Cardiac resynchronization therapy (CRT) with biventricular pacing has been FDA-approved for people with moderate or severe heart failure. But data from a new study reveal that it can also delay progression of the debilitating condition – opening the door for patients with early stage mild heart failure.

"It's already been proven to prolong life and reduce symptoms in heart failure patients," David Wilber, MD, a co-author of the MADIT-CRT study and director of the Cardiovascular Institute at Loyola University Chicago Stritch School of Medicine, told Medical Device Daily. "The issue is that instead of waiting until people get quite sick, giving them this treatment early on would prevent the severity of symptoms and delay the more severe symptoms from appearing."

The 1,820-patient study at 110 centers in the U.S., Canada and Europe, the results of which were reported at the European Society of Cardiology (Sophia Antipolis, France) annual meeting earlier this week in Barcelona (Medical Device Daily, Sept. 3, 2009), found that implanting biventricular pacemakers in these patients reduced the risk of serious heart failure events by 41%. But there was no data to prove that this earlier treatment had an effect on mortality.

"Regarding long term survival, the average file from this study is just two years and shows no difference in survival and that's no surprise," Wilber said. "Early stage heart failure mortality is only 1% to 2%, so these patients will need to be followed for a longer period of time to see if it would extend survival."

The Centers for Disease Control and Prevention (CDC; Atlanta) reports that more than 5 million people in the U.S. have heart failure and more than 287,000 die each year as a result of this condition in which the heart can't pump enough blood and oxygen to meet a body's needs.

A pacemaker delivers electrical impulses that help synchronize contractions of the left ventricle, the heart's main pumping chamber. In this study, all patients were diagnosed with early stage, mild heart failure, known as Class I and Class II on the New York Heart Association classification system. The patients were randomly assigned to two groups. A control group received an implanted defibrillator. The other group received a defibrillator plus cardiac resynchronization.

"Biventricular pacing with cardiac resynchronization provides an extra lead in the coronary sinus that paces the left ventricle in addition to the right ventricle," Wilber said.

He said that this therapy may be given already to some patients with mild, early heart failure and that there have even been some smaller studies indicating this approach might be helpful, but until now there was not a large body of information and no FDA approval for the procedure.

Wilber and his colleagues reported in the current issue of The New England Journal of Medicine that CRT was associated with a significant reduction in left ventricular volumes and improvement in the ejection fraction (the amount of blood pumped out of a ventricle with each beat of the heart).

An important aspect when considering this early treatment for potentially millions of people is that most of the patients with early heart failure were asymptomatic. The idea of forestalling onset of the condition is positive in theory, but the cost of a biventricular pacemaker and implantation can run more than $30,000 per patient, making it an expensive preemptive move. But compare that with overall costs: The CDC reports that the annual direct costs for heart failure in the U.S. are about $30 billion. The condition also is the most common reason for hospitalizations for people on Medicare.

This study was funded, in part by Boston Scientific (Natick, Massachusetts), which makes biventricular pacemakers for CRT.

Wilber said that patients with early stage heart failure would not need a new type of pacemaker – that existing devices would be appropriate.

Going forward, he's planning studies to assess whether or not other groups of patients with heart failure, but with normal ejection fractions, might also benefit from CRT.

Lynn Yoffee, 770-361-4789;
lynn.yoffee@ahcmedia.com