A 58-year-old man with hypertension and coronary artery disease presents to the emergency department with palpitations and dyspnea. ECG shows a regular wide-complex tachycardia at 180 bpm with a QRS duration of 140 ms. Blood pressure is 95/60 mmHg, and the patient is confused. What is the most appropriate immediate next step in management?

Explanation

## Clinical Assessment This patient presents with **hemodynamically unstable ventricular tachycardia (VT)** — evidenced by: - Wide-complex tachycardia (QRS ≥ 120 ms) - Hypotension (95/60 mmHg) - Altered mental status (confusion) - Rapid rate (180 bpm) ## Management Algorithm for Unstable VT ```mermaid flowchart TD A[Wide-complex tachycardia]:::outcome --> B{Hemodynamically stable?}:::decision B -->|No: hypotension, altered LOC, chest pain| C[Synchronized cardioversion]:::action B -->|Yes| D[IV antiarrhythmic]:::action C --> E[100 J biphasic or 200 J monophasic]:::action D --> F[Amiodarone or Procainamide]:::action E --> G[Repeat at higher energy if needed]:::action ``` ## Key Point: **Hemodynamic instability is the primary indication for immediate synchronized cardioversion, regardless of the underlying rhythm.** Drug therapy is secondary and time-consuming in unstable patients. ## High-Yield: The mnemonic **"ACLS SHOCK"** guides unstable arrhythmia management: - **A**lways check responsiveness - **C**ardioversion is first-line for unstable VT/VF - **L**oad IV access (secondary) - **S**ynchronize (for organized rhythms) - **H**igh energy (100 J biphasic, 200 J monophasic) - **O**xygen and airway - **C**ontinue CPR if needed - **K**eep drugs (amiodarone) for post-cardioversion ## Clinical Pearl: Synchronized cardioversion (not defibrillation) is used for organized rhythms (VT, atrial flutter, SVT) because the shock is timed to the QRS complex, avoiding the vulnerable period. Unsynchronized defibrillation is reserved for VF. ## Why Cardioversion Now? 1. **Altered mental status** = cerebral hypoperfusion → immediate threat 2. **Hypotension** = inadequate coronary perfusion → risk of cardiogenic shock 3. **Electrical therapy** works faster (seconds) than pharmacologic therapy (minutes) 4. **Success rate** for synchronized cardioversion in VT is 80–90% at 100 J ## Antiarrhythmic Drugs Are Secondary Amiodarone and procainamide are appropriate for **stable VT** or as post-cardioversion therapy. In unstable VT, they delay definitive treatment and may worsen hemodynamics due to negative inotropic effects. [cite:Harrison 21e Ch 226]