Pulmonary Vein Isolation with Very High Power–Short Duration Temperature-Controlled Lesions: The First-in-Human QDOT-FAST Multicenter Trial

Objectives: To evaluate the safety and acute performance of a novel catheter for very high power–short duration (vHPSD) ablation in the treatment of paroxysmal atrial fibrillation (PAF). Background: The vHPSD catheter is a novel contact force–sensing catheter optimized for temperature-controlled radiofrequency ablation with microelectrodes and 6 thermocouples for real-time temperature monitoring; the associated vHPSD algorithm modulates power to maintain target temperature during 90W/4s lesions. Methods: QDOT-FAST is a prospective, multicenter, single-arm study enrolling patients with symptomatic PAF indicated for catheter-based pulmonary vein isolation (PVI). Primary endpoints were acute effectiveness (confirmation of entrance block in all targeted pulmonary veins [PVs] after adenosine/isoproterenol challenge) and acute safety (primary adverse events [PAEs]). Participants were screened for silent cerebral lesions (SCLs) by MRI. Patients were followed for 3 months post-ablation. Results: A total of 52 patients underwent ablation and completed follow-up. PVI was achieved in all patients using the study catheter alone, with total procedure and fluoroscopy times of 105.2 ± 24.7 and 6.6 ± 8.2 minutes, respectively. Most patients (n=49; 94.2%) were in sinus rhythm at 3 months. Two PAEs were reported: one pseudoaneurysm and one asymptomatic thromboembolism. There were no deaths, stroke, atrioesophageal fistula, PV stenosis, or unanticipated adverse device effects. Six patients had identified SCLs—all classified as asymptomatic without clinical or neurologic deficits. Conclusions: This first-in-human study of a novel catheter with optimized temperature control demonstrated the clinical feasibility and safety of vHPSD ablation. Procedure and fluoroscopy times were substantially lower than historical standard ablation with point-by-point Condensed Abstract The very high power-short duration (vHPSD) ablation catheter is a novel contact force–sensing catheter optimized for temperature-controlled ablation with microelectrodes and 6 thermocouples. The associated vHPSD algorithm modulates power to maintain target temperature during vHPSD ablation (90W, 4s). This multicenter first-in-human QDOT-FAST study, which included 52 patients undergoing ablation of paroxysmal atrial fibrillation, demonstrated procedural success in all patients. Only two primary adverse events were reported (pseudoaneurysm and asymptomatic thromboembolism). Procedure and fluoroscopy times were substantially lower than reported with standard force and non-force sensing radiofrequency ablation catheters in prior clinical trials. Central Illustration: A Novel Temperature-Controlled Radiofrequency Ablation Catheter Shown on the left is the tip of catheter with the microelectrodes and 6 thermocouples. This allows the capacity for very high power-short duration (90W/4sec) lesions. As shown on the right, the procedural outcomes in the first-in-human QDOT-FAST study are substantially improved over other previous multicenter studies. The study actively screened for post-procedural cerebral lesions with MRI within 72 hours pre-ablation and 72 hours post-ablation. At follow-up, patients were required to undergo an MRI examination if cerebral ischemic lesions were identified in a prior evaluation or if the patient experienced neurologic symptoms. If cerebral lesions were detected, follow-up was performed 1 month later, including MRI and neurologic assessments (National Institutes of Health Stroke Scale [NIHSS], Montreal Cognitive Assessment [MoCA], and Modified Rankin Scale [mRS]). If neurologic symptoms or cerebral ischemic lesions were identified at a prior evaluation, subjects were required to undergo MRI and neurological assessments at the next evaluation.