A 44-year-old man was referred for assessment of a suspected cardiac murmur. He was asymptomatic and had no significant past medical history (particularly no history of trauma or medical intervention).

On examination a continuous bruit was heard in the upper chest, loudest beneath the right clavicle. Electrocardiography and echocardiography were normal. Suspicion of an arteriovenous malformation led to further investigation by computed tomography angiography. This did not identify any abnormality. The patient wanted a definitive diagnosis and elected to have selective angiography. This confirmed an arteriovenous fistula arising from the right subclavian artery (figs 1 and 2). In the absence of any history of trauma or vascular instrumentation, this was likely to be congenital in origin. Following discussion between cardiologists, interventional radiologists, cardiothoracic and vascular surgeons it was agreed that no intervention would be advised to close the fistula, in the absence of symptoms or evidence that it was placing the patient at significant risk.

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Figure 1

Angiographic demonstration of the catheter tip engaged in the ostium of the right subclavian artery fistula, fistula filling and contrast run off into the right innominate vein, superior vena cava and right atrium.

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Figure 2

Illustration of findings shown in fig 1.

A subclavian arteriovenous fistula usually occurs as a complication of previous trauma, percutaneous catheterisation or surgery. In contrast, congenital fistulas are rare. They may be asymptomatic or present with intermittent pain in the upper limb due to ischaemia1 or nerve compression. Large fistulas may cause a systemic shunt of sufficient magnitude to cause heart failure. Treatment options are observation, surgical ligation or catheter embolisation.2 Congenital chest wall arteriovenous malformations present rare differential diagnosis of a suspected cardiac murmur. Selective angiography is frequently necessary to establish the diagnosis as non-invasive imaging often fails to identify this abnormality.