Acquired left ventricle-to-right atrium shunt: clinical implications and diagnostic dilemmas

The acquired left ventricle-to-right atrium (LV-RA) shunt (Gerbode defect) is rare but it can sometimes be a critical condition. The diagnosis is quite challenging largely due to its exotic anatomic features and diagnostic difficulties. This study aims to present the clinical features and diagnostic solutions of this rare lesion.

Data source was based on a comprehensive literature retrieval of acquired LV-RA shunts of 1990–2014.

Most of the acquired LV-RA shunts are of either a postoperative or an infective etiology. Transthoracic echocardiography showed a 62.2 % accurate diagnosis, 13.4 % inclusive diagnosis, 9.8 % missed diagnosis, and 14.5 % misdiagnosis rate. The accurate diagnostic rate of transthoracic echocardiography was significantly lower than that of the transesophageal echocardiography or cardiac catheterization. The LV-RA shunts are often misinterpreted as mitral regurgitation, pulmonary hypertension, tricuspid regurgitation, Valsalva aneurysm rupture, and subaortic/high perimembrane/residual ventricular septal defect. Surgical, interventional, and conservative treatments were applied in 57.8, 24.4, and 17.8 % patients, respectively. Prognosis showed an event-free survival of 85 %, a comorbidity of 9.1 %, and a mortality of 13.6 %.

A high jet detected in the right atrium with uncertain origin and course has to appeal to additional diagnostic techniques including transesophageal echocardiography, cardiac catheterization, or cardiac magnetic resonance imaging for differential diagnoses. Small restrictive shunts are preferred with conservative treatments, high-risk patients are candidates of interventional therapy, and the patients with unstable hemodynamics warrant an open heart surgery. Careful operative maneuver, good control of intracardiac infection, preservation of heart function, etc., are mandatory for the prevention of the development of an acquired LV-RA shunt.