Left ventricular myocardial hypertrophy was found in patients with repeated myocardial infarctions, the greatest weight of the left ventricle being noted in those with congestive heart failure. A high correlation (r = 0.78) was established between the mass of the left ventricular myocardium calculated with the aid of echocardiography and the actual weight of the left ventricle. The important compensatory role of the ventricular septum is emphasized for the cases of myocardial infarction occurring in the free wall of the left ventricle. Left ventricular hypertrophy was detected by ECG in only 25% of those ischaemic heart disease cases in whom signs of myocardial hypertrophy were revealed by echocardiography.