Management of Widened QRS Complex
Initial Assessment and Stabilization
- The American College of Cardiology recommends that if the patient is hemodynamically unstable, prepare for immediate synchronized cardioversion, which is a Class I recommendation and takes absolute priority over diagnostic workup 4
- The American Heart Association suggests sedating the patient only if they are conscious and time permits, using etomidate 0.2-0.3 mg/kg IV given the hypotensive state 4
- The American College of Cardiology advises applying defibrillator pads immediately and establishing two large-bore IV lines (18-gauge or larger) 4
- Do not delay cardioversion to obtain a 12-lead ECG, though capture a rhythm strip from the defibrillator before shocking, as recommended by the American College of Cardiology 3, 4
Differential Diagnosis: Wide QRS Tachycardia
- The American College of Cardiology states that if you cannot definitively prove SVT, treat as ventricular tachycardia, as VT is the most common mechanism for wide QRS tachycardia 1, 2, 3, 5
- Giving verapamil or diltiazem for presumed SVT when VT is present causes hemodynamic collapse and death, according to the American College of Cardiology 1, 2, 3
Acute Management Algorithm
- The American College of Cardiology recommends placing the patient on continuous telemetry, establishing IV access, and drawing stat electrolytes (K+, Mg2+, Ca2+), troponin, BNP for hemodynamically stable wide QRS tachycardia 4
- The American Heart Association suggests using amiodarone 150 mg IV over 10 minutes as the first-line treatment for stable wide complex tachycardia, which is a Class IIa recommendation 4
- The American College of Cardiology advises against giving adenosine, verapamil, or diltiazem for wide complex tachycardia unless you have definitive proof of SVT with aberrancy 1, 2, 4
Special Consideration: QTc Measurement with Wide QRS
- The Mayo Clinic recommends applying the correction formula when measuring QTc in patients with wide QRS to avoid falsely elevated QTc readings 6, 7
- The adjusted QTc formula is: adjusted QTc = measured QTc - (QRS duration - 120 ms), as suggested by the Mayo Clinic 6, 7
Disposition and Follow-up
- The American College of Cardiology recommends ICU/CCU admission, immediate cardiology/electrophysiology consultation, and serial 12-lead ECGs for patients with unstable wide complex tachycardia 4
- The American Heart Association suggests considering electrophysiology study and possible ablation once the patient is stabilized 4