Worldwide clinical trial of cardiac resynchronization therapy

The University of Zurich has announced an investigator initiated large-scale prospective randomized controlled clinical trial to assess the clinical impact of Cardiac Resynchronization Therapy (CRT) in heart failure patients.

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 supported financially by BIOTRONIK.

"BIOTRONIK is proud to be funding this important trial and to be part of the industry-leading efforts towards medical research and therapy development. This is the largest and highest priority clinical project for our company. With the introduction of the Home Monitoring technology six years ago BIOTRONIK changed the paradigms of the entire area of cardiac rhythm management. Now we set ourselves the goal to expand the indication for CRT in order to provide more patients the way to better therapy", said Dr. Werner Braun, Managing Director at BIOTRONIK GmbH & Co KG.