A 55-year-old woman is brought to the ER with palpitations, dizziness, and near-syncope. 12-lead ECG shows a wide complex tachycardia at 195 bpm with AV dissociation and positive QRS concordance across V1–V6 with no RS complex visible. What is the most likely diagnosis?
- A SVT with aberrant conduction (bundle branch block)
- B Atrial flutter with 2:1 block and RBBB
- C Ventricular tachycardia ✓
- D Pre-excited AF (Wolff-Parkinson-White)
Correct answer: C. Ventricular tachycardia
Explanation
The Brugada criteria for wide complex tachycardia differentiate VT from SVT with aberrancy. Key features supporting VT: AV dissociation (P waves independent of QRS — most specific finding), positive concordance in precordial leads V1–V6 (all QRS positive = anterior VT), and absence of RS complex in any precordial lead (width from onset of R to nadir of S >100 ms). AV dissociation with a rate >150 bpm in a wide complex tachycardia is pathognomonic of VT. Treatment: stable VT → IV amiodarone or procainamide; hemodynamically unstable → synchronized DC cardioversion.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.