A cause of a murmur: an internal mammary arterio-venous fistula

A 73-year old lady underwent investigations into a continuous murmur 8 years after she had undergone aortic valve replacement for severe aortic stenosis. The subsequent cardiac computed tom-ography demonstrated an internal mammary arterio-venous fistula (Fig. 1). In this case, we postulate that a sternotomy wire has resulted in fistula formation. Figure 1: Branches of the internal mammary artery and vein joining to form a fistula around the insertion point of the median sternotomy wire.