Unit 4: Patient Treatment and Transport
Cardiac Emergencies & Resuscitation
Recognizing a heart attack and responding quickly to cardiac arrest are essential EMT skills. This NREMT study guide lesson covers acute coronary syndrome, heart failure, cardiopulmonary resuscitation (CPR), and automated external defibrillators (AEDs). You’ll learn to identify serious cardiac conditions, provide appropriate emergency treatment, and perform high-quality CPR. Five NREMT practice questions with detailed explanations will help you review these lifesaving skills.
The cardiovascular system circulates oxygenated blood throughout the body. When blood flow to the heart becomes restricted or the heart stops pumping effectively, a life-threatening emergency can develop.
EMTs must recognize cardiac warning signs, begin appropriate interventions, and arrange prompt transport.
Cardiovascular System Overview
The heart has four chambers:
- Right atrium: Receives oxygen-poor blood from the body.
- Right ventricle: Pumps blood to the lungs.
- Left atrium: Receives oxygen-rich blood from the lungs.
- Left ventricle: Pumps oxygen-rich blood throughout the body.
The heart muscle receives oxygen through the coronary arteries. When coronary blood flow decreases, the heart muscle may not receive enough oxygen.
This condition is called myocardial ischemia.
Acute Coronary Syndrome (ACS)
Acute coronary syndrome (ACS) describes conditions caused by a sudden reduction in blood flow to the heart muscle. It includes:
- Unstable angina: Chest discomfort caused by reduced coronary blood flow that may occur unexpectedly, including at rest.
- Acute myocardial infarction (AMI): A heart attack in which inadequate blood flow causes injury or death of heart muscle cells.
Common signs and symptoms include:
- Chest pressure, tightness, or discomfort.
- Pain spreading to the arms, back, neck, or jaw.
- Shortness of breath.
- Nausea or vomiting.
- Sweating, dizziness, or weakness.
Some patients, particularly older adults and people with diabetes, may experience a heart attack without typical chest pain.
Never rule out a cardiac emergency simply because chest pain is absent.
Emergency Care for Suspected ACS
When ACS is suspected:
- Assess airway, breathing, circulation, and vital signs.
- Have the patient rest in a comfortable position.
- Administer oxygen when clinically indicated.
- Give chewable aspirin when appropriate and authorized by EMS protocols.
- Assist with prescribed nitroglycerin when permitted and no contraindications are present.
- Request Advanced Life Support (ALS) when appropriate and arrange prompt transport.
The commonly recommended aspirin dose is 162–325 mg, chewed. Check for allergies and other contraindications.
Nitroglycerin can lower blood pressure and must not be given when contraindicated, including certain cases involving hypotension or recent use of medications for erectile dysfunction.
Heart Failure and Other Cardiac Emergencies
Heart Failure
Heart failure occurs when the heart cannot pump blood effectively enough to meet the body’s needs.
Fluid may accumulate in the lungs, causing pulmonary edema. Findings can include difficulty breathing, crackles, swollen ankles, and sometimes pink, frothy sputum.
Treatment may include appropriate oxygen therapy, an upright position, or CPAP when indicated by the patient’s condition and local protocols.
Cardiogenic Shock
Cardiogenic shock occurs when the heart cannot pump enough blood to maintain adequate tissue perfusion.
Signs may include a weak pulse, altered mental status, cool or clammy skin, and low blood pressure. Immediate supportive care and rapid transport are essential.
Aortic Dissection
An aortic dissection involves a tear in the inner layer of the aorta. It may cause sudden, severe chest or back pain, sometimes described as tearing or ripping.
Cardiac Arrhythmias
Arrhythmias are abnormal heart rhythms. They may cause palpitations, dizziness, fainting, or impaired circulation. Some dangerous arrhythmias can lead to cardiac arrest.
Recognizing Cardiac Arrest
Cardiac arrest occurs when the heart stops producing effective circulation.
An adult in cardiac arrest is typically:
- Unresponsive.
- Not breathing normally or only gasping.
- Without a definite pulse.
Agonal gasps are not normal breathing.
Healthcare providers should assess breathing and pulse simultaneously for no more than 10 seconds.
If an unresponsive patient is not breathing normally and has no definite pulse, begin CPR immediately and apply an AED as soon as one becomes available.
High-Quality CPR
Cardiopulmonary resuscitation (CPR) uses chest compressions and ventilation to circulate oxygenated blood during cardiac arrest.
High-quality CPR requires:
- A compression rate of 100–120 per minute.
- Appropriate compression depth.
- Complete chest recoil.
- Minimal interruptions.
- Avoiding excessive ventilation.
The following table summarizes the essential CPR recommendations.
| Patient | Compression Depth | One Rescuer | Two Rescuers |
| Adult | At least 2 inches (5 cm); avoid greater than 2.4 inches (6 cm) | 30:2 | 30:2 |
| Child | About 2 inches (5 cm), or one-third of chest depth | 30:2 | 15:2 |
| Infant | About 1.5 inches (4 cm), or one-third of chest depth | 30:2 | 15:2 |
The compression rate is 100–120 per minute for all three age groups.
For infant CPR, the 2025 American Heart Association guidelines recommend the two-thumb encircling-hands technique or the heel-of-one-hand technique.
The older two-finger technique is no longer recommended.
For children, use one or two hands depending on the child’s size.
Deliver each rescue breath over approximately one second, using enough air to produce visible chest rise. Rescuers should switch compression duties approximately every two minutes to reduce fatigue.
Automated External Defibrillators (AEDs)
An automated external defibrillator (AED) analyzes the heart’s rhythm and determines whether an electrical shock is appropriate.
Two shockable rhythms are:
- Ventricular fibrillation (VF): Chaotic electrical activity that prevents effective pumping.
- Pulseless ventricular tachycardia (pVT): A dangerously rapid ventricular rhythm without an effective pulse.
An AED does not deliver a shock for nonshockable rhythms such as asystole.
Use an AED as soon as one becomes available during cardiac arrest.
How to Use an AED
- Turn on the AED and follow its instructions.
- Expose the patient’s chest and attach the pads as indicated.
- Ensure everyone is clear while the AED analyzes the rhythm.
- If a shock is advised, ensure nobody is touching the patient and deliver the shock.
- Immediately resume CPR for approximately two minutes, until the AED prompts another analysis.
If no shock is advised, resume CPR immediately unless the patient shows clear signs of return of spontaneous circulation (ROSC).
Avoid unnecessary pauses in chest compressions.
AED Use in Children and Infants
For children and infants in cardiac arrest, use pediatric AED pads and an energy-reduction system when available and appropriate.
If pediatric pads are unavailable, adult pads may be used. Make sure the pads do not touch or overlap.
For smaller patients, placing one pad on the chest and the other on the back may be necessary.
Never cut or alter AED pads.
When to Stop CPR
Once CPR begins, continue until an appropriate reason to stop occurs, such as:
- The patient shows signs of ROSC.
- Another qualified provider takes over.
- An authorized termination-of-resuscitation order is given.
- The scene becomes unsafe.
- The rescuer becomes physically unable to continue.
Follow applicable laws and EMS protocols regarding do-not-resuscitate (DNR) orders and termination of resuscitation.
The absence of an AED is not a reason to stop CPR.
Key Tip
For cardiac arrest, prioritize high-quality CPR and early defibrillation. Remember the compression rate of 100–120 per minute, minimize interruptions, and resume CPR immediately after an AED shock. For suspected heart attacks, recognize the warning signs, provide appropriate care, and arrange prompt transport.