From the Guidelines
The initial energy setting for synchronized cardioversion is typically 100-200 joules for atrial fibrillation and 50-100 joules for atrial flutter and paroxysmal supraventricular tachycardia (PSVT).
Key Considerations
- The energy setting may vary depending on the type of arrhythmia and the specific defibrillator being used 1.
- For atrial fibrillation, an initial energy of 200 J or greater is recommended with biphasic defibrillators 1.
- If the initial shock is unsuccessful, energy levels can be gradually increased in subsequent attempts 1.
- Before performing cardioversion, ensure the patient is appropriately sedated and confirm they have been adequately anticoagulated if the arrhythmia has persisted for more than 48 hours 1.
- The synchronized mode must be activated on the defibrillator to ensure the shock is delivered during the QRS complex and not during the vulnerable T-wave period, which could induce ventricular fibrillation 1.
Important Factors
- Energy requirements are generally lower with modern biphasic defibrillators compared to older monophasic devices 1.
- The interval between consecutive shocks should be at least 1 minute to avoid myocardial damage 1.
- The success rate of cardioversion varies depending on the duration of the arrhythmia, underlying heart disease, and other factors 1.
From the Research
Synchronized Cardioversion Energy Settings
The initial energy setting for synchronized cardioversion can vary depending on the type and duration of the arrhythmia.
- For atrial fibrillation (AF) of 2 days or less, an initial energy setting of 100 J is recommended 2.
- For AF of more than 2 days, an initial energy setting of 150 J is recommended 2.
- For atrial flutter (AFL) or atrial tachycardia (AT), an initial energy setting of 50 J is recommended 2.
- Another study suggests that an initial energy setting of 100 J can be more efficient for restoration of sinus rhythm in patients with atrial flutter 3.
- In some cases, higher energy settings such as 200-360 J may be necessary for successful cardioversion, particularly in patients with longer duration of AF 4.
Energy Settings for Specific Arrhythmias
- Atrial fibrillation: 100 J for durations of 2 days or less, 150 J for durations of more than 2 days 2, or 200-360 J for longer durations 4.
- Atrial flutter: 50 J 2 or 100 J 3.
- Ventricular tachycardia: 0.025 to 2.0 J 5.
Considerations for Energy Settings
The choice of initial energy setting should be based on the individual patient's characteristics, including the type and duration of the arrhythmia, as well as the presence of any underlying heart disease 2, 4, 3.