Radiation therapy effective against deadly heart rhythm: study

Source: Xinhua| 2019-09-17 04:29:12|Editor: Mu Xuequan
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CHICAGO, Sept. 16 (Xinhua) -- A single high dose of radiation aimed at the heart significantly reduces episodes of a potentially deadly rapid heart rhythm, results of a phase one/two study at Washington University School of Medicine in St. Louis showed.

The phase one/two trial included 19 patients with ventricular tachycardia who had not responded to other therapies.

The researchers reported that the reduction in tachycardia episodes persisted in about 80 percent of patients for at least two years following the single treatment. At one year after therapy, overall survival was 72 percent, and at two years, survival was 52 percent.

"These numbers are encouraging given the condition of the patients, who are too sick to undergo any more catheter ablation procedures," said Clifford G. Robinson, an associate professor of radiation oncology and of cardiology at Washington University.

Of nine patient deaths, six were from cardiac causes, including heart failure and tachycardia recurrence, and three were from non-cardiac causes, including an accident, amiodarone toxicity and pancreatic cancer. Two surviving patients experienced inflammation of the heart lining, a common side effect of this type of radiation therapy, and another developed a fistula between the stomach and the heart and needed surgery to repair it.

All three of these adverse events occurred more than two years after therapy. Such side effects emphasized the importance of monitoring the patients for signs of cardiac injury, which is always a possibility following radiation therapy, Robinson said.

The new method is a noninvasive outpatient procedure that involves the use of electrocardiograms and computed tomography scans of a patient's heart to locate the origin of the arrhythmia. The 3D visual and electrical maps of the heart then guide the noninvasive radiation therapy. Doctors can target the problem area of the heart with a single high-dose beam of radiation that often takes less than 10 minutes to administer and requires no anesthesia or hospitalization. The patient can go home right after treatment.

Given the relative novelty of this treatment approach, the researchers emphasized that radiation therapy is the last option and only should be pursued when all other strategies have been exhausted. "We are continuing to follow our patients closely," Robinson added.

The research was reported on Sunday at the American Society for Radiation Oncology (ASTRO) Annual Meeting in Chicago.