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 spiroergometric 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.

Progression of changes in left ventricular function during four days of simulated multi-stage cycling

“…For these reasons, the findings of the current study supports that endurance trained athletes participating in multiday exercise in thermoneutral conditions with ideal fluid and carbohydrate intake, succumb to changes in cardiac function which appear to be physiological in nature as opposed to pathological. However, it is noteworthy that the long-term consequence of multiple episodes of cardiac suppression due to prolonged strenuous exercise in athletes remains controversial (Claessens et al 2000;Whyte 2008;Wilson et al 2011). Moreover, the reduced chronotropic response during exercise observed on the latter days of the current study support previous similar reports and endurance athletes should consider this when gauging exercise intensity based on heart rate.…”

The physical demands upon (Dutch) fire-fighters in relation to the maximum acceptable energetic workload

“…Fourth, the energetic peak loads during actual fire-fighting could trigger sudden cardiac death (Mittleman et al 1993, Jensen-Urstad 1995, Franklin et al 1997, Claessens et al 2000. It should be noted that the risk of sudden death during physical activity is extremely low for individuals without known heart disease who exercise regularly (Jensen-Urstad 1995).…”

“…The combination of irregular working hours and extra-high energetic peak loads during incidents on a 24-h shift might lead to symptoms of fatigue. But that is not all, for the heavy physical exertion required during peaks of high-intensity work could trigger acute myocardial infarction (Mittleman et al 1993, Jensen-Urstad 1995, Franklin et al 1997, Claessens et al 2000. These observations indicate that fire-fighting can be considered as an 'at risk' job.…”

Sudden Cardiac Death in Athletes

“…ECG of a healthy competitive triathlete (26 years old) showing moderate ST-segment elevation with incomplete RBBB and deep negative T waves in the left precordial leads [with permission, 142]. …”

“…Fibromuscular dysplasias of small coronary arteries, as well as old and recent degeneration of the sinoatrial node, atrioventricular node and His bundle were also attributed to sudden death in these individuals [141, 142, 143, 144]. …”