Impact of Baseline Right Bundle Branch Block on Outcomes after Pulmonary Vein Isolation in Patients with Atrial Fibrillation.
Right bundle branch block (RBBB) is one of the most frequent alterations of the electrocardiogram. Several studies have shown that RBBB is a risk factor of cardiovascular diseases. However, the clinical outcomes after pulmonary vein isolation (PVI) in patients with RBBB remain unclear. We enrolled consecutive atrial fibrillation (AF) patients who underwent PVI from the Osaka Rosai Atrial Fibrillation (ORAF) registry. We excluded patients with other wide QRS morphologies (left bundle branch block, ventricular pacing, and unclassified intraventricular conduction disturbances) and divided them into two groups: RBBB (QRS duration ≥120msec) and No-RBBB (QRS duration <120) groups. We compared the incidence of late recurrence of AF/atrial tachycardia (AT) (LRAF) between the two groups using a propensity score-matched analysis and evaluated the risk of LRAF using Cox regression model. We finally analyzed 671 consecutive AF patients. The RBBB group consisted of 50 patients (7.5%) and the No-RBBB group of 621 patients. Median follow-up duration was 734 [496, 1049] days. Hypertension and diabetes mellitus were significantly higher in RBBB group than No-RBBB group. Among the 46 matched patients pairs, Kaplan-Meier analysis demonstrated that RBBB group had a significantly greater risk of LRAF than the No-RBBB group (p=0.046). The Cox regression model revealed significantly higher risks of LRAF (HR, 2.30; 95% CI, 1.00-5.33; p=0.044) in RBBB group compared to No-RBBB group. Non-PV AF triggers were significantly higher in RBBB group than No-RBBB group (p=0.048). In conclusion, RBBB can be an important predictor of LRAF after PVI.