Tobias Reichlin1, Sven Knecht2, Christopher Lane3, Michael Kühne2, Eyal Nof4, Nagesh Chopra3, Thomas M Tadros3, Vivek Y Reddy5, Beat Schaer2, Roy M John3, Stefan Osswald2, William G Stevenson3, Christian Sticherling2, Gregory F Michaud3. 1. Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts; University Hospital, Basel, Switzerland. Electronic address: treichlin@uhbs.ch. 2. University Hospital, Basel, Switzerland. 3. Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts. 4. Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts; Leviev Heart Center, Sheba Medical Center, Tel Hashomer, Israel. 5. Helmsley Electrophysiology Center, The Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York.
Abstract
BACKGROUND: Good catheter-tissue contact force (CF) is critical for transmural and durable lesion formation during radiofrequency (RF) ablation but is difficult to assess in clinical practice. Tissue heating during RF application results in an impedance decrease at the catheter tip. OBJECTIVE: The purpose of this study was to correlate achieved CF and initial impedance decreases during atrial fibrillation (AF) ablation. METHODS: We correlated achieved CF and initial impedance decreases in patients undergoing ablation for AF with two novel open-irrigated CF-sensing RF catheters (Biosense Webster SmartTouch, n = 647 RF applications; and Endosense TactiCath, n = 637 RF applications). We then compared those impedance decreases to 691 RF applications with a standard open-irrigated RF catheter (Biosense Webster ThermoCool). RESULTS: When RF applications with the CF-sensing catheters were analyzed according to an achieved average CF <5 g, 5-10 g, 10-20 g, and >20 g, the initial impedance decreases during ablation were larger with greater CF. Corresponding median values at 20 seconds were 5 Ω (interquartile range [IQR] 2-7), 8 Ω (4-11), 10 Ω (7-16), and 14 Ω (10-19) with the SmartTouch and n/a, 4 Ω (0-10), 8 Ω (5-12), and 13 Ω (8-18) with the TactiCath (P <.001 between categories for both catheters). When RF applications with the SmartTouch (CF-sensing catheter, median achieved CF 12 g) and ThermoCool (standard catheter) were compared, the initial impedance decrease was significantly greater in the CF-sensing group with median decreases of 10 Ω (6-14 Ω) vs 5 Ω (2-10 Ω) at 20 seconds (P <.001 between catheters). CONCLUSION: The initial impedance decrease during RF applications in AF ablations is larger when greater catheter contact is achieved. Monitoring of the initial impedance decrease is a widely available indicator of catheter contact and may help to improve formation of durable ablation lesions.
BACKGROUND: Good catheter-tissue contact force (CF) is critical for transmural and durable lesion formation during radiofrequency (RF) ablation but is difficult to assess in clinical practice. Tissue heating during RF application results in an impedance decrease at the catheter tip. OBJECTIVE: The purpose of this study was to correlate achieved CF and initial impedance decreases during atrial fibrillation (AF) ablation. METHODS: We correlated achieved CF and initial impedance decreases in patients undergoing ablation for AF with two novel open-irrigated CF-sensing RF catheters (Biosense Webster SmartTouch, n = 647 RF applications; and Endosense TactiCath, n = 637 RF applications). We then compared those impedance decreases to 691 RF applications with a standard open-irrigated RF catheter (Biosense Webster ThermoCool). RESULTS: When RF applications with the CF-sensing catheters were analyzed according to an achieved average CF <5 g, 5-10 g, 10-20 g, and >20 g, the initial impedance decreases during ablation were larger with greater CF. Corresponding median values at 20 seconds were 5 Ω (interquartile range [IQR] 2-7), 8 Ω (4-11), 10 Ω (7-16), and 14 Ω (10-19) with the SmartTouch and n/a, 4 Ω (0-10), 8 Ω (5-12), and 13 Ω (8-18) with the TactiCath (P <.001 between categories for both catheters). When RF applications with the SmartTouch (CF-sensing catheter, median achieved CF 12 g) and ThermoCool (standard catheter) were compared, the initial impedance decrease was significantly greater in the CF-sensing group with median decreases of 10 Ω (6-14 Ω) vs 5 Ω (2-10 Ω) at 20 seconds (P <.001 between catheters). CONCLUSION: The initial impedance decrease during RF applications in AF ablations is larger when greater catheter contact is achieved. Monitoring of the initial impedance decrease is a widely available indicator of catheter contact and may help to improve formation of durable ablation lesions.
Authors: Sven Knecht; Tobias Reichlin; Nikola Pavlovic; Beat Schaer; Stefan Osswald; Christian Sticherling; Michael Kühne Journal: J Interv Card Electrophysiol Date: 2015-04-30 Impact factor: 1.900
Authors: Saurabh Kumar; Chirag R Barbhaiya; Samuel Balindger; Roy M John; Laurence M Epstein; Bruce A Koplan; Usha B Tedrow; William G Stevenson; Gregory F Michaud Journal: J Atr Fibrillation Date: 2015-10-31