Idiopathic Ventricular Tachycardia

Abstract

Idiopathic ventricular tachycardia (VT) is an important cause of morbidity and less commonly, mortality in patients with structurally normal hearts. Appropriate diagnosis and management are predicated on an understanding of the mechanism, relevant cardiac anatomy, and associated ECG signatures. Catheter ablation is a viable strategy to adequately treat and potentially provide a cure in patients that are intolerant to medications or when these are ineffective. In this review, we discuss special approaches and considerations for effective and safe ablation of VT arising from the right ventricular outflow tract, left ventricular outflow tract, left ventricular fascicles, papillary muscles, and moderator band.

Keywords: cardiac anatomy; catheter ablation; electrocardiogram; ventricular tachycardia.

Figure 10

Activation map with ablation lesions transecting the left posterior fascicle (orange dots) blue dots denote the left anterior fascicle, ablation was performed to transect the LPF at this level, which also included very fractionated signals locally.

Figure 11

Endocardial signals of IL-VT showing typical pre-systolic signals. Blue arrows denote the P1 signal and red arrows denote the P2 signal during tachycardia.

Figure 12

(A) Echo image showing a false tendon (orange arrow) on the anteroseptum of the LV, (B) ICE image showing the same structure. (C–E), ICE images of cryoablation on the false tendon with ablation lesions spanning the proximal, mid, and distal segments moving left to right noted by the green circles (Table 3).

Figure 1

Representative illustration of the right ventricle and left ventricle highlighting common locations of idiopathic VT.

Figure 2

Characteristic ECG of an RVOT-VT showing LBBB, inferior axis, transition at V3, lead 1 is negative. Successful ablation was performed just below the pulmonary valve on the leftward free wall.

Figure 3

ICE image of the RVOT with an ablation catheter (blue arrow) positioned on the anterior wall (star) below the pulmonic valve plane (blue dashed line), thick muscle bundles (red arrow) are visualized above and below the valve.

Figure 4

LAO view with ablation catheter in the RVOT retroflexed back onto the PV, and a left coronary angiogram showing the proximity to the catheter location.

Figure 5

ECG from LVOT showing a rightward inferior axis with early transition at V3. Successful ablation was performed at LSoV. This also required ablation at the AMC region.

Figure 6

RVOT/LVOT anatomy, showing proximity of posterior RVOT to the left main and anterior LVOT and the relationship of leads I and V1.

Figure 7

Trans-septal approach to the LSoV in the setting of a mechanical aortic valve (star). A multi-electrode catheter (blue arrow) is pushed through the coronary sinus into the Great Cardiac Vein/Anterior Interventricular Vein junction to span the relevant area. The ablation catheter (red arrow) traverses the trans-septal access and then is flexed back to underneath the LSoV (a) RAO projection, (b) LAO projection.

Figure 8

Retrograde approach to the LSoV, (a) RAO projection, (b) LAO projection.

Figure 9

Characteristic ECG of fascicular VT showing RBBB and LAFB pattern, diagnosis is clinched by the fusion beats (arrows). Successful ablation was performed by transecting the left posterior fascicle.

Figure 13

Characteristic ECG of posteromedial papillary muscle VT with a RBBB, left superior axis, and later precordial transition to R/S configuration.

Figure 14

ICE image of cryoablation catheter positioned in between the two heads of the papillary muscle (red arrow) during ablation for added stability.

Figure 15

Characteristic ECG of moderator band VT-showing LBBB, left superior axis with S wave more negative in III than II, transition occurs late at V5 (given the apical exit) and variable QRS morphology is seen. Successful ablation was performed on the moderator band towards the insertion onto the papillary muscle close to the free wall.

Figure 16

ICE image of a cryo catheter (red arrow) balancing on and adherent to moderator band (blue arrow).