Impact of atrioventricular node ablation and pacing therapy on clinical course in patients with permanent atrial fibrillation and unstable ventricular tachycardia induced by rapid ventricular response: follow-up study.

AIM: To evaluate prospectively the impact of atrioventricular (AV) node ablation and consequent pacing therapy on clinical course in patients with permanent atrial fibrillation and unstable ventricular tachycardia induced by rapid ventricular response.

METHODS: One hundred four patients with permanent atrial fibrillation and uncontrolled ventricular rate resistant to drug therapy underwent radiofrequency catheter ablation of the AV node and permanent pacemaker implantation. At baseline examination, 14 of them had unstable ventricular tachycardia induced by rapid ventricular response of atrial fibrillation (ventricular tachycardia group). The remaining 90 patients did not have this type of ventricular tachycardia (control group). After the ablation, all patients were followed-up without antiarrhythmic agents. The primary end point was sudden cardiac death.

RESULTS: Before the ablation, patients in ventricular tachycardia group had lower left ventricular ejection fraction (P<0.013), and higher ventricular rate at rest and during daily activities (P<0.001). During the follow up of 20+/-8 months (mean+/-standard deviation), the mortality rate of sudden cardiac death at two years was similar among the two groups (7% vs 5%, P=0.703). The observed cardiac and all-cause mortality were significantly higher in ventricular tachycardia group (21% vs 3.6%, P=0.014; 28.5% vs 4.4%, P=0.038; respectively) due to increased heart failure-related mortality (P=0.013).

CONCLUSION: In patients with permanent atrial fibrillation and ventricular tachycardia induced by rapid ventricular response, AV node ablation and pacing therapy have beneficial effect in the elimination of this arrhythmia. It seems that these patients do not need a cardioverter defibrillator therapy.