The Initial Part of Polymorphic Ventricular Tachycardia as a Clue for the Sustainability of Tachycardia and Ablation Success: A Varying Degree of Purkinje–Myocardial Complicity?

Figures

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  Figure 1:. Twelve-lead electrocardiograms taken at arrival (A) and the following day (B and C) are seen. D: Note the first several cycles of episodes before the development of the sustained polymorphic ventricular tachycardia, which, although polymorphic, may be nearly identical at different times on telemetry strips.

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  Figure 2:. Electrocardiograms recorded during the electrophysiology study show several episodes of non-sustained polymorphic (A), sustained polymorphic (B), pleomorphic (C) note the alternans changes in precordial leads), and monomorphic (D) ventricular tachycardia.

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  Figure 3:. A–C: Electrocardiograms recorded during the electrophysiology study. Note that the initiating first several cycles of episodes before the development of the sustained polymorphic ventricular tachycardia, although polymorphic, may be nearly identical to the preceding isolated premature beat (morphology 1, red rectangle with negative polarity in aVL; morphology 2, yellow rectangle with positive polarity in aVL).

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  Figure 4:. The high-frequency Purkinje potentials preceding the QRS at an early ventricular activation site with 1-to-1 Purkinje activity (A and C) or a dissociated form (B). The morphology of the ventricular complexes, originating from the Purkinje fibers, is changing (note the QRS changes in aVL in A–D), suggesting different Purkinje–muscle outbreak terminations of polymorphic ventricular tachycardia preceded by the slowing (B and C) or disappearance (D) of Purkinje potentials (C). C: Note also a pair of morphologically distinct premature beats with different conduction times to local muscle (morphology 1, red rectangle with negative polarity in aVL; morphology 2, yellow rectangle with positive polarity in aVL).

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  Figure 5:. The high-frequency Purkinje potentials preceding the QRS at an early ventricular activation site also precede activation during sinus rhythm. During sinus rhythm, fused Purkinje potentials are seen before the onset of the QRS (A). Premature beats originating from the left ventricular Purkinje system are seen as isolated (A) and interpolated (B) forms. The second Purkinje discharge is not conducted to the ventricle due to exit block (C; note red arrows). D: Note each QRS complex is morphologically different but preceded by a Purkinje potential with a varying conduction time. Note the mild changes in QRS morphology between the red and yellow rectangles (morphology 1, red rectangle with negative polarity in aVL; morphology 2, yellow rectangle with positive polarity in aVL).

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  Figure 6:. The 3-dimensional electroanatomic mapping shows the conduction system (yellow and red dots) and the Purkinje potential (blue dot) during the monomorphic ventricular tachycardia. The changes in ventricular cycles are preceded by a similar change in Purkinje cycles. Abbreviations: LAF, left anterior fascicle; LPF, left posterior fascicle.

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  Figure 7:. Both initiation and termination of the monomorphic ventricular tachycardia were determined by similar non-sustained ventricular cycles.

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  Figure 8:. It is important to distinguish between a fascicular Purkinje potential from isolated muscle potentials. Abbreviations: M, local abnormal ventricular activity; PP, Purkinje potential.