Mapping the unmappable—Rapid high-density contact mapping in hemodynamically unstable ventricular tachycardia using a novel star-shaped multipolar catheter

Figures

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  Figure 1. A: Intraprocedural setup in anteroposterior view: ST ablation catheter to left ventricle (LV) via trans-septal puncture (TSP) and Octaray (Biosense Webster) retrograde via aortic valve, quadripolar catheter in right ventricle (RV). Note cardiac resynchronization therapy defibrillator in situ and quadripolar electrophysiology catheter in RV apex. B: Corresponding 3D CARTO model of substrate map with large basal-midventricular scar on the septum in the bipolar map with multiple ablation lesions (dark red balls and circles), blue lesions representing tagged late potentials during substrate mapping, yellow lesions representing conduction system signals. C: Bipolar electrogram (EGM) during ventricular tachycardia of all 8 Octaray splines with magnification of selected bipolar EGMs with respective TRUEref unipolar EGMs using the central isolated shaft electrode as indifferent pole. Sharp, clear local potential on unipolar EGM with no relevant baseline drift. D: Octaray catheter, here shown with 2-5-2-5-2 electrode configuration.

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  Figure 2. Left panel shows ultra-high-density mapping with acquisition of >17,400 points in only 24 minutes for left ventricular substrate and activation mapping in ventricular tachycardia (VT). Each dot represents an acquisition point projected on the shell at maximum density setting. Magnification shows that nearly the entire area of interest is mapped with the maximum point density allowed by the system. Right panel shows wavefront algorithm during VT with presystolic potentials, with intermittent failure to annotate the low-amplitude near-field potentials.

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  Figure 3. Left image (panel 1): The 8 splines of the star-shaped Octaray (Biosense Webster) stretched out equally on the surface of the left ventricular septum covering an area of >11 cm2 representing 7.6% of the total internal surface of the dilated left ventricle and allowing for assessing activation patterns across the splines. Middle image (panel 2): A 12-lead electrocardiogram (ECG) of ventricular tachycardia (VT-1) with inferoseptal basal exit and intracardiac electrogram examples from spline G (with clear local potentials on unipolar G1 and G2) preceding spline F, which is positioned more basally on the septum, closer to the VT exit. Right image (panel 3): A 12-lead ECG of VT-2 (25 mm/s) with inferior axis and positive concordance in the precordial leads, suggesting an exit in the anterobasal segment.