Radiofrequency ablation for fascicular ventricular tachycardia causing tachycardiomyopathy and brief literature review

Abstract

A 10-years-old boy presented with a history of effort intolerance and palpitations for 4 months. His electrocardiogram showed wide complex tachycardia suggestive of fascicular ventricular tachycardia (VT). The echocardiogram showed moderate-to-severe left ventricular systolic dysfunction without any structural lesion. The tachycardia was unresponsive to adenosine and direct current cardioversion. It responded to oral verapamil. The electrophysiology study confirmed the tachycardia as left posterior fascicular VT. The tachycardia was successfully ablated guided by Purkinje potential on three-dimensional mappings. He showed improvement in ventricular functions before discharge. He is doing well on short-term follow-up.

Keywords: Fascicular ventricular tachycardia; radiofrequency ablation; tachycardiomyopathy.

Figure 1

Electrocardiogram showing regular wide complex tachycardia with QRS width of 140 msonds, right bundle branch morphology, and left axis deviation

Figure 2

Postverapamil administration electrocardiogram after 36 h showing sinus rhythm, rate 90 bpm, normal axis, and QRS width of 90 ms

Figure 3

(a) The repeat echocardiogram after conversion to sinus rhythm showing EF 46.4% in M Mode. (b) The left ventricular longitudinal strain in apical four-chamber − 14.6% and (c) in basal short-axis − 16.8%

Figure 4

Three dimensional map showing violet as ablation lesions in the lateral and right anterior oblique views

Figure 5

Electrogram showing (a) sustained ventricular tachycardia due to catheter manipulation in the septal area and (b) catheter-induced ectopics very similar to clinical tachycardia

Figure 6

Pace-map showing (a) good match of clinical tachycardia, (b) P2 (Purkinje potential) precedes the QRS, P1 (prePurkinje potential) follows QRS on ablation catheter and is delayed in distal ablation (1-2) compared to proximal (3-4)

Figure 7

Postradiofrequency ablation electrocardiogram showing deep q in lead III and rightward axis than baseline

Figure 8

Tachycardia circuit in fascicular ventricular tachycardia. The antegrade limb of the circuit proceeds through the verapamil sensitive zone (curved line) from the basal to apical left ventricular septum giving rise to the prePurkinje potential (P1) as seen in the accompanying electrogram. The lower turn around site of the reentrant circuit occurs in the lower third of the septum with the capture of the fast conduction Purkinje fibers producing Purkinje potential (P2) along the posterior fascicle. From here, antegrade activation occurs down the septum to break through septal myocardium below, and retrograde activation occurs over the posterior fascicle from apical to basal septum forming the retrograde limb of the tachycardia. The reentrant circuit is completed by a zone of slow conduction at the upper turn around point of the circuit located close to the main trunk of the left bundle branch[11]