Regional Myocardial Scar Research Articles

Deep Learning for Multi-Level Detection and Localization of Myocardial Scars Based on Regional Strain Validated on Virtual Patients

How well the heart is functioning can be quantified through measurements of myocardial deformation via echocardiography. Clinical assessment of cardiac function is generally focused on global indices of relative shortening; however, segmental strain indices have been shown to be abnormal in regions of myocardial disease such as scarring. In this work, we propose a single framework to predict myocardial scars at global, territorial, and segmental levels using regional myocardial strain traces as input to a convolutional neural network (CNN). An anatomically meaningful representation of the input data from the clinically standard bullseye representation to a multi-channel 2D image is proposed, thus enabling the use of state-of-the-art neural network configurations. A Fully Convolutional Network (FCN) is trained to detect and localize myocardial scar from regional left ventricular (LV) strain traces. Simulated regional strain data from a controlled dataset of virtual patients with varying degrees and locations of myocardial scar is used for training and validation. The proposed method successfully detects and localizes the scars on 98% of the 5490 left ventricle (LV) segments of the 305 patients in the test set using strain traces only. Due to the sparse existence of scar in the dataset, only 10% of the LV segments are scarred. Taking the imbalance into account, the class balanced accuracy is calculated as 95%. The proposed method proves successful on the strain traces of the virtual cohort and offers the potential to solve the regional myocardial scar detection problem on the strain traces of the real patient cohorts.

Predicting post-contrast information from contrast agent free cardiac MRI using machine learning: Challenges and methods.

ObjectivesCurrently, administering contrast agents is necessary for accurately visualizing and quantifying presence, location, and extent of myocardial infarction (MI) with cardiac magnetic resonance (CMR). In this study, our objective is to investigate and analyze pre- and post-contrast CMR images with the goal of predicting post-contrast information using pre-contrast information only. We propose methods and identify challenges.MethodsThe study population consists of 272 retrospectively selected CMR studies with diagnoses of MI (n = 108) and healthy controls (n = 164). We describe a pipeline for pre-processing this dataset for analysis. After data feature engineering, 722 cine short-axis (SAX) images and segmentation mask pairs were used for experimentation. This constitutes 506, 108, and 108 pairs for the training, validation, and testing sets, respectively. We use deep learning (DL) segmentation (UNet) and classification (ResNet50) models to discover the extent and location of the scar and classify between the ischemic cases and healthy cases (i.e., cases with no regional myocardial scar) from the pre-contrast cine SAX image frames, respectively. We then capture complex data patterns that represent subtle signal and functional changes in the cine SAX images due to MI using optical flow, rate of change of myocardial area, and radiomics data. We apply this dataset to explore two supervised learning methods, namely, the support vector machines (SVM) and the decision tree (DT) methods, to develop predictive models for classifying pre-contrast cine SAX images as being a case of MI or healthy.ResultsOverall, for the UNet segmentation model, the performance based on the mean Dice score for the test set (n = 108) is 0.75 (±0.20) for the endocardium, 0.51 (±0.21) for the epicardium and 0.20 (±0.17) for the scar. For the classification task, the accuracy, F1 and precision scores of 0.68, 0.69, and 0.64, respectively, were achieved with the SVM model, and of 0.62, 0.63, and 0.72, respectively, with the DT model.ConclusionWe have presented some promising approaches involving DL, SVM, and DT methods in an attempt to accurately predict contrast information from non-contrast images. While our initial results are modest for this challenging task, this area of research still poses several open problems.

Value of Fragmented QRS Complex on 12-lead ECG as A Valuable Marker of Myocardial Damage of CAD Patients

Background: Presence of Fragmented QRS (fQRS) on a 12-lead Electrocardiogram (ECG) was associated with various cardiac diseases. This phenomenon could represent as an electrical disruption of conduction system following myocardial damage due to coronary artery disease (CAD). We aimed to investigate the value of fQRS to detect the myocardial scar as detected by SPECT Myocardial Perfusion Imaging (MPI).
 Methods: A cross-sectional study of patients with clinical diagnosis of CAD who underwent Cardiac SPECT. The fQRS defined as morphologies of QRS wave (<120 ms), which included an additional R wave (R’), notching in the nadir of S wave, or >1 R’ (fragmentation) in 2 contiguous leads, corresponding to a major coronary artery territory. Pathological Q wave, paced rhythm, typical right or left bundle branch block pattern with QRS duration of ≥ 120 ms were excluded. MPI was interpreted by visual analysis and semi-quantitative scores on 17-segment assessment according to standard nomenclature.
 Results: Total of 72 patients (49 males, mean age 54.7 ± 9.8 years). fQRS was found in 46 patients (64%). The frequency of myocardial scar was significantly higher in patients with fQRS (89% vs. 15%, p<0.05). Sensitivity, specificity, positive and negative predictive value of fQRS for any of myocardial scar as detected by SPECT analysis were 91%, 81%, 89%, and 84%, respectively. From regional scar analysis, fQRS has sensitivity and specificity of 87% and 90% for anterior wall, 76% and 80% for inferior wall, 73% and 79% for lateral wall. LVEF was significantly lower in patients with fQRS (36.9±2.1 vs. 53.2±2.2, p< 0.05).
 Conclusion: The fragmented QRS could serve as a novel ECG marker to detect and localize the myocardial damage in CAD patients. Regional fQRS patterns denote the presence of regional myocardial scar and are a valuable diagnostic marker of CAD with good sensitivity and specificity.
 Keywords: fragmented QRS, SPECT

Baseline ST elevation and myocardial scar: Results from the multi-ethnic study of atherosclerosis

BackgroundThe mechanism of ST elevation on baseline electrocardiograms (ECG) unknown but it may be associated with abnormal myocardial substrate. This paper evaluates whether clinically unrecognized myocardial scar on cardiac magnetic resonance imaging (CMR) is associated with ST elevation at baseline. MethodsThe Multi-Ethnic Study of Atherosclerosis (MESA) study is a population-based cohort in the United States. Participants were aged 45 through 84 years and free of clinical cardiovascular disease at enrollment in 2000–2002. Our cohort included 1365 participants who underwent both ECG and contrast enhanced CMR in the 5th examination (2010−2012). Multivariable logistic regression examined the association of ST elevation and CMR defined regional myocardial scar after adjusting for cardiovascular risk factors. ResultsOf 1365 participants (58 ±9 years, 52% men), 105 (8%) had scar on CMR. Of these, the scar in 40 participants followed an ischemic pattern and in the other 65 participants followed a non-ischemic pattern. ST elevation at the 5th examination was present in 435 participants: 40 (0.9%) had ST elevations in inferior and 427 (98%) in lateral leads. 2/40 (5%) and 22/427 (5%) participants with inferior and lateral ST elevations, respectively, had evidence of scar. 15 (1.0%) had myocardial scar noted in the basal anterior region. In the fully adjusted models, ST elevation was associated with scar in basal anterior region (OR 18.2, p = 0.031). ConclusionsIn a community population, ST elevation at baseline in the inferior or lateral leads was associated with myocardial scar in the basal inferior and anterior segments. The previously described association between ST elevation and increased mortality may be mediated by myocardial scar.

Diagnostic value of fragmented QRS complex in myocardial scar detection: systematic review and meta-analysis of the literature.

The present study aimed to investigate the diagnostic value of fragmented QRS complex (fQRS) on 12-lead electrocardiogram (ECG) for myocardial scar detection, and presented the results in a systematic review and meta-analysis format. Medline, SCOPUS, and ISI Web of Knowledge were searched electronically with "Fragmented QRS" or "fQRS" as key words. All related studies that had evaluated the accuracy of fQRS for myocardial scar diagnosis were included. Eight studies (2560 patients) were finally included in the systematic review. Specificity assessment could be evaluated only by five out of these eight articles. Overall pooled sensitivity of fQRS, Q wave, and mixed Q-fQRS was 68% (65-71), 51% (47-55), and 74% (69-79) and the pooled specificity was 80% (79-81), 97% (97-98) and 92% (91-93), respectively. Fragmented QRS is a novel ECG marker with more sensitivity and less specificity than Q wave. A combination of fQRS with Q wave in a 12-lead ECG results in up to 74% sensitivity and 92% specificity. Additional studies are needed to assess the significance of this ECG parameter for regional myocardial scar detection.

Myocardial scarring in the left ventricular basal posterolateral region may negatively impact on response to cardiac resynchronization therapy: analysis with quantitative myocardial perfusion SPECT

Purpose: About 30% of patients with heart failure do not respond to Cardiac Resynchronization Therapy (CRT); ischemic cardiomyopathy negatively influences the response. The study objective was to determine the impact of global and regional myocardial scar burden on CRT outcomes by using AutoQUANT. Methods: We studied 38 consecutive CRT recipients (28 men; age 70±7 years old; ischemic cardiomyopathy, n= 12; Left Ventricular [LV] ejection fraction 23.5±9.4%; QRS duration 158±30ms). All the patients underwent resting 99mTc-MIBI gated-myocardial perfusion SPECT prior to CRT. The SPECT images were analyzed by AutoQUANT 7.2 to quantify the global Defect Extent (DE), an index of global scarring, as well as the regional DE in each of the 17 segments of the LV, an index of regional scar burden. CRT response was defined as a decrease of >10% in the LV end systolic volume at 6 months after CRT device implantation based on the QGS analysis of the SPECT images. Results: Twelve patients did not respond CRT. The response rate was lower in patients with ischemic cardiomyopathy than those with non-ischemic cardiomyopathy (25% vs. 85%, p<0.001). The non-responders had a higher global DE than responders (35±17% vs. 22±10%, p=0.004). The non-responders also showed higher regional DEs in the lateral adjoining areas as compared with the responders: the basal posterolateral region (45±30% vs. 14±23%, p=0.001), the mid posterolateral region (42±41% vs. 15±27%, p=0.02), and apical lateral region (41±39% vs. 16±21%, p=0.01). Logistic regression analysis disclosed the following significant predictors of negative response to CRT: global DE (crude odds ratio [OR] 1.08, 95% confidence interval [CI] 1.02-1.07, p=0.01), the basal posterolateral DE (crude OR 1.04, 95% CI 1.01-1.07, p=0.005), the mid posterolateral DE (crude OR 1.02, 95% CI 1.00-1.04, p=0.03), and apical lateral DE (crude OR 1.03, 95% CI 1.00-1.06, p=0.02). After adjusting the type of cardiomyopathies, only the basal posterolateral DE remained as a significant predictor (adjusted OR 1.04, 95% CI 1.00-1.07, p=0.03). Receiver operating characteristic curve analysis of this segment showed that the AUC was 0.828. Using a cutoff point of 23.5% provided a sensitivity of 84.0% and specificity of 76.9% for the prediction of negative response to CRT. Conclusions: Myocardial scarring assessed by myocardial quantitative perfusion SPECT may negatively impact response to CRT. The regional scar burden at the basal posterolateral wall is most likely to predict unfavorable response to CRT irrespectively of the type of cardiomyopathies.

Relation between fragmented QRS and collateral circulation in patients with chronic total occlusion without prior myocardial infarction

It has been shown that the fragmented QRS (fQRS) on electrocardiogram (ECG) signifies regional myocardial scar in patients with non-Q-wave myocardial infarction (MI). We hypothesized that presence of fQRS on ECG may be related with poorly-grown collateral coronary circulation (CCC) in patients with chronic total coronary occlusion (CTO) without prior MI. This retrospective observational study is included 56 patients (mean age 61.73±7.96 years; 67.9% men) with CTO in one of the major coronary arteries. Collateral circulation was graded according to Rentrop's classification. The fQRS was defined as the presence of an additional R wave or notching of R or S wave or the presence of fragmentation in two contiguous ECG leads corresponding to a major coronary artery territory. Patients with pathological Q-wave or history of MI, typical bundle brunch blocks (BBB) and incomplete right BBB were excluded from study. Statistical analysis was performed using Chi-square test, Student's t-test and logistic regression analysis. Fifteen patients had Rentrop grade 1, 15 patients had grade 2 and 26 patients had grade 3 CCC. Five (19%) of the patients who have grade 3 CCC, seven (47%) of the patients who had grade 2 CCC, ten (67%) of the patients who had grade 1 CCC had fQRS (p=0.002). Logistic regression analysis showed high predictive value of the presence of fQRS for Rentrop 1 CCC (OR=8.4, 95% CI 1.97-35.7; p=0.004). Results of our study may implicate the presence of fQRS on electrocardiogram as a predictor of a poorly grown CCC in patients with chronic total occlusion without prior MI.

Left Ventricular Basal Myocardial Scarring Detected by Delayed Enhancement Magnetic Resonance Imaging Predicts Outcomes After Surgical Therapies for Patients With Ischemic Mitral Regurgitation and Left Ventricular Dysfunction

Treatment of heart failure by surgical procedures such as mitral annuloplasty and left ventricular (LV) restoration is increasingly applied to patients with ischemic mitral regurgitation (IMR) and LV dysfunction. The clinical efficacy of delayed enhancement magnetic resonance imaging (DE-MRI) was studied to predict LV functional recovery and adverse outcomes after these therapies. In 26 patients with IMR and a LV ejection fraction < 40%, DE-MRI was performed before the operation and the percentage of regional myocardial scarring was quantified at the basal, mid, and apical LV. Calculated percentage of fibrosis was 12 ± 12% at the base, 24 ± 15% at the mid, and 35 ± 31% at the apical LV. The degree of basal fibrosis was a significant predictor of less improvement of LV ejection fraction and postoperative restrictive diastolic filling. A linear correlation was noted between basal fibrosis and postoperative ejection fraction (P = 0.001, R = -0.61), the early to late mitral valve flow ratio (P = 0.0005, R = 0.66), and deceleration time (P = 0.01, R = -0.51). Logistic regression analysis demonstrated that the percentage of basal fibrosis was the independent predictor of postoperative adverse clinical outcomes (odds ratio, 1.26; P = 0.04). In patients undergoing surgical heart failure therapy for IMR, the extent of basal fibrosis characterized by DE-MRI might be a useful predictor of postoperative LV systolic and diastolic functional recovery and postoperative adverse outcomes.

Fused Whole-Heart Coronary and Myocardial Scar Imaging Using 3-T CMR: Implications for Planning of Cardiac Resynchronization Therapy and Coronary Revascularization

The aim of this study was to demonstrate the feasibility of providing spatially matched, 3-dimensional (3D) myocardial scar and coronary imaging for the purpose of fused volumetric image display in patients undergoing cardiac resynchronization therapy (CRT) or coronary artery revascularization (CAR). Clinical success in coronary vascular-based interventions is mitigated by the presence of scar in related myocardium. Pre-procedural fused volumetric imaging of both myocardial scar and coronary vasculature may benefit pre-procedural planning and patient selection in populations referred for CRT or CAR. A total of 55 studies were performed in patients referred for either CRT (n = 42) or CAR (n = 13). Coronary-enhanced and scar-enhanced imaging was performed on a 3-T cardiac magnetic resonance scanner using the same cardiac-gated, 3D, free-breathing cardiac magnetic resonance technique during and 20 minutes following slow gadolinium infusion. Matched image datasets were fused and volume-rendered to simultaneously display coronary anatomy and myocardial scar. Visual scoring of coronary artery, coronary vein, and myocardial scar image quality (score 0 to 4) was performed. The clinical impact of imaging was also scored using a physician survey. Mean age was 57 ± 14 years. Combined 3D coronary and scar imaging was successful in 49 studies (89%). A quality score ≥ 2 was obtained for 97% of proximal- and mid-coronary artery and vein segments. The mean quality score of 3D scar imaging was 2.8 ± 1.0 and was scored as ≥ 2 in 86% of patients with myocardial scar. All patients with a scar quality score ≥ 2 achieved successful image fusion. Transmural scar was present below ≥ 1 planned target vessel in 9 patients (39%) planned for CRT and 8 patients (62%) planned for CAR. Physician surveys demonstrated incremental clinical impact in 67% of patients. Three-dimensional myocardial scar and coronary imaging with fused volumetric display is clinically feasible and may be valuable for the planning of vascular-based interventions when regional myocardial scar is pertinent to therapeutic success.

Fragmented QRS complexes not typical of a bundle branch block: A marker of greater myocardial perfusion tomography abnormalities in coronary artery disease

Fragmented QRS (FQRS) complexes, not typical of a bundle branch block, are a marker of regional myocardial injury. The extent of stress myocardial perfusion imaging (MPI) abnormalities with FQRS patterns is not known. Twelve-lead electrocardiograms (ECGs) in 501 patients undergoing stress MPI were studied. FQRS was defined as a QRS duration of 120 milliseconds or less, with notches or slurs of QRS complexes, on 2 contiguous leads of a coronary artery territory. Abnormal MPI was defined as a regional summed stress score (SSS) and summed rest score (SRS) of 3 or greater based on a 17-segment model. Patients with a typical bundle (n = 26), paced rhythm (n = 2), and Q waves (n = 64) were excluded. Of the remaining 409 patients (mean age, 58 +/- 13 years; 52% male), 155 (38%) had FQRS on the ECG. FQRS patients had a higher mean SSS, SRS, and global summed difference score and a lower left ventricular ejection fraction (all P < .001), as well as greater regional stress MPI scar (69% vs 11%, P < .001). FQRS pattern sensitivity was 75% and specificity was 94% for a corresponding regional MPI scar. On logistic regression, SSS, SRS, summed difference score, left ventricular ejection fraction, and regional scar were univariate predictors of the FQRS pattern on the ECG (all P < .01), and any regional scar (odds ratio, 32; P < .001) was a multivariate predictor. FQRS complexes on an ECG are a marker of higher stress MPI perfusion and functional abnormalities. Regional FQRS patterns denote the presence of a greater corresponding focal regional myocardial scar on stress MPI.

Relation of T-Wave Alternans to Regional Left Ventricular Dysfunction and Eccentric Hypertrophy Secondary to Coronary Heart Disease

Left ventricular (LV) hypertrophy and structural disease are associated with exaggerated repolarization dispersion and risk for cardiac arrest. We hypothesized that T-wave alternans (TWA) from the electrocardiogram, reflecting proarrhythmic repolarization dispersion, would increase with extent of eccentric LV hypertrophy and vary spatially with the distribution of myocardial scar. We studied 28 patients with coronary disease, systolic dysfunction, and nonsustained ventricular tachycardia. On echocardiography, 21 patients had wall motion abnormalities and 20 had LV hypertrophy (mass index > or =100 g/m(2)). TWA magnitude (voltage of alternation), which was computed spectrally during ventricular stimulation, varied linearly with LV mass index (p = 0.003). Spatially, positive TWA (magnitude > or =1.9 microV) in orthogonal electrocardiographic axes overlaid scar or wall motion abnormalities in corresponding echocardiographic segments (p <0.05 in x and y axes). After a follow-up of 35 +/- 13 months, positive TWA predicted the combined end point of death or sustained ventricular arrhythmias in all patients (p = 0.025), with a trend for those with echocardiographic LV hypertrophy (p = 0.058). In conclusion, in patients with systolic dysfunction due to coronary artery disease, TWA may indicate arrhythmic contributions from regional myocardial scar and eccentric LV hypertrophy.

Electrophysiological Characteristics of Septal Hypertrophy in Patients With Hypertrophic Obstructive Cardiomyopathy and Moderate to Severe Symptoms

In hypertrophic obstructive cardiomyopathy, regional hypertrophy, myocardial replacement scarring, expanded interstitial fibrosis, and myocardial disarray can be found. The electrophysiological consequences of this substrate have not yet been investigated. Thus, the aim of this study was to assess the local electrophysiological characteristics of regional left ventricular (LV) septal hypertrophy. In 9 patients with hypertrophic obstructive cardiomyopathy, electroanatomic voltage mapping of the LV was performed during sinus rhythm to determine the regional voltage amplitude. In addition, the morphology of the regional bipolar endocardial electrogram was assessed. During multisite LV stimulation, the stimulus-to-V intervals in both septal hypertrophy and the lateral LV myocardium were determined. Bipolar electroanatomic voltage mapping revealed a significant reduction in regional voltage amplitude in septal hypertrophic areas compared with lateral LV areas without evidence of hypertrophy (0.41+/-0.24 versus 13.5+/-1.85 mV; P<0,001). Local bipolar electrogram analysis demonstrated fractionated and prolonged endocardial potentials in septal hypertrophic areas (with split potentials present in 6 patients) that were not revealed at lateral myocardial sites (110.1+/-24.6 versus 80.1+/-6.6 ms; P=0.005). The stimulus-to-V interval was significantly longer (62.9+/-10.3 versus 24.1+/-9.1 ms; P=0.005) in septal hypertrophic areas compared with the lateral LV. In LV regions with extensive hypertrophy, a marked reduction of bipolar voltage amplitude can be found, as well as local conduction delay and conduction block. This result is consistent with the findings of regional myocardial scarring and may contribute to the increased incidence of ventricular tachyarrhythmias in patients with hypertrophic obstructive cardiomyopathy.

5.32 Fragmented QRS complexes not related to typical bundle branch block: A marker of regional myocardial scar by SPECT

5.32 Fragmented QRS complexes not related to typical bundle branch block: A marker of regional myocardial scar by SPECT

Ischemic Mitral Regurgitation: Impact of the Left Ventricle and Mitral Valve in Patients with Left Ventricular Systolic Dysfunction

Mitral regurgitation (MR) is a common complication of ischemic heart disease, and its presence portends adverse outcomes. As the exact mechanisms of ischemic MR are not well defined, we characterized left ventricular global geometry, regional function, and regional myocardial scarring, in addition to mitral valve apparatus geometry, using magnetic resonance imaging (MRI) of ischemic heart disease patients with left ventricular dysfunction and varying degrees of ischemic MR. Sixty patients with varying degrees of MR (none, mild, moderate, and severe) determined by echocardiography and referred for MRI assessment of ischemic heart disease were included. Left ventricular geometric, functional, and scar measurements in addition to mitral valve geometric measurements were evaluated. Clinical characteristics found to be significant predictors of degree of MR included severity of coronary artery disease (p < 0.05), completeness of myocardial perfusion (p < 0.005), and average systolic blood pressure (p < 0.05). Mitral systolic tenting area (p < 0.0001) in a statistical model with scarring of the anterior-lateral region (p < 0.05) proved to be the most powerful predictor of MR severity (r2 = 0.31). Mitral annular dilatation in the anterior-posterior direction (p < 0.0001) and diminished LV systolic function (p < 0.005) were important determinants of mitral systolic tenting area (r2 = 0.57). Mitral tenting in combination with regional left ventricular myocardial scarring are important mechanisms to the development of ischemic MR. Surgical annuloplasty addresses mitral tenting, but has little impact on the effect of regional scarring. Moderate-to-severe ischemic MR develops in patients with regional scarring of the anterior-lateral and inferior-posterior regions, and new surgical developments should take this into account.

Complete atrioventricular block associated with regional myocardial scarring in a patient with coxsackie B2 myocarditis.

Transient atrioventricular (A-V) conduction abnormalities are often experienced in patients with evolving acute viral myocarditis, but persistent complete A-V block requiring permanent cardiac pacing is rare. We describe a case who developed irreversible complete A-V block during the long-term course of Coxsackie B2 myocarditis. The endomyocardial biopsy revealed inflammatory cellular infiltrates and myocyte necrosis. A left ventriculogram and echocardiogram consistently demonstrated an aneurysm in the basal portion of the interventricular septum. It was speculated that the extensive myocardial scar caused by acute myocarditis resulted in the ventricular aneurysm of this particular myocardial region involving the A-V conduction system.