Interatrial block as a predictor of embolic stroke.

Interatrial block (IAB), defined as a prolonged (>/=110 ms) P wave, is remarkably prevalent in general hospital populations and is associated with an enlarged, poorly contractile left atrium. The investigators sought to determine whether there is an increased incidence of IAB in patients with embolic strokes. Patients' medical records were reviewed for evidence of embolic cerebrovascular events and IAB. One hundred four patients were identified. In 61 patients in normal sinus rhythm, 49 (80%) had IAB. This was almost twice the prevalence of 2 previous studies (41% and 47%). Therefore, IAB may represent a new risk factor for stroke.