The Majority of Participants With Suspected Hypertrophic Cardiomyopathy Documented During Screening Echocardiography Have a Normal Electrocardiogram.

Abstract

Patients with hypertrophic cardiomyopathy (HCM) usually have abnormal electrocardiograms consistent with left ventricular hypertrophy (LVH). The goal of this study was to evaluate the prevalence of abnormal ECG findings (LVH, T wave inversion, left bundle branch block, and left atrial enlargement) in participants with suspected HCM detected during screening echocardiography. The Anthony Bates Foundation has been performing screening echocardiography across the United States for the prevention of sudden death since 2001. A total of 682 subjects between the ages of 8 and 71 underwent echocardiographic screening together with ECG documentation. We evaluated the prevalence of abnormal ECG in participants with suspected HCM defined as any left ventricular wall thickness ≥15 mm. The prevalence of LVH and T wave inversion were higher in HCM subjects as expected [HCM occurred in 23.5% (4/17) vs. 5.6% (37/665), P = 0.002, T wave inversion occurred in 17.6% (3/17) vs. 4.1% (27/664), P = 0.007]. However, despite adding these 2 common ECG abnormalities in this population, the presence of detected abnormal ECG remained less than 25% (23.5% of HCM subjects had LVH or T wave inversion on ECG vs. 8.7% of control, P = 0.036). Left bundle branch block or abnormal left atrium on ECG were not found in any participants with suspected HCM. The prevalence of abnormal ECG in the participants with suspected HCM detected during screening echocardiography is less than 25%. This suggests that ECG alone is not a sensitive marker for the detection of HCM.