November 9, 2001

MIRACLE study offers new pacemaker option

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MIRACLE study offers new pacemaker option

Not long ago Patrick DiRito, 77, moved his family from Florida to rural Kentucky. His goal was to ensure that his wife was near family when he died.

That was four years ago.

“Doctors told me I had about three to five years to live,” DiRito recalled. “It was after a heart attack that they told me there was no way to repair the damage without major surgery, and I was not a candidate for a transplant.

“Besides, with the long lists, I probably would have died waiting. My cardiologist referred me to the doctors at Vanderbilt who were enrolling folks in a study.”

The six-month study, the Multicenter Insync Randomized Clinical Evaluation or MIRACLE study, was looking at whether using a new type of pacemaker in congestive heart failure patients would prove to be a viable treatment option.

Vanderbilt was one of 44 centers in the United States and Canada testing the device-based therapy, the first major therapeutic option for heart failure since the development of specialized drugs.

The FDA recently announced the approval of this device as a treatment option for congestive heart failure patients. Prior to this, treatment options were limited to chronic drug therapy or transplant. And while advances continued, mortality rates for those suffering from congestive heart failure remained high, and the overall quality of life was poor.

For DiRito, not only was he expecting to die, his quality of life was dismal.

“Before I received the device, my life was horrible,” DiRito said. “I had been an active guy, traveling the world and constantly on the go. All of that ended when I had my heart attack. I couldn’t climb stairs. I couldn’t put my socks on. I couldn’t tie my shoes. I spent most of my time in bed

“All of that has changed,” he continued. “Now I drive myself to Vanderbilt—the entire 300 miles in one day. I feel great. I have my life back.”

Dr. Mark Wathen, assistant professor of Medicine and director of the Electrophysiology Lab at Vanderbilt, along with Dr. John Wilson, professor of Medicine and director of the Vanderbilt Heart Failure Program, were principal investigators for the new device. Wathen said the use of the system has been successful in restoring quality of life for patients, as well as improving classification within the New York Heart Functional (NYHA) guidelines. The key element in the use of the new cardiac-pacing device is that it is a pacemaker for congestive heart failure patients.

Traditionally, pacemakers are used in patients with faulty heart rhythms. Two leads, generally configured with one in the right atrium and one in the right ventricle, electrically stimulate the heart to produce normal heart contractions.

The new device involves the placement of a third lead in the left ventricle. The new system is used to pace both ventricles (the lower chambers of the heart) at the same time, simulating a “normal” heartbeat. This is also known as bi-ventricular pacing.

The electrical stimulation to the heart provides more coordinated contractions, allowing for improved pumping action by the heart and increased blood flow throughout the body.

“We have now found a new form of therapy for severe congestive heart failure patients,” said Wathen. “It may be useful for patients being considered for heart transplants or other severe interventions.

“Our goal was to find another option other than transplant. There are not enough donors and we need other forms of therapy. And this represents a new area of therapy.”

Wathen said study results show increases in quality of life measurements, exercise tolerance and decreases in heart failure classifications and heart size.

All patients enrolled in the study were classified as level 3 or 4. Class 3 patients become short of breath with any activity, while Class 4 patients are short of breath at rest.

According to Wathen, study results show that 90 percent of patients enrolled in the study were Class 3 and 10 percent were Class 4. At the end of the study (six months), 13 percent were deemed Class 1—patients can function without any limitations; 52 percent were Class 2—patients noticed a shortness of breath during height of activity; 32 percent were Class 3 and the rest were Class 4.

“This is a great improvement in the lives of these patients,” Wathen said. “Two-thirds moved up to Class 1 or 2. Another significant improvement was the reduction in size of the chamber of the left ventricle at six months.

“This is an important finding because this shows improvement in the cardiac function. Anytime we can reduce the size of the heart, we have done something important.”

Congestive heart failure is a condition in which the heart is unable to pump enough blood to meet the needs of the body. As the disease progresses, the heart’ s chambers become more and more dilated and enlarged, which causes the conduction system and mechanical properties to change, contributing to an inefficient pumping ability.

Nearly five million Americans have heart failure. An estimated 650,000 heart failure patients are candidates for this new device-based therapy.

“Although we didn’t change every person’s classification or health status, the change in the majority of patients was significant enough that we feel this is a valuable therapy for some patients,” Wathen said.

“We significantly improved the lives of people who had little hope,” he said. “They went from a bed-ridden situation to doing much of what they wanted. That’s important data.”

DiRito said the improvement in his heart has given him more than hope.

“It saved my life,” he said. “I’m planning for the future. Before, there was nothing. I know that it will only get better. I can’t tell you how good it feels to keep on living.”