Terrorist attacks increased dangerous irregular heartbeats

The rate of life-threatening heart rhythms more than doubled among New York heart patients the month after the September 11, 2001 terrorist attacks, researchers have reported. The study evaluated patients with an implantable cardioverter-defibrillator (ICD). An ICD is an electrical generator the size of a pocket watch that is inserted into the heart to monitor heart rhythm. It detects life-threatening abnormal rhythms, called arrhythmias, and delivers an electrical shock to restore normal rhythm.