January 27, 2006

New pacing device tested to help hearts keep the beat

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VUMC is testing this device, which is designed to pace the heart and improve cardiac function.

New pacing device tested to help hearts keep the beat

Mark Wathen, M.D.

Mark Wathen, M.D.

Vanderbilt is one of 40 centers nationwide to enroll patients in a study to determine the efficacy and safety of a new pacing device for heart failure patients.

This is the first time the device, called the Optimizer III, will be implanted in humans.

Until now, the traditional treatment for heart failure patients has been drug therapy — one that has proven to be ineffective, said Mark Wathen, M.D., director of Vanderbilt Arrhythmia Clinical Research.

“This is a new development, a whole new concept,” said Wathen. “This is based on implanting a device that paces the heart and improves cardiac function. The pharmaceutical industry has spent over a decade developing drugs to accomplish the same goal. Those have failed.”

The trial, called FIX-HF-5 (Fix Heart Failure 5), is a multi-center, prospective, randomized study that is open to 418 patients nationwide. Vanderbilt will enroll up to 20 patients and follow them for up to a year. Impulse Dynamics is the maker of the device.

The study will utilize Cardiac Contractility Modulation (CCM) as a treatment to assist the heart when it is not electrically excitable, which means it is not pacing. This resynchronization through CCM therapy sends signals to the heart to stimulate calcium release and uptake, which causes improved cardiac strength.

“Every heartbeat occurs through the release of calcium, which stimulates proteins to activate the contraction process,” Wathen said. “Calcium is the energy monetary system of the cell. Higher calcium improves the cells' economy so that the whole cell is stronger and therefore every heart beat is stronger. CCM increases the amount of calcium released with each heart beat, thereby improving the heart cell strength with each heart beat.”

Heart failure is caused by weak or damaged heart muscle that is unable to pump enough blood throughout the body.

The most common forms of the disease are treated with drugs and implanted devices such as pacemakers and implantable cardiac defibrillators (ICD). But because these treatment methods are not always successful, Wathen is excited about this new effort to develop a significant addition to heart failure therapies.

Drug therapy has been shown to stiffen the heart, increase heart arrhythmia, cause sudden death and cell fatigue, which in the long-term is detrimental, said Wathen. Because of those side effects, medicinal interventions are primarily used for a brief period, he said.

The FIX-HF-5 entry criteria calls for patients to have moderate to severe congestive heart failure, classification 3 or 4 despite maximum medical therapy; moderately to severely reduced heart strength; a normal QRS width; and already have an ICD.

“The patients enrolling in this study don't have many choices as far as treatment options go,” Wathen said. “The next step for many of them would be transplantation or LVAD.

“In this case, either they receive the device or not. It is a 50-50 chance, which is better than zero. This patient population is desperate for alternatives. They have had most everything done for them and will be pleased to have another opportunity for help.”

There are nearly 5 million heart failure patients in the United States and nearly 20 million worldwide.