Left coronary arteriovenous malformation with fistulous connections to the left and right ventricles

A 20-year-old man with right bundle branch block in recorded ECG was referred to our department. His physical examination was unremarkable. Transthoracic echocardiography showed a severe hypertrophy of the interventricular septum (22 mm) which contained multiple echo-free spaces of the vascular nature. A flow pattern suggestive to a coronary artery fistula into the left ventricle was recorded. The patient was referred for a coronary angiography, which revealed an arteriovenous malformation starting from the septal branch of the enlarged left anterior descending artery. The malformation communicated with the lumen of the left (arterial phase) and right ventricle (venous phase) as well. The posterior descending artery was fed exclusively from the described arteriovenous malformation. 99mTc MIBI SPECT images showed a moderately reversible perfusion defect in the inferior wall, suggesting non-critical ischemia of this region