SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
A 64-year-old male with prior aortic valve endocarditis and mild aortic regurgitation, treated with a standard antibiotic course was found to have a new murmur on physical exam. He reported being physically active and denied any cardiac or respiratory symptoms. Echocardiogram showed a probable ventricular septal defect and he was referred for further management.
Diagnostic Techniques and Their Most Important Findings:
Echocardiogram: Transthoracic echocardiogram demonstrated normal biventricular cavity size (LEVDD 5.4 cm, LVESD 3.6 cm) and systolic function (left ventricular ejection fraction 60%). A membranous ventricular septal defect was suspected based on Doppler and color flow data. Due to poor echocardiographic windows, cardiac magnetic resonance (CMR) was ordered to better delineate this finding and to quantify the degree of shunting.
CMR: First pass perfusion imaging demonstrated an intra-cardiac shunt between the left ventricle (LV) and right atrium (RA) with the defect measuring 5 mm. Cine imaging using steady-state free precession confirmed this finding. The ventricles were normal in size and function. (LVEDVI 84 ml/m2, RVEDVI 80 ml/m2, LA area 26 cm2, RA 24cm2. Qp:Qs was calculated at 1.4. Given the small size of the defect and no significant hemodynamic sequelae, the patient was managed conservatively. Subsequent CMR performed four months later showed four chamber dilatation (LVEDVI 104 ml/m2, RVEDVI 115 ml/m2, LA area 30 cm2 and RA 31 cm2) and increased shunt fraction (Qp:Qs=1.7). The patient was subsequently referred for surgical closure of this defect.
Learning Points from this Case:
An acquired Gerbode defect is a rare, but important intracardiac anomaly that has been previously described in the setting of endocarditis, trauma and aortic valve/root surgery. Typically an LV-RA shunt leads to four chamber dilatation, which is unique to this shunt lesion. While most cases require intervention, small defects without hemodynamic consequences can be observed. Multiple cine images demonstrate flow across the membranous portion of the interventricular septum extending into the RA.The role of CMR in shunt lesions and congenital heart disease has expanded immensely over the last decade with its superb ability to reveal complex anatomy and physiology. In the present case, as compared to echocardiography, CMR demonstrated its superiority in delineating the defect as well as providing hemodynamic consequences of this shunt. Our case demonstrates the effectiveness of CMR in portraying this rare intracardiac defect, as well as an enhanced ability to impact patient care by accurately quantifying the degree of shunting and ventricular volumes, thus leading to timely therapeutic intervention.