An echolucent structure on the anterolateral wall of the right atrium

Abstract

To the Editor,A 34-year-old patient was diagnosed with mitral regur-gitation (MR) on routine examination. A transthoracicechocardiogram revealed a bileaflet prolapse, moderatelysevere regurgitation (regurgitant fraction 39%), a dilatedleft ventricle (left ventricular end-diastolic diameter =6.9 cm), and impaired left ventricle (LV) systolic functionwith an ejection fraction (EF) of 56% (in context of MR).As part of his participation in a clinical trial, the patientalso received a magnetic resonance imaging (MRI) scanwhich confirmed significant LV dilatation and the presenceof systolic dysfunction. Based on these findings, mitralvalve surgery was planned.An intraoperative transesophageal echocardiography(TEE) revealed an unusual echo on the anterolateral surfaceof the right atrium which, after the pericardium was opened,was confirmed as being a dilated right coronary artery(RCA) (Fig. 1). In addition, a large leash of blood vesselswas found on the right ventricle. Due to the presence of thethrill of a pansystolic murmur, it was impossible to delineateif a fistula was associated with the dilated RCA. However,there was excessive blood return in the surgical field (evenwith caval snares in place), suggesting the presence of afistula. After an attempted repair failed, the mitral valve wasreplaced with a mechanical valve and an annuloplasty ring.The patient was successfully weaned from cardiopulmonarybypass and he recovered uneventfully. On follow up, thepatient remains well, but he continues to have a soft con-tinuous murmur most likely due to a fistula.The related TEE and clinical findings of this case pre-sented an interesting diagnostic and management dilemma.The diagnosis of the echolucent structure was apparentfrom direct inspection of the surgical field, but the presenceor absence of a large fistula could not be established byechocardiography. After careful consideration and discus-sion, the surgeons decided not to explore the lesion furtherin the absence of volume overload of the right ventricle. Aretrospective examination of the MRI revealed a dilatedRCA (Fig. 2) that had been overlooked in the initial report.Had this been known at the time, a coronary angiogramwould have been performed based on the associationbetween the ectasia of the coronary arteries and the pres-ence of a fistula.Mitral valve prolapse, coronary artery ectasia, andcoronary artery fistulae (CAF) occur in 2–3%, 0.3–5.3%,and 0.08–0.3% of patients, respectively. Coronary arteryfistulae are rare and mostly congenital in origin. Theygenerally represent an incidental finding on coronaryangiography, and their diagnosis is described as ‘‘ClassII- Relevant’’ based on the classification of coronaryartery anomalies in adults.