When patients undergo radiation treatments for cancer, oncologists take great care to spare the heart from radiation exposure because of the cardio-toxic effects it can have on the organ. But doctors at Orlando Health recently used targeted radiation therapy to treat a dangerous arrhythmia in one patient’s heart.

Dewey Caldwell was virtually bedridden before the procedure. After having suffered more than two dozen heart attacks, Caldwell’s heart was severely damaged and would often fall out of rhythm. When the arrhythmia episodes would occur, the defibrillator implanted in his chest would deliver a shock to his heart to halt the irregular heartbeat, sometimes knocking him to the ground.

Caldwell had already had one ablation, a catheter-based procedure, to try to correct the problem and wasn’t up for another. As time went by, the defibrillator was delivering painful jolts so frequently and upon such minimal exertion that Caldwell and his wife were considering discontinuing treatment.

That’s when Roland Filart, a cardiac electrophysiologist at Orlando Health, suggested trying a noninvasive, experimental approach he and a colleague had read about that uses a fine beam of radiation to destroy the heart tissue causing rapid and irregular heartbeats.

Orlando Health clinicians spent months planning for the procedure, mapping the hearts electrical circuits and incorporating those maps into CT scans that the radiation oncology team used to pinpoint the exact trouble spot in Caldwell’s heart where they would target the high-dose radiation.

The procedure itself took about 30 minutes and required Caldwell simply to lie down on a table while the radiation machine rotated around him. That half-hour has made a profound impact on his life, reducing the number of shocks he now gets from his defibrillator and allowing him to get out and enjoy life more, including attending his 60th high school reunion.

Justin Rineer, a radiation oncologist at Orlando Health who treated Caldwell in collaboration with Filart, says there is still a lot to be learned about the experimental therapy — which is only approved for compassionate use and not as a first-line treatment — but that it is a “valid” and “life-changing” treatment for patients who have run out of other treatment options.