Haemodynamic Effects of Bopindolol and Atenolol in Coronary Artery Disease A Noninvasive Study

Abstract

Bopindolol, a new non-selective betablocker, and atenolol, a conventional betablocker, were studied in parallel groups of eight normotensive patients with NYHA II-III angina pectoris. Non-invasive haemodynamic measurements were made using echocardiography and systolic time intervals. Drug doses were 1 mg bopindolol and 100 mg atenolol once daily; measurements were made immediately and at one and six weeks intervals. Both drugs reduced heart rate, atenolol from 62 to 47 beats/minute (24%, P less than 0.01) and bopindolol from 64 to 56 beats/minute (13%, P less than 0.05) at 24 hours. Only atenolol reduced mean blood pressure. Rate pressure product was persistently reduced by atenolol (30% at 24 hours), while with bopindolol this effect lessened with time. Opposite trends in left ventricular enddiastolic and endsystolic diameters were observed; with atenolol tending to increase and bopindolol to lower them. Atenolol had no influence on cardiac contractility, while bopindolol increased it, which was shown by enhancements in the fractional shortening, ejection fraction and maximum velocity of fibre shortening. Neither drug changed peripheral vascular resistance or systolic time intervals. Two patients on bopindolol left the study because of worsening symptoms of coronary artery disease, and two on atenolol owing to side effects, bradycardia and syncope in one and diarrhea in the other. In conclusion, bopindolol showed less beta-blocking effect than atenolol and it had a positive inotropic effect. Its benefit in treating coronary artery disease remains to be proved.