RESUMO
INTRODUCTION AND OBJECTIVES: The lack of specificity of electrocardiographic (ECG) recording showing isoelectric T-waves often leads to diagnostic doubts. This study attempts to demonstrate that asymptomatic patients who demonstrate benign forms of hypertrophic cardiomyopathy may be identified from a typical ECG pattern showing isoelectric T-waves. METHODS: In 45 out of 5,126 asymptomatic healthy aircrew members, an ECG pattern which showed isoelectric T-waves in all leads, but were normal in V2 and V3, was found. 12 of them had negative T-waves in III and aVF leads. Cardiac echo-Doppler, Bruce test and 24-hour Holter recordings were performed in 29 of the 45 cases; all were males aged 30-55 (43.1 +/- 7.1) without any associated disorder nor engaged in heavy exercise, and a control group of 15 healthy subjects. In each of the 29 cases, 2-21 ECG's (11.1 +/- 6.3) performed over a period of 2 to 20 years (13.0 +/- 5.9) were reviewed. RESULTS: In 23 of the 29 cases (79.3%), echo-Doppler criteria of non obstructive mild hypertrophic cardiomyopathy were found. T-waves became normal during exercise testing, returning to isoelectric during recovery, in 19 of the 23 cases. In 17 of these cases, reversible T-wave changes were observed between successive ECG's; T-wave changes became clearly negative when the level of exercise was increased. Holter recordings did not show pathological findings. CONCLUSIONS: We believe that echo-Doppler studies must be performed in asymptomatic patients showing the ECG pattern described above, because they are strongly suspicious of having mild hypertrophic cardiomyopathy.
