Role of the Presence of Interatrial Block as a Prediction Pathway of Atrial Fibrillation During the Postoperative Period of Patients Undergoing Cardiac Surgery.

Background: Atrial fibrillation (AF) is the most frequently recorded arrhythmia in clinical practice, and its appearance conditions high risk of morbidity and mortality. The role of the interatrial block (IAB) as a predictor pathway of the development of AF in the postoperative period of patients undergoing cardiac surgery has been studied scantly.

Methods: Partial IAB was defined as the P wave >120 ms and advanced IAB as the P wave >120 ms with biphasic morphology in inferior leads. The presurgical electrocardiography was analyzed, and the frequency of AF onset in the postoperative period was determined. A comparative analysis was performed between the patients who presented AF and those who did not.

Results: A total of 94 patients were included, with a mean age of 61 ± 16 years. Of the total number of patients, 42 (45%) presented some degree of IAB (partial 42.8% and advanced 57.1%). There was a significant relationship between patients with IAB and those who developed AF postcardiac surgery (21.3%; P < 0.01). The presence of IAB had an area under the curve of 0.75 (95% confidence interval, 0.66-0.85) and demonstrated a specificity of 69%, a sensitivity of 83%, and a negative predictive value of 92% for predicting AF development.

Conclusions: IAB has a relatively frequent incidence in patients undergoing cardiac surgery. There was a significant association between the presence of IAB and the development of AF in the postoperative period. Our findings establish for the first time that IAB has high specificity, sensitivity, and negative predictive value for predicting AF development postcardiac surgery.