Exercise-Induced Quantitative Microvolt T-Wave Alternans 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 μV; p < 0.0001). A 53 μV-cutpoint, 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).