As reported in this New York Times article, radiation has been used as a successful treatment in five patients with ventricular arrhythmias who had previously failed standard treatment using catheter radiofrequency ablation.  The complete study was published last week in the New England Journal of Medicine.

Because long term effects of radiation to the heart are unknown, this method is still quite experimental and could potentially cause long term side effects such as lung and heart damage.  Science Daily reported that the researchers have performed the procedure on 23 patients to date, and are currently enrolling patients in a clinical trial.