Exercise-induced quantitative microvolt T-wave altemans in hypertrophic cardiomyopathy

Abstract

Background/Purpose: Patients with hypertrophic cardiomyopathy (HCM) have elevated risk for sudden cardiac death (SCD). Our study aimed to quantitatively characterize microvolt T-wave alternans (TWA), a potential arrhythmia risk stratification tool, in this HCM patient population. Methods: TWA was analyzed with the quantitative modified moving average (MMA) in 132 HCM patients undergoing treadmill exercise testing, grouped according to Maron score risk factors as high-risk (H-Risk, n = 67,), or low-risk (L-Risk, n = 65, without these risk factors). Results: TWA levels were much higher for the H-Risk than for the L-Risk group (101.40 +/- 75.61 vs. 54.35 +/- 46.26 mu V; p < 0.0001). A 53 mu V cut point, set by receiver operator characteristic (ROC), identified H-Risk patients (82% sensitivity, 69% specificity). Conclusions: High TWA levels were found for hypertrophic cardiomyopathy patients. Abnormal TWA associated with major risk factors for SCD: non-sustained ventricular tachycardia on Holter (p = 0.001), family history of SCD (p = 0.006), septal thickness >= 30 mm (p < 0.001); and inadequate blood pressure response to effort (p = 0.04).