High-Output Heart Failure due to a Giant Left Circumflex Coronary Aneurysm with a Left Atrial Fistula and Atrial Septal Defect: A Case Report

A coronary artery aneurysm is a rare cardiac anomaly that may be incidentally detected on echocardiography. When associated with a coronary cameral fistula, an aneurysm can become symptomatic. We present a unique case of a giant left circumflex coronary aneurysm with a fistula to the left atrium and a large atrial septal defect causing acute heart failure in a young woman during the peripartum period. A 33 year-old woman who presented with hypoxia after the delivery of her fourth child was found to have heart failure with severe mitral regurgitation and multiple abnormal intracardiac shunts. Echocardiography showed a large circular structure with Doppler color flow into the left atrium and between the atria. Cardiac computed tomography showed multiple dilated coronary arteries including a left circumflex coronary artery aneurysm measuring greater than 10 cm in diameter with fistulous communication to the left atrium and a large atrial septal defect. A right heart catheterization was performed and the patient was diagnosed with high-output heart failure. Surgical closure of the coronary cameral fistula was deferred due to risk of worsening pressure in the coronary aneurysm and the patient was referred for cardiac transplantation. This case illustrates severe heart failure as a complication of a giant coronary artery aneurysm with fistulization to the left atrium and subsequent shunting through a large atrial defect. Echocardiography allows for detection of a coronary aneurysm and shunting and cardiac computed tomography provides detailed visualization of a coronary cameral fistula.