Key result
Ultralow temperature cryoablation using near-critical nitrogen achieved acute bidirectional conduction block in 100% of patients, with 82.4% of atrial flutter patients remaining free of recurrence at 12 months.
Why the study?
Cryoablation is a safe alternative to radiofrequency ablation for supraventricular arrhythmias, but is limited by the properties of the cryogen used.
Does ultralow temperature cryoablation using near-critical nitrogen safely achieve bidirectional conduction block in patients undergoing cavotricuspid isthmus ablation?
Does ultralow temperature cryoablation using near-critical nitrogen safely achieve bidirectional conduction block in patients undergoing cavotricuspid isthmus ablation?
Ultralow temperature cryoablation using near-critical nitrogen is a feasible and safe energy source for achieving acute cavotricuspid isthmus block in humans.
Supports feasibility for CTI ablation in small cohort; leaves open need for randomized trials on durability and safety.
INTRODUCTION: Cryoablation has evolved as a safe alternative to radiofrequency ablation in the treatment of several supraventricular arrhythmias and has potential advantages, yet is limited by the properties of the cryogen used. We investigated a novel ultralow temperature cryoablation (ULTC) system using nitrogen near its liquid-vapor critical point as a freezing source, achieving temperatures as low as -196 degrees Celsius in a long linear catheter with a continuous energy release. Initial safety, procedural and efficacy outcomes of ULTC are described in patients undergoing cavotricuspid isthmus (CTI) ablation. METHODS AND RESULTS: The Cryocure studies (NCT02355106, NCT02839304) are prospective, single-arm, multi-center, first-in-human clinical studies in 17 patients with atrial flutter (AFL) and 13 patients with atrial fibrillation (AF). A total of 30 patients, mean age 65 ± 8 years old and 67% male, were enrolled and underwent ablation of the CTI. Acute success, defined as the confirmation of stable bidirectional conduction block across the CTI, was achieved in all 30 patients. After 12 months of follow-up, 14 out of 17 AFL patients remained free from any AFL. One (3.3%) procedure-related but not device-related serious adverse event was reported, involving transient inferolateral ST-elevation associated with temporary AV conduction block. CONCLUSION: In this first-in-human clinical study the safety and performance results demonstrate the capabilities of ultralow temperature near-critical nitrogen as an effective energy source for CTI ablation. Ongoing, larger, studies should confirm our findings and evaluate the capabilities to create linear and focal transmural lesions in other arrhythmias.
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Klaver et al. (2021) studied Atrial flutter and atrial fibrillation (n=30). Ultralow temperature cryoablation using near-critical nitrogen was evaluated on Acute success (stable bidirectional conduction block across the cavotricuspid isthmus). Ultralow temperature cryoablation using near-critical nitrogen achieved acute bidirectional conduction block in 100% of patients, with 82.4% of atrial flutter patients remaining free of recurrence at 12 months.
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