[Cardiac resynchronization therapy: who is suitable? Who requires an additional ICD as a backup?].

Cardiac resynchronization therapy (CRT) has significant positive effects on the quality of life, enables patients to cope more efficiently with cardiopulmonary stress and leads to a reduction of total mortality in patients suffering from congestive heart failure NYHA classes III and IV, reduced ventricular function and left bundle branch block with a QRS complex wider than 150 ms. In a large number of patients suited for CRT, an additional defibrillator function seems to work out well concerning an additional prognostic improvement by means of reducing sudden cardiac death. Due to partially contradictory study outcomes, it still remains to be discussed whether all patients suited for CRT really need an ICD.