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Ventricular Tachycardia

Monomorphic Non-Sustained Ventricular Tachycardia (Example)
Monomorphic Sustained Ventricular Tachycardia (Example 1)
Monomorphic Sustained Ventricular Tachycardia (Example 2)

Ventricular tachycardia (VT) occurs when multiple ectopic ventricular beats occur in succession. If all of the QRS complexes appear the same or very similar, then it is termed monomorphic VT. If the QRS complexes appear different from beat-to-beat, then it is termed polymorphic. Another name for polymorphic VT is "Torsades de Pointes".  VT can be hemodynamically unstable resulting in syncope and can degenerate into the universally fatal rhythm ventricular fibrillation.

When describing ventricular tachycardia, the following should be mentioned:

1) Monomorphic versus polymorphic (Torsades)
2) Sustained versus non-sustained (sustained defined as > 30 seconds in duration or symptomatic)
3) The heart rate at which it is occurring (electrophysiologist use the "cycle length" or the number of milliseconds between the QRS complexes)

The Brugada Criteria for determining if the rhythm is indeed VT is below, only 1 is required to establish a diagnosis of VT:

1) The absence of an R-S complex on ALL of the precordial leads (aka "concordance"). Meaning all of the QRS complexes are either all positive or all negative, no in betweens.
2) R-S interval > 100 ms in ANY precordial lead
3) The presence of atrioventricular dissociation (try to identify P waves amongst the QRS complexes going at a different rate, if present then you have AV dissociation and VT is the rhythm)
4) Specific morphology criteria for the QRS complexes

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