Double-Chambered Left Ventricle: Unusual Presentation with an Apical Defect in a Thallium Scan in a Middle-Aged, Asymptomatic Woman.

A left ventricular apical filling defect was found in a whole-body thallium scan performed for routine follow-up for surgically cured thyroid cancer in a 51-year-old woman. She had no cardiovascular symptoms, and her electrocardiogram at rest and during exercise was unremarkable. Transthoracic and transesophageal echocardiography revealed a double-chambered left ventricle. A prominent fibromuscular ridge distal to the papillary muscles was seen dividing the left ventricular cavity into a small apical portion and a large basal portion. There was no significant intraventricular gradient. No treatment was necessary, and the patient has remained asymptomatic in a 4-year follow-up.