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BookmarkScienceDaily (June 26, 2007) — The University of Zurich announces today an investigator initiated large-scale prospective randomized controlled clinical trial to assess the clinical impact of Cardiac Resynchronization Therapy (CRT) in heart failure patients.
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The worldwide study, called "Echocardiography guided Cardiac Resynchronization Therapy (EchoCRT)", is the first prospective randomized clinical trial to evaluate the impact of cardiac resynchronization therapy in patients with advanced heart failure (NYHA Class III) and a narrow QRS complex who show mechanical dyssynchrony as assessed by echocardiography.
"It is established that CRT provides clinical benefit for heart failure patients with wide QRS," said Johannes Holzmeister, MD, University of Zurich, and co-principal investigator of the study. "Now it is imperative that we understand the effects of CRT in patients with narrow QRS complex (<120 ms) of whom more than 30% exhibit echocardiography evidence of dyssynchrony".
"As the majority of heart failure patients present with narrow QRS complex but still suffer from the clinical consequences of dyssynchrony, this trial could potentially expand therapeutic options for a patient population in need", said Frank Ruschitzka, MD, University of Zurich, and co-principal investigator of the study. "We expect the results of EchoCRT to pave the way to better outcomes."
More than 1000 patients with advanced heart failure (NYHA class III) will be randomized to CRT or no CRT and patients in both study arms will receive an implantable cardioverter-defibrillator (ICD) backup to protect against sudden cardiac death. The primary objective of the study is to determine whether CRT will reduce the combined endpoint of all-cause mortality or hospitalization for cardiovascular events.
Heart Failure and Ventricular Dyssynchrony -- Implications and Therapy Approaches
Heart failure (HF), with its high morbidity and mortality, remains a major unresolved public health problem worldwide. HF affects nearly 5 million people in the United States, 6 million people in Europe and more than 22 million people worldwide, claiming more than 1.5 million lives annually. In many heart failure patients, the clinical condition and outcome is worsened by poor coordination of the heart chambers in squeezing blood (known as ventricular dyssynchrony) leading to inefficient function of the heart as a pump.
This can be helped by a device therapy called CRT. CRT has been proven effective as an adjunct to drug therapies in patients with advanced heart failure and dyssynchrony indirectly assessed by changes in the electrocardiogram or ECG, specifically a wide QRS duration of more than 120 msec. In contrast, an ultrasound of the heart or echocardiogram provides a direct measure of ventricular dyssynchrony and may be particularly helpful in identifying patients without indirect evidence for dyssynchrony (narrow QRS patients) as candidates for CRT. EchoCRT is novel in that it will for the first time select patients who show dyssynchrony directly assessed by echocardiography, but not by ECG.
EchoCRT is governed by an Executive Committee.
Josep Brugada, MD, Department of Cardiology, Thorax Institute, Hospital Clínic, University of Barcelona, Spain and Executive Committee member said, "So far, patients with heart failure and a narrow QRS complex can not benefit from cardiac resynchronization therapy because so far no evidence has been provided. This study will explore whether these patients might also benefit from CRT."
Henry Krum, MD, Professor of medicine, Monash University, Melbourne and Executive Committee member said, "Positive trial results would add significant validity to the combination of device based therapies with drug regimens in the treatment of heart failure."
