Atrioventricular fistula: an unusual complication of a ventricular pseudoaneurysm after myocardial infarction.

A 68 year old man was referred to the cardiology outpatient department for investigation of deteriorating angina control. Three years earlier he had sustained an inferoposterior myocardial infarction complicated only by a transient episode of hypotension and bradycardia. Clinical examination was unremarkable apart from the finding of a soft systolic murmur at the apex and axilla. Investigations included an ECG, which confirmed an old inferior infarction, and chest radiography, which showed a normal cardiac silhouette and lung fields. An exercise tolerance test was abnormal at a low cardiac workload. Transthoracic echocardiography suggested an inferoposterior false aneurysm with otherwise normal left ventricular function. An abnormal structure of uncertain cause was also noted within the left atrial cavity. Transoesophageal echocardiography (fig 1) confirmed the presence of both an inferoposterior false aneurysm and an unusual ring structure within the left atrium. The latter appeared to be an extension of the false aneurysm itself invaginating the posterior left atrial wall. Colour flow Doppler imaging (fig 2) suggested a fistulous communication between this structure and the true left atrial cavity. To confirm this suspicion cardiac catheterisation was performed. Left ventriculography (fig 3) again showed a large inferoposterior false aneurysm, which passed posterior to the left atrium and invaginated it. In ventricular systole, opacification and pulsatile expansion was noted of both Figure 1 Transoesophageal echocardiogram showing the ventricular pseudoaneurysm (pa) invaginating the left atrial cavity (la). LV, left ventricle.