What is the treatment for persistent ventricular fibrillation?

Treatment of Persistent Ventricular Fibrillation

For persistent ventricular fibrillation that continues after initial defibrillation attempts, immediately administer intravenous amiodarone 150 mg over 10 minutes while continuing high-quality CPR and repeated defibrillation attempts at maximum energy (360 J for monophasic or manufacturer-recommended settings for biphasic defibrillators). 1, 2

Immediate Defibrillation Strategy

• Continue high-quality CPR at a rate of at least 100 compressions per minute with minimal interruptions between shocks 1
• Deliver unsynchronized shocks using escalating energy levels: start at 200 J (monophasic) or per manufacturer recommendations (biphasic), then 200-300 J, then maximum 360 J 1
• Resume CPR immediately after each shock, beginning with chest compressions rather than checking rhythm 1
• Biphasic waveforms are superior to monophasic waveforms for defibrillation success, with 200 J biphasic showing 100% first-shock success versus 90% for 200 J monophasic 3
• If initial lower energy shocks fail, escalate quickly to 360 J as conversion rates increase substantially at this energy level (38.95% success rate) 4

Pharmacological Management

First-Line: Amiodarone

• Administer amiodarone 150 mg IV over 10 minutes as the primary antiarrhythmic for shock-resistant ventricular fibrillation 1, 2
• Amiodarone is FDA-approved specifically for initiation of treatment and prophylaxis of frequently recurring VF in patients refractory to other therapy 2
• Follow with continuous infusion: 1 mg/min for 6 hours, then 0.5 mg/min thereafter (total ~1000 mg over first 24 hours) 2
• Repeat 150 mg boluses can be given for breakthrough episodes of VF 2
• Amiodarone is supported by two randomized clinical trials showing it is acceptable, safe, and useful for shock-resistant VF 5

Alternative: Lidocaine

• Lidocaine 1.5 mg/kg IV/IO may be considered if amiodarone is unavailable 1
• However, lidocaine is not recommended as first-line for shock-resistant VF based on current evidence 5

Vasopressor Support

• Administer epinephrine 1 mg IV/IO every 3-5 minutes throughout resuscitation 1
• Establish IV/IO access while continuing CPR 1

Airway and Ventilation Management

• Consider advanced airway placement after initial shocks if personnel are available 1
• Once advanced airway is placed, deliver 1 breath every 6 seconds (10 breaths/min) with continuous compressions 1
• Use waveform capnography to confirm endotracheal tube placement and monitor CPR quality 1
• Avoid excessive ventilation, which decreases cardiac output during CPR 1

Addressing Reversible Causes

Search for and treat the "Hs and Ts" that may be perpetuating VF 1:

• Hypovolemia: Administer volume expansion as needed
• Hypoxia: Ensure adequate oxygenation and ventilation
• Hydrogen ion (acidosis): Consider sodium bicarbonate if prolonged arrest
• Hypo/hyperkalemia: Correct electrolyte abnormalities, particularly potassium and magnesium 1
• Hypothermia: Rewarm if present
• Tension pneumothorax: Decompress if suspected
• Tamponade: Perform pericardiocentesis if indicated
• Toxins: Consider specific antidotes
• Thrombosis (coronary/pulmonary): Consider thrombolytics or mechanical intervention

Special Considerations for Ischemic VF

• In the context of acute myocardial infarction with recurrent VF, consider beta-blockers if all other therapies fail 1
• For drug-refractory polymorphic VT/VF, aggressively reduce myocardial ischemia with beta-blockade, intra-aortic balloon pumping, and emergency revascularization 1
• Primary VF is most common (3-5%) in the first 4 hours after acute MI 1

Post-Resuscitation Care

• Maintain adequate ventilation and oxygenation after return of spontaneous circulation 1
• Correct electrolyte abnormalities (potassium and magnesium) to prevent recurrent VF 1
• Continue amiodarone infusion for 48-96 hours until ventricular arrhythmias are stabilized 2
• Transition to oral amiodarone when patient can tolerate oral medications 2

Critical Pitfalls to Avoid

• Do not delay defibrillation for witnessed VF arrest 1
• Avoid excessive interruptions in chest compressions, including for rhythm checks 1
• Never use synchronized cardioversion for VF—always use unsynchronized shocks 1
• Do not use bretylium or magnesium as first-line therapy for shock-resistant VF, as they are not recommended 5
• Procainamide is acceptable but not recommended for shock-resistant VF 5
• Do not use vasopressin as first-line (evidence comes from only small trials) 5