Ventricular tachycardia classification

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]

Overview

Ventricular tachycardia refers to a rhythm with a heart rate in excess of 100 (and in some definitions 120) beats per minute that arises distal to the bundle of His.

Ventricular tachycardia can be classified under three main categories:

1. The morphology of complexes on EKG (monomorphic ventricular tachycardia vs polymorphic ventricular tachycardia
2. The duration of the episode
3. The symptoms associated with the episode

Classification Based Upon Morphology of the QRS Complexes

Monomorphic ventricular tachycardia

Monomorphic ventricular tachycardia is defined as a QRS complex morphology that is identical from beat-to-beat in all leads of the surface electrocardiogram (EKG).

12 lead electrocardiogram showing a run of monomorphic ventricular tachycardia (VT)

Polymorphic ventricular tachycardia

Polymorphic ventricular tachycardia, is defined as QRS complexes with beat-to-beat variability in morphology. This most commonly appears as a cyclical progressive change in cardiac axis referred to by its French eponym Torsade de pointes (literally twisting of the points).

Example

Polymorphic VT

Polymorphic VT

Classification Based Upon Duration of Episode

Another way to classify ventricular tachycardias is the duration of the episodes: Technically, three or more beats in a row on an EKG that originate from the ventricle at a rate of more than 100 beats per minute constitute a ventricular tachycardia. If the fast rhythm self-terminates within 30 seconds, it is considered a non-sustained ventricular tachycardia. If the rhythm lasts more than 30 seconds it is known as a sustained ventricular tachycardia (even if it terminates on its own after 30 seconds).

Sustained Ventricular Tachycardia

• Ventricular tachycardia originates from a ventricular focus
• Lasts more than 30 seconds
• Broad QRS complexes: rate of >90 beats/minute

Paroxysmal Ventricular Tachycardia(Non Sustained Ventricular Tachycardia)

• Rapid succession of three or more ectopic beats.
• Sustained if it lasts longer than 30 seconds.

Incessant Ventricular Tachycardia

• The ventricular tachycardia is recurrent and the episodes are interrupted by only a few sinus beats.

Classification Based Upon Symptoms

A third way to classify ventricular tachycardia is on the basis of its symptoms: Pulseless VT is associated with no effective cardiac output, hence, no effective pulse, and is a cause of cardiac arrest. In this circumstance it is best treated the same way as ventricular fibrillation (VF) and is recognized as one of the shockable rhythms on the cardiac arrest protocol. Some VT is associated with reasonable cardiac output and may even be asymptomatic. The heart usually tolerates this rhythm poorly in the medium to long term, and patients may certainly deteriorate to pulseless VT or to VF.

Catecholamine-induced polymorphic ventricular tachycardia [exact_synonym]	• Catecholaminergic polymorphic ventricular tachycardia [exact_synonym]
• Familial polymorphic ventricular tachycardia [exact_synonym]	• Stress-induced polymorphic ventricular tachycardia [exact_synonym]
• Catecholamine-induced polymorphic ventricular tachycardia [synonym]	• Catecholaminergic polymorphic ventricular tachycardia [synonym]
• Familial polymorphic ventricular tachycardia [synonym]	• Stress-induced polymorphic ventricular tachycardia