Magnetic Resonance Technique in the Assessment of Exercise-induced Long- and Short-Term Changes in Cardiac Function and Morphology

Overview

Until now it has been assumed that regular endurance training has a positive influence on cardiac function and that the positive effect increases with increasing intensity. However, little is known about the effects of intense endurance stress on the heart. According to current knowledge repeated exposure to strenuous endurance activity may lead to minor but possibly irreversible damage to the heart with resultant scarring of the heart's muscle. Within this study the investigators attempt to find out by different analytical methods - in particular magnetic resonance imaging (MRI) and ultrasound of the heart - to what extent the heart muscle is affected by long term intense endurance exercise and which changes in cardiac function and morphology can possibly be found. Therefore the investigators compare former national competitive endurance athletes with sedentary controls.

Background Despite the well documented cardio-protective effects of aerobic exercise of moderate intensity, short- and long-term consequences of strenuous exercise are less clear. There is increasing evidence that maintaining a high cardiac workload over a prolonged duration may result in transient impairment of cardiac function. Recent studies have also reported a transient increase in cardiac biomarkers after prolonged strenuous exercise. While in patients with cardiac disease the presence of cardiac dysfunction and increased cardiac biomarkers generally reflects myocardial damage, the impact of these observations in athletes is ill defined. It is a matter of concern whether in athletes such findings simply reflect a reversible response or whether repetitive events may lead to an accumulative cardiac damage. Traditional echocardiographic methods used to determine potential cardiac changes in morphology or function are investigator-dependent and may be subject to interference by cardiac pre- and afterload. Cardiac magnetic resonance imaging provides an investigator-independent and objective method to quantify cardiac dimensions and function. Delayed contrast enhancement MR imaging is a highly reproducible cardiovascular magnetic resonance imaging technique to directly visualize myocardial edema, necrosis and fibrosis. Objective To use cardiac and delayed contrast enhancement magnetic resonance imaging in combination with echocardiographic methods to to assess whether athletes involved in prolonged strenuous exercise over years reveal persistent alterations of cardiac morphology and function. Methods Cardiac and delayed contrast enhancement magnetic resonance imaging will be used in combination with echocardiographic methods to investigate whether involvement in prolonged strenuous exercise over years leads to changes in cardiac function and morphology. Therefore we study and compare 15 veteran elite athletes and 15 sedentary controls. The use of cardiac MRI and delayed contrast enhancement magnetic resonance imaging techniques will be paralleled by echocardiographic and tissue Doppler measurements to allow comparative analyses of the two methods.