Changes in escape rhythms several years after radiofrequency ablation of the atrioventricular junction combined with pacemaker implantation.

OBJECTIVE

Escape rhythm is thought to play a considerable role in protection against adverse outcome due to pacemaker malfunction. We studied the escape rhythms in 32 patients with supraventricular tachyarrhythmia refractory to medical therapy who underwent radiofrequency ablation of the atrioventricular junction combined with implantation of a pacemaker.

METHODS AND

RESULTS

We performed the escape rhythm analysis immediately and 2.6 +/- 1.9 years after the radiofrequency ablation by decreasing the pacing rate. In the initial study, escape rhythms (41 +/- 8 beats/min) were documented in 20 patients (63%). Non-cardiac death occurred in 3 patients with escape rhythm, and cardiac death occurred in I patient without escape rhythm. In the follow-up study, escape rhythms were detected in 22 of 28 patients (79%). Escape rhythm had developed in 6 (55%) of 11 patients who were without escape rhythm initially, while escape rhythm disappeared in 1 of 17 (5.9%) patients who had escape rhythm initially. The changes in escape rhythm were not related to QRS width of the intrinsic beat. There was no correlation between the number of radiofrequency applications or the ratio between atrial and ventricular electrocardiogram voltages of radiofrequency applications and the development of escape rhythms.

CONCLUSIONS

The present long-term follow-up study demonstrated that the emergence of an escape rhythm increased several years after ablation, but was unrelated to procedural factors. There are, however, certain patients in whom the disappearance of escape rhythms occur. The evaluation of escape rhythms is thus necessary to determine the risk associated with pacemaker failure.