Association between different catheter designs for the characterization of the left atrial substrate

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Private company. Main funding source(s): The study was supported by an investigator sponsored grant (Boston Scientific). BACKGROUND: Bipolar voltage electrograms (BVE) for left atrial (LA) substrate characterization strongly depend on the catheter design and electrode configuration. PURPOSE: The aim of the study was to compare bipolar voltage electrograms (BVE) obtained from the left atrium using four different established mapping catheters and to deduce the individual catheter-specific cut-offs for scar and healthy myocardial tissue. METHODS: We prospectively included 25 consecutive patients referred for catheter ablation for atrial fibrillation recurrence after index PVI. The pipeline of the analysis leading to the individual cut-off for every catheter based on a reference catheter value is shown in the figure. In detail, consecutive high-resolution electroanatomic mapping was performed using a multipolar catheter (Orion), a duo-decapolar variable circular mapping catheter (Lasso), an irrigated ablation catheter with micro electrodes (MIFI) and a 4.5 mm tip-size irrigated ablation catheter (Nav). BVEs for the four catheters were compared in voxels with a size of 3x3x3mm^3 (Figure, top left). Total least squares regression was performed for every patient to investigate the logarithmic relationship between the BVE measured by two different catheter types (Figure, top right). The mean equivalent BVE cut-off over all patients for every catheter was calculated for the reference cut-offs of 0.1 mV, 0.2 mV, 0.5 mV, 1.0 mV, and 1.5 mV (Figure, bottom left). RESULTS: Correlation between the four different BVE maps for the 25 patients showed a slight individual variation between the patients. Compared to the BVE cut-offs from the standard Nav catheter with a 4.5 mm tip, the scar cut-off using the Orion catheter must be lowered to 0.034 mV for a 0.1 mV cut-off, to 0.09 mV for a 0.2 mV cut-off, and to 0.35 mV for the 0.5 mV cut-off (Figure). Similar values hold true for a Lasso map as comparator (Figure). For healthy tissue above 1 mV, similar cut-offs to the reference values might be advisable. CONCLUSION: In contrast to the established Nav or Lasso catheter, the scar voltage cut-off for the Orion catheter needs to be lowered to 0.1 mV instead of the 0.2 mV cut-off and approx. 0.35 mV for a 0.5 mV cut-off. At lower voltages the difference between the catheters increases. The presented connective table enables to transfer the studies of left atrial substrate characterizations using different catheter types. [Figure: see text]