No abstract

A 62 year old man was referred to hospital as an emergency with a three week history of worsening dyspnoea and orthopnoea. His general practitioner had previously noted a late systolic murmur, and a transthoracic echocardiogram performed seven months previously had shown prolapse of the posterior mitral valve leaflet with moderate mitral regurgitation.Examination on admission showed a regular tachycardia of 150 beats per minute with a systemic blood pressure of 140/90 mm Hg. His apex beat was hyperdynamic and displaced laterally toward the anterior axillary line. At auscultation a loud, apical, pansystolic murmur with an associated thrill was heard. There were fine crepitations at both lung bases but no signs of right ventricular failure. An electrocardiogram revealed atrial flutter with 2 to 1 atrioventricular block, and on chest x ray there was cardiomegaly and evidence of pulmonary venous congestion. The patient was treated with intravenous frusemide to good effect and the atrial flutter, which did not respond to initial treatment with intravenous amiodarone, was successfully DC cardioverted to sinus rhythm under general anaesthesia. Transthoracic echocardiography showed severe mitral regurgitation with evidence of acute chordal rupture of the mitral valve. Subsequent cardiac catheterisation confirmed grade IV mitral regurgitation but selective coronary angiography also showed a large, tortuous coronary artery fistula running between the left circumflex artery and the superior vena cava (fig 1). An oxygen saturation run showed a small saturation jump at the level of the high right atrium, indicating a left to right heart shunt (Qp/Qs 1 2: 1) at that level. The coronary arteries were otherwise normal. Left ventricular end diastolic pressure was 18 mm Hg, pulmonary artery pressure was 42/20 mm Hg, and mean pulmonary artery wedge pressure was 17 mm Hg (v wave of 30 mm Hg).The patient was referred for surgery and operative findings confirmed the diagnosis of chordal rupture of the posterior mitral valve leaflet. The valve was repaired using a quadrangular resection of the posterior leaflet, apposition of the leaflet edges, and an annuloplasty with a size 34 Carpentier ring. Examination of the fistula showed a large vessel arising from the circumflex system, traversing across the roof of the left atrium, and entering the superior vena cava at its junction with the right atrium. The fistula was initially ligated securely and divided at its distal junction with the superior vena cava. Perioperative transoesophageal echocardiography (TOE) confirmed a satisfactory mitral valve repair but also showed persistent flow through the fistula (fig 2). Further proximal ligation of the fistula was performed closer to the circumflex system after which TOE confirmed that flow in the fistula had been abolished. Postoperatively the patient made an uncomplicated recovery.Coronary artery fistulas are rare, with an incidence of 0-2% in one large angiographic series.' Such fistulas arise in about equal proportions from the right and le...