A 'game changer' for patients with irregular heart rhythm

The patients were gravely ill, their hearts scarred by infections or heart attacks. In each, the electrical system that maintains a regular heartbeat had been short-circuited.

They suffered frequent bursts of rapid heartbeats, which can end in sudden death. The condition kills an estimated 325,000 Americans each year, the most common cause of death in this country. And these people had exhausted all conventional treatments.

So researchers at Washington University in St Louis offered the patients something experimental: short bursts of radiation aimed at their hearts in an effort to obliterate the cells that were causing the electrical malfunctions.

Results in the first five patients were published on Thursday in the New England Journal of Medicine, and the experiment seems to have worked — offering hope to similar patients everywhere who have had no alternatives except a heart transplant.

“This is a game changer,” said Melvin Scheinman a professor of medicine at the University of California, San Francisco, and past president of the Heart Rhythm Society. “There is no question that this will catch on.”

“This is a game changer,” said Melvin Scheinman a professor of medicine at the University of California, San Francisco, and past president of the Heart Rhythm Society. “There is no question that this will catch on.”

Roderick Tung, director of cardiac electrophysiology at the University of Chicago Medicine, described the new procedure as “a paradigm shift.”

The treatment requires weeks to take full effect, so it cannot be used for cardiac patients who need immediate help. And the method must be studied in larger groups of patients over longer times, an effort that has already begun.

“The worst thing we can do is adopt it with unbridled enthusiasm and then, after five or ten years, say, ‘Whoa, we are starting to see side effects. What were we thinking?’” Tung said.

The patients in the study had tried drugs to control their heart rates. When drugs failed, they endured an invasive and risky surgical procedure called ablation, during which doctors use a catheter to burn off each cell contributing to the heart’s short circuits.

Yet the patients still were having thousands of episodes of ventricular tachycardia, during which a heart may beat 200 times a minute as blood pressure plummets. Defibrillators in their chests shocked their hearts back to a normal rhythm when necessary, but the devices did not prevent these episodes.

In the three months before they tried the experimental treatment, the five patients together suffered more than 6,500 bouts of tachycardia. It took a month for their hearts to recover from treatment, but in the year afterward the patients collectively had just four episodes of tachycardia, and two did not have any at all.

What made the new method possible was the fusion of two techniques. The first, stereotactic radiation, is used at some medical centres to treat cancer patients. It employs a highly focused and intense beam of radiation to destroy tumours.

The other technique maps the heart to pinpoint the exact location of scar tissue. The patients wears a vest made of chains of electrocardiogram leads — 256 in all, compared with 10 for the usual electrocardiogram. The doctors overlay data from the vest with images from scans of the patient’s heart.

“That gives us a beautiful three-dimensional image of where the arrhythmia is coming from,” said Phillip S Cuculich, a heart rhythm expert at Washington University in St Louis and first author of the new study.

Clifford G Robinson, a radiation oncologist at the university and senior author of the report, was wary at first when Cuculich proposed using focused radiation to burn off scar tissue in malfunctioning hearts.

Oncologists go to great lengths to avoid the heart when they treat cancer, because radiation can damage valves, arteries and other cardiac tissue in ways that may not show up until years later. The trickiest part: hitting a moving heart in a breathing patient with a beam that must be precisely targeted.

But these patients were so ill that the researchers thought it was worth taking a chance. The scars on the patients’ hearts ranged from the size of a cherry to the size of a walnut, calculated Francis Marchlinski, director of cardiac electrophysiology at the University of Pennsylvania, who was not involved with the study.
 

© 2017 The New York Times