AHA ACLS Provider key terms

A chaotic, disorganized ventricular electrical rhythm with no identifiable QRS complexes. The heart quivers instead of pumping, so there is no effective pulse and immediate defibrillation is required.

A rapid ventricular rhythm, often wide-complex, that fails to produce a palpable pulse. It is treated like ventricular fibrillation with immediate high-quality CPR and defibrillation.

A cardiac arrest rhythm showing a flat line or nearly flat line with no electrical activity. It is not shockable; treatment focuses on high-quality CPR, epinephrine, and finding reversible causes.

A cardiac arrest rhythm with organized electrical activity on the monitor but no palpable pulse. It is not shockable; treatment includes CPR, epinephrine, and correcting reversible causes.

A sinus rhythm with a heart rate below 60 beats per minute. It may be normal in athletes or sleep, but can cause symptoms such as hypotension, dizziness, or syncope when perfusion is inadequate.

A delay in conduction from the atria to the ventricles that lengthens the PR interval beyond 0.20 seconds. Every P wave is followed by a QRS, and the rhythm is usually benign.

Progressive lengthening of the PR interval until a P wave is not conducted, causing a dropped QRS. This Wenckebach pattern often reflects AV node disease and can cause symptomatic bradycardia.

Intermittent failure of P waves to conduct to the ventricles without progressive PR lengthening. It often indicates infranodal disease and can suddenly progress to complete heart block.

Complete failure of atrial impulses to reach the ventricles, so P waves and QRS complexes occur independently. The escape rhythm is usually slow, and symptomatic patients need pacing.

A fast, regular rhythm originating above the ventricles, usually with narrow QRS complexes and rates often above 150 beats per minute. Symptomatic patients may need vagal maneuvers or adenosine.

An irregularly irregular narrow-complex rhythm without distinct P waves and a rapid ventricular rate. Treatment depends on stability and may include rate control, cardioversion, or treating underlying causes.

A rapid ventricular rhythm with wide QRS complexes that all look similar in shape. A pulse may or may not be present; unstable patients with a pulse may need synchronized cardioversion.

A polymorphic ventricular tachycardia with QRS complexes that twist around the baseline. It is associated with a prolonged QT interval and is treated with magnesium and correction of causes.

The time from the start of the QRS complex to the end of the T wave, representing ventricular depolarization and repolarization. A prolonged QT interval increases the risk of torsades de pointes.

Chest compressions delivered at the correct rate and depth with full recoil, minimal interruptions, and appropriate ventilations. It maximizes blood flow and improves the chance of survival from cardiac arrest.

The proportion of resuscitation time during which chest compressions are actually being performed. A higher fraction, ideally above 60%, improves coronary and cerebral perfusion during cardiac arrest.

The distance the sternum is pushed down during chest compressions. For adults, aim for at least 2 inches (5 cm) but avoid more than 2.4 inches (6 cm).

The number of chest compressions delivered per minute. For adults, use 100 to 120 compressions per minute, allowing complete chest recoil between compressions.

A technique for delivering positive-pressure breaths using a self-inflating bag and a mask. It requires a good seal and an open airway; give each breath over about 1 second until the chest rises.

A curved plastic device inserted into the mouth to keep the tongue from blocking the upper airway in an unresponsive patient. It is used only when the patient lacks a gag reflex.

A soft tube inserted through the nose into the nasopharynx to maintain an open airway. It can be used in patients with a gag reflex but is avoided when significant facial trauma is suspected.

Continuous measurement and display of exhaled carbon dioxide. It confirms advanced airway placement, monitors ventilation, and can help assess CPR quality and return of spontaneous circulation.

Delivery of an unsynchronized electrical shock to stop chaotic ventricular activity and allow a normal rhythm to resume. It is indicated for ventricular fibrillation and pulseless ventricular tachycardia.

A portable device that analyzes the heart rhythm and advises whether a shock is needed. It delivers a defibrillation shock and guides the rescuer with voice prompts during cardiac arrest.

A timed electrical shock that is synchronized to the QRS complex to treat unstable tachyarrhythmias with a pulse. It avoids shocking during the vulnerable repolarization period.

Temporary electrical pacing through pads placed on the chest to stimulate the heart when the intrinsic rate is too slow. It is used for symptomatic bradycardia when other measures fail.

A medication used in cardiac arrest, given intravenously or intraosseously every 3 to 5 minutes. It improves coronary and cerebral perfusion during CPR and is also used for severe allergic reactions.

An antiarrhythmic drug given for refractory ventricular fibrillation or pulseless ventricular tachycardia that does not respond to CPR and defibrillation. It can also be used for stable ventricular tachycardia.

A fast-acting medication that briefly slows conduction through the AV node. It is used for stable supraventricular tachycardia and can help diagnose the rhythm.

An anticholinergic medication that increases heart rate by blocking vagal effects on the SA and AV nodes. It is used for symptomatic bradycardia, though it may not work in complete heart block.

A medication used for torsades de pointes and other conditions such as severe asthma or preeclampsia. In ACLS, it is given for polymorphic ventricular tachycardia associated with a prolonged QT interval.

A cardiac arrest rhythm that responds to defibrillation, specifically ventricular fibrillation and pulseless ventricular tachycardia. Rescuers should defibrillate as soon as possible when this rhythm is present.

A cardiac arrest rhythm that does not respond to defibrillation, including asystole and pulseless electrical activity. Treatment focuses on CPR, epinephrine, and correcting reversible causes.

Return of spontaneous circulation, meaning the patient has a palpable pulse and signs of circulation after cardiac arrest. Post-arrest care then focuses on oxygenation, blood pressure, and neurologic support.

Controlled cooling or maintenance of a specific body temperature after cardiac arrest to protect the brain. It is part of post-arrest care for patients who do not follow commands.

A complex condition after cardiac arrest involving brain injury, myocardial dysfunction, systemic inflammation, and the effects of the cause of arrest. It requires careful hemodynamic and neurologic support.

A team communication technique in which the sender gives a clear message, the receiver repeats it back, and the sender confirms. It reduces misunderstandings during resuscitation.

The person who coordinates the resuscitation, assigns roles, monitors performance, and makes treatment decisions. A clear leader helps the team work efficiently and avoid errors.

A structured review after a resuscitation or training event that examines what went well and what could improve. It supports learning and better team performance.