BACKGROUND: Catheter ablation using radiofrequency (RF) energy is an established treatment for ventricular tachycardia (VT). Tissue temperature is a key determinant of successful lesion creation, and yet, it is difficult to measure during conventional RF ablation because of the cooling effect of high-flow rate saline irrigation. The TRAC-VT study evaluated the safety and efficacy of a novel irrigated RF ablation system modulating power based on real-time tissue temperature. METHODS: Patients with sustained monomorphic VT and structural heart disease (SHD) were enrolled. Catheter ablation was performed in temperature-control mode (irrigation 8 ml/min, temperature set-points 55 or 60 °C, and power output ≤ 50 W), with RF applications for ≤ 45 s. The primary safety endpoint was a composite of cardiovascular-specific serious procedure-related adverse events within 30 days post-ablation. The primary effectiveness endpoint was acute success (i.e., non-inducibility of all clinically relevant VTs). RESULTS: Thirty-eight patients were enrolled with monomorphic VT (age 68 ± 12 years and 84% male), with an average of 1.7 ± 1.2 VTs targeted per patient. In total, 41 ± 23 RF applications per patient were delivered. Acute procedural success was 100% (95% CI, 91-100%). No primary safety endpoints were observed. Six-month follow-up was completed in 92% of patients with 81% (95% CI, 65-91%) freedom from sustained or treated VT. A repeat ablation was performed in three patients. CONCLUSIONS: Ablation of VT in SHD, using a temperature-controlled irrigated RF catheter, was safe and effective with a low rate of VT recurrence at 6 months.

• Keywords
• Cardiac arrhythmia, DiamondTemp, Radiofrequency catheter ablation, Temperature controlled, Ventricular tachycardia,
• MeSH
• Equipment Design MeSH
• Catheter Ablation * methods   instrumentation   adverse effects   MeSH
• Tachycardia, Ventricular * surgery   mortality   MeSH
• Therapeutic Irrigation methods   instrumentation   MeSH
• Middle Aged MeSH
• Humans MeSH
• Aged MeSH
• Treatment Outcome MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH
• Observational Study MeSH

BACKGROUND: Catheter ablation (CA) technology development reflects the need to improve the effectiveness of atrial fibrillation (AF) treatment. Recently, the DiamondTemp Ablation (DTA) RF generator software was updated with a more responsive power ramp. METHODS: DIAMOND FASTR-AF was a prospective, single-arm, multicenter trial. This study sought to characterize the performance of the updated DTA system for the treatment of patients with drug-refractory paroxysmal and persistent AF (PAF and PsAF). The primary effectiveness endpoint was freedom from atrial arrhythmia recurrence following a 90-day blanking period through 12 months, and the primary safety endpoint was a composite of serious adverse events. RESULTS: In total, 60 subjects (34 PAF and 26 PsAF) underwent CA at three centers. Patients were 71.7% male, (age 63.9 ± 10.2 years, with an AF diagnosis duration 3.1 ± 3.9 years and left atrial size 4.4 ± 0.8 cm). Pulmonary vein isolation-only ablation strategy was performed in 34 (56.7%) subjects. The procedural characteristics show a procedure time 90.8 ± 31.6 min, total RF time 14.7 ± 7.7 min, ablation duration 10.7 ± 3.6 s, and fluid infusion 284.7 ± 111.5 ml. The serious adverse event rate was 8.3% (5/60), 3 pulmonary edema and 2 extended hospitalizations. Freedom from atrial arrhythmia recurrence was achieved in 67.6% of subjects by 12 months. CONCLUSIONS: The updated DTA system demonstrated long-term safety and effectiveness through 12 months of post-ablation follow-up for patients with atrial fibrillation. Additionally, procedures were demonstrated to be highly efficient with short procedure times and low levels of fluid infusion. TRIAL REGISTRATION: Sponsored by Medtronic, Inc.; FASTR-AF ClinicalTrials.gov; NCT03626649.

• Keywords
• Atrial fibrillation, Catheter ablation, DiamondTemp, Radiofrequency,
• MeSH
• Atrial Fibrillation * surgery   MeSH
• Catheter Ablation * methods   MeSH
• Middle Aged MeSH
• Humans MeSH
• Prospective Studies MeSH
• Recurrence MeSH
• Aged MeSH
• Temperature MeSH
• Pulmonary Veins * surgery   MeSH
• Treatment Outcome MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH

BACKGROUND: A novel QDOT MICRO (Biosense Webster, Inc., Irvine, CA) catheter with optimized temperature control and microelectrodes was designed to incorporate real-time temperature sensing with contact force detection and microelectrodes to streamline ablation workflow. The QDOT-MICRO feasibility study evaluated the workflow, performance, and safety of temperature-controlled catheter ablation in patients with symptomatic paroxysmal atrial fibrillation with conventional ablation setting. METHODS: This was a non-randomized, single-arm, first-in-human study. The primary outcome was pulmonary vein isolation (PVI), confirmed by entrance block after adenosine and/or isoproterenol challenge. Safety outcomes included incidences of early-onset primary adverse events (AEs) and serious adverse device effects (SADEs). Device performance was evaluated via physician survey. RESULTS: All evaluated patients (n = 42) displayed 100% PVI. Two primary AEs (4.8%) were reported: 1 pericarditis and 1 vascular pseudoaneurysm. An additional SADE of localized infection was reported in 1 patient. No stroke, patient deaths, or other unanticipated AEs were reported. Average power delivered was 32.1±4.1 W, with a mean temperature of 40.8°C±1.6°C. Mean procedure (including 20-minute wait), fluoroscopy, and radiofrequency application times were 129.8, 6.7, and 34.0 minutes, respectively. On device performance, physicians reported overall satisfactory performance with the new catheter, with highest scores for satisfaction and usefulness of the temperature indicator. CONCLUSIONS: Initial clinical experience with the novel catheter showed 100% acute PVI success and acceptable safety and device performance in temperature-controlled ablation mode. There were no deaths, stroke, or unanticipated AEs. Fluoroscopy and procedural times were short and similar or better than reported for prior generation catheters.

• Keywords
• Arrhythmia, Atrial fibrillation, Catheter ablation, Pulmonary vein isolation, Workflow,
• Publication type
• Journal Article MeSH