Effects of epanolol and metoprolol on the heart measured by 24-hour holter monitoring

Abstract

Continuous 24-hour ECG monitoring was performed as an additional objective in 87 patients from 5 centres in the VISA 1 study. The aim of the study was to compare the continuous 24-hour ECG recordings before the study and during treatment with epanolol ('Visacor') or metoprolol. Parameters of particular interest were heart rate and premature ventricular contractions (PVCs). Using the Oxford 4000 system with a 5-lead recorder, 24-hour monitoring was carried out on entry to the study (no antianginal therapy was allowed, with the exception of short acting nitrates), and at the end of both treatment periods. Measurements included the total number of heart beats and PVCs and the incidence of bradycardia. 87 patients, of mean age 59 (range 32 to 80) years, were included in the study. 62 patients had evaluable tapes available on both active treatment periods. The mean heart rate during 24 hours was significantly lower with metoprolol compared with epanolol treatment (64 vs 72 beats/min, respectively, p less than 0.001). The total number of PVCs in 24 hours was similar in both treatment groups and not significantly different from the value recorded at entry. The median total duration of bradycardia (heart rate less than 60 beats/min) in 24 hours was significantly (p less than 0.001) less for epanolol (60 minutes) than metoprolol (428 minutes). Plots of the mean hourly heart rates show that during daytime, epanolol was associated with a mean heart rate in between the rate observed without treatment and with metoprolol treatment. At night-time, almost identical values were found in the groups treated with epanolol compared with the non-treatment period, whereas the metoprolol treatment induced significant lower heart rate levels. Thus, it was shown that there was greater heart rate reduction with metoprolol than with epanolol (p less than 0.001), and that there was no heart rate reduction at night with epanolol. No arrhythmogenic effect was seen for either drug.