The current ACLS guidelines represent the most evidence-based framework for managing adult cardiac arrest, peri-arrest dysrhythmias, acute coronary syndromes, and stroke in the hospital and field environment. Updated by the American Heart Association (AHA) and harmonized with the International Liaison Committee on Resuscitation (ILCOR) Consensus on Science with Treatment Recommendations, the 2026 guidelines refine drug dosing, CPR quality metrics, defibrillation strategies, airway choices, and post-cardiac-arrest care. Providers must master these protocols cold because seconds matter and chaotic codes do not allow time to look anything up.

This guide breaks down every major recommendation in the current AHA algorithm set so registered nurses, paramedics, respiratory therapists, physicians, advanced practice providers, and pharmacists can walk into a code prepared. We will cover the adult cardiac arrest algorithm, bradycardia, tachycardia with and without a pulse, acute coronary syndrome, suspected stroke, opioid emergencies, and the targeted temperature management bundle that defines modern post-arrest neurologic protection.

If you are renewing certification, the ACLS guidelines also dictate megacode performance, written test content, and skills station expectations. Recent versions emphasized team dynamics, closed-loop communication, and high-quality chest compressions over flashy interventions. Compression depth, rate, full recoil, and minimized pauses outrank almost every drug push you can perform. Knowing why the guidelines downgraded high-dose epinephrine, atropine for asystole, and routine sodium bicarbonate is just as important as memorizing what stayed in.

The 2026 update preserves the chain of survival framework — recognition and activation, immediate high-quality CPR, rapid defibrillation, advanced resuscitation, post-arrest care, and recovery — but expands the recovery link with explicit attention to survivor rehabilitation, family debriefing, and rescuer mental health. Resuscitation no longer ends at return of spontaneous circulation (ROSC); it ends when the patient returns to a meaningful quality of life or transitions to comfort with dignity.

Drug therapy continues to support, not replace, the basics. Epinephrine 1 mg every 3 to 5 minutes remains the cornerstone vasopressor in cardiac arrest, with stronger evidence that early administration in non-shockable rhythms improves ROSC. Amiodarone and lidocaine are still the antiarrhythmics of choice for refractory ventricular fibrillation and pulseless ventricular tachycardia. Calcium, magnesium, and bicarbonate remain situational — used only when a specific reversible cause justifies them, not as routine code drugs.

Defibrillation guidance has also matured. Single-shock strategies with biphasic devices, manufacturer-recommended energy settings, and minimal interruption to compressions form the modern shock paradigm. Double sequential external defibrillation (DSED) and vector-change defibrillation are now reasonable considerations for refractory ventricular fibrillation based on the DOSE-VF trial and follow-up data, though they remain rescue strategies rather than first-line therapy.

Before diving into the algorithms, it helps to know how to study them. Reviewing the AHA provider manual, watching algorithm walkthroughs, and pairing reading with active recall through scenario questions delivers far better retention than passive reading. Many candidates also book a brick-and-mortar refresher; you can find local options through this overview of ACLS training near me to compare in-person, blended, and skills-only formats before you commit to a course date.

The adult cardiac arrest algorithm is the backbone of every ACLS course and every real code blue you will ever run. It begins the moment a provider confirms unresponsiveness, abnormal or absent breathing, and no definite pulse within 10 seconds. The first action is to start chest compressions while the team simultaneously calls for help, attaches monitor pads, and prepares the defibrillator. Compressions should never wait for an IV, an airway, or a medication; they begin first and continue with minimal interruption throughout the entire resuscitation.

Once monitor pads are on, the team performs a rhythm check. If the rhythm is shockable — ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) — the team delivers a single biphasic shock at the manufacturer's recommended dose (commonly 120 to 200 joules), then immediately resumes compressions for two minutes. The rhythm is reassessed only after that two-minute cycle. Pulse checks are bundled with rhythm checks and limited to 10 seconds to protect coronary perfusion pressure.

If the rhythm is non-shockable — asystole or pulseless electrical activity (PEA) — the team continues compressions and gives epinephrine 1 mg IV or IO as soon as possible. Early epinephrine in non-shockable arrest has consistently been associated with higher ROSC and survival rates. For shockable rhythms, epinephrine is still recommended but delivered after the first or second shock has failed, so the initial defibrillation is not delayed by drug administration.

After two cycles of CPR with persistent shockable rhythm, the team adds an antiarrhythmic: amiodarone 300 mg IV/IO bolus (followed by a 150 mg bolus if needed) or lidocaine 1 to 1.5 mg/kg as an alternative. The team simultaneously evaluates the reversible causes — the famous H's and T's: hypoxia, hypovolemia, hydrogen ion (acidosis), hypo/hyperkalemia, hypothermia, tension pneumothorax, tamponade, toxins, thrombosis (pulmonary), and thrombosis (coronary). Identifying and reversing the cause is often what actually saves the patient.

Advanced airway management is no longer required at a fixed point in the algorithm. Bag-mask ventilation with high-quality compressions is acceptable for much of the early arrest, and a supraglottic airway or endotracheal tube is placed when the team is ready and it will not interrupt compressions. Once an advanced airway is in place, compressions become continuous at 100-120 per minute and ventilations are delivered at one breath every six seconds (10 breaths per minute) without pausing compressions.

Waveform capnography is the gold-standard adjunct. An end-tidal CO2 (ETCO2) consistently below 10 mm Hg after 20 minutes of high-quality CPR is a poor prognostic sign and, together with other clinical factors, can support a decision to terminate efforts. A sudden rise in ETCO2 — typically a jump above 35-40 mm Hg — often signals ROSC before a pulse becomes palpable, prompting careful pulse and rhythm reassessment without stopping compressions prematurely.

Team dynamics make or break code performance. The guidelines call out closed-loop communication, clear role assignment, mutual respect, knowledge sharing, and constructive intervention. A confident team leader, a dedicated timekeeper, a CPR coach focused on compression quality, and a recorder tracking medications and shocks transform a chaotic event into a coordinated resuscitation. Pair your algorithm review with the structured drills in this ACLS study guide to reinforce both knowledge and team behavior.

Bradycardia and tachycardia algorithms live alongside the adult cardiac arrest algorithm and are tested heavily on the written exam and during megacode. The bradycardia algorithm starts with the question every ACLS provider should reflexively ask: is the slow rhythm causing the patient harm? Acutely altered mental status, hypotension, ischemic chest discomfort, signs of shock, or acute heart failure define unstable bradycardia. Asymptomatic bradycardia — common in athletes, on beta-blockers, or during sleep — is monitored, not treated.

For symptomatic adult bradycardia, atropine 1 mg IV is the first-line drug, repeated every 3 to 5 minutes to a maximum of 3 mg. If atropine fails or is unlikely to succeed (high-degree AV blocks or wide-complex escape rhythms), the algorithm moves to transcutaneous pacing or to an IV chronotrope infusion of dopamine 5-20 mcg/kg/min or epinephrine 2-10 mcg/min. Transvenous pacing and expert cardiology consultation follow if the patient remains unstable or pacing capture is poor.

The adult tachycardia algorithm hinges on whether the patient has a pulse and is stable or unstable. Unstable tachycardia with a pulse — hypotension, altered mental status, ischemic chest pain, shock, or heart failure — is treated with synchronized cardioversion. Initial energy depends on rhythm: narrow regular about 50-100 J, narrow irregular about 120-200 J biphasic, wide regular about 100 J, and wide irregular (polymorphic VT) is treated as VF with unsynchronized high-energy defibrillation, not cardioversion.

Stable narrow-complex regular tachycardia is approached with vagal maneuvers (Valsalva, modified Valsalva with leg lift, carotid massage in young patients without bruits) and adenosine 6 mg rapid IV push followed by a 20 mL saline flush; a 12 mg dose can be repeated if needed. The modified Valsalva maneuver has the highest conversion rate of any non-pharmacologic technique. Stable narrow-irregular tachycardia (atrial fibrillation or flutter with variable conduction) usually calls for rate control with diltiazem, metoprolol, or amiodarone.

Stable wide-complex regular tachycardia is presumed ventricular until proven otherwise. Options include procainamide, amiodarone, or sotalol, with adenosine considered only if the rhythm is clearly monomorphic and regular. Polymorphic VT — particularly torsades de pointes from QT prolongation — is treated with magnesium 1-2 g IV, defibrillation if pulseless, correction of electrolyte abnormalities, and removal of offending QT-prolonging drugs. Underlying causes such as hypokalemia and hypomagnesemia must be aggressively corrected.

Acute coronary syndrome (ACS) integrates into ACLS through the suspected STEMI and NSTEMI pathways. Early aspirin 162-325 mg chewed, nitroglycerin if not contraindicated, oxygen only if SpO2 below 90 percent, and pain control with morphine if symptoms persist are the immediate steps. A 12-lead ECG within 10 minutes of arrival guides reperfusion: percutaneous coronary intervention within 90 minutes of first medical contact for STEMI, or fibrinolysis within 30 minutes if PCI is not available within 120 minutes.

Suspected stroke is the other major peri-arrest pathway. The guidelines emphasize the stroke chain of survival: rapid recognition with FAST or BE-FAST, EMS notification, prehospital severity scales, transport to a stroke center, CT or MRI within 20 minutes of arrival, and tenecteplase or alteplase within 4.5 hours plus mechanical thrombectomy for large-vessel occlusions up to 24 hours from last known well. Time is brain, and every link in this chain is graded by minutes.

Post-cardiac-arrest care begins the moment ROSC is achieved and is where modern ACLS has evolved most aggressively over the past decade. The first priority is securing oxygenation and ventilation: titrate FiO2 to an SpO2 of 92-98 percent to avoid both hypoxia and hyperoxia, and ventilate to a PaCO2 of 35-45 mm Hg or an ETCO2 of about 35-40 mm Hg. Hyperventilation increases intrathoracic pressure, reduces coronary perfusion, and induces cerebral vasoconstriction — all bad for the freshly resuscitated brain.

Hemodynamic optimization follows. The guidelines recommend maintaining systolic blood pressure above 90 mm Hg and mean arterial pressure above 65 mm Hg using IV fluids, norepinephrine, epinephrine, or dopamine infusions. Many centers now target a higher MAP (80-100 mm Hg) for the first 24 hours to improve cerebral perfusion in post-arrest patients, particularly those with a history of hypertension. An arterial line and central venous access are usually placed for accurate monitoring and titration.

A 12-lead ECG is obtained as soon as possible after ROSC. STEMI patients go to the cath lab for emergent coronary angiography. Patients without obvious STEMI who arrested from a presumed cardiac cause are increasingly considered for early angiography as well, especially if hemodynamically unstable. Echocardiography helps assess left ventricular function, identify wall-motion abnormalities, and rule out tamponade or right-heart strain suggestive of pulmonary embolism.

Targeted temperature management (TTM), now often called temperature control, is the cornerstone neurologic intervention. Current guidelines recommend actively controlling temperature in the 32-36°C range (or, per the most recent updates, anywhere from 32°C to 37.5°C with fever avoidance) for at least 24 hours in comatose adults after cardiac arrest from any rhythm. Fever above 37.5°C in the first 72 hours must be actively prevented because it worsens neurologic outcomes after global ischemia.

Sedation, analgesia, and shivering control are critical during TTM. Shivering generates heat, raises oxygen consumption, and defeats temperature control. Step-wise management includes acetaminophen, magnesium, skin counter-warming, dexmedetomidine or propofol, opioids, and finally neuromuscular blockade if the patient continues to shiver despite optimized sedation. Continuous EEG monitoring is recommended in comatose post-arrest patients to detect non-convulsive seizures and status epilepticus, which occur in up to 20 percent of cases.

Neuroprognostication is delayed at least 72 hours after ROSC (or after rewarming if TTM was used) and combines multiple modalities: clinical exam, somatosensory evoked potentials, EEG patterns, neuron-specific enolase trends, and MRI. No single test is reliable enough on its own to predict poor outcome, and the guidelines explicitly warn against early withdrawal of life-sustaining therapy in the first 72 hours unless other indications justify it. Family discussions during this window should emphasize uncertainty.

Recovery and rehabilitation now anchor the final link of the chain of survival. Survivors face cognitive deficits, fatigue, depression, anxiety, and PTSD, and many require structured outpatient cardiac and neurologic rehab. The guidelines recommend formal screening before discharge, a recovery plan, and follow-up at 1 and 3 months. For deeper structured prep on these protocols, this ACLS course overview shows how the recovery link is integrated into the modern provider curriculum.

Mastering the ACLS guidelines is less about memorization and more about building reliable reflexes you can execute under stress. The candidates who perform best in megacode are not the ones with the deepest pharmacology knowledge; they are the ones who can verbalize their algorithm out loud, assign clear roles, and keep compressions flowing while they think. Practice talking through codes — narrating each step aloud — until the words come automatically. That verbal fluency is what evaluators score and what real teams will hear from you.

Build a study plan that mirrors the exam. Spend the first week reviewing core BLS, rhythm interpretation, and the universal algorithm. Spend the second week drilling drug indications, doses, and contraindications for epinephrine, amiodarone, lidocaine, atropine, adenosine, magnesium, and naloxone. The third week should focus on bradycardia, tachycardia (stable and unstable), ACS, stroke, and opioid emergencies. Use the final days for full megacode simulations and timed multiple-choice practice that mirrors the AHA written test blueprint.

Active recall beats passive reading every time. After reading each algorithm, close the book and try to write or recite it from memory. Identify gaps, restudy them, and repeat. Spaced repetition with flashcards for drug doses works particularly well because the doses are highly testable but easy to confuse. A focused 20 minutes of recall daily outperforms a passive 90-minute reread on the weekend, and it leaves you with usable knowledge during a real arrest, not just on test day.

Take simulation seriously. Find a partner, a manikin, or even a chair and a stopwatch and run codes. Practice running the team as leader, calling out the rhythm, ordering the shock, requesting drugs with closed-loop confirmation, and managing the airway. Then rotate roles and play the recorder, the compressor, and the medication nurse. Each role builds different muscle memory, and instructors will assess your ability to fluidly move between them during megacode evaluations and group skills stations.

Pre-course preparation is mandatory and dramatically affects your performance. Most providers underestimate how much pre-work the AHA expects: the precourse self-assessment, the algorithm reading, the ECG and pharmacology review, and the BLS prerequisite. Treat this like a real exam. Block 8 to 12 hours of focused study in the two weeks before class, and walk in able to identify the major rhythms cold and recite the cardiac arrest algorithm without looking at a card. Your instructor will notice immediately.

Use multiple-choice question banks aggressively. The ACLS written exam typically requires a passing score of 84 percent, and the question stems often hide the correct answer behind subtle wording: stable vs unstable, narrow vs wide, regular vs irregular, with-a-pulse vs pulseless. Practice questions teach you how the AHA phrases problems. Reviewing a free ACLS practice test bank in the days before your course is one of the highest-yield study activities you can do.

Finally, remember that the guidelines exist to serve patients, not to satisfy testing centers. Every dose, every joule, every minute of compression depth was set by data from real cardiac arrest registries and randomized trials. When you understand why a recommendation exists, you remember it better and apply it more flexibly when reality does not match the textbook. Approach ACLS as a clinical framework first and a certification second, and both your test scores and your code performance will improve.