Faulty design resulting in temporary pacemaker failure

A 77-year-old man became asystolic 3 days after aortic valve replacement and coronary artery bypass surgery. A dual-chamber temporary pacemaker generator was turned on but failed to discharge; instead, an obscure error message appeared on the liquid crystal display of the pacemaker. The intensive-care nurses and physicians were unable to activate the pacemaker. We describe the pacemaker design that led to this instance of pacemaker failure. This case is important because it illustrates how a medical equipment design flaw can turn a human error into a potentially catastrophic event.