Wide-Complex Tachycardia

Question 1

Define wide-complex tachycardia in adults.

Answer 1

HR > 100 associated with wide-complex QRS complexes ( > 0.12 ms).

Question 2

What are the clinical features of wide-complex tachycardia?

Answer 2

1. HR > 100
2. Dizziness, syncope
3. Chest pain, palpitations
4. Dyspnea

Question 3

What is the differential diagnosis for wide-complex tachycardia?

Answer 3

Ventricular tachycardia
Ventricular fibrillation
Supraventricular tachycardia with aberrancy
Monitor artifact
Also consider the possibility of misdiagnosed narrow-complex tachycardia

Question 4

What is the management of a wide-complex tachycardia?

Answer 4

1. Check pulse, proceed to BLS/ACLS if not present.
2. Ensure adequate oxygenation and ventilation
3. Check EKG tracing to identify rhythm if possible; confirm rate with SpO2 tracing
4. Assess patient stability
5. If unstable–>synchronized cardioversion
6. If stable and irregular, probably afib with aberrancy
7. If torsades–>magnesium load + infusion
8. If regular wide-complex–>amiodarone
9. Observe closely and arrange cardiology follow-up

Question 5

If a patient presents with unstable wide-complex VT how should you treat?

Answer 5

Immediate synchronized cardioversion:
for monomorphic VT using monophasic waveform–>initial shock 100J. Increase dose as needed stepwise (200, 300, 360).
For biphasic use 120 to 200J

Question 6

If a patient presents with stable wide-complex VT that is irregular what are the likely rhythms and how should you treat?

Answer 6

Probably atrial fibrillation with aberrance, but could be pre-excited atrial fibrillation (WPW) in which case AV-nodal agents are contraindicated. If any doubt, cardiovert electrically or use procainamide (17mg/kg at 50mg/min maximum infusion rate) or amiodarone 150mg

Question 7

If a patient presents with torsades de pointes should you treat pharmacologically?

Answer 7

Magnesium 1 to 2 grams load followed by infusion

Question 8

How should one treat a wide-complex irregular rhythm caused by pre-excited atrial fibrillation?

Answer 8

WPW should be treated either with electrical cardioversion or converted with procainamide 17mg/kg at 50 mg/min maximum infusion rate ) or amiodarone 150mg.

Question 9

What class of drugs might be harmful if used to treat a stable wide-complex irregular tachycardia?

Answer 9

AV-nodal agents such as diltiazem, adenosine, verapamil, digoxin. Although it is probably atrial fibrillation with aberrancy, it could also be due to something like WPW, and AV-nodal agents are contraindicated as they can increase the rate of transmission through the accessory pathway and cause increased ventricular rates or VF.

Question 10

How should one treat wide-complex regular rhythm in a stable patient?

Answer 10

Amiodarone 150mg IV