Margaret Infeld, M.D., M.S., clinical cardiac electrophysiology fellow and clinical instructor in the Department of Medicine

(MARCH 15, 2023) Margaret Infeld, M.D., M.S., clinical cardiac electrophysiology fellow and clinical instructor in the Department of Medicine, explained the results of her recent MyPace study on so-called stiff hearts in an interview with WCAX-TV.

Cardiomyopathy is a disease of the heart muscle that makes it harder for the heart to pump blood to the rest of the body. In restrictive cardiomyopathy, also known as “stiff heart” — the least common type of cardiomyopathy — the heart muscle becomes stiff and less flexible, so it can’t expand and fill with blood between heartbeats.

“There are few effective therapies for patients with a stiff heart,” Infeld said. She says about 50 to 80 percent of the three million Americans with stiff heart failure are on medications to slow their heart rate. The idea is to give the heart more time to fill up before pumping blood out. But she says there’s a growing body of research showing the medications might hurt, not help. “This can make patients feel worse and have less capacity for exercise.”

Her recent “MyPace” study took a different approach. Instead of slowing the patients’ resting heart rates, they increased them using specialized pacemakers. They assigned either a personalized resting heart rate based on how many beats per minute they would have if their heart were healthy, or the standard pacemaker rate of 60 beats per minute. After a year, she says those with the individualized approach felt better. “The patients with the more personalized ‘normal’ heart rates had improvement in symptoms, improved pressures on their heart based on a lab test. They were more physically active and they had less atrial fibrillation,” Infeld said.