Haemodynamic effects of atenolol and bopindolol at rest and during isometric exercise. A non-invasive study in healthy volunteers.

Circulatory effects of bopindolol, a new nonselective beta blocking agent with intrinsic sympathomimetic activity and atenolol were compared. After baseline and first dose measurements atenolol 25 mg twice daily and bopindolol 1 mg daily were given to 10 healthy young subjects. Haemodynamic measurements were made noninvasively using echocardiography and systolic time intervals. Clinical and circulatory indices were measured at baseline, after initial dose and after one week of regular treatment at rest and at isometric handgrip exercise (IE) (HG). Atenol reduced the heart rate from 62 bpm to 49 and blunted totally the HR increase during IE (p less than 0.01). Bopindolol caused a 10% fall in heart rate (NS) at rest and a 15% fall (p less than 0.05) during IE. BP fell by 6% after atenol administration and 4% after bopindolol (NS) at rest and similarly during IE. In contrast to bopindolol, atenolol caused small increases initially in left ventricular end-diastolic dimension (LVEDD) and left ventricular end-systolic dimension (LVESD). A 10% increase in FS was seen at rest after bopindolol administration (NS). With the fall in heart rate the estimated cardiac output (CO) also fell from 3.66 to 3.151/min (P less than 0.05) after atenolol but rose from 3.87 to 3.93 after bopindolol (NS) during chronic treatment. Consecutively the total peripheral resistance (TPR) was increased to some extent by atenolol, whereas bopindolol reduced it at rest and during IE. A similar response was also found in systolic time intervals PEP/LVET which were reduced during bopindolol administration.(ABSTRACT TRUNCATED AT 250 WORDS)