P-367: Influence of long-term of carvedilol and metoprolol therapy on R-R variability in younger and older adults with chronic heart failure

Recent evidence shows that beta-blockers help in preventing sudden death during chronic heart failure (CHF). Our aim in this study was to examine the effect of metoprolol and carvedilol on heart rate variability in younger and older subjects with CHF. We subdivided subjects with CHF for age (younger than 65 years and 65 years or older) and submitted them to a short placebo run-in followed by they were then assigned to a 12-month course of therapy with metoprolol or carvedilol. All subjects underwent short time resting recording of RR and then power spectral analysis and calculation of the power law (PL), a measure of heart rate variability. A total 53 subjects completed the study, 32 in the younger group (15 assigned to metoprolol and 17 to carvedilol) and 22 in the older group (10 assigned to metoprolol and 11 to carvedilol). Both treatments significantly increased the PL. In older subjects both treatments induced a similar increase (metoprolol group from -1.61±0.1 to -0.99±0.1, p