[Vectorcardiographic criteria of ventricular hypertrophy in a population of athletes].

Competitive sports and the physical training involved give rise to cardiac hypertrophy. The vectocardiographic criteria of hypertrophy (Frank's system) were examined in a population of 1800 athletes of varying disciplines. Hypertrophy, essentially ventricular, was common (78% of cases); it was mainly left (46%) but right sided (18%) and bilateral ventricular hypertrophy (I4%) were also observed. Isolated left ventricular hypertrophy was most common in disciplines with high energy requirements (cycling, rowing athletics). Right ventricular hypertrophy was observed in nearly all activities. The most commonly positive criteria were those related to increased amplitude of the electrical signals, especially during depolarisation. The degree of hypertrophy was modest as shown by the absence of certain very specific criteria (clockwise rotation of QRS in the horizontal plane in right ventricular hypertrophy) and by the average numerical values which remained lower than those recorded in patients with pathological hypertrophy. The electrical recordings were suggestive of several different anatomical and haemodynamic forms of hypertrophy. The degree of hypertrophy was variable and depended most of all on the degree of physical training. Some electrical syndromes appeared to vary in time. The incidence of some electrical changes varied when the population was studied after a 10 year interval: for example, the incidence of atypical repolarisation fell from II,4% to 5%. These results suggest that the development of cardiac hypertrophy in competing athletes may have more than one mechanism.