Implications of QRS Prolongation in Patients With Atrial Fibrillation (from a Multicenter Outpatient Registry)

Patients with atrial fibrillation (AF) at the highest risk of progression to heart failure (HF) need to be identified. We investigated whether QRS duration can stratify patients with AF at risk for poor clinical outcomes, including health-related quality of life (HR-QoL). We analyzed data from a multicenter registry-based cohort study of patients with AF. Patients were grouped according to the QRS duration (narrow: <120 ms; wide: ≥120 ms) at registration (baseline). The primary outcome was a composite of all-cause death and HF hospitalizations during a 2-year follow-up. In addition, the AF effect on the quality-of-life overall summary score was compared between the groups. In 3,269 patients, 302 (9.2%) had a wide QRS; these patients were more likely to be older, male, and have higher CHA₂DS₂-VASc scores than those with a narrow QRS. The incidence of the composite outcome was higher in patients with a wide QRS than those with a narrow QRS (13.1% vs 4.9%, p <0.001). After adjustment, a wide QRS was an independent predictor of the primary outcome (adjusted hazard ratio 1.58, 95% confidence interval 1.09 to 2.29, p = 0.016), and the results persisted after the exclusion of patients with bundle branch block or cardiac implantable electronic devices. Regarding HR-QoL outcomes, patients with a wide QRS were less likely to improve AF effect on quality-of-life overall summary scores at 1 year than those with a narrow QRS (adjusted difference -2.31, 95% confidence interval -4.06 to -0.57, p = 0.009). QRS prolongation, even for a nonspecific conduction disturbance, was an independent predictor of adverse outcomes and worse HR-QoL in patients with AF.