A 58-year-old man with a history of anterior wall myocardial infarction 6 months ago presents to the emergency department with palpitations and syncope. On examination, blood pressure is 80/50 mmHg, heart rate 180 bpm. ECG shows a wide complex tachycardia with AV dissociation and fusion beats. Echocardiography reveals an ejection fraction of 35% with anteroseptal wall motion abnormality. Which is the most appropriate immediate management?

Explanation

## Clinical Diagnosis **Key Point:** This patient has ventricular tachycardia (VT) with hemodynamic instability (hypotension, syncope). The presence of AV dissociation and fusion beats on ECG confirms the diagnosis of VT rather than supraventricular tachycardia with aberrancy. ## Hemodynamic Status Assessment | Feature | Finding | Significance | |---------|---------|---------------| | Systolic BP | 80 mmHg | Hypotensive | | Consciousness | Syncope | Loss of cerebral perfusion | | Ejection fraction | 35% | Severely reduced LV function | | Arrhythmia | Wide complex, HR 180 | Rapid, unstable rhythm | **High-Yield:** Any patient with VT AND hemodynamic instability (SBP < 90 mmHg, altered mental status, chest pain, pulmonary edema, or syncope) requires **immediate synchronized DC cardioversion**, not pharmacological therapy. ## Management Algorithm ```mermaid flowchart TD A[Wide complex tachycardia]:::outcome --> B{Hemodynamically stable?}:::decision B -->|No: SBP < 90, syncope, shock| C[Synchronized DC cardioversion]:::action B -->|Yes: SBP > 90, alert| D{VT or SVT with aberrancy?}:::decision D -->|Confirmed VT| E[IV amiodarone or procainamide]:::action D -->|SVT with aberrancy| F[IV verapamil or adenosine]:::action C --> G[Repeat if needed, escalate energy]:::action ``` ## Why Cardioversion is Correct 1. **Immediate life threat:** Syncope indicates loss of consciousness and cerebral hypoperfusion—this is a medical emergency. 2. **Hemodynamic collapse:** BP 80/50 mmHg is shock-level hypotension. 3. **Guideline standard:** ACC/AHA and ESC guidelines mandate synchronized DC cardioversion as first-line for hemodynamically unstable VT. 4. **Safety:** Synchronized cardioversion avoids the R-on-T phenomenon and is safer than drugs in unstable patients. **Clinical Pearl:** Amiodarone is reserved for hemodynamically stable VT or post-cardioversion to prevent recurrence. Verapamil is contraindicated in VT (risk of cardiovascular collapse). Procainamide is an alternative for stable VT but not for unstable VT. [cite:Harrison 21e Ch 297]