According to the 2025 AHA guidelines, what are the recommended biphasic synchronized shock energies (in joules) for cardioversion of atrial fibrillation, typical atrial flutter, supraventricular tachycardia, and pulseless ventricular tachycardia?

AHA 2025 Cardioversion Energy Recommendations

For atrial fibrillation cardioversion, start with 200 J biphasic synchronized shock rather than escalating from lower energies, as this approach demonstrates greater initial shock success, reduced risk of inducing ventricular fibrillation, and lower cumulative electrical burden 1.

Specific Energy Recommendations by Rhythm

Atrial Fibrillation

• Initial shock: 200 J biphasic 1
• The 2025 guidelines explicitly moved away from the previous incremental approach (starting low and escalating)
• This recommendation is based on new evidence showing superior outcomes with higher initial energy
• Benefits include:
  • Greater first-shock success rate
  • Reduced likelihood of inducing VF
  • Shorter anesthesia duration
  • Smaller cumulative electrical burden

Atrial Flutter

• Initial shock: 50 J biphasic is effective for typical atrial flutter 2
• Atrial flutter typically converts successfully with energies <50 J 3
• Can escalate to 250 J if initial shock fails 2

Supraventricular Tachycardia (SVT)

• The guidelines do not provide specific joule recommendations for synchronized cardioversion of SVT
• General principle: unstable SVT requires urgent electrical cardioversion 1
• Lower energies are typically effective given the organized nature of the rhythm

Pulseless Ventricular Tachycardia (pVT)

• Treat as VF with immediate defibrillation (not synchronized cardioversion)
• Follow manufacturer's recommended energy settings for biphasic defibrillation 4
• When manufacturer settings unknown: use maximum dose setting for that device 4
• Both fixed energy (150 J) and escalating energy (200-300-360 J) approaches are highly effective 4

Key Algorithmic Approach

For stable rhythms requiring cardioversion:

1. Atrial fibrillation → Start at 200 J biphasic
2. Atrial flutter → Start at 50 J biphasic
3. Polymorphic VT → Immediate defibrillation (treat as unstable regardless of apparent clinical status) 1

For cardiac arrest rhythms (VF/pulseless VT):

• Use defibrillation (not synchronized cardioversion)
• Single shock strategy followed by immediate CPR 4
• Defer to manufacturer's energy specifications; if unknown, use maximum device setting 4

Important Caveats

Biphasic vs. Monophasic: The guidelines strongly favor biphasic waveforms, which expose patients to lower peak current with equivalent or greater efficacy 4. Monophasic defibrillators were last manufactured in the late 1990s but some may still be in use 4.

No superiority between biphasic waveforms: There is no conclusive evidence that one proprietary biphasic waveform is superior to another 4. Energy settings are prespecified by manufacturers for each device due to variability in electrical characteristics.

Single shock strategy: For VF/pVT, immediately resume CPR after the first shock rather than delivering stacked shocks, as this results in shorter CPR interruptions and improved survival to hospital discharge 4.