Pick an algorithm below to see a step-by-step flowchart, the drug doses and energies you need to know, and the key points we review in your HeartCode ACLS skills session.
When an adult has no pulse, the team works in 2-minute cycles of high-quality CPR, pausing only for rhythm checks. The first rhythm check decides the path: VF and pulseless VT get early defibrillation, while asystole and PEA get epinephrine as early as possible. Both paths share the same goal: keep blood moving, fix what caused the arrest, and watch for return of spontaneous circulation (ROSC).
Step-by-step flowchart
Start CPR
Bag-mask ventilation with oxygen
Attach monitor/defibrillator
Is the rhythm shockable?
Yes — VF / pVT
Shock
CPR 2 minutes
Establish IV access (IO if IV fails)
Rhythm check: still shockable?
No → switch to the Asystole/PEA path
Shock
CPR 2 minutes
Epinephrine every 3–5 min
Consider advanced airway + waveform capnography
Rhythm check: still shockable?
No → switch to the Asystole/PEA path
Shock
CPR 2 minutes
Amiodarone or lidocaine
Treat reversible causes (H's & T's)
No — Asystole / PEA
Epinephrine as soon as possible
CPR 2 minutes
IV/IO access
Epinephrine every 3–5 min
Consider advanced airway + capnography
Rhythm check: shockable?
Yes → go to the Shock path
CPR 2 minutes
Treat reversible causes (H's & T's)
Rhythm check: shockable?
Yes → go to the Shock path
Signs of ROSC?
No → continue CPR and epinephrine cyclesYes → go to Post–Cardiac Arrest Care
Continuously reassess whether ongoing resuscitation is appropriate
ACLS Algorithm
Adult Bradycardia With a Pulse
HR typically < 50/min
Many slow heart rates are normal. This algorithm asks one key question: is the slow rate causing poor perfusion? If not, monitor and look for a cause. If it is, support the airway and breathing, then move through atropine, pacing, or a vasopressor infusion until the patient stabilizes.
Step-by-step flowchart
Assess: does the clinical picture fit?
Heart rate typically below 50/min
Signs the slow rate is causing compromise?
No → identify and treat the cause, 12-lead ECG, monitor
Support & monitor
Open airway, give oxygen as needed
Assist breathing if needed
Cardiac monitor, pulse checks
Bradycardia still causing compromise?
No → monitor and treat underlying cause
Atropine 1 mg IV
Repeat every 3–5 min
Maximum total 3 mg
If atropine fails
Transcutaneous pacing
and/or
Dopamine infusion
5–20 mcg/kg/min, titrate, taper slowly
and/or
Epinephrine infusion
2–10 mcg/min, titrate to response
Consider expert consultation and transvenous pacing
ACLS Algorithm
Adult Tachyarrhythmia With a Pulse
HR typically ≥ 150/min
A fast rhythm with a pulse is handled by stability first. If the rhythm is causing hypotension, altered mental status, shock, chest pain, or heart failure, the answer is synchronized cardioversion. If the patient is stable, there is time for a 12-lead ECG and the QRS width guides the next step.
Step-by-step flowchart
Assess & support
Airway and breathing; oxygen if hypoxemic
Monitor rhythm, BP, SpO₂
IV access; 12-lead ECG if available
Persistent tachyarrhythmia causing compromise?
Yes — unstable
Synchronized cardioversion
Sedate whenever feasible
Regular narrow-complex: consider adenosine
If it fails: treat cause, raise energy, add antiarrhythmic, call an expert
No — stable
Is the QRS wide (≥ 0.12 sec)?
Narrow QRS
Vagal maneuvers (if regular)
Adenosine (if regular)
Beta blocker or calcium-channel blocker
Consider expert consultation
Wide QRS
Adenosine only if regular and monomorphic
Consider antiarrhythmic infusion
Expert consultation
ACLS Algorithm
Suspected Stroke
Time is brain
Stroke care is a race against the clock. Every step, from the 911 call to the CT scanner, is built to get eligible patients to clot-busting medication or clot removal as fast as possible. The single most important piece of history is the time the patient was last known to be normal.
Step-by-step flowchart
Recognize signs of stroke
Face drooping, arm weakness, speech difficulty
Call 911 / activate stroke alert
EMS assessment
Stroke scale, check blood glucose
Establish last known well time
Notify the receiving stroke center
Arrival at hospital
Immediate assessment by the stroke team
Emergent CT or MRI of the brain
Hemorrhage on imaging?
No hemorrhage
Candidate for thrombolytic?
Usually within 4.5 hr of last known well
Review contraindications; control BP
Large-vessel occlusion?
Evaluate for endovascular thrombectomy (selected patients up to 24 hr)
Hemorrhage
Hemorrhagic stroke care
Neurosurgery / neurology consult
Reverse anticoagulation if present
Manage BP and ICP
Admit to stroke unit or ICU; frequent neuro checks
ACLS Algorithm
Acute Coronary Syndrome (ACS)
STEMI / NSTE-ACS
ACS covers heart attacks and unstable angina. The first 10 minutes matter most: get an ECG, give aspirin unless contraindicated, and sort the patient by what the ECG shows. A STEMI needs a blocked artery reopened as soon as possible, either in the cath lab or with fibrinolytics when the cath lab is too far away.
Step-by-step flowchart
Symptoms suggest ischemia or infarction
Chest pressure, shortness of breath, sweating, nausea
EMS / ED first steps
12-lead ECG within 10 min
Aspirin 162–325 mg chewed
Oxygen if SpO₂ below 90%
Nitroglycerin if SBP ≥ 90 and no PDE-5 inhibitor use
What does the 12-lead show?
ST elevation (STEMI)
Activate the cath lab
First contact to PCI: 90 min or less
If PCI not available in time: fibrinolytic within 30 min of arrival
ST depression / T-wave changes
High-risk NSTE-ACS
Cardiology consult, anticoagulation
Early invasive strategy if high risk
Normal / nondiagnostic
Observe and repeat
Serial ECGs and troponins
Admit or further testing if positive
ACLS Algorithm
Adult Post–Cardiac Arrest Care
After ROSC
Once the heart restarts, the brain and heart are still at risk. Care focuses on avoiding too little or too much oxygen, keeping blood pressure up, controlling temperature, and finding the cause of the arrest, often in the cath lab.
Step-by-step flowchart
ROSC achieved
Initial stabilization
Confirm or place advanced airway (waveform capnography)
100% oxygen until SpO₂ can be measured, then SpO₂ 90–98%
PaCO₂ 35–45 mmHg
MAP ≥ 65 mmHg with fluids/vasopressors
Early diagnostics
12-lead ECG
Consider CT and/or ultrasound
Treat causes & complications
Consider emergency coronary angiography or mechanical support
Does the patient follow commands? (off sedation if possible)
Yes
Ongoing critical care
Coronary angiography when appropriate
No / unsure
Ongoing critical care
Avoid glucose below 70 mg/dL and hyperglycemia
Consider antibiotics
Temperature control
Deliberate strategy, goal 32–37.5 °C
EEG and seizure check; angiography when appropriate
Multimodal prognosis, usually ≥ 72 hr after ROSC
ACLS Algorithm
Cardiac Arrest in Pregnancy
Two patients
High-quality CPR and defibrillation work the same in pregnancy. What changes: the uterus can compress major blood vessels, so it is pushed to the left by hand, and a specialized team gets ready right away for resuscitative delivery if circulation does not return.
Step-by-step flowchart
Start BLS/ACLS
High-quality CPR; AED/defibrillator as indicated
Fundus at or above umbilicus: continuous manual left uterine displacement
Activate the maternal cardiac arrest team
Identify and treat the cause
Optimize resuscitation
Pregnancy-specific steps
Early airway management by the most experienced provider
Continue ACLS; resuscitate the newborn with the neonatal algorithm
These summaries are a study aid created by Hale CPR LLC based on the 2025 American Heart Association Guidelines for CPR and ECC. They do not replace an AHA course, your provider manual, or your facility's protocols and medical direction. Always verify doses against current references.
