This study is enrolling subjects with an abnormal heart rhythm called ventricular tachycardia (VT - rapid heart beat coming from the bottom of the heart) that has come back despite treatment. This is a randomized study meaning subjects will be assigned to one of two groups and then undergo either a standard catheter ablation or a new treatment called cardiac radioablation for their VT. You will have a 50:50 chance of being assigned to either group. A standard catheter ablation is done by placing catheters (long hollow tubes) into a large blood vessel at the top of the leg, guiding them to the heart to first identify the signals causing the VT and then use radiofrequency (heat) energy to burn and stop these signals to stop the VT. The cardiac radioablation is an investigational treatment meaning it is not yet approved for routine clinical use by the Food and Drug Administration (FDA). Cardiac radioablation is performed in the radiation oncology department and uses radiation therapy to treat the signals causing the VT. Participation in this study will last up to 5 years and inlcude about 15 visits. Study related procedures include medical record review and data collection, electrocardiogram (tracing of heart's electrical activity), echocardiogram (ultrasound test of the heart), CT scans, blood work, questionnaires, implantable cardioverter defibrillation (ICD - device implanted in your chest that monitors and treats abnormal heart rhythms), and ablation procedure per randomization. Risks include fatigue, changes in the appearance of the lungs in the cardiac radioablation group, fatigue, pain, low or high blood pressure or excessive bruising or bleeding at the catheter insertion side in the cardiac ablation arm. There are also study procedure related risks, and risks that are not known. There is potential benefit to you and to others in learning how to better treat others in the future with this condition.

This study is enrolling participants who completed the FARAPULSE ADVENT study and are now nearing the 3 year post atrial fibrillation ablation timepoint. Atrial fibrillation is an irregular heart rhythm caused by electrical signals misfiring. An ablation is a procedure in which those signals are targeted and destroyed to stop the atrial fibrillation. This study will consist of reviewing and collecting medical records since the ablation procedure as well as optional questionnaires and wearing a heart monitor for 7 days to capture the heart's electrical activity. There are no study related follow up visits. Study related risks include loss of confidentiality and possible skin reaction to the electrodes (sticky patches placed on the chest to detect the heart's electrical activity). Individual benefit is not expected but the information learned may contribute to knowledge in this field.