Interatrial block (IAB), recorded as a prolonged (> 110 msec) P wave, is remarkably prevalent in general hospital populations and is commonly associated with an enlarged, poorly contractile and multiply malfunctioning left atrium, which may predispose patients to blood stasis and thrombosis. Among patients considered to have an embolic stroke we investigated whether there is an increased incidence of IAB.
Patients’ medical records with the ICD codes 433, 434, 435, 436, 437 and 438 were reviewed between 01/2000 and 12/2001 for evidence of embolic cerebrovascular events. To qualify for our study the patient had to have a probable embolic cerebrovascular event diagnosed by a neurologist with or without imaging techniques, such as MRI or CT. Then, the ECGs of all patients so diagnosed were reviewed for presence of IAB and atrial fibrillation.
One hundred four patients qualified for our criteria for probable embolic cerebrovascular event (n = 82) and transient ischemic attack (n = 22). Forty- three patients had a history of atrial fibrillation or presented with newly diagnosed atrial fibrillation. In the remaining group, patients in normal sinus rhythm (61 patients), 49 (80%) had IAB on a recent ECG. This was almost twice the prevalence of two prior studies, where the prevalence of IAB was determined in all-comers in two general hospitals and shown to be 44%.
Among patients with a probable embolic cerebrovascular event IAB is almost twice as common as in the general population and may represent a new risk factor for stroke.
If IAB proves to be a risk factor for stroke, anticoagulation may need to be instituted in these patients.
M. Lorbar, None.