Comparison of the Extent of Coronary Artery Disease in Patients With Versus Without Interatrial Block and Implications for New-Onset Atrial Fibrillation.

Interatrial block (IAB) represents delay or block of conduction between the atria. IAB has been shown to predict the development or recurrence of atrial fibrillation (AF) in various clinical scenarios. Few studies have examined the correlation between coronary artery disease and the prevalence of IAB and its impact on AF. The aim of this study was to determine if specific coronary artery lesions (location and number) are associated with the presence of IAB and development of new-onset AF. Retrospective analysis of patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI) to our institution. Data were recorded for clinical, echocardiographic, angiographic, electrocardiographic, and outcome variables. Semiautomatic calipers and scanned electrocardiograms at 300 DPI maximized × 8 were used to measure P-wave duration, with a follow-up for a minimum of 1 year. The chi-square and independent-sample t tests were done using IBM SPSS. A total of 322 patients were included in the analysis. Men 72.3%, mean age 65.4 ± 11.9 years, mean ejection fraction of 55.2 ± 12.7% and mean left atrial diameter of 38.7 ± 6 mm. The prevalence of partial IAB was 31.9%, and advanced IAB was 6.5%. Patients with IAB were significantly older (<0.001) and had a greater prevalence of hypertension (0.014). The presence of diffuse coronary artery disease defined as >1 significant coronary artery lesion was associated with IAB (0.026). No specific coronary artery lesion location was found to be associated with IAB nor increased P-wave duration. Patients who developed AF during the follow-up had a significantly higher prevalence of IAB (p = 0.021) and also higher prevalence of diffuse coronary artery disease (p = 0.001). IAB is significantly associated with diffuse coronary artery disease in patients with NSTEMI. IAB is significantly associated with the development of new-onset AF within 12 months after NSTEMI.