INFLUENCE OF ANTIARRHYTHMICS ON HEART-RAT E-VARIABILITY

Since analysis of heart rate variability (HRV) is able to identify sub jects at risk of sudden death and as antiarrhythmics can interfere wit h this prognosis, the objective of this study was to determine whether antiarrhythmics (AA) modified the HRV measured on a 24-hour Holter re cording and after rapid ventricular stimulation and whether the initia l HRV and its possible modification during treatment with AA were corr elated with the results of AA treatment in patients with ventricular t achycardia (sustained VT). The HRV was studied in 50 patients with hea rt disease and spontaneous sustained VT, reproduced by programmed vent ricular stimulation. This analysis was performed at baseline with anti arrhythmic treatment consisting of low-dose beta-blocker and quinidine s in 26 patients (group I) or amiodarone in 24 patients (group II). Tr eatment was effective (i.e. prevented induction of VT) in 9 patients i n group I (group Ia) and 5 patients in group II (group IIa). Treatment was ineffective in the other 17 patients of group I (group Ib) and 19 patients of group II (group IIb). The initial HRV was similar in the patients of groups Ia and Ib or groups IIa and IIb. Temporal analysis did not reveal any significant variation of HRV during AA treatment. I n contrast, spectral analysis of HRV and the HRV observed during ventr icular stimulation demonstrated a significant reduction of this parame ter (p < 0,05 for groups I and II combined). In conclusion: the initia l HRV is not predictive of the results of treatment. Quinidines and am iodarone tend to decrease HRV regardless of the effect of the AA on th e prevention of VT.