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.