Sometimes the biggest medical advances begin with a simple “what if.”

What if a heart rhythm disorder could be treated without surgery, anesthesia or catheters? What if radiation therapy — used for decades to destroy cancer cells — could be safely aimed at the heart? For WashU Medicine cardiologist Phillip Cuculich, MD, and radiation oncologist Clifford D. Robinson, MD, that question sparked a medical revolution.

Together they developed a noninvasive cardiac radiation therapy for ventricular tachycardia — a fast, life-threatening heart rhythm that causes roughly 300,000 deaths in the U.S. each year. Their unconventional collaboration, first published in The New England Journal of Medicine in 2017, is reshaping how physicians think about treating the most dangerous arrhythmias.

A life at risk

Ventricular tachycardia often develops after injury to the heart, typically following a heart attack. Scar tissue interrupts normal electrical signaling, triggering erratic, rapid beats that can lead to sudden cardiac death. Standard treatments — medications, implanted defibrillators and catheter ablation procedures — can save lives but aren’t always effective. Ablation involves threading a catheter through a vein into the heart to burn off misfiring cells, a complex procedure that can take six hours or more and requires hospitalization. For some patients, it’s simply too risky or fails to provide lasting relief.

“These patients have defibrillators implanted to act like a paramedic and save their lives if a bad heart rhythm starts up,” said Cuculich. “While it’s wonderful that we can stop people from dying in that situation, the shock can be a traumatic event. Patients understand that they have just avoided death. And when this happens repetitively, often without warning, it can be devastating for patients.”

An unlikely collaboration

Robinson spent his career carefully avoiding the heart while using radiation to target lung tumors. Cuculich, meanwhile, was seeking alternatives for patients who could not withstand another invasive ablation. When Cuculich proposed using stereotactic body radiation therapy (SBRT) to interrupt the electrical circuits of the heart — an approach that would later become known as stereotactic arrhythmia radiotherapy (STAR) — Robinson’s initial reaction was disbelief, but curiosity prevailed.

“As a radiation oncologist who specializes in treating lung cancer, I’ve spent most of my career trying to avoid irradiating the heart,” said Robinson, an associate professor of radiation oncology. “But I also have been exploring new uses for stereotactic body radiation therapy that we use almost exclusively for cancer.”

Working with biomedical engineer Yoram Rudy, PhD, inventor of electrocardiographic imaging (ECGI), the team developed a way to create 3D electrical maps of the heart without inserting catheters. By overlaying these electrical maps with CT, MRI and PET images, they could pinpoint exactly where arrhythmias began and target those regions externally with radiation.

The result was a completely noninvasive, image-guided treatment that takes only 10 to 15 minutes to deliver.

A new era in treatment

The early outcomes were dramatic. In the six weeks after therapy, patients’ arrhythmia events dropped from 6,500 to 680, and within a year, only four total episodes were recorded. Two patients experienced none at all. All but one — an elderly patient with multiple other conditions — were alive a year later, enjoying vastly improved quality of life.

Compared with catheter ablation, which demands hours under anesthesia and days of recovery, this single-dose radiation therapy allowed patients to walk out of the treatment room the same day. While researchers continue to monitor long-term side effects, the short-term safety profile and success rates point to a transformative new option for those who have run out of options.

This type of cross-disciplinary innovation — where cardiology, radiation oncology and engineering converge — reflects WashU Medicine’s unique environment that fosters collaboration across specialties to solve medicine’s most complex challenges.

Redefining what’s possible

Today, Cuculich and Robinson continue refining their approach through clinical trials that have now treated more than 100 patients. This year marks the 10th anniversary of the first patient treated with stereotactic arrhythmia radiotherapy — and since their initial collaboration, this powerful physician team has helped more than 100 centers begin STAR programs of their own. Their work demonstrates what’s possible when disciplines intersect and bold ideas take root.