Landmark BLOCK HF Trial Demonstrates Clinical Benefits of Biventricular Pacing in New Patient Population

Medtronic, Inc. has announced that the U.S. Food and Drug Administration (FDA) approved an expanded indication for biventricular (BiV) pacing with Medtronic cardiac resynchronization therapy-pacemakers and -defibrillators (CRT-P and CRT-D). Medtronic CRT devices are now approved to treat patients with atrioventricular (AV) block and left ventricular (LV) systolic dysfunction, reducing heart failure hospitalizations and mortality, and improving cardiac function in these patients.

The expanded indication allows patients designated as New York Heart Association (NYHA) Class I, II and III with AV block that are expected to require a high percentage of ventricular pacing, and who have an ejection fraction (measure of the heart's pumping ability) less than or equal to 50 percent, to receive BiV pacing via Medtronic CRT devices.

The FDA's approval was based on the landmark BLOCK HF clinical trial, which demonstrated significant clinical advantages of BiV pacing compared with traditional right ventricular (RV) pacing in this patient population, including a 27 percent relative risk reduction in the composite study endpoint of heart size, heart failure hospitalizations and mortality.

"For patients with AV block and LV dysfunction, traditional RV pacing may escalate the progression of heart failure," said Anne B. Curtis, M.D., BLOCK HF lead investigator and chair of the Department of Medicine at the University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, NY. "The BLOCK HF clinical trial provided strong clinical evidence validating the safety and efficacy of BiV pacing in this patient population."

More than 1 million Americans have AV block, which reduces the heart's ability to properly function by blocking the electrical signals between its top and bottom chambers. Symptoms of the condition are fainting, dizziness and shortness of breath. A debilitating and often deadly disease, heart failure will cost the United States an estimated $32 billion in 2013, with projections showing a 120 percent increase in cost by 2030 for a total of $70 billion.1

"Medtronic is pleased with the FDA's decision to expand the use of BiV pacing with Medtronic CRT-P and CRT-D devices in this new patient population," said David Steinhaus, M.D., vice president and general manager, Heart Failure, and medical director for the Cardiac Rhythm Disease Management business at Medtronic. "We have more than a decade of evidence showing that CRT improves quality of life for heart failure patients, and we now have also demonstrated improved outcomes for AV block patients with these devices, as well."

1 American Heart Association. Heart Disease and Stroke Statistics - 2013 Update. Circulation. Available at