1. Atenolol (100 mg/day) was given to 12 hypertensive patients for 8 weeks, and its effects on mean arterial pressure, cardiac index and ejection phase indices of myocardial performance were examined by echocardiography.
2. Echocardiographic studies were made before treatment after 4 weeks on placebo and repeated after 4 and 8 weeks of atenolol therapy. Mean arterial pressure fell by 14 and 21% after 4 and 8 weeks respectively. Cardiac index fell by 22 and 20%, and stroke index fell by 11 and 7%. Calculated peripheral resistance did not change significantly.
3. Ejection phase indices, namely fractional shortening, ejection fraction and normalized mean rate of circumferential fibre shortening, did not change. End-diastolic volume index did not change and there was no relationship between changes in heart rate and end-diastolic volume index.
4. The study shows that atenolol in the resting state has no effect on certain echocardiographic indices of left ventricular function when given orally to hypertensive patients with normal left ventricular size and function. The reduction in cardiac and stroke indices were presumably secondary to a decrease in cardiac venous filling.