Myocardial fibrosis predicts sudden cardiac death in patients with hypertrophic cardiomyopathy after cardiac electronic device implantation: Insights from cardiovascular magnetic resonance imaging

Figures

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  Figure 1. Cardiovascular magnetic resonance in hypertrophic cardiomyopathy. Short-axis late gadolinium enhancement cardiovascular magnetic resonance images were first visually assessed to determine the presence of myocardial fibrosis. If fibrosis was visually detected, quantitative analysis was subsequently performed. Fibrosis quantification was performed using multiple signal thresholding techniques to define total fibrosis (TF) and gray zone fibrosis (GZF). In this representative case, TF6SD areas are shown in yellow and GZF6SD areas in orange across the basal, midventricular, and apical slices, demonstrating diffuse, patchy enhancement localized to the interventricular septum and adjacent anterior, inferior, and apical walls. The signal intensity scale ranges from 0% in green to 100% in black.

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  Figure 2. Forest plots for cardiovascular magnetic resonance indicators on predicting sudden cardiac risk. A: Model 1 adjusted for age and sex. B: Model 2 adjusted covariates in model 1, plus systolic blood pressure, loop diuretics, left atrial size, family history of SCD, unexplained syncope, left ventricular aneurysm, LVEF of <50%, maximum left ventricular wall thickness, nonsustained ventricular tachycardia, and left ventricular outflow tract gradient. CI = confidence interval; HR = hazard ratio; LVEF = left ventricular ejection fraction; SCD = sudden cardiac death; SD = standard deviation.

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  Figure 3. Adjusted Kaplan-Meier survival curves stratified by the location and pattern of fibrosis. Fibrosis in the inferior wall (A) and fibrosis in the transmural wall (B) were shown. Adjusted for age, sex, systolic blood pressure, loop diuretics, left atrial size, family history of SCD, unexplained syncope, left ventricular aneurysm, LVEF of <50%, maximum left ventricular wall thickness, nonsustained ventricular tachycardia, and left ventricular outflow tract gradient. LVEF = left ventricular ejection fraction; SCD = sudden cardiac death.

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  Figure 4. Adjusted Kaplan-Meier survival curves stratified by the percentage of gray zone fibrosis. GZF was quantified using 3-SD (A), 5-SD (B), 6-SD (C), and FWHM (D) methods. Adjusted for age, sex, systolic blood pressure, loop diuretics, left atrial size, family history of SCD, unexplained syncope, left ventricular aneurysm, LVEF of <50%, maximum left ventricular wall thickness, nonsustained ventricular tachycardia, and left ventricular outflow tract gradient. FWHM = full-width at half-maximum; GZF = gray zone fibrosis; SCD = sudden cardiac death; SD = standard deviation.

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  Figure 5. Receiver operating characteristic curves for updated models on predicting sudden cardiac death risk. Compared with the 2023 ESC 5-year SCD risk, adding transmural fibrosis and increased GZF6SD showed significantly increased predictive value (A). Compared with 2024 AHA risk factors, adding transmural fibrosis and increased GZF6SD showed increased predictive value, but did not reach statistical significance (B). AHA = American Heart Association; AUC = area under the curve; ESC = European Society of Cardiology; IDI = integrated discrimination improvement; NRI = net reclassification improvement; SCD = sudden cardiac death.