• Cardiology Clinical Trials
• Heart Failure
• Imaging Modalities

• Cardiology Clinical Trials
• Cardiology & Cardiovascular Medicine
• Heart Failure
• Imaging Modalities

The current 2012 European Society of Cardiology Guidelines for the diagnosis and treatment of acute and chronic heart failure (HF) recommend cardiac resynchronization therapy (CRT) for symptomatic HF and a QRS complex ≥120 msec [McMurray JJV et al. Eur Heart J 2012]. Although CRT is not currently recommended for HF patients with a QRS complex <120 msec, many such patients have evidence of mechanical dyssynchrony by echocardiography.

The Echocardiography Guided Cardiac Resynchronization Therapy study [EchoCRT; Ruschitzka Fetal. N Engl J Med 2013] was a prospective, multicenter, randomized, clinical trial designed to evaluate the effect of CRT on morbidity and mortality in patients with symptomatic HF, a QRS complex <130 msec, and evidence of mechanical dyssynchrony. On March 13, 2013, the trial was stopped for futility at the recommendation of the Data and Safety Monitoring Board. The results of the trial were presented by Johannes Holzmeister, MD, University of Zurich, Zurich, Switzerland.

At enrollment, patients had NYHA Class III to IV HF, stable pharmacologic therapy, left-ventricular systolic dysfunction and dilation (ejection fraction ≤35%; left-ventricular end diastolic diameter ≥55 mm), QRS <130 msec, and ventricular dyssynchrony by tissue Doppler imaging and speckle-tracking radial strain on echocardiography. Of the 855 eligible patients, 809 had a successful implantation with a Lumax HF-T CRT-D device and underwent randomization [CRT turned “on” group (n=404); CRT turned “off” group (n=405)].

The primary efficacy endpoint was all-cause mortality or first hospitalization for worsening HF. The primary safety endpoint was freedom from complications due to the CRT-D system at 6 months. Baseline characteristics were similar in both groups, with the exception of chronic kidney disease, which was more common in the CRT group. Utilization of standard HF therapies was very high in both groups (angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker 95%, β-blocker 96% to 98%, and aldosterone antagonist 59% to 60%).

The study terminated at a median follow-up of 19.4 months. The primary efficacy endpoint occurred in 28.7% of patients in the CRT group and 25.2% of patients in the control group (HR, 1.20; 95% CI, 0.92 to 1.57; p=0.15; Table 1). Secondary efficacy endpoints including all-cause mortality (Table 2), cardiovascular mortality, and hospitalization for worsening HF occurred more frequently in the CRT group. It is important to interpret the secondary outcomes with caution, especially in the context of the early termination of the trial.

The rate of freedom from complications related to the CRT-D system at 6 months was 89.6% for all patients who underwent attempted device implantation. Total serious adverse events (939 vs 732) and CRT-D-system related events (74 vs 32) were higher in the CRT arm.

The results of EchoCRT study confirm that patients with a narrow QRS complex should not receive CRT. Even following current guidelines (QRS ≥120 msec), the rate of “nonresponders” to CRT is very high and further research is needed to better identify those patients with moderate QRS widening (120 and 150 msec) who are most likely to benefit.

• © 2013 MD Conference Express®