Korean Circ J.  2021 Jan;51(1):15-42. 10.4070/kcj.2020.0436.

Updates in Ventricular Tachycardia Ablation

• Campbell T
• Bennett RG
• Kotake Y
• Kumar S

• KMID: 2509901
• DOI: http://doi.org/10.4070/kcj.2020.0436

Abstract

Sudden cardiac death (SCD) due to recurrent ventricular tachycardia is an important clinical sequela in patients with structural heart disease. As a result, ventricular tachycardia (VT) has emerged as a major clinical and public health problem. The mechanism of VT is predominantly mediated by re-entry in the presence of arrhythmogenic substrate (scar), though focal mechanisms are also important. Catheter ablation for VT, when compared to standard medical therapy, has been shown to improve VT-free survival and burden of device therapies. Approaches to VT ablation are dependent on the underlying disease process, broadly classified into idiopathic (no structural heart disease) or structural heart disease (ischemic or non-ischemic heart disease). This update aims to review recent advances made for the treatment of VT ablation, with respect to current clinical trials, peri-procedure risk assessments, pre-procedural cardiac imaging, electro-anatomic mapping and advances in catheter and non-catheter based ablation techniques.

Keyword

Ventricular tachycardia; Ventricular arrhythmias; Radiofrequency ablation; Multimodal imaging; Sympathectomy

Figure

• 

  Figure 1 Preprocedural imaging of scar. (A) LGE-MRI 3-dimensional reconstruction of the LV from a porcine infarct model with ADAS-VT. To delineate tissue characteristics PSI set to 60%/40%. Red region core scar location and blue is healthy tissue. Reconstruction of LV with small tube denoting conducting channel identified by ADAS (Red arrow). MRI images of associated location of conducting channel. (B) Music images of LV and RV in EAM system. White structure is scar reconstruction at the peri-aortic and basal septal region. ICD leads shown in purple. Music images courtesy of Dr. Saagar Mahida, Liverpool Heart and Chest Hospital, Liverpool, UK.
EAM = electro-anatomic mapping; ICD = implantable cardioverting defibrillator; LGE = late gadolinium enhanced; LV = left ventricle; MRI = magnetic resonance imaging; PSI = pixel signal intensity; RV = right ventricle; VT = ventricular tachycardia.

• 

  Figure 2 ILAM and pace mapping correlation map. (A) LV EAM reconstruction of substrate voltage in RVp (Bipolar 0.5–1.5mV). (B) LV EAM reconstruction of activation time in RVp. ILAM displayed at red circle. Note rapid change in colors denoting slow conduction over a small area. (C) Pace map correlation for VT. Best pace map for VT (white region) localizes to same regions as ILAM and low voltage in substrate mapping. (D) Pace mapping signals from ILAM region shows 94% match to VT morphology with 80 ms stimulation to QRS delay.EAM = electro-anatomic mapping; ILAM = isochronal late activation mapping; LV = left ventricle; RVp = right ventricular pacing; VT = ventricular tachycardia.

• 

  Figure 3 Conducting channels on ripple mapping in inferior view of LV. Blue arrow denotes course of conducting channels identified with Ripple mapping. (A) EAM reconstruction of voltage map with Ripple bars displayed and associated EGM at border zone. Voltages cutoff values are reduced (0.1–0.25 mV) to show viable tissue below standard cutoffs. Ripple bars at entrance point to conducting channel. (B) Ripple bars show conducting channel propagation through low voltage from mid to annular region of scar and associated EGMs of this region. (C) Termination of conducting channel at annular region. EGMs show latest activation of conducting channel. (D) Ablation that rendered the patient non-inducible for all VT at completion of procedure. Ablation tags in red.EAM = electro-anatomic mapping; EGM = electrogram; LV = left ventricle; VT = ventricular tachycardia.

• 

  Figure 4 Focal ventricular tachycardia in patients with structural heart disease.Reprinted from Robert D. Anderson, Geoffrey Lee, Ivana Trivic, Timothy Campbell, Timmy Pham, Chrishan Nalliah, Eddy Kizana, Stuart P. Thomas, Siddharth J. Trivedi, Troy Watts, Jonathan Kalman and Saurabh Kumar, Focal Ventricular Tachycardias in Structural Heart Disease: Prevalence, Characteristics, and Clinical Outcomes After Catheter Ablation. JACC Clinical Electrophysiology 2020;6(1):56-69, with permission from Elsevier.LV = left ventricle; RV = right ventricle; RVOT = right ventricular outflow tract.

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