Reuters: Patients with heart rhythm disturbances who have an implantable heart defibrillator are particularly vulnerable to air pollution, a Swedish study indicates. In patients with these devices, known as implantable cardioverter defibrillators, or ICDs, exposure to air pollution may rapidly (within 2 hours) prompt ventricular arrhythmia — a potentially life-threatening condition in which the heart rhythm becomes irregular, the study shows. Previous studies have documented an …