Coronary angioplasty. View of a team of surgeons carrying out a coronary angioplasty operation. In the foreground a monitor displays the patient's electrocardiogram (ECG) readout. An ECG monitors the electrical activity of the heart. Coronary angioplasty is a minimally-invasive technique for clearing obstructions in the arteries that supply the heart. A thin balloon catheter is passed through a small incision in the groin & directed via a vein towards the obstructed coronary artery using real-time X-ray imaging. Once in position, the balloon is carefully inflated so as to compress the obstructing plaque and restore blood flow.