Ventricular Tachycardia

Alexander Mazur, MD

Professor, University of Iowa Carver College of Medicine

No Disclosures

Learning Objectives

• Recognize different types of VT

• Understand mechanisms of different types of VT

• Distinguish between VT in patients with and without structural heart disease

• Understand therapeutic approaches to VT in patients with and without structural heart disease

Ventricular ArrhythmiaPVCs

Non-sustained VT: ≥ 3 beats < 30 sec Sustained VT: ≥ 30 sec or syncope or hemodynamic compromise

VF

Structurally Normal Heart Structural Heart Disease

Idiopathic Channelopathies

Ventricular Tachycardia

• Monomorphic: Uniform beat-to-beat QRS morphology

• Pleomorphic: > one distinct QRS morphology during same VT episode

• Polymorphic: Variable beat-to-beat QRS morphology and axis

Electrophysiological Mechanisms

• Reentry

• Triggered activity (EADs and DADs)

• Abnormal automaticity

“Idiopathic” Ventricular Arrhythmia

Tanawuttwwat et al. Eur Heart J 2016

Outflow Tract VT

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

+

+

+

-

- -

III

VT in Structural Heart DiseaseDid you mean: dilated cardiomyopathy arrhythmia substrate

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dilated cardiomyopathy arrhythmia

Post Myocardial Infarction Scar Myocardial Fibrosis in Dilated Cardiomyopathy

Monomorphic VT

Atrial TachycardiaAtrial FlutterAVNRTAVRT (orthodromic)

Atrial TachycardiaAtrial FlutterAVNRTAVRT (antidromic)

Wellens HJJ, Heart 2001

SVT Aberrant Conduction

SVT Accessory Pathway (WPW)

VT

ECG Criteria Supporting VT

Alzand BSN and Crijns HJGM, Europace 2011

His - Purkinje System

Bundle Branch Reentrant VTAlexander Mazur, Jairo Kusniec Boris Strasberg, “Bundle Branch Reentrant 90

Ventricular Tachycardia”

further validation. Application of the pacing maneuvers during bundle branch reentry is often

hampered by fast VT rates commonly associated with hemodynamic compromise. Furthermore,

entrainment of BBR VT by atrial pacing has a limited success and usually requires isoproterenol

infusion to improve atrio-ventricular (AV) nodal conduction.

Figure 2. Twelve-lead ECG during a spontaneous episode of bundle branch reentrant

tachycardia (A). Surface ECG leads I, II, III, V1, V2, V6 (B) or II, III, V1 (C) and intracardiac

recordings from the His bundle (His) and right ventricular apex (RVA) during bundle branch

reentrant tachycardia induced in the same patient. The recordings show many characteristic

diagnostic features of bundle branch reentrant tachycardia: (1) typical LBBB morphology and

left superior axis (A); (2) AV dissociation (C); (3) H preceding every V with the HV interval

(112 ms) greater than that recorded during sinus rhythm (68 ms) (B and C); (5) H precedes the

right bundle deflection. This sequence is consistent with ventricular activation through the right

bundle branch and is appropriate for a LBBB morphology of tachycardia (B); (6) spontaneous

changes in the HH intervals preceded similar changes in the VV intervals (C); and (7)

spontaneous termination of tachycardia with retrograde conduction block to H (C). A, H, RB,

and V denote atrial, His bundle, right bundle, and ventricular electrograms, respectively. (From:

Mazur A, Iakobishvili Z, Kusniec J, Strasberg B. Bundle branch reentrant ventricular

tachycardia in a patient with the Brugada electrocardiographic pattern. A.N.E. 2003;8:252-255,

with permission of Blackwell Futura Publishing, Inc.)

Interfascicular tachycardia

Interfascicular tachycardia has been less commonly reported9,19,28,32-34. BBR and interfascicular

tachycardia may be present in the same patient9,19,33,34. The tachycardia usually has RBBB

morphology. The orientation of the frontal plain axis is variable and may depend on the

Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 5(2): 86-95 (2005)

His

Left Bundle

Right Bundle

Fascicular VTLAF

LPF

Left Bundle

Short-Coupled Variant of Torsades de Pointes

Heart Rhythm Case Reports 2019;5:363-366

Circulation 2019;139:2315-2325

Torsades de Pointes

Bidirectional VT

Sudden Death Prophylaxis • Sustained VT in patients with cardiomyopathies:

• Is associated with a high risk of SD

• Usually an indication for an ICD - the only proven modality (versus antiarrhythmics and catheter ablation) that prolongs survival in these patients

Antiarrhythmic Drugs

• Adjunctive to ICD - to minimize painful ICD shocks

• Limited efficacy

• Increased risk of pro-arrhythmia

• High rate of discontinuation because of intolerance and side effects

• Class I - contraindicated (negative inotropic properties and possible risk of pro-arrhythmia)

• Class III: Amiodarone, Sotalol, Dofetilide (?)

• Others: Mexiletine (Class IIB), Ranolazine (Late sodium current blocker)

Antiarrhythmic Drugs for Prevention of Ventricular Arrhythmia in Patients with ICD

VT Recurrence All-Cause Mortality

Santangeli et al. Heart Rhythm 2016;13:1552-1559

Catheter Ablation

2019 HRS/EHRA/APHRS/LAHRS Expert Consensus statement on Catheter Ablation of Ventricular Arrhythmias

• 259 ICD patients with recurrent VT despite AADs

• Randomized to escalated-AADs vs ablation

• Escalated AADs: • Amiodarone (if amiodarone-naive)

• On amiodarone - ↑ > 300 mg/day or + mexiletine

• Primary endpoint: a composite of death or appropriate ICD shocks for VT/VF

• F-U 27.9 ± 17.1 months

• Primary outcomes: 68.5% AADs vs 59.1% ablation

• VT recurrence: 33.1% AADs vs 24.1% ablation

N Engl J Med 2016;375:111-121

Use of Amiodarone at baseline No use of Amiodarone at baseline

N Engl J Med 2016;375:111-121

2019 HRS/EHRA/APHRS/LAHRS Expert Consensus statement on Catheter Ablation of Ventricular Arrhythmias

2017 AHA/ACC/HRS Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Death

Most Common Mechanism of Monomorphic VT in Patients with Ischemic Cardiomyopathy is Scar-

Related Reentry

2019 HRS/EHRA/APHRS/LAHRS Expert Consensus statement on Catheter Ablation of Ventricular Arrhythmias

2017 AHA/ACC/HRS Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Death

Take Away Points

• Idiopathic VTs are usually benign

• The most common mechanism of monomorphic VT in patients with structural heart disease is scar-related reentry

• Sustained VT in patients with cardiomyopathies is associated with high risk of sudden death. ICD is the only proven modality for prevention of sudden death in these patients.

• The role of antiarrhythmic medications and ablation in patients with an ICD is prevention of recurrent ICD shocks. There is no proven mortality benefit.

Thank You and Stay Safe!