VINTAGE (Ventricular Intramyocardial Navigation for Tachycardia Ablation Guided by Electrograms) Using Commercial Off-The-Shelf (COTS) Catheters

Background: Ventricular arrhythmia is an abnormal pulse rhythm that starts in the lower part of the heart (ventricles). Treatment includes ablation; ablation uses heat to destroy small portions of the heart that are causing short circuits in the normal heartbeats. But ablation does not always work well because some parts of the heart are hard to reach with current tools. Researchers want to try a new method called VINTAGE (ventricular intramyocardial navigation for tachycardia ablation guided by electrograms). VINTAGE may be better able to treat portions of the heart that are harder to reach with standard techniques. Objective: To test VINTAGE in people with ventricular arrhythmia. Eligibility: People aged 21 years and older with ventricular arrhythmia that did not respond to standard treatment. Design: Participants will have baseline tests. They will have blood tests and tests of their heart function. They will have imaging scans. They will complete a health questionnaire. Participants will undergo the VINTAGE procedure. They will be either completely or partially asleep. Doctors will insert tubes through large blood vessels in the groin. Tubes may also be inserted through the chest and wrist. They will use x-rays and ultrasound to guide tubes and guidewires directly into the heart muscle to do the ablation. Participants will stay in the hospital 1 or more nights after the procedure. Participants will have 3 follow-up visits over 6 months. These visits are for standard care after heart ablation. They will include blood tests, imaging scans, and tests of heart function. Participants may also wear a device to monitor their heart rhythms at home.