Predictors of rhythm outcomes after cardiac resynchronization therapy in atrial fibrillation patients: When should we use an atrial lead?

BACKGROUND: Cardiac resynchronization therapy (CRT) is widely used in atrial fibrillation (AF) patients and could impact rhythm stability. HYPOTHESIS: We aimed to identify predictors of sinus rhythm (SR) stability or AF progression in a real-word cohort of CRT-AF patients. METHODS: From 330 consecutive implantable cardioverter-defibrillator implantations due to ischemic or dilated cardiomyopathy, 65 (20%) patients with AF history (paroxysmal, n = 32) underwent a CRT implantation with an atrial electrode and were regularly followed every 4-6 months. Rhythm restoration was attempted for most AF patients based on symptoms, biventricular pacing (BP), and lack of thrombi. RESULTS: After 33 months, 18 (28%) patients progressed to permanent mode switch (MS≥99%) and 20 (31%) patients had stable SR (MS < 1%). Logistic regression showed that history of persistent AF (OR: 8.01, 95%CI: 2.0-31.7, p = .003) is associated with higher risk of permanent MS. In persistent AF patients, a bigger left atrium (OR: 1.2 per mm, 95%CI: 1.03-1.4, p = .025) and older age (OR: 1.15 per life-year, 95%CI: 1.01-1.3, p = .032) were predictors of future permanent MS. Paroxysmal AF at implantation (OR: 5.96, 95%CI: 1.6-21.9, p = .007) and increased BP (OR: 1.4 per 1%, 95%CI: 1.05-1.89, p = .02) were associated with stable SR. In persistent AF patients, stable SR correlated with higher BP (98 ± 2 vs. 92 ± 8%, p < .001). CONCLUSION: In patients with AF undergoing CRT implantation, persistent AF, LA dilatation and advanced age relate to future permanent MS (AF), whereas high BP promotes SR stability. These findings could facilitate the management of CRT-AF patients and guide therapy in order to maximize its effect on rhythm.