Interatrial Block Predicts Atrial Fibrillation and Total Mortality in Patients with Cardiac Resynchronization Therapy

Abstract

Interatrial block (IAB) and abnormal P-wave terminal force in lead V 1 (PTFV 1) are electrocardiographic (ECG) abnormalities that have been shown to be associated with new-onset atrial fibrillation (AF) and death. However, their prognostic importance has not been proven in cardiac resynchronization therapy (CRT) recipients. Objective: To assess if IAB and abnormal PTFV 1 are associated with new-onset AF or death in CRT recipients. Methods: CRT recipients with sinus rhythm ECG at CRT implantation and no AF history were included (n = 210). Automated analysis of P-wave duration (PWD) and morphology classified patients as having either no IAB (PWD <120 ms), partial IAB (pIAB: PWD ≥120 ms, positive P waves in leads II and aVF), or advanced IAB (aIAB: PWD ≥120 ms and biphasic or negative P wave in leads II or aVF). PTFV 1 0.04 mm•s was considered abnormal. Adjusted Cox regression analyses were performed to assess the impact of IAB and abnormal PTFV 1 on the primary endpoint new-onset AF, death, or heart transplant (HTx) and the secondary endpoint death or HTx at 5 years of follow-up. Results: IAB was found in 45% of all patients and independently predicted the primary endpoint with HR 1.9 (95% CI 1.2-2.9, p = 0.004) and the secondary endpoint with HR 2.1 (95% CI 1.2-3.4, p = 0.006). Abnormal PTFV 1 was not associated with the endpoints. Conclusions: IAB is associated with new-onset AF and death in CRT recipients and may be helpful in the risk stratification in the context of heart failure management. Abnormal PTFV 1 did not demonstrate any prognostic value.