Cerebral Embolism Beyond Atrial Fibrillation: Interatrial Block

This paper is devoted to conditions that imply a risk for cerebral embolism beyond atrial fibrillation (AF). We focus on advanced interatrial block (IAB) and its relationship with stroke in elderly patients with no documented arrhythmias. Advanced IAB is manifested in the surface electrocardiogram (ECG) as a P-wave duration >120 ms plus biphasic morphology (positive and negative deflection) in leads II, III, and aVF. Several data suggest that AF is not necessarily the leading cause of stroke, but rather a risk factor. In fact, a high stroke risk has been described even in the absence of AF in patients with high CHA2DS2VASc-score (Congestive Heart failure, hypertension, Age ≥75 years [doubled], Diabetes, Stroke [doubled], Vascular disease, Age 65-74 years, Sex category [female sex]). Moreover, excessive atrial ectopy and short atrial runs also increase stroke risk. Some of the previously mentioned stroke risk factors in patients without documented arrhythmias might be combined to determine thrombotic risk. That risk is particularly high in elderly patients with advanced IAB, structural heart disease, CHA2DS2-VASc score ≥3, and frequent ambient atrial arrhythmias. Systematic screening for advanced IAB in elderly patients can be performed with a simple surface ECG. Advanced IAB is a risk marker of stroke.