Pseudoaneurysms of the mitral-aortic intervalvular fibrosa are a well-described complication of aortic valve prosthetic endocarditis. Pseudoaneurysms in this location may be complicated by formation of fistulous tracts with adjacent structures. Herein we describe a case in which fistulous flow into the left atrium produced an eccentric jet on color flow Doppler imaging which masqueraded as severe mitral regurgitation.