Marginal Overlap between Electrocardiographic Abnormalities in patients with Hypertrophic Cardiomyopathy and Trained Athletes: Implications for Preparticipation Screening.

Background: Hypertrophic cardiomyopathy (HCM) is usually associated with ECG abnormalities such as left ventricular hypertrophy (LVH), repolarization changes, and pathologic Q waves; instead, physiologic hypertrophy in trained athletes manifests as an isolated increase of QRS amplitude. We assessed whether the ECG pattern of pathologic hypertrophy of HCM overlaps with that of physiologic hypertrophy of athlete’s heart, particularly by evaluating what proportion of individuals from both groups had pure QRS voltage criteria (Sokolow-Lyon) for LVH. Methods: Using accepted diagnostic criteria, we examined and compared the ECG tracings of 260 consecutive patients with clinical and echocardiographic diagnosis of HCM and those of 1005 trained athletes undergoing preparticipation cardiovascular evaluation, including ECG and echocardiography. Results: An abnormal ECG was found in 246 of 260 (94.6%) patients with HCM and in 817 of 1005 athletes (81.3%). The majority of patients with HCM had one or more of the following ECG changes: repolarization ST/T abnormalities in 209 (80%), pathologic Q waves (Q waves ≥0.04 s in duration or ≥25% of the height of the ensuing R wave) in 103 (39.6%); left atrial enlargement in 75 (28.8%), intraventricular conduction abnormalities (QRS duration ≥90 ms) in 71 (27.3%) and left axis deviation in 9 (3.5%). ECG tracings showed isolated increase of QRS voltages in 5 HCM patients (1.9%) and were completely normal in 14 (5.4%). Compared with patients with HCM, trained athletes significantly more often had isolated voltage criteria for LVH (403, 40%; p<0.0001), but less often showed negative T waves (27, 2.7%; p<0.0001), pathologic Q waves (17, 1.7%; p<0.0001), and nonvoltage criteria of LVH (13, 1.3%; p<0.0001). No athletes with isolated voltage criteria had echocardiographic evidence of HCM. Conclusions: ECG in HCM overlaps marginally with ECG findings in trained athletes. An isolated increase of QRS voltage is an unusual pattern (1.9%) of LVH in patients with HCM, while is frequently observed in trained athletes. Systematic echocardiographic evaluation of athletes fulfilling isolated QRS voltage criteria at preparticipation screening is not justified, resulting in a considerable cost savings.