| Feature | Synchronized Cardioversion | Unsynchronized Cardioversion (Defibrillation) |
|---|---|---|
| Patient | Has a PULSE | PULSELESS |
| Rhythm | Unstable Tachyarrhythmias: - A-fib, A-flutter, SVT - Monomorphic VT | Lethal Arrhythmias: - Ventricular Fibrillation (VF) - Pulseless VT |
| Mechanism | Interrupts a single reentrant circuit, allowing the SA node to resume pacemaking. | ”Resets” the entire myocardium by depolarizing all cells at once to terminate chaotic electrical activity. |
| Timing | Shock synchronized to R-wave (avoids T-wave) | Shock is unsynchronized (delivered immediately) |
| Energy | LOW Energy (50-200 J) | HIGH Energy (≥200 J for biphasic) |
| Sedation | YES (patient is conscious) | NO (patient is unconscious) |