cardiolab logocardiolab

Monomorphic VT

critical
Lead II
25 mm/s10 mm/mV
Heart rate
72bpm
RR
833ms
QT
378ms
Type

Monomorphic VT

A rapid, regular tachycardia originating from a single focus in the ventricles. The re-entrant circuit or automatic focus fires at 100–250 bpm, bypassing the normal conduction system entirely.

Recognition· 4
  • Wide QRS complex (>120 ms)
  • Regular rapid rhythm (140-200 bpm)
  • Uniform (monomorphic) morphology
  • AV dissociation may be present
Mechanism

Ventricular focus fires rapidly, bypassing normal conduction system

A re-entrant circuit or automatic focus in the ventricles generates rapid impulses at 100-250 bpm. The impulse spreads abnormally through ventricular muscle rather than the His-Purkinje system, creating wide, bizarre QRS complexes. The atria may continue firing independently (AV dissociation).

Findings· 4
  • Regular wide-complex tachycardia.
  • QRS >120 ms with uniform (monomorphic) beat-to-beat morphology.
  • AV dissociation may be present.
  • Rate typically 140–200 bpm.
Clinical Impact
Degeneration to ventricular fibrillation
↓
Hemodynamic collapse
↓
Sudden cardiac death if untreatedRISK

Life-threatening — can degenerate to V-fib → cardiac arrest

Management· 3
1

Unstable

immediate synchronized cardioversion.

2

Stable

IV amiodarone or procainamide.

3

Long-term Management

Identify and treat underlying cause (MI, electrolyte imbalance, cardiomyopathy).

Differential· 2
SVT with Aberrancy

Both are wide complex tachycardias. SVT + BBB has preceding P waves and typical BBB morphology.

Polymorphic VT

Both ventricular tachycardias. Polymorphic shows changing QRS morphology beat-to-beat.