P3838Evaluation of echocardiographic determinants of interatrial block in patients with essential hypertension

Introduction Interatrial block (IAB), defined as a conduction delay between the right and left atrium, is manifested on the electrocardiogram as a prolonged P-wave duration. Large number of studies recently have been published regarding the prevalence of IAB and its associations with cardiovascular events. It has been previously reported that myocardial fibrosis may cause conduction delays in hypertensive patients. In this study, we aimed to investigate the echocardiographic determinants of IAB in patients with hypertension. Methods This study enrolled a total of 220 patients [male: 93 (42.3%), mean age: 61.8±7.8 years] with hypertension. Patients with atrial fibrillation were excluded. IAB was defined as P wave duration of ≥120 ms with or without presence of notching. Routinely obtained 12-lead electrocardiography recordings were examined, and patients were divided into two groups as those with and without IAB. All patients were evaluated by transthoracic echocardiography. Results Electrocardiography revealed IAB in 70 patients. The baseline demographic characteristics of the patients with and without IAB were similar in both groups. Left atrial diameter (LAD), interventricular septal thickness, posterior wall thickness, left ventricular mass, left ventricular mass index, and the prevalence of left ventricular hypertrophy (LVH) were found to be significantly increased in hypertensive patients with IAB. Increased LAD (OR=1.082; 95% CI: 1.006–1.164; p=0.034) and LVH (OR=3.051; 95% CI: 1.164–7.994; p=0.023) were found to be independent predictors of IAB. In the receiver operating characteristic curve analyses, LAD values above 38 mm predicted IAB with a sensitivity of 68%, and a specificity of 58% (AUC= 0.678; 95% CI: 0.601–0.754; p<0.001). Conclusion A significant association exists between the presence of IAB and echocardiographic parameters related to left ventricular hypertrophy and left atrial dilatation in patients with essential hypertension. The presence of IAB may be used as an electrocardiographic marker of cardiac remodelling and myocardial fibrosis in hypertensive patients.