Ventricular Fibrillation

When rhythm analysis identifies VF or pulseless VT, deliver an immediate unsynchronized shock and immediately resume high-quality CPR. For biphasic defibrillators, use the manufacturer-recommended initial energy, commonly 120-200 J; use 360 J with a monophasic device. For subsequent shocks, use the same or a higher energy, escalating according to the defibrillator manufacturer until the maximum available energy is reached. PubMed+1PubMedVentricular Fibrillation - StatPearls - NCBI BookshelfPubMedDefibrillation - StatPearls - NCBI Bookshelf

Perform rhythm checks only at scheduled pulse/rhythm assessments and resume compressions immediately after each shock rather than waiting to assess electrical conversion. Early defibrillation and high-quality chest compressions with minimal interruption are the primary treatments for shockable cardiac arrest. ScienceDirect+1ScienceDirectEuropean Resuscitation Council Guidelines for Resuscitation: 2018 Update – Antiarrhythmic drugs for cardiac arrestPubMedDefibrillation - StatPearls - NCBI Bookshelf

Ensure that the rhythm is truly VF or pulseless VT before shocking. VF has fibrillatory waves without identifiable P waves, QRS complexes, or T waves; pulseless VT is also shockable. A nonshockable organized rhythm without a pulse requires the nonshockable-arrest pathway rather than repeated defibrillation. PubMed+1PubMedVentricular Fibrillation - StatPearls - NCBI BookshelfPubMedDetection of Life Threatening Ventricular Arrhythmia Using Digital Taylor Fourier Transform

For persistent VF/pulseless VT after unsuccessful defibrillation, administer epinephrine 1 mg IV or IO every 3-5 minutes. In the shockable-rhythm sequence summarized in current ACLS references, epinephrine is given after an unsuccessful shock and continued while VF/pulseless VT persists. PubMed+1PubMedVentricular Fibrillation - StatPearls - NCBI BookshelfPubMedDefibrillation - StatPearls - NCBI Bookshelf

If VF/pulseless VT persists at the next rhythm check after ongoing shocks and CPR, administer amiodarone 300 mg IV/IO bolus. A further 150-mg dose may be used if an additional dose is needed. Amiodarone and lidocaine are both reasonable antiarrhythmic options for VF/pulseless VT unresponsive to defibrillation; comparative international guidance suggests any benefit is similar. AHA Journals+3AHA Journals2018 American Heart Association Focused Update on Pediatric Advanced Life Support: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care | CirculationScienceDirectEuropean Resuscitation Council Guidelines for Resuscitation: 2018 Update – Antiarrhythmic drugs for cardiac arrestPubMedDefibrillation - StatPearls - NCBI BookshelfPubMedLidocaine - StatPearls - NCBI Bookshelf

When selecting lidocaine instead of amiodarone, use 1-1.5 mg/kg IV/IO initially, followed by 0.5-0.75 mg/kg for a second dose if needed. Avoid serially layering antiarrhythmics without a protocolized rationale; continue defibrillation, CPR, and search for a reversible trigger because antiarrhythmics do not replace electrical termination of VF. PubMed+2PubMedDefibrillation - StatPearls - NCBI BookshelfPubMedLidocaine - StatPearls - NCBI BookshelfPubMedBeyond Standard Shocks: A Critical Review of Alternative Defibrillation Strategies in Refractory Ventricular Fibrillation

Use a practical refractory-VF designation when VF/pulseless VT remains present after at least three failed standard defibrillation attempts. Separate true refractory VF from recurrent VF: recurrent VF terminates after a shock but returns later, whereas refractory VF remains present through sequential analyses and shocks. This distinction matters because recurrent VF has better reported survival than persistent refractory VF. PubMed+2PubMedEnhancing Patient Safety in Refractory Ventricular Fibrillation: A Systematic Review of Double Sequential and Vector Change Defibrillation BarriersPubMedBeyond Standard Shocks: A Critical Review of Alternative Defibrillation Strategies in Refractory Ventricular FibrillationPubMedContemporary Practices in Refractory Out-of-Hospital Cardiac Arrest: A Narrative Review

Before changing defibrillation technique, verify pad contact and placement, ensure shocks are delivered at an appropriate escalating energy, and maintain short CPR interruptions. Persistent VF is not proof that a waveform-derived device metric should override standard care: ECG waveform analysis and machine-learning models can predict refractory VF in retrospective cohorts, but their clinical role remains decision support under investigation rather than a replacement for rhythm-based ACLS. The Lancet+3The Lanceta small open-label, pseudo-randomized controlled multicenter trialPubMedPrediction of Shock-refractory Ventricular Fibrillation in Patients with Out-of-Hospital Cardiac Arrest: External Validation of an ECG-based Approach - PMCPubMedPrediction of Shock-Refractory Ventricular Fibrillation during Resuscitation of Out-of-Hospital Cardiac Arrest - PMCPubMedWolf Creek XVIII Part 3: Innovations in Defibrillation Science☆

For refractory VF in systems with an established protocol, consider vector-change defibrillation by moving pads to an anterior-posterior configuration or double sequential external defibrillation (DSED), which delivers rapid sequential transthoracic shocks from two defibrillators. In a cluster-randomized trial of 405 refractory-VF patients, both DSED and vector-change defibrillation were associated with higher survival to discharge; DSED, but not vector change, was associated with better neurologic outcome. PubMedPubMedManagement of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC—endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society - PMC

During ongoing VF/pulseless VT, pursue correctable causes in parallel with defibrillation rather than pausing to complete a broad diagnostic evaluation. In refractory out-of-hospital VF, coronary artery disease is frequently present in observational reports; VF waveform analysis has also been studied as an early indicator of acute myocardial infarction, but coronary diagnosis is generally established after ROSC with formal evaluation. PubMed+1PubMedComputerized Analysis of the Ventricular Fibrillation Waveform Allows Identification of Myocardial Infarction: A Proof‐of‐Concept Study for Smart Defibrillator Applications in Cardiac Arrest - PMCPubMedContemporary Practices in Refractory Out-of-Hospital Cardiac Arrest: A Narrative Review

After ROSC, obtain a 12-lead ECG and determine whether the patient has evidence of myocardial ischemia, structural heart disease, conduction disease, bradycardia or pauses, valve disease, pulmonary embolism, aortic dissection, acute heart failure, tamponade, or cardiomyopathy. These findings should direct urgent coronary, echocardiographic, electrophysiologic, or disease-specific evaluation rather than assigning an idiopathic VF label prematurely. facs+1facs[PDF] BEST PRACTICES GUIDELINES - The American College of SurgeonsPubMedManagement of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC—endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society - PMC

Reserve idiopathic VF for patients in whom structural, channelopathic, metabolic, and toxicologic etiologies have been excluded. This exclusion is clinically important because patients with apparently idiopathic VF may have subtle microstructural abnormalities or premature ventricular complex triggers identified by invasive mapping studies. PubMedPubMedManagement of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC—endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society - PMC

After ROSC, monitor for hemodynamic instability, recurrent ventricular arrhythmia, and neurologic injury while expediting evaluation of the precipitating cause. Post-arrest patients with VF/VT have historically shown variation in access to coronary catheterization, electrophysiologic study, and implantable cardioverter-defibrillator therapy; ensure that candidacy for these potentially lifesaving interventions is assessed without inequitable exclusion. PubMedPubMedIn-Hospital Cardiac Arrest and Post-Arrest Care - Strategies to Improve Cardiac Arrest Survival - NCBI Bookshelf

For patients with recurrent VF or clustered ventricular arrhythmias, evaluate ischemic, structural, inherited channelopathy, metabolic, and toxicologic drivers. The electrical-storm consensus statement emphasizes that idiopathic VF requires exclusion of these etiologic categories and that invasive mapping can identify arrhythmogenic substrate in selected patients. PubMedPubMedManagement of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC—endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society - PMC

Refer survivors for electrophysiology-based recurrence-risk assessment and consideration of ICD therapy when appropriate to the underlying substrate and post-arrest evaluation. The immediate resuscitation decision remains defibrillation; definitive prevention is cause-directed and should follow stabilization and diagnostic clarification. PubMed+1PubMedIn-Hospital Cardiac Arrest and Post-Arrest Care - Strategies to Improve Cardiac Arrest Survival - NCBI BookshelfPubMedManagement of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC—endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society - PMC