Abstract

A 2D exercise echocardiographic study of 40 subjects is reported. Twenty of these subjects were top-ranking athletes (10 engaging in prevalently isometric and 10 in prevalently isotonic sports activities). The other twenty were untrained controls. All the subjects were studied at rest and during muscular work on the bicycle ergometer, in a semi-supine position, with increasing loads of 50 W/3, until maximum heart rate was reached or until physical exhaustion. The 2D echocardiographic examination was carried out using apical (2 and 4 chamber) and short axis parasternal (at the mitral valve and papillary muscle levels) projections. In this way it was possible to obtain the following morphological and functional parameters: systodiastolic variation of the areas subtended by the endocardial outlines at the levels of the mitral valve and the papillary muscles; diastolic volumes, stroke volume, ejection fraction and cardiac output. The data obtained with 2D are in substantial agreement with those obtained using M-mode. In the initial stages of the exercise, a Frank-Starling mechanism comes into play in increasing the cardiac output, while as the work load increases there is an increase in the myocardial contractility, mainly due to increased adrenergic activity. The differences in the behaviour of the parameters examined during exercise in the three groups studied have probably to be attributed to the different morphological and functional basal conditions (heart prevalently dilated in the isotonic subjects, heart prevalently hypertrophic in the isometric subjects). The authors conclude that the use of the 2D method during exercise with the study of not only diameter, but also of areas and volume: (a) permits data obtained with M-mode to be confirmed and made more valuable; (b) supplies informations for more precise quantification of the various patterns of adaptation of the cardiovascular apparatus to physical exercise in the various sports. Verf.-Referat