The authors examined 112 subjects free from cardiac disease, with essential hypertension and myocardial infarction. In all subjects a 12-lead ECG at rest was made as well as a polycardiographic and echocardiographic examination. The authors found that in the group of healthy subjects there is a direct significant linear correlation between the size of the systole of the left atrium and age. The size of the left atrium and the atrial filling fraction were significantly smaller in healthy subjects than in subjects with hypertension and myocardial infarction. The authors draw attention to the necessity to re-evaluate the accepted norm of left atrial size in patients with hypertension and myocardial infarction. The authors found that between the magnitude of the systole of the left atrium and the ejection fraction of the left ventricle a significant relationship of parabolic shape exists. The mentioned correlations suggest that with deterioration of left ventricular function the ratio of the left atrial systole increases up to a certain extent (40% of the ejection fraction); after this borderline is exceeded, the haemodynamic contribution of the left atrium declines again till it is insignificant. PTF-V1 on the ECG which is generally considered a sign of an enlarged atrium reflects in the group of patients with acute myocardial infarction above all the degree of reduction of systolic and diastolic left ventricular function and not changes in the size and function of the left atrium.

Keywords: Adult; Aged; Aged, 80 and over; Coronary Disease /physiopathology/; Echocardiography; Electrocardiography; Female; Heart Atria /physiopathology/; Humans; Hypertension /physiopathology/; Male; Middle Aged; Stroke Volume; Systole