[Clinical benefit in cardiac resynchronization]

Despite the improvement in pharmacologic treatment of heart failure, many patients continue to have severe persistent symptoms, and their prognosis remains poor. One of the most recent advances in heart failure management is the concept of cardiac resynchronization therapy (CRT). Large clinical trials have demonstrated morbidity and mortality benefits of CRT in patients with moderate to severe drug refractory heart failure (New York Heart Association [NYHA] functional class III or IV), and ejection fraction < or = 35% with QRS duration > or = 120 ms.