EFFECTS OF ATENOLOL ON 24-HOUR HEART-RATE-VARIABILITY AND LEFT-VENTRICULAR FUNCTION IN HEART-FAILURE PATIENTS TREATED WITH HIGH-DOSE ANGIOTENSIN-CONVERTING ENZYME-INHIBITION

To assess the effects of betaadrenergic beta-1 receptor blockade in pa tients with moderate congestive heart failure remaining symptomatic de spite high dose angiotensin converting enzyme inhibition with fosinopr il 40 mg/day, 16 patients were enrolled in a controlled pilot study. T he patients received either atenolol 75 mg/day or no drug. Baseline me asurements included analysis of 24 hour heart rate variability, and in cluded measurements of left ventricular enddiastolic dimension and qua ntification of aortic stroke volume. These measurements were repeated after eight months. Measures of heart rate variability did not change in the control group. In the atenolol group, mean NN increased from 73 4 +/- 40 to 867 +/- 45 ms (P<0.01), SDANN increased from 97 +/- 7 to 1 16 +/- 10 ms (P<0.10), total power increased from 11531 +/- 2182 to 23 103 +/- 4888 ms2 (P<.01) and power in the ULF domain increased from 60 24 +/- 866 to 13964 +/- 3035 ms2 (P<.05). Parameter of short-term vari ability did not change over time, neither in the atenolol, nor in the control group. Left ventricular function improved in the atenolol grou p only. Left ventricular enddiastolic diameter decreased from 69.3 +/- 3.4 to 65.3 +/- 3.3 (P<0.05) and stroke volume increased from 59.2 +/ - 4.9 to 66.6 +/- 5.9 mi (P<0.05). These data suggest a sustained bene fit of additional betablockade in patients with moderate congestive he art failure treated with high dose angiotensin converting enzyme inhib ition.