Interatrial Conduction Block in an Obstructive Sleep Apnea Patient

Abstract

Obstructive sleep apnea (OSA) is an important sleep disorder and is associated with increased cardiovascular morbidity and mortality. Several recent studies have demonstrated an association OSA and atrial fibrillation (AF). Therefore, it is of great importance understanding the pathophysiological substrate and the interaction between OSA and AF. Moreover, it is well accepted that interatrial block (IAB), evaluated not only by the P-wave duration but also by the P-wave morphology, has the potential to give information about the anatomical substrate predisposing to AF. OSA and AF share many risk factors and comorbidities, including older age, male gender, obesity, hypertension, heart failure, and coronary artery diseases. IAB is defined when the P-wave is ≥120 ms which signifies excessive time for sinus impulses to conduct from the right atrium to the left atrium and may predict future AF events. Accordingly, recent studies have suggested that OSA is associated with atrial functional and structural remodeling which indeed are associated with increased risk of AF. We speculate that IAB, a known factor to predict future AF episodes, may associate with OSA and contribute to the development of arrhythmic events. In the present case, the report presents a woman with OSA and IAB on the surface electrocardiogram (ECG)automatic P-wave analysis and some short episodes of AF in the external event recorder monitoring.

Interatrial Block, Bayés Syndrome, Left Atrial Enlargement, and Atrial Failure

“…IAB, particularly advanced IAB, is a strong predictor of AF. This association has been demonstrated in several clinical scenarios including heart failure, ischemic heart disease, Takotsubo syndrome, transcatheter aortic valve implantation, cardiac amyloidosis, sleep apnea, cavotricuspid isthmus and pulmonary vein ablation, and following electrical/pharmacological cardioversion [32][33][34][35][36][37][38]. However, the predictive power of IAB appears to be lower in other situations, such as severe chronic kidney disease [39].…”