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

BACKGROUND: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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.