Abstract 2858: A Four-Chamber Comparison of Contact Force Mapping and Ultrasound to Achieve Adequate Catheter Tip-Tissue Contact
Introduction: During mapping and ablation, sufficient catheter tip-tissue contact is required to achieve adequately sized and appropriately targeted lesions, while excessive contact force can predispose to tamponade or injury to nearby structures.
Methods: Therefore, in a feasibility test case, a healthy canine underwent contact force (CF) mapping using a novel CF catheter. Two operators manipulated the catheter in all cardiac chambers, with left-sided access from transseptal and retroaortic approaches. During inside-out mapping, with operators blinded to CF measurements, four levels tissue contact were applied (0=none, 1=minimal, 2=consistent, 3=tissue tenting), as determined by 2-D phased array, intracardiac echocardiography (ICE) and biplane fluoroscopy. During outside-in mapping, catheter pressure was applied to produce 10g gradations in CF and the level of contact by ICE was assessed.
Results: During inside-out mapping, 52 measurements were performed in all chambers. The mean peak force associated with a given level of contact on ICE differed by chamber, with consistent contact occurring at 56.0±9.9g in the left atrium (LA), 33.3±28.0g in the left ventricle, 20.6±12.9g in the right ventricle, and 12.6±6.7g in the right atrium, and tissue tenting occurring at 65.3±15.3g in the LA, 65.0±18.4g in the left ventricle, 27.0±20.4g in the right ventricle, and 38.7±16.3g in the right atrium. During outside-in mapping, 43 catheter applications were performed. Tissue contact for a given CF was minimal at 1–10g, minimal or consistent at 11–20g, consistent at 20 –30, consistent or tenting at 30 – 40g, and tenting at >40g. This was chamber dependent. For example, in the LA, a CF of 45.2±18.2g resulted in consistent tissue contact. This was 10 –20g higher than the amount required in the RA, and 10g lower than the level applied when guided by ICE alone.
Conclusions: Quantification of CF may provide a more accurate assessment of catheter tip-tissue contact than ICE and fluoroscopy alone. This is relevant to ablation in the LA, where high CF’s are required, and the window between consistent contact and excessive tissue tenting is narrow.