Hippokratia 1999, 3(2): 77 - 81
G Boudonas, D. Psirropoulos, A. Efthimiadis, G. Kazinakis, M. Parthenis, C. Keskilidis, N. Lefkos
The aim of the study was to investigate the effectiveness of quinidine (QY) and amiodarone (AM) on paroxysmal atrial fibrillation (PAF) conversion.Methods: 476 patients who admitted because of recent onset (<24 hours) PAF were studied. Patients were randomly divided into two groups, age and sex matched. Group A comprised 337 patients who were treated with QY in combination with digoxin and group Β 139 patients who were treated with AM. In the case where PAF was not converted into sinus rhythm with the one drug, an attempt to conversion with the other drug was undertaken. The Q-Tc interval was determined before and after PAF conversion.
Results: With the administration of QY (group A) conversion of PAF into sinus rhythm achieved in 312 (92.6%) patients and with the administration of AM in 23 of the remaining 25. In group Β patients, conversion of PAF with AM achieved in 122 (87.8%) and with the administration of QY in 13 of the remaining 17. The Q-Tc interval was measured in all patients in the after conversion ECG but only in a minority in the initial ECG, attributed to the difficulty of accurate Τ wave end determination because of fibrillation. Although there were no statistically significant differences of Q-Tc interval duration between the two group of patients (412.7±21.9 msec in group A and 417.6±31.2 msec in group B), in the subgroups of patients who were not converted with the initially administered drug, a statistically significant difference in Q-Tc interval duration was found. Especially, in the subgroup of patients who were not converted with the initial administration of QY and digoxin the duration of Q-Tc was significantly smaller compared with that of patients who were not converted with the initial administration of AM (392.8±15.9 msec and 432.1±21.3 msec respectively, p<0.001).Conclusions: QY and AM are strong antiarrythmic agents in PAF conversion, both effective and safe; but in a small proportion of these patients, the extreme values of Q-Tc interval duration may predict the conversion of PAF into sinus rhythm by either QY or AM.