cured with techniques such as catheter ablation, drug treatment and prediction of the risk of sudden death remain fairly primitive. The identification of key candidate genes for monogenic arrhythmia syndromes shows that to bring basic biology to the clinic is a powerful approach. Increasingly sophisticated experimental models and methods of measurement, including stem cell-based models of human cardiac arrhythmias, are being deployed to study how perturbations in several biologic pathways can result in an arrhythmia-prone heart. The biology of arrhythmia is largely quantifiable, which allows for systematic analysis that could transform treatment strategies that are often still empirical into management based on molecular evidence. PMID:23101717

  9. [Cardiac support and replacement therapies].

    PubMed

    Lotz, Christopher; Roewer, Norbert; Muellenbach, Ralf M

    2016-09-01

    Circulatory support represents an integral part within the treatment of the critically ill patient. Sophisticated pharmacologic regimens help to maintain systemic perfusion pressure by increasing vascular tone as well as mediating positive inotropic effects. Besides the administration of catecholamines and phosphodiesterase-III-inhibitors, in particular the administration of levosimendan represents a promising alternative during low-cardiac-output. Nevertheless, sufficient evidence demonstrating a survival benefit for any pharmacologic regimen is nonexistent. In case pharmacological measures do not suffice mechanical cardiopulmonary support (MCS) may be used. MCS may be used during cardiopulmonary resuscitation or a "low-cardiac-output-syndrome" as bridging towards decision, recovery or long-term support. Venoarterial extracorporeal membrane oxygenation (vaECMO) may take over cardiopulmonary function and may improve survival as well as neurological outcome after cardiogenic shock or cardiopulmonary resuscitation. PMID:27631451

  10. Heart fields and cardiac morphogenesis.

    PubMed

    Kelly, Robert G; Buckingham, Margaret E; Moorman, Antoon F

    2014-10-01

    In this review, we focus on two important steps in the formation of the embryonic heart: (i) the progressive addition of late differentiating progenitor cells from the second heart field that drives heart tube extension during looping morphogenesis, and (ii) the emergence of patterned proliferation within the embryonic myocardium that generates distinct cardiac chambers. During the transition between these steps, the major site of proliferation switches from progenitor cells outside the early heart to proliferation within the embryonic myocardium. The second heart field and ballooning morphogenesis concepts have major repercussions on our understanding of human heart development and disease. In particular, they provide a framework to dissect the origin of congenital heart defects and the regulation of myocardial proliferation and differentiation of relevance for cardiac repair.

  11. Cardiac regeneration: epicardial mediated repair

    PubMed Central

    2015-01-01

    The hearts of lower vertebrates such as fish and salamanders display scarless regeneration following injury, although this feature is lost in adult mammals. The remarkable capacity of the neonatal mammalian heart to regenerate suggests that the underlying machinery required for the regenerative process is evolutionarily retained. Recent studies highlight the epicardial covering of the heart as an important source of the signalling factors required for the repair process. The developing epicardium is also a major source of cardiac fibroblasts, smooth muscle, endothelial cells and stem cells. Here, we examine animal models that are capable of scarless regeneration, the role of the epicardium as a source of cells, signalling mechanisms implicated in the regenerative process and how these mechanisms influence cardiomyocyte proliferation. We also discuss recent advances in cardiac stem cell research and potential therapeutic targets arising from these studies. PMID:26702046

  12. Nutritional status and cardiac autophagy.

    PubMed

    Ahn, Jihyun; Kim, Jaetaek

    2013-02-01

    Autophagy is necessary for the degradation of long-lasting proteins and nonfunctional organelles, and is activated to promote cellular survival. However, overactivation of autophagy may deplete essential molecules and organelles responsible for cellular survival. Lifelong calorie restriction by 40% has been shown to increase the cardiac expression of autophagic markers, which suggests that it may have a cardioprotective effect by decreasing oxidative damage brought on by aging and cardiovascular diseases. Although cardiac autophagy is critical to regulating protein quality and maintaining cellular function and survival, increased or excessive autophagy may have deleterious effects on the heart under some circumstances, including pressure overload-induced heart failure. The importance of autophagy has been shown in nutrient supply and preservation of energy in times of limitation, such as ischemia. Some studies have suggested that a transition from obesity to metabolic syndrome may involve progressive changes in myocardial inflammation, mitochondrial dysfunction, fibrosis, apoptosis, and myocardial autophagy.

  13. Systems biology and cardiac arrhythmias.

    PubMed

    Grace, Andrew A; Roden, Dan M

    2012-10-27

    During the past few years, the development of effective, empirical technologies for treatment of cardiac arrhythmias has exceeded the pace at which detailed knowledge of the underlying biology has accumulated. As a result, although some clinical arrhythmias can be cured with techniques such as catheter ablation, drug treatment and prediction of the risk of sudden death remain fairly primitive. The identification of key candidate genes for monogenic arrhythmia syndromes shows that to bring basic biology to the clinic is a powerful approach. Increasingly sophisticated experimental models and methods of measurement, including stem cell-based models of human cardiac arrhythmias, are being deployed to study how perturbations in several biologic pathways can result in an arrhythmia-prone heart. The biology of arrhythmia is largely quantifiable, which allows for systematic analysis that could transform treatment strategies that are often still empirical into management based on molecular evidence.

  14. Monitoring chaos of cardiac rhythms

    SciTech Connect

    Mayer-Kress, G.

    1989-01-01

    Chaos theory provides a new paradigm in monitoring complexity changes in heart rate variability. Even in cases where the spectral analysis only shows broad band characteristics estimations of dimensional complexity parameters can show quantitative changes in the degree of chaos present in the interbeat interval dynamics. We introduce the concept of dimensional complexity as dynamical monitoring parameter and discuss its properties in connection with control data and data taken during cardiac arrest. Whereas dimensional complexity provides a quantitative indicator of overall chaotic behavior, recurrence plots allow direct visualization of recurrences in arbitrary high dimensional pattern-space. In combination these two methods from non-linear dynamics exemplify a new approach in the problem of heart rate monitoring and identification of precursors of cardiac arrest. Finally we mention a new method of chaotic control, by which selective and highly effective perturbations of nonlinear dynamical systems could be used for improved pacing patterns. 11 refs., 6 figs.

  15. Pathophysiology and clinical management of cardiac sarcoidosis.

    PubMed

    Hamzeh, Nabeel; Steckman, David A; Sauer, William H; Judson, Marc A

    2015-05-01

    Cardiac sarcoidosis is a potentially life-threatening condition characterized by formation of granulomas in the heart, resulting in conduction disturbances, atrial and ventricular arrhythmias, and ventricular dysfunction. The presentation of cardiac sarcoidosis ranges from asymptomatic with an abnormal imaging scan, to palpitations, syncope, symptoms of congestive heart failure, and sudden cardiac death. Screening for cardiac sarcoidosis has not been standardized, but the presence of cardiac symptoms on medical history and physical examination, and an abnormal electrocardiogram (ECG), Holter monitoring, or echocardiogram has been shown to be highly sensitive for detecting cardiac sarcoidosis. A signal-averaged ECG might also have a role in screening for cardiac sarcoidosis in asymptomatic patients. Although endomyocardial biopsies are highly specific for the diagnosis of cardiac sarcoidosis, procedural yield is very low and appropriate findings on cardiac MRI or PET are, therefore, often used as diagnostic surrogates. Treatment for cardiac sarcoidosis usually involves immunosuppressive therapy, particularly corticosteroids. Additional therapy might be required, depending on the clinical presentation, including implantation of an internal defibrillator, antiarrhythmic agents, and catheter ablation.

  16. Cardiac arrhythmias misdiagnosed as epilepsy.

    PubMed Central

    Rutter, N; Southall, D P

    1985-01-01

    A mother and three children presenting with syncope induced by exercise and emotion were diagnosed as epileptic. They, and three symptom free children, showed frequent ventricular and supraventricular tachyarrhythmias on ambulatory electrocardiographic monitoring. Three died before the correct diagnosis of disordered sympathetic innervation of the heart was made, but episodes of syncope and cardiac arrhythmias in the survivors have been successfully treated by propranolol. Images Fig. 2 PMID:3970569

  17. Intensive Hemodialysis Preserved Cardiac injury.

    PubMed

    Chan, Christopher T; Li, Guo Hua; Valaperti, Alan; Liu, Peter

    2015-01-01

    Cardiac injury triggers cellular responses involving both cardiomyocytes and nonmuscle cells to process cardiac structural remodeling. End-stage renal disease (ESRD), despite conventional dialysis, is associated with adverse cardiac remodeling and increased cardiovascular events. Intensification of hemodialysis with nocturnal home hemodialysis (NHD; five sessions per week; 6-8 hours per treatment) was associated with regression of left ventricular hypertrophy and downregulation of genes in apoptosis and fibrosis. In this pilot study, we hypothesize that NHD achieves its cardiac effects in part through attenuation of innate immune activation resulting in amelioration of cardiomyocytes apoptosis and fibrosis. Eight patients (4M:4F; age, 59 ± 9 years) with ESRD were studied. Half of the cohort was converted to NHD, whereas the rest of the patients were maintained on conventional hemodialysis (CHD). At baseline, CHD was associated with an increase in cardiomyocyte apoptosis detected by flow cytometry using Annexin V (mean fluorescence index in CHD and in normal control is 1.00 ± 0.05 vs. 0.66 ± 0.01, p < 0.05). After conversion to NHD, cardiomyocyte apoptosis was reduced compared with baseline CHD situation (p < 0.05) and approached that of normal control (0.59 ± 0.09 vs. 0.66 ± 0.01, p > 0.05). The CHD serum was associated with a coordinated augmentation innate immunity pathway, significantly increasing myeloid differentiation factor-88 and interleukin-1 receptor-associated kinase-4; NHD was able to reduce their levels. Heat shock protein 60 was augmented during CHD condition and fell after NHD. In addition, CHD increased fibroblast proliferation and myofibroblast transformation. Uremia is associated with activation of common innate immune signaling pathways leading to fibrosis and apoptosis. Amelioration of uremic clearance by NHD may attenuate this pathological signaling cascade. PMID:26164598

  18. Minimum Information about a Cardiac Electrophysiology Experiment (MICEE): standardised reporting for model reproducibility, interoperability, and data sharing.

    PubMed

    Quinn, T A; Granite, S; Allessie, M A; Antzelevitch, C; Bollensdorff, C; Bub, G; Burton, R A B; Cerbai, E; Chen, P S; Delmar, M; Difrancesco, D; Earm, Y E; Efimov, I R; Egger, M; Entcheva, E; Fink, M; Fischmeister, R; Franz, M R; Garny, A; Giles, W R; Hannes, T; Harding, S E; Hunter, P J; Iribe, G; Jalife, J; Johnson, C R; Kass, R S; Kodama, I; Koren, G; Lord, P; Markhasin, V S; Matsuoka, S; McCulloch, A D; Mirams, G R; Morley, G E; Nattel, S; Noble, D; Olesen, S P; Panfilov, A V; Trayanova, N A; Ravens, U; Richard, S; Rosenbaum, D S; Rudy, Y; Sachs, F; Sachse, F B; Saint, D A; Schotten, U; Solovyova, O; Taggart, P; Tung, L; Varró, A; Volders, P G; Wang, K; Weiss, J N; Wettwer, E; White, E; Wilders, R; Winslow, R L; Kohl, P

    2011-10-01

    Cardiac experimental electrophysiology is in need of a well-defined Minimum Information Standard for recording, annotating, and reporting experimental data. As a step towards establishing this, we present a draft standard, called Minimum Information about a Cardiac Electrophysiology Experiment (MICEE). The ultimate goal is to develop a useful tool for cardiac electrophysiologists which facilitates and improves dissemination of the minimum information necessary for reproduction of cardiac electrophysiology research, allowing for easier comparison and utilisation of findings by others. It is hoped that this will enhance the integration of individual results into experimental, computational, and conceptual models. In its present form, this draft is intended for assessment and development by the research community. We invite the reader to join this effort, and, if deemed productive, implement the Minimum Information about a Cardiac Electrophysiology Experiment standard in their own work.

  19. Inherited arrhythmias: The cardiac channelopathies.

    PubMed

    Behere, Shashank P; Weindling, Steven N

    2015-01-01

    Ion channels in the myocardial cellular membrane are responsible for allowing the cardiac action potential. Genetic abnormalities in these channels can predispose to life-threatening arrhythmias. We discuss the basic science of the cardiac action potential; outline the different clinical entities, including information regarding overlapping diagnoses, touching upon relevant genetics, new innovations in screening, diagnosis, risk stratification, and management. The special considerations of sudden unexplained death and sudden infant death syndrome are discussed. Scientists and clinicians continue to reconcile the rapidly growing body of knowledge regarding the molecular mechanisms and genetics while continuing to improve our understanding of the various clinical entities and their diagnosis and management in clinical setting. Two separate searches were run on the National Center for Biotechnology Information's website. The first using the term cardiac channelopathies was run on the PubMed database using filters for time (published in past 5 years) and age (birth-18 years), yielding 47 results. The second search using the medical subject headings (MeSH) database with the search terms "Long QT Syndrome" (MeSH) and "Short QT Syndrome" (MeSH) and "Brugada Syndrome" (MeSH) and "Catecholaminergic Polymorphic Ventricular Tachycardia" (MeSH), applying the same filters yielded 467 results. The abstracts of these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles where further explored and read in full. PMID:26556967

  20. Sudden cardiac death risk stratification.

    PubMed

    Deyell, Marc W; Krahn, Andrew D; Goldberger, Jeffrey J

    2015-06-01

    Arrhythmic sudden cardiac death (SCD) may be caused by ventricular tachycardia/fibrillation or pulseless electric activity/asystole. Effective risk stratification to identify patients at risk of arrhythmic SCD is essential for targeting our healthcare and research resources to tackle this important public health issue. Although our understanding of SCD because of pulseless electric activity/asystole is growing, the overwhelming majority of research in risk stratification has focused on SCD-ventricular tachycardia/ventricular fibrillation. This review focuses on existing and novel risk stratification tools for SCD-ventricular tachycardia/ventricular fibrillation. For patients with left ventricular dysfunction or myocardial infarction, advances in imaging, measures of cardiac autonomic function, and measures of repolarization have shown considerable promise in refining risk. Yet the majority of SCD-ventricular tachycardia/ventricular fibrillation occurs in patients without known cardiac disease. Biomarkers and novel imaging techniques may provide further risk stratification in the general population beyond traditional risk stratification for coronary artery disease alone. Despite these advances, significant challenges in risk stratification remain that must be overcome before a meaningful impact on SCD can be realized.

  1. Sudden Cardiac Death Risk Stratification

    PubMed Central

    Deyell, Marc W.; Krahn, Andrew D.; Goldberger, Jeffrey J.

    2015-01-01

    Arrhythmic sudden cardiac death (SCD) may be due to ventricular tachycardia/fibrillation (SCD-VT/VF) or pulseless electrical activity/asystole. Effective risk stratification to identify patients at risk of arrhythmic SCD is essential for targeting our health care and research resources to tackle this important public health issue. Although our understanding of SCD due to pulseless electrical activity/asystole is growing, the overwhelming majority of research in risk stratification has focused on SCD-VT/VF. This review focuses on existing and novel risk stratification tools for SCD-VT/VF. For patients with left ventricular dysfunction and/or myocardial infarction, advances in imaging, measures of cardiac autonomic function, and measures of repolarization have shown considerable promise in refining risk. Yet the majority of SCD-VT/VF occurs in patients without known cardiac disease. Biomarkers and novel imaging techniques may provide further risk stratification in the general population beyond traditional risk stratification for coronary artery disease alone. Despite these advances, significant challenges in risk stratification remain that must be overcome before a meaningful impact on SCD can be realized. PMID:26044247

  2. The history of cardiac catheterization.

    PubMed

    Bourassa, Martial G

    2005-10-01

    The evolution of cardiac catheterization has occurred over at least four centuries. One of the first major steps was the description of the circulation of the blood by William Harvey in 1628. The next milestone was the measurement of arterial pressure by Stephen Hales, one century later. However, the 19th century represented the golden age of cardiovascular physiology, highlighted by the achievements of Carl Ludwig, Etienne-Jules Marey and Claude Bernard, among others. Human cardiac catheterization developed during the 20th century. The first right heart catheterization in a human was performed by Werner Forssmann on himself in 1929. Diagnostic cardiac catheterization was introduced by André Cournand and Dickinson Richards in the early 1940s, and selective coronary angiography was described by Mason Sones in the early 1960s. More recently, with the advent of catheter-based interventions, pioneered by Andreas Gruentzig in the late 1970s, there has been considerable progress in the refinement and expansion of these techniques. Currently, the Sones technique is used only infrequently, and coronary angiography and percutaneous coronary intervention rely mainly on percutaneous femoral and percutaneous radial artery approaches. On the occasion of the 50th anniversary of the Montreal Heart Institute, it seems appropriate to highlight the contribution of this institution in these two areas. PMID:16234881

  3. Inherited arrhythmias: The cardiac channelopathies

    PubMed Central

    Behere, Shashank P; Weindling, Steven N

    2015-01-01

    Ion channels in the myocardial cellular membrane are responsible for allowing the cardiac action potential. Genetic abnormalities in these channels can predispose to life-threatening arrhythmias. We discuss the basic science of the cardiac action potential; outline the different clinical entities, including information regarding overlapping diagnoses, touching upon relevant genetics, new innovations in screening, diagnosis, risk stratification, and management. The special considerations of sudden unexplained death and sudden infant death syndrome are discussed. Scientists and clinicians continue to reconcile the rapidly growing body of knowledge regarding the molecular mechanisms and genetics while continuing to improve our understanding of the various clinical entities and their diagnosis and management in clinical setting. Two separate searches were run on the National Center for Biotechnology Information's website. The first using the term cardiac channelopathies was run on the PubMed database using filters for time (published in past 5 years) and age (birth-18 years), yielding 47 results. The second search using the medical subject headings (MeSH) database with the search terms “Long QT Syndrome” (MeSH) and “Short QT Syndrome” (MeSH) and “Brugada Syndrome” (MeSH) and “Catecholaminergic Polymorphic Ventricular Tachycardia” (MeSH), applying the same filters yielded 467 results. The abstracts of these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles where further explored and read in full. PMID:26556967

  4. Inherited arrhythmias: The cardiac channelopathies.

    PubMed

    Behere, Shashank P; Weindling, Steven N

    2015-01-01

    Ion channels in the myocardial cellular membrane are responsible for allowing the cardiac action potential. Genetic abnormalities in these channels can predispose to life-threatening arrhythmias. We discuss the basic science of the cardiac action potential; outline the different clinical entities, including information regarding overlapping diagnoses, touching upon relevant genetics, new innovations in screening, diagnosis, risk stratification, and management. The special considerations of sudden unexplained death and sudden infant death syndrome are discussed. Scientists and clinicians continue to reconcile the rapidly growing body of knowledge regarding the molecular mechanisms and genetics while continuing to improve our understanding of the various clinical entities and their diagnosis and management in clinical setting. Two separate searches were run on the National Center for Biotechnology Information's website. The first using the term cardiac channelopathies was run on the PubMed database using filters for time (published in past 5 years) and age (birth-18 years), yielding 47 results. The second search using the medical subject headings (MeSH) database with the search terms "Long QT Syndrome" (MeSH) and "Short QT Syndrome" (MeSH) and "Brugada Syndrome" (MeSH) and "Catecholaminergic Polymorphic Ventricular Tachycardia" (MeSH), applying the same filters yielded 467 results. The abstracts of these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles where further explored and read in full.

  5. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization.

    PubMed

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-08-19

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress.

  6. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    NASA Astrophysics Data System (ADS)

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-08-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress.

  7. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    PubMed Central

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-01-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress. PMID:26286628

  8. Development of new anatomy reconstruction software to localize cardiac isochrones to the cardiac surface from the 12 lead ECG.

    PubMed

    van Dam, Peter M; Gordon, Jeffrey P; Laks, Michael M; Boyle, Noel G

    2015-01-01

    Non-invasive electrocardiographic imaging (ECGI) of the cardiac muscle can help the pre-procedure planning of the ablation of ventricular arrhythmias by reducing the time to localize the origin. Our non-invasive ECGI system, the cardiac isochrone positioning system (CIPS), requires non-intersecting meshes of the heart, lungs and torso. However, software to reconstruct the meshes of the heart, lungs and torso with the capability to check and prevent these intersections is currently lacking. Consequently the reconstruction of a patient specific model with realistic atrial and ventricular wall thickness and incorporating blood cavities, lungs and torso usually requires additional several days of manual work. Therefore new software was developed that checks and prevents any intersections, and thus enables the use of accurate reconstructed anatomical models within CIPS. In this preliminary study we investigated the accuracy of the created patient specific anatomical models from MRI or CT. During the manual segmentation of the MRI data the boundaries of the relevant tissues are determined. The resulting contour lines are used to automatically morph reference meshes of the heart, lungs or torso to match the boundaries of the morphed tissue. Five patients were included in the study; models of the heart, lungs and torso were reconstructed from standard cardiac MRI images. The accuracy was determined by computing the distance between the segmentation contours and the morphed meshes. The average accuracy of the reconstructed cardiac geometry was within 2mm with respect to the manual segmentation contours on the MRI images. Derived wall volumes and left ventricular wall thickness were within the range reported in literature. For each reconstructed heart model the anatomical heart axis was computed using the automatically determined anatomical landmarks of the left apex and the mitral valve. The accuracy of the reconstructed heart models was well within the accuracy of the used

  9. Sudden cardiac death in athletes.

    PubMed

    Schmied, C; Borjesson, M

    2014-02-01

    A 'paradox of sport' is that in addition to the undisputed health benefits of physical activity, vigorous exertion may transiently increase the risk of acute cardiac events. In general, the risk of sudden cardiac death (SCD) approximately doubles during physical activity and is 2- to 3-fold higher in athletes compared to nonathletes. The incidence of SCD in young athletes is in fact very low, at around 1-3 per 100,000, but attracts much public attention. Variations in incidence figures may be explained by the methodology used for data collection and more importantly by differences between subpopulations of athletes. The incidence of SCD in older (≥ 35 years) athletes is higher and may be expected to rise, as more and older individuals take part in organized sports. SCD is often the first clinical manifestation of a potentially fatal underlying cardiovascular disorder and usually occurs in previously asymptomatic athletes. In the young (<35 years), SCD is mainly due to congenital/inherited cardiac abnormalities, whilst coronary artery disease (CAD) is the most common cause in older athletes. Cardiac screening including family/personal history, physical examination and resting electrocardiogram (ECG) may identify individuals at risk and has the potential to decrease the risk of SCD in young athletes. Screening including the ECG has a high sensitivity for underlying disease in young athletes, but the specificity needs to be improved, whereas the sensitivity of screening without the use of ECG is very low. The screening modality recommended for young athletes is of limited value in older athletes, who should receive individualized screening with cardiac stress testing for patients with high risk of underlying CAD. As cardiovascular screening will never be able to identify all athletes at risk, adequate preparedness is vital in case of a potentially fatal event at the sporting arena/facility. Firstly, we will review the magnitude of the problem of SCD in athletes of

  10. Evaluation of Known or Suspected Cardiac Sarcoidosis.

    PubMed

    Blankstein, Ron; Waller, Alfonso H

    2016-03-01

    Sarcoidosis is a multisystem disorder of unknown cause, and cardiac sarcoidosis affects at least 25% of patients and accounts for substantial mortality and morbidity from this disease. Cardiac sarcoidosis may present with heart failure, left ventricular systolic dysfunction, AV block, atrial or ventricular arrhythmias, and sudden cardiac death. Cardiac involvement can be challenging to detect and diagnose because of the focal nature of the disease, as well as the fact that clinical criteria have limited diagnostic accuracy. Nevertheless, the diagnosis of cardiac sarcoidosis can be enhanced by integrating both clinical and imaging findings. This article reviews the various roles that different imaging modalities provide in the evaluation and management of patients with known or suspected cardiac sarcoidosis.

  11. Quality Control Systems in Cardiac Aging

    PubMed Central

    Quarles, Ellen K; Dai, Dao-Fu; Tocchi, Autumn; Basisty, Nathan; Gitari, Lemuel; Rabinovitch, Peter S

    2015-01-01

    Cardiac aging is an intrinsic process that results in impaired cardiac function, along with cellular and molecular changes. These degenerative changes are intimately associated with quality control mechanisms. This review provides a general overview of the clinical and cellular changes which manifest in cardiac aging, and the quality control mechanisms involved in maintaining homeostasis and retarding aging. These mechanisms include autophagy, ubiquitin-mediated turnover, apoptosis, mitochondrial quality control and cardiac matrix homeostasis. Finally, we discuss aging interventions that have been observed to impact cardiac health outcomes. These include caloric restriction, rapamycin, resveratrol, GDF11, mitochondrial antioxidants and cardiolipin-targeted therapeutics. A greater understanding of the quality control mechanisms that promote cardiac homeostasis will help to understand the benefits of these interventions, and hopefully lead to further improved therapeutic modalities. PMID:25702865

  12. Evaluation of Known or Suspected Cardiac Sarcoidosis.

    PubMed

    Blankstein, Ron; Waller, Alfonso H

    2016-03-01

    Sarcoidosis is a multisystem disorder of unknown cause, and cardiac sarcoidosis affects at least 25% of patients and accounts for substantial mortality and morbidity from this disease. Cardiac sarcoidosis may present with heart failure, left ventricular systolic dysfunction, AV block, atrial or ventricular arrhythmias, and sudden cardiac death. Cardiac involvement can be challenging to detect and diagnose because of the focal nature of the disease, as well as the fact that clinical criteria have limited diagnostic accuracy. Nevertheless, the diagnosis of cardiac sarcoidosis can be enhanced by integrating both clinical and imaging findings. This article reviews the various roles that different imaging modalities provide in the evaluation and management of patients with known or suspected cardiac sarcoidosis. PMID:26926267

  13. Cardiac mechanics: Physiological, clinical, and mathematical considerations

    NASA Technical Reports Server (NTRS)

    Mirsky, I. (Editor); Ghista, D. N.; Sandler, H.

    1974-01-01

    Recent studies concerning the basic physiological and biochemical principles underlying cardiac muscle contraction, methods for the assessment of cardiac function in the clinical situation, and mathematical approaches to cardiac mechanics are presented. Some of the topics covered include: cardiac ultrastructure and function in the normal and failing heart, myocardial energetics, clinical applications of angiocardiography, use of echocardiography for evaluating cardiac performance, systolic time intervals in the noninvasive assessment of left ventricular performance in man, evaluation of passive elastic stiffness for the left ventricle and isolated heart muscle, a conceptual model of myocardial infarction and cardiogenic shock, application of Huxley's sliding-filament theory to the mechanics of normal and hypertrophied cardiac muscle, and a rheological modeling of the intact left ventricle. Individual items are announced in this issue.

  14. Cardiac CT vs. Stress Testing in Patients with Suspected Coronary Artery Disease: Review and Expert Recommendations

    PubMed Central

    Rahsepar, Amir Ali; Arbab-Zadeh, Armin

    2015-01-01

    Diagnosis and management of coronary artery disease represent a major challenge to our health care systems affecting millions of patients each year. Until recently, the diagnosis of coronary artery disease could be conclusively determined only by invasive coronary angiography. To avoid risks from cardiac catheterization, many healthcare systems relied on stress testing as gatekeeper for coronary angiography. Advancements in cardiac computed tomography angiography technology now allows to noninvasively visualize coronary artery disease, challenging the role of stress testing as the default noninvasive imaging tool for evaluating patients with chest pain. In this review, we summarize current data on the clinical utility of cardiac computed tomography and stress testing in stable patients with suspected coronary artery disease. PMID:26500716

  15. Prior image constrained image reconstruction in emerging computed tomography applications

    NASA Astrophysics Data System (ADS)

    Brunner, Stephen T.

    Advances have been made in computed tomography (CT), especially in the past five years, by incorporating prior images into the image reconstruction process. In this dissertation, we investigate prior image constrained image reconstruction in three emerging CT applications: dual-energy CT, multi-energy photon-counting CT, and cone-beam CT in image-guided radiation therapy. First, we investigate the application of Prior Image Constrained Compressed Sensing (PICCS) in dual-energy CT, which has been called "one of the hottest research areas in CT." Phantom and animal studies are conducted using a state-of-the-art 64-slice GE Discovery 750 HD CT scanner to investigate the extent to which PICCS can enable radiation dose reduction in material density and virtual monochromatic imaging. Second, we extend the application of PICCS from dual-energy CT to multi-energy photon-counting CT, which has been called "one of the 12 topics in CT to be critical in the next decade." Numerical simulations are conducted to generate multiple energy bin images for a photon-counting CT acquisition and to investigate the extent to which PICCS can enable radiation dose efficiency improvement. Third, we investigate the performance of a newly proposed prior image constrained scatter correction technique to correct scatter-induced shading artifacts in cone-beam CT, which, when used in image-guided radiation therapy procedures, can assist in patient localization, and potentially, dose verification and adaptive radiation therapy. Phantom studies are conducted using a Varian 2100 EX system with an on-board imager to investigate the extent to which the prior image constrained scatter correction technique can mitigate scatter-induced shading artifacts in cone-beam CT. Results show that these prior image constrained image reconstruction techniques can reduce radiation dose in dual-energy CT by 50% in phantom and animal studies in material density and virtual monochromatic imaging, can lead to radiation

  16. A triad: cardiac rhabdomyosarcoma, stroke and tamponade.

    PubMed

    Ashraf, Tazeen; Day, Thomas George; Marek, Jan; Hughes, Marina; Giardini, Alessandro

    2013-03-01

    The case report describes a 9-year-old boy who presented with an acute cerebrovascular accident and was found to have cardiac tamponade caused by cardiac rhabdomyosarcoma. Symptoms of rhabdomyosarcoma can be indolent and nonspecific, even with metastatic disease. Echocardiography and cardiac magnetic resonance imaging are explored as adjuncts to diagnosis. The radiologic features that helped with the diagnosis of this rare condition are described.

  17. Sudden cardiac death – Historical perspectives

    PubMed Central

    Abhilash, S.P.; Namboodiri, Narayanan

    2014-01-01

    Sudden cardiac death (SCD) is an unexpected death due to cardiac causes that occurs in a short time period (generally within 1 h of symptom onset) in a person with known or unknown cardiac disease. It is believed to be involved in nearly a quarter of human deaths, with ventricular fibrillation being the most common mechanism. It is estimated that more than 7 million lives per year are lost to SCD worldwide. Historical perspectives of SCD are analyzed with a brief description on how the developments in the management of sudden cardiac arrest evolved over time. PMID:24568828

  18. New electrical plethysmograph monitors cardiac output

    NASA Technical Reports Server (NTRS)

    Kubicek, W. B.; Patterson, R. P.; Witsoe, D. A.

    1968-01-01

    Four-electrode impedance plethysmograph measures ventricular stroke volume of cardiac output of humans. The instrument is automatic, operates with only one recording channel, and minimizes patient discomfort.

  19. Cardiac Arrhythmias: Diagnosis, Symptoms, and Treatments.

    PubMed

    Fu, Du-Guan

    2015-11-01

    The cardiac arrhythmia is characterized by irregular rhythm of heartbeat which could be either too slow (<60 beats/min) or too fast (>100 beats/min) and can happen at any age. The use of pacemaker and defibrillators devices has been suggested for heart arrhythmias patients. The antiarrhythmic medications have been reported for the treatment of cardiac arrhythmias or irregular heartbeats. The diagnosis, symptoms, and treatments of cardiac arrhythmias as well as the radiofrequency ablation, tachycardia, Brugada syndrome, arterial fibrillation, and recent research on the genetics of cardiac arrhythmias have been described here.

  20. A cardiac electrical activity model based on a cellular automata system in comparison with neural network model.

    PubMed

    Khan, Muhammad Sadiq Ali; Yousuf, Sidrah

    2016-03-01

    Cardiac Electrical Activity is commonly distributed into three dimensions of Cardiac Tissue (Myocardium) and evolves with duration of time. The indicator of heart diseases can occur randomly at any time of a day. Heart rate, conduction and each electrical activity during cardiac cycle should be monitor non-invasively for the assessment of "Action Potential" (regular) and "Arrhythmia" (irregular) rhythms. Many heart diseases can easily be examined through Automata model like Cellular Automata concepts. This paper deals with the different states of cardiac rhythms using cellular automata with the comparison of neural network also provides fast and highly effective stimulation for the contraction of cardiac muscles on the Atria in the result of genesis of electrical spark or wave. The specific formulated model named as "States of automaton Proposed Model for CEA (Cardiac Electrical Activity)" by using Cellular Automata Methodology is commonly shows the three states of cardiac tissues conduction phenomena (i) Resting (Relax and Excitable state), (ii) ARP (Excited but Absolutely refractory Phase i.e. Excited but not able to excite neighboring cells) (iii) RRP (Excited but Relatively Refractory Phase i.e. Excited and able to excite neighboring cells). The result indicates most efficient modeling with few burden of computation and it is Action Potential during the pumping of blood in cardiac cycle.