EFFECTS OF D-NEBIVOLOL AND L-NEBIVOLOL ON LEFT-VENTRICULAR SYSTOLIC AND DIASTOLIC FUNCTION - COMPARISON WITH D-L-NEBIVOLOL AND ATEONOLOL

(D-L) Nebivolol is a new beta(1)-selective adrenoceptor blocker which in normal individuals preserves rest and exercise hemodynamics. We ass essed the effects of the enantiomers (L-and D-nebivolol) on left ventr icular (LV) systolic and diastolic function and compared their effects with those of the racemic mixture, LV angiography (+ Millar) was perf ormed before and after intravenous (i.v.) infusion of either D-or L-ne bivolol (1.25-2.5 mg, n = 22) in patients with ischemic heart disease and previous myocardial infarction, Neither L-nor D-nebivolol produced significant changes in heart rate (HR), peak (+) dP/dt, (dP/dt) DP40, cardiac index (CI) or ejection fraction (EF), Diastolic distensibilit y, evaluated from the shift of the pressure-volume data at the time of mitral valve opening, did not improve after D-or L-enantiomers admini stration, In contrast, both D-L-nebivolol 2.5 mg (n = 9) and atenolol 15 mg (n = 9) significantly reduced HR and peak (+) dP/dt, but in comp arison to atenolol D-L-nebivolol improved EF (+4% after D-L-nebivolol vs. -4% after atenolol; p < 0.05 D-L-nebivolol vs. atenolol) and maint ained cardiac output (GO) (+2% vs. -21%; p > 0.05 between groups). Mor eover, unlike any of the other drugs in the study, the racemate shifte d the diastolic pressure-volume data downward, suggesting improved LV distensibility. The beneficial effects of nebivolol on LV systolic and diastolic function appear to require the presence of both D-and L-ena ntiomers.