Celiprolol (C) is a new selective beta 1-blocker with partial beta 2-agonistic activity. The purpose of this study was to explore its antihypertensive efficacy and its short-term effect on systemic vascular resistances (SVR), cardiac output (CO), left ventricular ejection fraction (LVEF), and left ventricular diastolic performance (LVDP). The Doppler technique was used. In an open-label study, 20 hypertensive patients (15 males, 5 females, age range of 29-68 years) with left ventricular hypertrophy detected by echography were daily treated with 400 mg of C in a single dose, for a period of 4 weeks. C reduced significantly the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) (158 +/- 12 vs. 142 +/- 11 mm Hg, p < 0.05 and 101 +/- 6 vs. 87 +/- 4 mm Hg, p < 0.001, respectively) with a decrease in heart rate (74 +/- 12 vs. 67 +/- 8 beats/min, p = NS). The SVR decreased significantly (2,050 +/- 22 vs. 1,495 +/- 23 dyn/s/cm5, p < 0.001) with a slight but not significant increase in the CO (4.5 +/- 0.69 vs. 5.11 +/- 0.82 L/min). The LVEF did not decrease significantly (58 +/- 5 vs. 56.9 +/- 6%, p = NS) while the LVDP was modified favorably, significantly reducing the early diastolic deceleration time (EDDT) (199 +/- 61 vs. 132 +/- 80 ms, p < 0.01) and reducing the isovolumetric relaxation time (IVRT) (167 +/- 16 vs. 117 +/- 23 ms, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)