April 26, 2026 – New results from the pivotal multicenter trial FULCRUM-VT show that ultra-low temperature ablation (ULTA) may offer a promising new treatment option for patients with ventricular tachycardia (VT) and structural heart disease. Researchers presented these findings as a late-breaking clinical trial at Heart Rhythm 2026 in Chicago.
VT occurs when the heart’s lower chambers beat dangerously fast, preventing the heart from pumping blood effectively. It is a leading cause of sudden cardiac death, which accounts for an estimated 15-20% of deaths worldwide.i In the United States alone, more than 356,000 out-of-hospital cardiac arrests occur each year, many because of ventricular arrhythmias such as VT.ii VT most commonly affects patients with structural heart disease, in which scar tissue disrupts normal cardiac electrical conduction and leads to potentially life-threatening rhythm disturbances.
While ablation is commonly used to treat VT, conventional approaches may be less effective in reaching deeper or heavily scarred tissue. ULTA offers a promising alternative. By using extreme cold — near-critical nitrogen with a boiling point of -196°C — this approach can more effectively target these challenging areas and may provide a new treatment option for patients with difficult-to-manage arrhythmias.
The pivotal FULCRUM-VT trial evaluated the safety and effectiveness of ULTA in 209 patients with structural heart disease undergoing VT ablation at 19 sites across the United States and Canada. The study enrolled patients with both ischemic and non-ischemic cardiomyopathy, many of whom had implantable cardioverter-defibrillators (ICDs) and were already receiving antiarrhythmic medications, including amiodarone. This high-risk population had advanced disease, with a mean left ventricular ejection fraction of 35%, and continued to experience arrhythmias despite prior therapy. During each procedure, physicians used the ULTA system to precisely target and ablate the areas of heart tissue responsible for initiating and supporting VT.
The study found that ULTA demonstrated high effectiveness and a favorable safety profile for treating scar-related VT in patients with cardiomyopathy. Post-ablation testing confirmed that the treating physicians could no longer induce 98% of targeted VTs, demonstrating successful elimination of these abnormal heart rhythms. Investigators observed major adverse events in only 2.5% of patients, indicating that the procedure was generally well tolerated.
“Ventricular tachycardia in cardiomyopathy patients can be challenging to treat, particularly when scar tissue interferes with the heart’s normal electrical pathways,” said Atul Verma, MD, Senior Scientist at the Research Institute of the McGill University Health Centre at Montreal General Hospital. “This study points to using ultra-low-temperature ablation as a new approach to safely and effectively target difficult arrhythmia circuits, potentially improving treatment options for patients.”
Researchers will continue assessing how ULTA procedures affect VT recurrence over time and will share upcoming data on six-month and longer-term patient outcomes.
HRS Session Details
“Late-Breaking Clinical Trials: Ventricular Tachycardia: Effectiveness and Safety of Ultra-low Temperature Ablation of Ventricular Tachycardia in Patients with Structural Heart Disease: Outcomes of the Pivotal FULCRUM-VT Trial” [April 26, 2026]
i Priori SG, Blomström-Lundqvist C, Mazzanti A, et al. 2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. European Heart Journal. 2015;36(41):2793–2867.
ii American Heart Association. Cardiac arrest statistics. American Heart Association; 2023. Available at: https://cpr.heart.org/en/resources/cpr-facts-and-stats
April 24, 2026 
