Successful catheter ablation for verapamil-sensitive idiopathic left ventricular tachycardia guided by dual post–QRS wave P1 potentials after catheter-induced mechanical block

Figures

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  Figure 1. Twelve-lead electrocardiogram (left, ventricular tachycardia; right, sinus rhythm). HIS = bundle of His; HRA = high right atrium; LAO, left anterior oblique; RV = right ventricle.

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  Figure 2. A: Intracardiac electrogram and fluoroscopic image at the moment of the “bump” phenomenon. B: Atrial programmed pacing that demonstrates decremental conduction in the late-appearing P1 potential. C: Two types of delayed P1 potentials, recorded by the DECANAV (DECA) catheter in the CARTO3 system (Biosense Webster, Diamond Bar, CA). The left panel displays the site recorded for the early-to-mid-appearing P1 potential, marked with a light blue tag, while the right panel displays the site recorded for the late-appearing P1 potential, marked with a green tag. D: The upper panel displays the local potentials of the ablation catheter at the beginning of radiofrequency ablation. The presumed bump site is identified by the blue tag and the ablation sites are identified by red or pink tags in the lower panel. E: Best pace map at the ablation site.

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  Figure 3. A: Illustration showing the appearance of the P1 potential in typical idiopathic left ventricular tachycardia (left, ventricular tachycardia; right, sinus rhythm). B: Illustration showing the mechanisms that cause the 2 types of delayed P1 potentials (left, before ablation; right, after ablation). ABL = ablation; LAF = left anterior fascicle; LB = left bundle; LPF = left posterior fascicle; RB = right bundle; SR = sinus rhythm; VT = ventricular tachycardia.