INDUCTION OF TRANSIENT 3RD-DEGREE ATRIOVENTRICULAR-BLOCK DURING RADIOFREQUENCY CATHETER ABLATION IN A PATIENT WITH VENTRICULAR-TACHYCARDIA AND REMOTE MYOCARDIAL-INFARCTION

Introduction: Radiofrequency catheter ablation has been demonstrated to be an effective with so-called idiopathic ventricular tachycardia, whereas the benefit/risk profile for ablation in patients with chronic myocardial infarction and severely compromised left ventricular. function still needs to be determined. The present report describes the unintended induction of transient third-degree atrioventricular block in a patient with remote myocardial infarction who underwent radiofrequency catheter ablation of ventricular tachycardia. Methods and Results: Endocardial catheter mapping and I radiofrequency ablation were performed in a 57-year-old patient with chronic recurrent ventricular tachycardia, who had previously suffered from myocardial infarction. Additionally, the patient presented with complete right bundle branch block during sinus rhythm. Radiofrequency energy applied to a critical site of the reentrant tachycardia at the left ventricular basal septum during sinus rhythm induced third-degree atrioventricular block after 20 s of current delivery, which lasted for 24 h. At this site a presumable left bundle branch potential was recorded during sinus rhythm. Conclusions: Radiofrequency current application for ablation of ventricular tachycardia may induced third-degree atrioventricular block in patients with remote myocardial infarction. When current is delivered to ventricular basal septum, radiofrequency energy should be applied during sinus rhythm to allow continuous monitoring of atrioventricular conduction. Special caution should be given to patients with right bundle branch block during sinus rhythm.