MEHAU KULYK / SCIENCE PHOTO LIBRARY MEHAU KULYK / SCIENCE PHOTO LIBRARY
Heart pacemaker. Coloured chest X-ray showing a surgically-implanted heart pacemaker (oval, upper left). The two lungs (large black areas) and the heart (pink, centre) are also seen. The pacemaker supplies electrical impulses along a lead (white) to the heart to keep it beating regularly. Pacemakers are fitted in patients with a malfunctioning sinoatrial node, the part of the heart which initiates each heartbeat, or a heart block impairing the nerve impulses generated by the node. Heart pacemakers may provide a regular impulse (fixed rate pacemaker) or discharge only when a heartbeat is missed (demand pacemaker).
Model release not required. Property release not required.