e0663 Initial experience of synchronised electrical cardioversion for atrial fibrillation after bipolar radiofrequency ablation Maze operation

Abstract

Background The purpose was to explore clinical experience of electrical cardioversion for atrial fibrillation (AF) after bipolar radio- frequency ablation Maze operation. Methods From July 2006 to July 2009, 223 patients underwent bipolar radiofrequency maze operation for AF Out-patient were followed up after discharge on a regular basis. If effects of oral administration drugs such as digoxin, amiodarone and metoprolol were not obvious, with AF staying alive, patients should receive electrical cardioversion therapy. There were 13 cases underwent cardioversion therapy. After admission, ECG monitoring was needed. After intravenous anaesthesia using propofol, electrical cardioversion was carried out with dose of 1~2 J/kg. Three times had they failed to turn to normal sinus rhythm (NSR), cardioversion be given up. Results Four cases within 6 months after operation were given electrical cardioversion, three cases (75%) turned to NSR and one case (25%) was in AF instantly, the same until now. Of nine cases more than 6 months after operation, four cases (44.45%) turned to NSR instantly, two cases (22.22%) were still in AF, three cases (33.33%) were in junctional rhythm, however, five cases (55.56%) were in NSR, three cases (33.33%) were in AF and one (11.11%) was in junctional rhythm by far. Of three cases more than one year after operation, two cases (66.67%) were in NSR, one case (33.33%) was in AF. The cardiac function (NYHA) of 84.62% was gradeI and 15.38% gradeII. No thrombo-embolism occurred. Sinus bradycardia occurred in two cases during hospitalisation. 13 patients were followed up, reviewing ECG and echocardiography. The overall results of follow-up of cardiac rhythm were NSR in eight cases (61.54%), AF in four cases (30.77%), and junctional rhythm in one case (7.69%). Within seven cases whose heart rhythm immediately were able to turn NSR, one case converted to AF later, the rate of maintenance of NSR was 85.71%, however, six patients could not be transferred into NSR instantly, only two cases (33.33%) turned into NSR. In NSR group left atrial diameter ECG (LAD) values reduced significantly after cardioversion (t=6.9580, p=0.0000), while LAD in AF group had no significant changes (t=0.7308, p=0.4925). The successful transfer rate was 71.43% in patients whose AF duration was less than 5 years and was 50% in patients whose AF duration was more than 5 years. There was no significant difference between the two AF duration groups (X2=0.174, p=0.6788). Conclusion Electrical cardioversion after bipolar radiofrequency maze operation was an effective option for the treatment of AF. The best time for cardioversion was within 6 months, which had high immediate success rate and be able to maintain a higher rate of NSR. Those who can be instantly converted to NSR, NSR maintenance rates are relatively high, but cannot be converted to NSR immediately who were less likely to NSR. With the prolonged time, successful rate of turning to NSR after electrical cardioversion reduced gradually. The effect of electrical cardioversion would be better if LAD were significantly reduced.