Twelve-Lead ECG of Ventricular Tachycardia in Structural Heart Disease

Abstract

951I n patients with structural heart disease (SHD), defined by the presence of myocardial scarring either on cardiac imaging or electroanatomical mapping, catheter ablation is increasingly used for the treatment of ventricular tachycardia (VT).With more detailed knowledge of potential substrates and anatomic structures involved in VT, not only the endocardium of the left ventricle (LV) and right ventricle (RV) but also more complex structures like the aortic root, the cardiac veins, or the epicardium have become areas of interest for ablation.Preprocedural analysis of the clinically documented VT 12-lead ECG is often used to predict the VT site of origin (SoO), and it is considered to be an important tool for planning the ablation, to estimate the probability of success, and to recognize potential procedural limitations and related risks. These factors may have important implications not only for patient advice and decision making but also for the selection of a center capable to perform the expected procedure.Because the majority of inducible VTs in patients with SHD are not hemodynamically tolerated, 1,2 a detailed analysis of the VT 12-lead ECG of each induced VT may also be helpful. Combining the ECG with information of the scar size and distribution obtained from electroanatomical mapping during sinus rhythm or from preprocedural imaging may direct mapping to the area of interest with the potential of increasing procedural success and to reduce procedural duration.In this review, we will focus on the reported evidence for the value of the 12-lead VT ECG as a mapping tool in patients with scar-related VT and discuss its potential implications when combined with scar information from electroanatomical mapping or imaging. VT SoOThe mechanism of the majority of VTs in patients with structurally normal hearts is focal, and the 12-lead ECG can be helpful to predict its SoO because rapid activation of the normal myocardium from a focal source results in typical QRS patterns. 3As a general rule, VTs originating from the structurally normal LV have a right bundle branch block (RBBB) morphology (defined as predominant R in lead V1) and VTs from the normal RV have a left bundle branch block (LBBB) morphology (defined as predominant S in lead V1). The precordial transition for RBBB VTs (first lead with a predominant S) changes from positive concordant for VTs originating from the base of the LV to progressively earlier transition in V2-V4 as the VT origin moves toward the apex of the ventricle. For LBBB VTs, VTs originating from the basoseptal area of the RV have an early transition (first lead with a predominant R), and the transition becomes progressively later as the VT origin moves toward the ventricular free wall. With regard to the frontal plane axis, VTs originating from the superior aspect of the ventricles show an inferior axis (predominant R in aVF), VTs from the inferior aspect of the ventricles show a superior axis (predominant S in aVF), LV free wall VTs have typically a right axis (with a dominant S in I...

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

“…Several algorithms have been devised to predict the exit site in post-MI VT. As noted above, these all have the important limitation that (to the degree they can reveal localizing information about the arrhythmia) they indicate the exit site of the circuit, not the location of the midportion of the diastolic corridor ( S5.2.8.14 – S5.2.8.17 ). Although the distance from the exit site to a vulnerable portion of the diastolic corridor can be 1 cm or less, it could be more.…”

A case report reappraising the usefulness of Valsalva manoeuvre in drug-refractory ventricular tachycardia

“…Twelve-lead ECG can crudely predict the site of origin of scar-related VT coinciding with scar border. 10 A general guide to aid ECG localization of the origin of VT is provided in Figure 5 . Using these simple rules, VT-1 typified by LBBB morphology and inferior axis ( Figure 1 ), is localized to an anteroseptal exit, corroborated by cardiac MRI findings of scarring in this region.…”

“…Using these simple rules, VT-1 typified by LBBB morphology and inferior axis ( Figure 1 ), is localized to an anteroseptal exit, corroborated by cardiac MRI findings of scarring in this region. The second VT with RBBB morphology and inferior axis ( Figure 2 ) hinted at a more basal location, and is potentially a Purkinje VT, 10 with the sharp initial QRS deflection suggesting the VT arising from the His-Purkinje conducting system. Indeed, it is conceivable that VT-2 is an interfascicular VT utilizing the left anterior fascicle as the antegrade limb.…”

Feasibility assessment of proton treatment for ventricular tachycardia—treatment planning study

“…For the photon treatment plan, the gross tumor volume (GTV), internal target volume (ITV) and planning target volume (PTV) were defined. The GTV was defined by the contouring of five common recurrent VT regions by cardiology physician, including apical anterior (AA), apical inferior (AI), basal septal (BS), inferior basal (IB), lateral basal (LB) (16)(17)(18)(19)(20). The five regions are shown in Figure 1, and were separated into 2 groups for organ at risk (OAR) dose analysis: AA and AI in Group 1; BS, IB and LB in Group 2, due the locations at the center or surface of the heart.…”