Cardiologists and radiation oncologists at the Washington University School of Medicine in St. Louis have pioneered the use of low-dose radiation therapy, typically employed against cancer, to treat patients with ventricular tachycardia, a potentially fatal irregular heart rhythm. The research team discovered that this unconventional approach appears to enhance heart function in various forms of heart failure. The study, published in the journal Med, suggests that low-dose radiation therapy improves cardiac function, at least in part, by reducing the amount of inflammatory immune cells in the heart muscle.
Heart failure affects about 6.2 million American adults, with over half of patients hospitalized for the condition dying within five years of the first hospitalization. The failing heart gradually loses its ability to properly supply the body with oxygenated blood, and heart failure can result from various triggers, including past heart attacks, viral infections, or chronic arrhythmias such as ventricular tachycardia.
“The radiation therapy used to treat ventricular tachycardia is targeted to a specific location in the heart; however, a large portion of the rest of the heart gets a low-dose exposure,” stated co-senior author and cardiologist Ali Javaheri, MD, PhD, an assistant professor of medicine.
“We wanted to understand the effects of that low-dose radiation on these patients’ hearts. There was concern that it could be harmful to overall heart function, even though it treats dangerous arrhythmia. We were surprised to find the opposite: Heart function appeared to be improved after radiation therapy, at least in the short term.”
The research involved evaluating a group of nine patients with ventricular tachycardia using cardiac MRI before and after radiation treatment. The MRIs showed improved heart function soon after radiation, particularly an enhanced pumping capacity of the left ventricle, which supplies blood to the entire body. Similar positive effects were observed in mice with heart failure from different causes, including increased survival rates.
The study suggests that low-dose radiation therapy may reduce fibrosis (scar tissue) and the presence of cardiac macrophages (immune cells that drive inflammation in the heart). Additionally, irradiated hearts showed fewer rapidly proliferating cells, such as immune cells and fibroblasts, which are known contributors to worsening heart failure. While more research is needed before testing this therapy in heart failure patients, the study implies that the effects of radiation on wounded hearts with high levels of inflammation may be more variable and potentially helpful than previously recognized.
“We know that rapidly dividing cells — such as cancer cells, for example — tend to be more susceptible to death by radiation,” stated co-senior author and radiation oncologist Carmen Bergom, MD, PhD, an associate professor of radiation oncology.
“The effect we see in these hearts is likely more complex than a simple reduction of rapidly dividing inflammatory immune cells. We are continuing our research to delve more deeply into what else may be happening, but we have been pleasantly surprised to see evidence that low-dose radiation in these hearts may reduce inflammation and help remodel the heart in a way that is beneficial.”
Disclaimer:
The information contained in this article is for educational and informational purposes only and is not intended as a health advice. We would ask you to consult a qualified professional or medical expert to gain additional knowledge before you choose to consume any product or perform any exercise.
