[The implantable cardiac defibrillator: indications and complications].

The implantation of an implantable cardiac defibrillator (ICD) is indicated as a secondary prevention measure for sudden cardiac death in patients surviving a life-threatening ventricular arrhythmia that had no reversible or treatable cause. An ICD is indicated as a primary prevention measure for sudden cardiac death in patients with a left-ventricular ejection fraction (LVEF) ≤ 35%. A biventricular ICD is indicated in patients with heart failure class ≥ II according to the New York Heart Association classification, a widened QRS complex and an LVEF ≤ 35%. Guidelines do not differentiate between men and women or according to age, but there is no evidence in the literature for decreased mortality from applying ICD therapy in women and in patients older than 70-75 years. This is relevant in discussions over the cost-effectiveness of the treatment. Sudden cardiac death occurs most frequently in patients with an LVEF ≥ 35%; the effect of ICDs as a primary prevention measure in this patient group has, however, never been investigated. The most important complications following ICD implantation are inappropriate ICD shocks and lead dysfunction. Automated home-monitoring enables early detection of technical defects.