[Cardiac resynchronization therapy].

Fifteen years after the birth of resynchronization therapy, this technique has become one of the recommended treatments in severe heart failure patients, with low ejection fraction (4 35%), and conduction disorders (ORS > or = 120 ms). Based on large randomized clinical trials, the European recommendation is class I type (level of evidence A), to improve symptoms and survival of this patient population. Recommendations have been extended to patients already implanted with a conventional pacemaker, and to those with chronic atrial fibrillation. Recent results