[Complete atrioventricular block, a possible complication of radiofrequency ablation of reciprocating nodal tachycardia].

Radiofrequency ablation of the slow pathway of the reentry circuit is the usual radical treatment of nodal tachycardia. It is, however, possible to create atrioventricular conduction defects, the significance of which is not known. The aim on this study was to report the history of these conduction defects created during ablation of the slow pathway of the intranodal reentry circuit. Four cases were observed in a series of 27 patients. In one female patient, complete atrioventricular block was observed for 5 minutes before conduction returned to normal followed by recurrence of the tachycardias. Three other women developed complete atrioventricular block one to four days after the ablation. The block regressed after a maximum delay of 7 days. Six months to one year after the procedure, these three patients remain free of tachycardia and have only first degree atrioventricular block on the surface ECG. These patients were not implanted with a pacemaker. The authors conclude that complete atrioventricular block after ablation of the slow pathway may be treated conservatively, providing it is well tolerated. It normally regresses within few days.