Initial Presentation of an Accessory Left Ventricle in a Patient With Syncope

A 39-year-old woman was referred for a transthoracic echocardiogram after presenting to her primary care provider following an episode of unexplained loss of consciousness. Her past medical history was notable for fibromyalgia and migraine headaches. She had a normal cardiac and neurological physical examination with no extra heart sounds or murmurs. Her transthoracic echocardiogram (Movie I of the online-only Data Supplement) revealed a large outpouching of the lateral wall of the left ventricle (LV) that contracted in synchrony with the ventricle (Figure 1A and 1B). The initial differential for this finding included an LV diverticulum or an accessory ventricle. An LV pseudoaneurysm was considered unlikely because of the synchronous contraction of the outpouching with the rest of the ventricle. Figure 1. Transthoracic echocardiogram demonstrating the apical 4-chamber view of the LV. The outpouching (arrow) originating from the lateral aspect of the midventricular wall is shown in both diastole (A) and systole (B). The outpouching contracted synchronously with the LV. To further evaluate this …