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Polymorphic VT

critical
Lead II
25 mm/s10 mm/mV
Heart rate
—
RR
—
QT
—
Type

Torsades de Pointes

A specific form of polymorphic VT occurring in the setting of QT prolongation. The QRS complexes appear to twist around the baseline with a characteristic spindle-shaped waxing and waning amplitude.

Mechanism

A specific form of polymorphic VT occurring in the setting of QT prolongation. The QRS complexes appear to twist around the baseline with a characteristic spindle-shaped waxing and waning amplitude.

Findings· 3
  • Polymorphic wide-complex tachycardia with characteristic spindle-shaped envelope.
  • QRS amplitude waxes and wanes, appearing to rotate around the isoelectric line.
  • Rate 150–300 bpm.
Clinical Impact

Life-threatening. Associated with prolonged QT interval (congenital or acquired). Treatment: IV magnesium, isoproterenol or temporary overdrive pacing to shorten QT. Remove offending drugs. Defibrillation if pulseless.

Differential· 2
Polymorphic VT

Same appearance but normal baseline QT. Treatment differs — polymorphic VT needs amiodarone, not magnesium.

Ventricular Fibrillation

Degenerated Torsades appears chaotic. Both require defibrillation if pulseless.