Different impact of carvedilol and transdermal scopolamine on cardiovascular performance of mild-moderate chronic heart failure patients: evidence of useful effects of scopolamine on tolerance to work load.
Słowa kluczowe
Abstrakcyjny
OBJECTIVE
To verify and compare the effects respectively exercised in chronic heart failure patients by transdermal, slow release scopolamine patch and by the beta and alfa adrenoreceptor blocker carvedilol upon the main indexes derived from maximal cardiopulmonary stress test, as well as from analysis of heart rate variability.
METHODS
In each of 14 patients suffering from NYHA class II chronic heart failure, admitted to study, the maximal cardiopulmonary test and heart period power spectrum assessment were performed, firstly during usual therapy, then after 7 days of continuous adjunctive treatment with scopolamine patch, and, finally after 3 months of regular administration of oral carvedilol, added to the basal therapy. The need of time enough to the adaptation of the cardiovascular system against the carvedilol pharmacodynamics, together with the need of slow, progressive dose titration, caused that the onset of therapy with carvedilol was separated from assessment of its effects on ergometric and spectral parameters by an interval period of 3 months.
RESULTS
During administration of low doses of scopolamine, the values of VO2max, exercise time and double product were respectively 24 +/- 5.3 ml/kg/min, 12 +/- 3 min and 23630 +/- 3760, and resulted significantly higher than basal (p < 0.05 in all cases) and carvedilol-related readings (p < 0.01 by comparisons with VO2max and double product; p < 0.05 by comparison with exercise time). Again during scopolamine, the total variance, LF and HF powers exhibited the values reported as follows: 1255 msec2 and, respectively, 430 and 250 msec2, thus exceeding significantly the basal levels (p < 0.05 from comparison with total power, p < 0.01 from comparisons with LF and HF bands) as well as the levels reached during adrenergic blockade with carvedilol (LF scopolamine vs LF carvedilol: p < 0.01; total power and HF scopolamine vs corrispective carvedilol values p < 0.05). Compared to the basal findings, the carvedilol induced a significant reduction in VO2max (p < 0.05), double product (p < 0.01), peack of heart rate (p < 0.05) and LF power (p < 0.05), and elicited no significant decreases in exercise time; similarly a weak, not significant surge was product by carvedilol in total and HF powers.
CONCLUSIONS
Therefore, in patients with left ventricle asymptomatic dysfunction, the low doses of scopolamine potentiate simultaneously the spontaneous heart rare variability and cardiopulmonary maximal testing; whereas, the carvedilol acts upon LF oscillatory component only, the effects upon total variance and HF band being negligible; moreover, this drug depress the myocardial functional capability; in fact, the carvedilol has been demonstrated to produce a remarkable fall in VO2max, this significant reduction in O2 maximal uptake involving the poor rise in cardiac output during the effort or less effective O2 removal from capillary beds or both.
