SUMMARY Cardiac dimensions and left ventricular function were investigated at rest with non-invasive methods in 14 professional road race cyclists and in 11 age-matched sedentary control subjects.The electrocardiographic findings were in agreement with previous studies in endurance athletes and the vectocardiographic data showed anterior displacement of the electrical forces.Echocardiographic dimensions at end-diastole showed higher values in the cyclists for left ventricular internal diameter, left ventricular posterior wall thickness, and interventricular septal thickness. Derived values for left ventricular volume and left ventricular mass were also much larger in the cyclists and there was excellent agreement between total heart volume measured with radiology and total left ventricular volume measured by echocardiography.There was a significant correlation between maximal oxygen consumption and end-diastolic left ventricular diameter.The term "athlete's heart" is used to describe a variety of alterations in the cardiac function of athletes engaged in vigorous competitive sports. These anomalies include bradycardia, often associated with intermittent tachyarrhythmias, repolarisation abnormalities, systolic murmurs, gallop rhythm, and ventricular hypertrophy.Previous studies suggested that the response of the heart to "endurance" sports was ventricular enlargement without thickening of the wall, whereas the response to "resistance" or "isometric" sports was thickening of the ventricular wall without an increase in size. ' Recently, however, other investigators found both an enlarged ventricular cavity and an increased wall thickness in endurance athletes such as long distance runners.2'The controversy may be partly explained by differences in the type of sport and in the performance level of the athletes under study, and by differences in the habitual activity and exercise performance of the control subjects.To get a better insight into the "athlete's heart" more data are needed on top class athletes specifically engaged in "endurance" or "resistance" sports.The purpose of the present study was to investigate the cardiac dimensions and left ventricular
1. In 70 patients with untreated essential hypertension, blood pressure variability was correlated to plasma catecholamines and to the response of blood pressure and peripheral flow to cold pressure and handgrip tests. 2. Supine blood pressure was recorded every 5 min, during 3 h. Variability was defined as the standard deviation of the mean of the readings in that period. 3. Blood pressure variability is positively and significantly correlated to the level of pressure and to age. 4. No significant correlation could be found with plasma catecholamines and sympathetic function tests. 5. It is concluded that blood pressure variability is related to the level of pressure but not to activity of the sympathetic nerves.
β-Thromboglobulin (β-TG) and platelet factor 4 (PF-4) are specific platelet proteins released during in vivo platelet activation. An increase in PF-4 after exercise- induced myocardial ischemia was reported by Green, L.H. et al.. This observation prompted us to measure β-TG and PF-4 in patients with chronic occlusive arterial disease of the lower limbs and to look for increments during treadmill exercise. β-TG was measured using the Amersham test kit and PF-4 using the radioimmunoassay kit of Abbott Diagnostics Division. Plasma levels in 28 normal individuals ranged for β-TG from 7 to 39 ng/ml with a mean value of 21.0 ng/ml, for PF-4 from 1 to 19 ng/ml with a mean value of 6.0 ng/ml. β-TG and PF-4 were measured in 59 patients with chronic peripheral arterial disease before and 5 min. after treadmill exercising till occurrence of claudication. Plasma levels of β-TG before treadmill exercising ranged from 24 to 260 ng/ml with a mean of 77.9 ng/ml, PF-4 levels ranged from 2 to 240 ng/ml with a mean of 30.4 ng/ml. These levels were significantly higher than those measured in normal individuals.After treadmill exercise β-TG levels showed a statistically significant increase to a mean value of 87.3 ng/ml but PF-4 did not rise significantly (mean value : 32.4 ng/ml). The supplementary increase of already elevated β-TG levels may be explained by enhanced in vivo platelet activation during treadmill exercising till occurrence of claudication. As the clearance of PF-4 from human plasma has been shown to be much faster than the clearance of β-TG increases in PF-4 levels may be more difficult to detect during dynamic explorations of the vascular system.
The effect of beta-adrenergic blockade on blood pressure variation was studied in ten patients with moderate hypertension. Supine systolic and diastolic blood pressures were measured every 5 min during six hours sessions, using an ultrasonic method. Systolic and diastolic variation in each six hour session was defined as the standard deviation of the mean of systolic and diastolic readings made in that period. After 3 weeks of single-blind placebo, a 12 week double-blind randomized crossover study was initiated with placebo (6 weeks) and atenolol (100 mg b.i.d. for 3 weeks and 200 mg b.i.d. for 3 weeks). Systolic and diastolic blood pressure and heart rate decreased significantly (p less than 0.01) during atenolol treatment. Diastolic variation did not change significantly, whereas systolic variation decreased slightly but significantly (p less than 0.05) when expressed in absolute values, but not when expressed as a percentage of systolic blood pressure. It is concluded that beta-adrenergic blockade decreases blood pressure and heart rate without causing significant changes in spontaneous systolic or diastolic variation.
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