A 70-year-old male presented with groin pain and swelling 11 days following a pulmonary vein isolation procedure via an unguided femoral venous puncture for atrial fibrillation. On the fourth visit, his haemoglobin level had dropped from 14.2 gl-1 to 10.7g l-1. Repeat duplex imaging revealed a large haematoma with deep flow. A CT angiogram revealed a pseudoaneurysm of a right common femoral branch artery. A subsequent angiogram revealed active bleeding, and the feeding artery was coiled. Pseudoaneurysms are recognized complications of vascular intervention, but more commonly occur anteriorly in major vessels. This elusive presentation reminds us of several important points. First, with the increasing use of interventional techniques across all medical specialties, the use of image guidance to aid vessel access is paramount for safety; not all specialties currently practise this routinely. Furthermore, we should consider arterial injury in all patients, including those who have had venous puncture. Injuries may not necessarily occur at the anterior vessel wall, and may well be deeper. Finally, there should be a low threshold for alternative imaging if symptoms are out of context with clinical findings.