Byophisical Characterization and Procedural Outcomes of Irrigated, Temperature-Controlled Radiofrequency Ablation of Macroreentrant Atrial Tachycardia

Background and Objective: Irrigated, temperature-controlled radiofrequency (RF) ablation has been reported in atrial fibrillation patients. However, its impact in macroreentrant atrial tachycardia (MRAT) ablation is unknown. Our goal was to analyze experimental lesion characteristics and procedural impact of the DiamondTemp (DT) catheter compared with standard catheters in the treatment of MRAT. Methods: In a pre-clinical study, we compared DT temperature-controlled (60oC/50W) with 25 and 50W power-controlled lesions from a standard irrigated catheter. Subsequently, we performed a single-center prospective observational study among consecutive patients undergoing MRAT ablation with DT catheter/Rhythmia mapping (study group) vs. state-of-the-art systems (control group). Results: In swine myocardium, lesions with DT 60oC/50W were wider and deeper when compared with the control catheter at 25W and smaller vs. the control catheter at 50W, except with poor catheter-tissue contact (2g contact: diameter: 56,8{±}1,64 vs. 54,2{±}2,28 mm, p=0,02; depth: 36,4{plus minus}1,81 vs. 33,8{±}2,86, p=0,03 for 20-second lesions). In 38 patients, use of DT reduced total RF time (19,7{±}9,1 vs. 48,6{±}21,2 minutes, p 5mm) displacement between ablation tags and effective ablated area. Conclusions: The use of temperature-controlled radiofrequency ablation in complex atrial tachycardia cases is safe and reduces radiofrequency time, which may help improve acute procedural outcomes. The catheter can be used with Rhythmia mapping system without compromising accuracy and may offer an advantage in lesions created with poor catheter-tissue contact.