Mean Scar Entropy by Late Gadolinium Enhancement Cardiac Magnetic Resonance Is Associated With Ventricular Arrhythmias Events in Hypertrophic Cardiomyopathy

Figures

• 

  Figure 1. Flow diagram showing the selection and group of hypertrophic cardiomyopathy (HCM) with scar patients. CMR, cardiac magnetic resonance; DCG, dynamic electrocardiogram; HCM, hypertrophic cardiomyopathy; VA, ventricular arrhythmias.

• 

  Figure 2. (A) Levels of scar entropy in HCM patients with or without ventricular arrhythmia (VA) (Groups VA and non-VA). (B) The receiver operator characteristic (ROC) curve of the scar entropy to predict the presence of VAs in the HCM cohort. AUC, area under the curve; CI, confidence interval; HCM, hypertrophic cardiomyopathy; VAs, Ventricular arrhythmias; The ROC curve of the percentage of the LGE (%LGE), scar entropy, and combined %LGE and scar entropy to predict the presence of VAs in the HCM cohort.

• 

  Figure 3. Scar entropy model and signal intensity (SI) histograms in two HCM subjects with or without VAs. The image demonstrates the uniformity of signal intensity in the scar, with the epicardial border in green and the endocardial border in red. The area shaded in red identifies the scar detected by the full width at the 5-SD method. (A) Image from an HCM patient who experienced VA events. (C) Image from an HCM patient who experienced non-VA events. (B) The histogram (middle) shows the probability distribution of the pixel signal intensities for both patients. Note the high frequency of pixels within a narrow range of SIs for patient B (blue line), suggesting little heterogeneity of the scar tissue and this patient had scar entropy of 6.09. Note the more dispersed distribution of SIs for patient A (orange line). The patient had scar entropy of 6.88, indicating a much more heterogeneous scar. Both patients were scanned using 1.5-T scanners.

• 

  Figure 4. Incremental value of scar entropy >6.166 and LGE > 6.14% over the conventional 5-year sudden cardiac death (SCD) risk stratification score. The %LGE significantly improves the risk stratification of VAs when added to the 5-year SCD risk score ≥4% while scar entropy further significantly improved the %LGE-modified 5 year SCD risk stratification score.