Preprocedural Ventricular Rate Predicts Subsequent Sick Sinus Syndrome after Ablation for Long‐Standing Persistent Atrial Fibrillation

BACKGROUND: Concealed sick sinus syndrome may become manifest after restoration of sinus rhythm by ablation in patients with long-standing persistent atrial fibrillation (AF). The purpose of this study was to investigate the association between the preprocedural ventricular rate during AF and sinus node function in patients with long-standing persistent AF. METHODS: Consecutive patients (n = 102) who underwent ablation for long-standing persistent AF were enrolled. We measured the ventricular rate during AF before ablation in the absence of antiarrhythmic drugs. Sinus node function was assessed by electrophysiological study and serial Holter recordings after ablation. RESULTS: Patients in the lowest quartile of ventricular rate during AF had longer corrected sinus node recovery time (1.06 ± 1.39 seconds) than those in the other quartiles (0.54 ± 0.31 seconds; P = 0.006) and lower mean heart rate on 24-hour Holter recording 3 months after ablation (68 ± 9 beats/min vs 75 ± 10 beats/min, P = 0.01). During a mean follow-up of 23 ± 10 months, sick sinus syndrome necessitating permanent pacemaker implantation developed in five (5%) patients, and multivariate analysis revealed that a low ventricular rate during AF rate was an independent risk factor for sick sinus syndrome (odds ratio = 0.90 for a 1 beat/min increase in AF rate, P = 0.04). CONCLUSIONS: A low preprocedural ventricular rate during AF indicates the existence of sinus node dysfunction after restoration of sinus rhythm by ablation in patients with long-standing persistent AF.