Myocardial edema measured by T2 mapping is an independent predictor of ventricular arrhythmias in hypertrophic cardiomyopathy

Abstract

Abstract Introduction Clinical outcome of patients with hypertrophic cardiomyopathy (HCM) largely depends on ventricular arrhythmias. Parametric T2 mapping from Cardiac MRI (CMR) was found to be a measure of myocardial edema. We sought to study whether elevated T2 values on CMR in patients with hypertrophic cardiomyopathy (HCM) might predict ventricular arrhythmias (VA) and adverse clinical outcome. Methods Consecutive patients with HCM (n = 59) and healthy volunteers (n = 21) underwent 3 Tesla CMR. T2 mapping values were independently analyzed by 2 independent readers and presented using a 16-segment AHA model. VA was recorded by 24-hour Holter monitoring and/or during exercise stress test. Composite outcome was defined as ventricular tachycardia (VT) per Holter and/or ergometry, admission due to arrhythmias, ICD insertion and all-cause mortality. Statistical analysis was a t-test for VA and multi-variant logistic regression model adjusted for age and gender. Results Septal and apical variants of HCM were found in 42 and 17 patients, respectively. We found good interobserver agreement in T2 values (ICC=0.92, 95% CI 0.86 - 0.96, p value <0.001). The 3rd tertile of T2 values (48 ± 8 msec) was significantly associated with VA 92% vs. 57 and 40% in lower tertiles, p = 0.02. Logistic regression analysis showed the 3rd tertile was an independent predictor of composite outcome (VT per Holter and/or ergometry, admission due to arrhythmias, ICD and all-cause mortality) OR 95% CI = 22.8 (1.4 - 361.6), p = 0.026. ROC analysis to find best cut-off of T2 for prediction of outcome showed AUC 0.7 (Figure 1). Conclusion Elevated T2 is an independent predictor of VA and adverse outcome in HMC patients. These results suggest the impact of myocardial edema in myocardial disease activity in HCM.ROC analysis to find best cut-off of T2