Combined Endocardial Pulsed Field

Figures

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  Visual Summary. Immediate VT Termination With Successive Endocardial PF-RF Lesions Directly Apposed to Far-Field Midmyocardial Isthmus (Left) 12-lead electrocardiogram of the recurrent clinical VT. (Middle) Graphical representation of the multiplanar nature of the VT circuit alongside the VT activation map with midmyocardial/epicardial isthmus. The wave of propagation progresses from the entrance on the endocardium, then disappears beneath the surface, and finally re-emerges at the exit. (Right) Ablation catheter positioned endocardially atop the suspected midmyocardial/epicardial isthmus. VT termination occurred upon the seventh PF application, once critical ablation depth was achieved with successive applications at the same site. Abl = ablation; Abl D = ablation catheter distal; Abl M = ablation catheter mid; LAT = local activation time; PF = pulsed field; PFA = pulsed field ablation; RF = radiofrequency; RFA = radiofrequency ablation; RVA = right ventricular apex proximal; RVA d = right ventricular apex distal; SR = sinus rhythm; VT = ventricular tachycardia.

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  Figure 1. High-Density Electroanatomic Maps of Left Ventricle (Left) High-density bipolar voltage map demonstrating a large scar area of the inferior left ventricle, extending from the base to the apex, sparing the apical tip. (Middle) Peak frequency map, set to >500 Hz, demonstrating a discrete zone of interest along the basal mid-LV inferior wall. (Right) Isochronal late activation map (ILAM) demonstrating a discrete deceleration zone along the mid–left ventricle inferior wall toward the apex.

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  Figure 2. 12-Lead Electrocardiogram 12-lead electrocardiogram of the clinical VT demonstrating a right bundle right superior axis with transition at lead V2. VT = ventricular tachycardia.

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  Figure 3. Strategic Multielectrode Activation Mapping of VT Sequential catheter movements on the endocardial surface delineate the diastolic pathway with a clear absence of mid-diastolic electrograms, inferring midmyocardial/epicardial activation. VT = ventricular tachycardia.

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  Figure 4. Activation Map of Multiplanar Ventricular Tachycardia (A) Ventricular tachycardia activation map with midmyocardial/epicardial isthmus. The wave of propagation progresses from the entrance on the endocardium, then disappears beneath the surface, manifested as an absence of signals, and finally re-emerges at the exit. (B) Graphical representation of the multiplanar nature of the ventricular tachycardia circuit. The activation gap is in fact the wave of propagation “diving under” the endocardial surface. LAT = local activation time.

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  Figure 5. Positioning the Ablation Catheter Endocardially Atop the Suspected Midmyocardial/Epicardial Isthmus VT termination occurred upon the seventh application using an R-wave–gated, 5-burst, 2,200-V waveform ablation catheter. Termination likely occurred upon increasing the ablation depth achieved with successive applications at the same site. Abl = ablation; Abl d = ablation catheter distal; Abl M = ablation catheter mid; PFA = pulsed field ablation; RVA = right ventricular apex proximal; RVA d = right ventricular apex distal; SR = sinus rhythm; VT = ventricular tachycardia; other abbreviations as in Figure 4.

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  Figure 6. Respective Ablation Lesion Sets of PFA and RFA Overlayed Upon the Ventricular Tachycardia Activation Map Ablation targeted interruption of the re-entrant activation at the isthmus, as well as the funnels at the entry (red) and exit (turquoise and blue) of the ventricular tachycardia channel. PFA = pulsed field ablation; RF = radiofrequency; RFA = radiofrequency ablation.