Confusion in the Emergency Room

Confusion in the Emergency Room

Learning Objectives:

1. Describe treatment of unstable polymorphic ventricular tachycardia.

2. Describe ECG criteria for torsades de pointes.

3. Describe treatment for torsades.

ECG Criteria for Torsades de Pointes:

1. The heart rate is fast and the rhythm is irregular.

2. The QRS complex is wide and the direction of polarity is changing. Torsades de Pointes is a variant form of ventricular tachycardia in which the polarity periodically changes from positive to negative. The name means twisting of the points.

3. P waves are not apparent.

4. The relationship between the P waves and QRS complexes is not defined since the P waves are not identifiable.

Treatment of Torsades de Pointes:

1. It is important to distinguish Torsade de Pointes from ventricular tachycardia since the treatment is different. Torsades de Pointes is associated with a long QT interval. Agents such as quinidine and procainamide can prolong the QT interval and worsen the arrhythmia.

2. Torsades is an unstable rhythm and decays rapidly to ventricular fibrillation.

3. Torsades is associated with electrolyte abnormalities, drug overdose or other toxins.

4. Magnesium may be beneficial for Torsade de Pointes associated with long QT syndrome.

Treatment of Unstable Polymorphic Ventricular Tachycardia

1. Use defibrillation rather than synchronized cardioversion for polymorphic ventricular tachycardia since it will be difficult to sync to the irregular waveform.

2. For monophasic defibrillators, use 360 Joules for all delivered shocks.

3. For biphasic truncated exponential waveform defibrillators, use 150 - 200 Joules.

4. For biphasic rectilinear waveform defibrillators, use 120 Joules.

5. For biphasic defibrillators of unknown type, use 200 Joules.

6. For subsequent biphasic shocks, use the same or higher energy

7. Low energy level shocks can cause ventricular fibrillation.

8. Apply CPR and the remainder of the pulseless arrest algorithm.