Physiological or pseudophysiological ECG changes in endurance-trained athletes

Abstract

"Sudden cardiac death" in seemingly healthy, active, and asymptomatic people has always been a tragic fact and is now occurring more frequently. Thus, the preventive detection of "subjects at risk" becomes a priority. A traditional resting electrocardiogram can sometimes give useful indications. Fifty-two competitive triathletes were compared with 22 control persons with similar anthropometric parameters. All subjects underwent the same noninvasive cardiac exploration with electrocardiography, bidimensional echo-Doppler examination, and maximal spiro-ergometric exercise tests, on a stationary bicycle as well as on a treadmill. In the triathletes we noted manifest signs of eccentric as well as concentric left ventricular hypertrophy with arguments for a supernormal diastolic left ventricular function, with important hemodynamic adjustments and with consequences on the resting electrocardiogram. We described "ten commandments" in evaluating the resting electrocardiogram of healthy competitive athletes. We suspect that the occurrence of ventricular premature beats at peak load of a maximal exercise could be the first expression of a pathological cardiac adaptation to sports activities. The resting electrocardiogram can show interesting details in detecting the "subjects at risk" for problems such as possible lethal arrhythmias and "sudden cardiac death." The analysis of the four subgroups of triathletes compels us to feel dubious about the "athletic heart syndrome" as a physiological entity. In several cases the "athletic heart" is possibly a transitional situation to a pathological hypertrophic and dilated cardiomyopathy.