Short term escape rhythm characteristics after radiofrequency ablation of the atrioventricular junction

Radiofrequency ablation of the atrioventricular (AV) node has become an established method of treating drug-resistant supraventricular arrhythmias, especially atrial fibrillation. Although it is routine to implant a permanent pacemaker following ablation, one of the potential adverse effects of the procedure is that many patients become pacemaker-dependent and are at risk of an adverse outcome in the event of pacemaker malfunction. Obtaining information about the characteristics of the escape rhythm would be helpful in risk-stratifying these patients and might facilitate modifications of the procedure that would reduce the incidence of this problem. We prospectively studied the clinical parameters and escape rhythm characteristics in 24 patients undergoing radiofrequency ablation of the AV node. Initially, 2 patients had no detectable escape beats and 4 had escape rates <30 beats/min. At 12 hours, 3 of these 4 had adequate (>30 beats/min) escape rates (there were no 12-hour data in 2). The escape rhythm was stable in 17 of the other 18 while 1 had no escape beats at 12 hours. Patients developing right bundle branch block had a greater chance of having an inadequate escape rhythm at 12 hours but this difference was not seen at 24 hours. We conclude that an adequate escape rhythm is usually present immediately after radiofrequency ablation of the AV node and tends to remain stable up to 24 hours. The absence of an escape rhythm immediately after ablation is of limited prognostic value since reliable escape rhythms may emerge subsequently.