Efficacy of CRT shown in mild-moderate heart failure

Cardiac-resynchronisation therapy (CRT) benefits patients with severe (NYHA III or IV) symptoms of left ventricular systolic dysfunction and a wide QRS complex, reducing both mortality and morbidity, and is often combined with implantable cardioverter-defibrillator (ICD) therapy. Many patients with milder degrees of heart failure (NYHA II or III) are candidates for ICDs but it is unclear whether the addition of CRT in this group would lead to any additional benefits.

In the multi-centre, prospective Resynchronisation–Defibrillation for Ambulatory Heart Failure Trial the authors randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more, or a paced QRS duration of 200 msec or more to receive either an ICD alone or an ICD plus CRT in addition to optimal medical therapy. The primary outcome was death from any cause or hospitalisation for heart failure. One thousand seven hundred and nighty-eight patients were followed for a mean of 40 months. The primary outcome occurred in 297 of 894 patients (33.2%) in the ICD-CRT group and 364 of 904 patients (40.3%) in the ICD group (HR in the ICD-CRT group, 0.75; 95% CI 0.64 to 0.87; p<0.001). In the ICD-CRT group, 186 patients died, as compared with 236 in the ICD group (HR, 0.75; 95% CI 0.62 to 0.91; p=0.003), and 174 patients were hospitalised for heart failure, as compared with 236 in the ICD group (HR, 0.68; 95% CI 0.56 to 0.83; p<0.001). However, at 30 days after device implantation, adverse events had occurred in 124 patients in the ICD-CRT group, as compared with 58 in the ICD group (p<0.001) driven mainly by lead dislodgements requiring reintervention in the CRT group. In sub-group analysis, there appeared to be no difference in benefit between patients in class II or III at baseline and, in concurrence with the results of the MADIT-CRT trial, patients with an intrinsic QRS duration of 150 msec or more appeared to benefit more from the addition of an ICD.

Conclusions

Among patients with NYHA class II or III heart failure, a wide QRS complex, and left ventricular systolic dysfunction, the addition of CRT to an ICD reduced rates of death and hospitalisation for heart failure. This trial hugely increases the indications for ICD-CRT.

▶ Tang AS, Wells GA, Talajic M, et al; the Resynchronization–Defibrillation for Ambulatory Heart Failure Trial (RAFT) Investigators. Cardiac-resynchronization therapy for mild-to-moderate heart failure. N Engl J Med 2010 Nov 14. [Epub ahead of print]

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