Background: Recently, a novel irrigated RF catheter was designed with a diamond-embedded tip for rapid cooling and 6 surface thermocouples to reflect real-time tissue temperature. The new technology allows for temperature-controlled irrigated ablation, very high-resolution electrograms (EGMs) from the split-tip electrode, as well as real-time rapid lesion assessment.

Aim: This study aimed to access lesion formation and efficacy of the novel DiamondTemp (DT) ablation catheter for atrial fibrillation (AF) ablation using magnetic resonance imaging (MRI).

Methods: In this prospective observational study, 31 patients underwent pulmonary vein isolation (PVI) with the DT catheter in a temperature control mode (60C°/50 W/ 10 seconds). The ipsilateral pulmonary veins (PV) were divided into 6 anatomical segments (12 segments in total) to record ablation data. Patients underwent preprocedural imaging (computer tomography or magnetic resonance imaging (MRI)) and received additional postprocedural late gadolinium enhancement (LGE) MRI of the left atrium 3 months after ablation to access lesion formation for each PV segment and to rule out PV stenosis.

Results: Acute PVI was achieved in all patients. Three patients received additional ablation at the cavotricuspid isthmus due to typical atrial flutter. No charring at the catheter tip was found and no procedure related complications were observed. The mean procedure duration (skin-to-skin) was 98.9±30.1 minutes, mean LA dwell time was 77±24.3 minutes. RF time was 13.1±5.2 minutes with a mean of 75±31 RF applications. We measured a mean impedance drop per RF application of 8.2±4.9 ohm. Fluoroscopy time was 4.6±2.1 minutes and the fluoroscopy dose was 183.8±178.1 cGy*cm² at a. LGE MRI at 3 months after ablation demonstrated a homogeneous and continuous ablation lesion set around the ipsilateral PVs and there was no evidence for PV stenosis.