Abstract
A 54-year-old male with a history of unrepaired ventricular septal defect (VSD) suffered from easy fatigability on exertion. A Levine grade V/VI continuous murmur was auscultated. Transthoracic echocardiogram showed a ruptured sinus of Valsalva aneurysm (SVA) and a significant left-to-right shunting from the ascending aorta to the right ventricle (RV). In addition, a 36 mmHg of pressure gradient was observed between the inflow and outflow tract in the RV, suggesting double-chambered RV (DCRV). Cardiac catheterization also revealed 33 mmHg of the pressure gradient in the mid-potion of the RV, which was coincident with DCRV. A calculated pulmonary-to-systemic flow ratio was 3.0. Therefore, the patient was offered surgical repair of the ruptured SVA and VSD, which was successfully performed. During the surgery, an anomalous muscle band, which is usually the cause of DCRV, was not found, instead, a thickened RV free-wall due to the exposure of the left-to-right shunt flow, so-named jet lesion, was found. Therefore, surgical resection of the anomalous muscle band was not required. The protruded SVA toward the RV, the jet lesion, and the increased RV stroke volume, which could induce relative stenosis, were the causes of the unusual DCRV. .