Localization of unstable intramural ventricular tachycardia circuit using live directional activation mapping

Figures

• 

  Figure 1. A: Twelve-lead electrocardiograms illustrating VT1 and associated pace maps at the basal anterolateral left ventricle. B: Intracardiac recordings for VT1 and a pace map are displayed. HD denotes the HD grid mapping catheter, which was positioned on the EPI surface of the basal anterolateral wall of the left ventricle. Note the presence of a small, fractionated electrogram complex that precedes the onset of the QRS by 59 ms during VT1 (yellow arrows). The pace map at HD B1,2 showed a perfect match with VT1, demonstrating the same latency to QRS onset. AIV-GCV = anterior interventricular vein and the great cardiac vein; ENDO = endocardium; EPI = epicardium.

• 

  Figure 2. Left: Bipolar voltage map of the LV ENDO. Center: Unipolar voltage map of the LV ENDO. Right: Bipolar voltage map of the LV EPI recorded during sinus rhythm. In the EPI bipolar voltage map (EPI), the area of the perfect pace map for VT1 is indicated by a yellow dotted circle. ENDO = endocardium; EPI = epicardium; LV = left ventricular.

• 

  Figure 3. A: Twelve-lead electrocardiograms depicting VT2 and pace maps at both the EPI and ENDO surfaces of the basal anterolateral left ventricle. B: Intracardiac recordings of VT2 are presented. ABL refers to the recording from a TactiFlex catheter in the LV EPI, and ENDO refers to the recording from a FlexAbility catheter in the LV ENDO. The ABL Uni displayed a QS pattern. ABL Uni = unipolar recording; ENDO = endocardium; EPI = epicardium; LV = left ventricular.

• 

  Figure 4. A:Upper panel: Live activation direction (AD) mapping during VT2 is shown, with activation vectors revealing a centrifugal activation pattern (OT certainty was 0.3). Lower panel: The positions of the ablation catheters during bipolar ablation at the LV basal lateral wall are depicted. Endo = endocardium; Epi = epicardium; LAO = left anterior oblique; LV = left ventricular; OT = Omnipolar Technology; RAO = right anterior oblique.

• 

  Figure 5. Schematic diagrams illustrating the potential mechanisms underlying VT1 and VT2. ENDO = endocardium; EPI = epicardium.