Relationship of Nonseptal Late Gadolinium Enhancement to Ventricular Tachyarrhythmia in Hypertrophic Cardiomyopathy:

Localization of Late Gadolinium Enhancement and Its Association with Ventricular Tachycardia in Patients with Cardiac Sarcoidosis

Sustained ventricular tachycardia (sVT), leading to sudden cardiac death, is one of the common manifestations in cardiac sarcoidosis (CS). Although late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) has been reported to be associated with sVT, the relationships of its localization to sVT have not been fully evaluated.To evaluate the localization of LGE and its relationships to sVT in patients with CS, we reviewed medical record of consecutive 31 patients with CS who underwent CMR. The localization of LGE was divided into four categories: Left ventricular (LV) septum, LV free wall, right ventricular (RV) septum, and RV free wall. We investigated the association of sVT with localization of LGE and other parameters including serum biomarkers LV ejection fraction on echocardiography and Fluorine-18-fluorodeoxyglucose (FDG) accumulation on positron emission tomography (PET) -CT.Of the studied population, 8 patients (25.8%) were known to present with sVT among 31 CS patients. LGE was observed in the RV free wall in 6 patients with sVT, whereas it was in 5 patients without sVT (75.0% versus 21.7%, P = 0.022). Univariate analysis showed that only LGE in the RV free wall was associated with sVT (odds ratio [OR]: 10.80; 95% confidence interval [CI]: 1.64-70.93, P = 0.013).LGE in the RV free wall was associated with sVT in patients with CS.

Risk factors of sudden cardiac death in hypertrophic cardiomyopathy

PURPOSE OF REVIEW

Hypertrophic cardiomyopathy (HCM) is one of the leading causes of sudden cardiac death (SCD) in younger people and athletes. It is crucial to identify the risk factors for SCD in individuals with HCM. This review, based on recent systematic literature studies, will focus on the risk factors for SCD in patients with HCM.

RECENT FINDINGS

An increasing number of studies have further explored the risk factors for SCD in patients with HCM, and new risk markers have emerged accordingly. In addition, more accurate SCD risk estimation and stratification methods have been proposed and continuously improved.

SUMMARY

The identification of independent risk factors for HCM-related SCD would likely contribute to risk stratification. However, it is difficult to predict SCD with absolute certainty, as the annual incidence of SCD in adult patients with HCM is approximately 1%. The review discusses the established risk factors, such as a family history of SCD, unexplained syncope and some new risk factors. Taken together, the findings of this review demonstrate that there is a need for further research on individual risk factors and that SCD risk stratification in HCM patients remains a clinical challenge.

The Clinical Prognosis of Presence and Location of Late Gadolinium Enhancement by Cardiac Magnetic Resonance Imaging in Patients with Hypertrophic Cardiomyopathy: a Single-Center Cohort Study

Increasing data have indicated that late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) images is associated with the clinical prognosis of hypertrophic cardiomyopathy (HCM). Recently, pioneer studies indicated that the location of LGE in CMR images also had potential predictive value for HCM prognosis. The aim of the present study was to investigate the prognostic value of the location of LGE for HCM. This present cohort study included 557 HCM patients who underwent LGE-CMR imaging, and the LGE location was classified as LGE in interventricular septum only (IVS-LGE) and LGE outside the IVS with or without IVS involvement (other than IVS-LGE). All-cause mortality, cardiovascular mortality/cardiac transplantation, and sudden cardiac death (SCD) were evaluated. During a mean follow-up time of 83.0±37.8 months, there was a significantly higher all-cause mortality, cardiovascular mortality/cardiac transplantation, and SCD in patients with other than IVS-LGE than in those with IVS-LGE. Multivariate Cox regression suggested that other than IVS-LGE were one of independent prognostic predictors. Risk reclassification for prognosis showed that there were no differences between the prediction values of the presence of LGE and the location of LGE. The presence and location of LGE in CMR images are equally independent prognostic predictors of HCM, and other than IVS-LGE location is associated with an adverse clinical prognosis. Prognosis Trial Registration: ChiCTR-ONRC-11001902.

Late gadolinium enhancement location assessed by magnetic resonance and arrhythmogenic risk in hypertrophic cardiomyopathy

INTRODUCTION AND OBJECTIVES

Late gadolinium enhancement (LGE) extent has emerged as a predictor of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM), however little is known about the arrhythmogenic relevance of its specific location in the left ventricle. Our aim was to analyze the influence of LGE location on the occurrence of ventricular arrhythmias (VA) and SCD in patients with HCM.

METHODS

We performed a retrospective analysis of clinical and Holter records of HCM patients who underwent cardiac magnetic resonance at our center. LGE extent and distribution were assessed using the American Heart Association 17-segment model. VA was defined as non-sustained or sustained ventricular tachycardia, ventricular fibrillation or SCD.

RESULTS

Sixty-one patients (age 57.0±16.7 years) were included and VA occurred in 24.6% (n=15). Patients with VA showed greater LGE extent than those without (7.40±5.3 vs. 3.52±3.0 segments, p=0.007). Analyzing the distribution of LGE, a set of arrhythmogenic segments (apex/basal inferior/basal anterolateral/mid inferoseptal) was found. The extent of LGE involvement in these segments was also greater in patients with VA (2.07±1.03 vs. 0.65±0.71 segments, p<0.001; area under the curve 0.861 for VA) and this difference remained significant after adjustment for potentially confounding variables.

CONCLUSIONS

The extent of LGE involvement of a set of segments with an apparent relation to cardiac areas of increased mechanical stress was significantly and independently associated with the occurrence of VA, suggesting that not only the extent but also the location of LGE is important for the assessment of SCD risk in HCM patients.

Risk stratification in hypertrophic cardiomyopathy

Sudden cardiac death (SCD) is the most devastating complication of hypertrophic cardiomyopathy (HCM). The greatest challenge in the management of HCM is identifying those at increased risk, since an implantable cardioverter-defibrillator (ICD) is a potentially life-saving therapy. We sought to summarize the available data on SCD in HCM and provide a clinical perspective on the current differing and somewhat conflicting data on risk stratification, with balanced guidance regarding rational clinical decision-making. Additionally, we sought to determine the status of the current implementation of guidelines compiled by HCM experts worldwide. The HCM Risk-SCD model helps improve the risk stratification of HCM patients for primary prevention of SCD by calculating an individual risk estimate that contributes to the clinical decision-making process. Improved risk stratification is important for decision-making before ICD implantation for the primary prevention of SCD.

Assessment of ventricular tachyarrhythmia in patients with hypertrophic cardiomyopathy with machine learning-based texture analysis of late gadolinium enhancement cardiac MRI

OBJECTIVE

To assess the diagnostic value of machine learning-based texture feature analysis of late gadolinium enhancement images on cardiac magnetic resonance imaging (MRI) for assessing the presence of ventricular tachyarrhythmia (VT) in patients with hypertrophic cardiomyopathy.

MATERIALS AND METHODS

This retrospective study included 64 patients with hypertrophic cardiomyopathy who underwent cardiac MRI and 24-hour Holter monitoring within 1 year before cardiac MRI. There were 42 men and 22 women with a mean age of 48.13±13.06 (SD) years (range: 20-70 years). Quantitative textural features were extracted via manually placed regions of interest in areas with high and intermediate signal intensity on late gadolinium-chelate enhanced images. Feature selection and dimension reduction were performed. The diagnostic performances of machine learning classifiers including support vector machines, Naive Bayes, k-nearest-neighbors, and random forest for predicting the presence of VT were assessed using the results of 24-hour Holter monitoring as the reference test. All machine learning models were assessed with and without the application of the synthetic minority over-sampling technique (SMOTE).

RESULTS

Of the 64 patients with hypertrophic cardiomyopathy, 21/64 (32.8%) had VT. Of eight machine learning models investigated, k-nearest-neighbors with SMOTE exhibited the best diagnostic accuracy for the presence or absence of VT. k-nearest-neighbors with SMOTE correctly identified 40/42 (95.2%) VT-positive patients and 40/43 (93.0%) VT-negative patients, yielding 95.2% sensitivity (95% CI: 82.5%-99.1%), 93.0% specificity (95% CI: 79.8%-98.1%) and 94.1% accuracy (95% CI: 88.8%-98%).

CONCLUSION

Machine learning-based texture analysis of late gadolinium-chelate enhancement-positive areas is a promising tool for the classification of hypertrophic cardiomyopathy patients with and without VT.

Histogram Analysis of Native T1 Mapping and Its Relationship to Left Ventricular Late Gadolinium Enhancement, Hypertrophy, and Segmental Myocardial Mechanics in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

The use of native T₁ mapping for evaluation of hypertrophic cardiomyopathy (HCM) is being explored, and its combination with histogram analysis may benefit the accuracy of such assessments.

PURPOSE

To investigate the relationship of segmental left ventricular wall thickness (LVWT), myocardial fibrosis, and strain parameters with segmental histogram parameters of native T₁ mapping in HCM patients.

STUDY TYPE

Retrospective.

SUBJECTS

Ninety-three HCM patients without previous cardiovascular diseases were included.

FIELD STRENGTH/SEQUENCE

3.0T cardiac MR. Steady-state free precession cine imaging, modified Look-Locker inversion recovery, phase-sensitive inversion recovery.

ASSESSMENT

Images were assessed by three experienced radiologists.

STATISTICAL TESTS

Mann-Whitney U-tests, area under the curve (AUC), Spearman's rank correlation, intraclass correlation coefficient, and Bland-Altman test were used for statistical analysis.

RESULTS

A higher LVWT value correlated with higher means, minimums, 10^th /25^th /50^th /75^th /90^th percentiles, maximums, kurtosis, entropy, and lower SD and energy of T₁ mapping (P < 0.05 for all), with the correlation being stronger for entropy and energy (Spearman's rho = 0.439 and -0.413, respectively) than other parameters. Late gadolinium enhancement positive (LGE+) segments exhibited higher mean, minimum, 10^th /25^th /50^th /75^th /90^th percentiles, maximum, entropy, and lower energy of T₁ times than late gadolinium enhancement negative (LGE-) segments (P < 0.001 for all). Impaired strain function parameters (peak thickening and thickening rate in radial, circumferential, and longitudinal directions) demonstrated a weak correlation with higher entropy (P < 0.001 for all) and lower energy (P < 0.001 for all).

DATA CONCLUSION

Histogram parameters of native T₁ mapping provide more information than mean T₁ times alone. Among these parameters, entropy and energy may correlate better with LVWT, myocardial late gadolinium enhancement, and strain parameters than mean T₁ times in HCM patients.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:668-677.