Double-Chambered Left Ventricle: How Cardiac Magnetic Resonance Overturned the Diagnosis

Double-chambered left ventricle (DCLV) is a rare congenital heart anomaly and can be easily misdiagnosed with transthoracic echocardiography. Cardiac magnetic resonance (CMR) can help in the diagnostic process and risk stratification.

A 15-year-old girl diagnosed with left ventricular noncompaction and unsustained ventricular tachycardia was referred to our institution for further characterization. The CMR scan demonstrated instead a DCLV with normal ejection fraction and tissue characterization parameters within normal limits. The patient was started on bisoprolol, which was effective in reducing the arrhythmic burden, and she is currently under regular follow-up.

DCLV has been described only in anecdotal case reports since the first classification was published in 1981. In our case, a prominent paraseptal trabecula was the anatomical fingerprint, but it could not be properly identified with transthoracic echocardiography. CMR instead was pivotal in the diagnosis, which allowed us to properly identify the morphology of the left ventricle and provided tissue characterization, therefore refining arrhythmic risk stratification. In addition, it excluded other differential diagnosis such as ventricular septal defects.

This case highlights the importance of CMR in the diagnosis of rare congenital cardiac abnormalities, such as DCLV, especially when the echocardiographic window is suboptimal or unclear.