## Clinical Diagnosis **Key Point:** The combination of wide complex tachycardia with AV dissociation and fusion beats is pathognomonic for **ventricular tachycardia (VT)**. The presence of hemodynamic instability (hypotension, syncope) mandates immediate electrical therapy. ## Why Synchronized DC Cardioversion? **High-Yield:** In hemodynamically unstable VT, synchronized DC cardioversion is the definitive first-line treatment. The patient is hypotensive (80/50) and syncopal — this is a **pulsed VT** requiring urgent rhythm conversion. **Clinical Pearl:** Fusion beats (fusion of sinus and ectopic QRS complexes) and AV dissociation are diagnostic hallmarks of VT and distinguish it from SVT with aberrancy. Their presence confirms the diagnosis and reinforces the need for cardioversion rather than pharmacotherapy. ## Why Not Pharmacotherapy First? **Warning:** Amiodarone and verapamil are appropriate for hemodynamically stable VT or as adjuncts *after* cardioversion in unstable patients. In this case, the patient is already hypotensive and syncopal — delaying electrical therapy risks cardiac arrest. ## Algorithm ```mermaid flowchart TD A[Wide complex tachycardia]:::outcome --> B{Hemodynamically stable?}:::decision B -->|No: Hypotensive/Syncope| C[Synchronized DC cardioversion]:::action B -->|Yes: BP adequate| D{VT confirmed?}:::decision D -->|Yes| E[Amiodarone or other antiarrhythmic]:::action D -->|No: SVT with aberrancy| F[AV nodal blocking agent]:::action C --> G[Post-cardioversion: Amiodarone infusion + ICD evaluation]:::action ``` **Citation:** [cite:Harrison 21e Ch 297]
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