Chart — Emergency Respiratory Care
Cardiac Arrest Rhythms
The four cardiac arrest rhythms matter to the RT because the single most important split — shockable versus non-shockable — changes what the team does next. This grid lines up each rhythm with whether to defibrillate and the drug priority, while the RT keeps oxygenation, ventilation, and capnography going throughout.
Written by Apex Respiratory Editorial Team
Educational use only. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
The Four Rhythms
| Rhythm | Group | Description | Defibrillate? | Drug / Priority |
|---|---|---|---|---|
| Ventricular fibrillation (VF) | Shockable | Chaotic, disorganized electrical activity with no effective contraction | Yes - immediate defibrillation | Epinephrine every 3-5 min; amiodarone or lidocaine if refractory; high-quality CPR |
| Pulseless ventricular tachycardia (pVT) | Shockable | Organized wide-complex tachycardia with no pulse | Yes - immediate defibrillation | Epinephrine; amiodarone or lidocaine; high-quality CPR |
| Pulseless electrical activity (PEA) | Non-shockable | Organized electrical activity on the monitor but no pulse | No | Epinephrine as soon as possible; find and treat the cause (the H's and T's) |
| Asystole | Non-shockable | A flat line with no electrical activity | No | Epinephrine as soon as possible; high-quality CPR; treat reversible causes; confirm in another lead |
How to Use This Chart
Read the chart by group first. The single most important question in any arrest is whether the rhythm is shockable, because that decides whether the next action is a defibrillation or a search for a cause. Real resuscitations always follow current ACLS protocol and physician orders — this grid is a study aid, not a code-cart substitute.
- The single most important split is shockable versus non-shockable: VF and pulseless VT get immediate defibrillation; PEA and asystole do not.
- For all four, high-quality CPR and early epinephrine matter; for the non-shockable rhythms, survival hinges on finding and reversing the cause (the H’s and T’s).
- The RT’s job is uninterrupted oxygenation and ventilation with capnography throughout — confirm the tube, gauge CPR quality, and catch ROSC.
Related Resources
Sources
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Emergency cardiac care chapters.
- Panchal AR, Bartos JA, Cabanas JG, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020;142(16_suppl_2):S366-S468.