Cardiac resynchronisation therapy ( CRT ), a standard care for heart failure patients with wide QRS durations, offered no benefit for patients with a narrow QRS duration of less than 130 ms in the investigator-initiated EchoCRT study. The trial, which was stopped early after the first pre-planned analysis showed futility with the potential for harm, found that CRT may increase mortality among these patients.

The study was published in the New England Journal of Medicine ( NEJM ).

Current guidelines strongly recommend CRT in patients in sinus rhythm with symptoms that persist despite tailored medical treatment, a low left ventricular ejection fraction, and a wide QRS complex. Benefit appears to be greatest in patients with the most prolonged QRS duration and left bundle-branch block. Many patients with heart failure, however, have QRS durations of less than 120 ms, and CRT is not currently recommended.

The Echocardiography Guided Cardiac Resynchronization Therapy ( EchoCRT ) study set out to assess the impact of CRT on morbidity and mortality among patients with narrow QRS complexes. In the study 809 patients with NYHA class III or IV heart failure, left ventricular ejection fractions of 35% or less, were randomised 1:1 to CRT ( n=404 ) or control ( n=405 ), with the device turned off in the control group. Patients were enrolled from 115 Centres in the US, Canada, Australia and Europe.

Results showed at a mean follow-up of 19.4 months the primary outcome ( a combination of death from any cause or first hospitalisation for worsening heart failure ) occurred in 28.7% of patients in the CRT group and 25.2% in the control group. Additionally, 11.1% of patients died in the CRT group vs 6.4% in the control group, with cardiovascular mortality in 9.2% of CRT patients and 4.2% in the control group. A subgroup analysis found no signal’ for any benefit of CRT. ( Xagena )

Source: European Society of Cardiology ( ESC ) Congress, 2013

XagenaMedicine2013