4 Cardiology and Resuscitation

Where cardiac emergencies fit

Cardiac emergencies may be tested across the National Registry EMT examination’s five domains: Scene Size-up and Safety, Primary Assessment, Secondary Assessment, Patient Treatment and Transport, and Operations. Questions may focus on what to recognize and do first, not only on disease names.

Use the applicable state scope of practice, medical direction, and local protocols for all care. The resuscitation guidance covered here is based on the 2025 American Heart Association CPR and Emergency Cardiovascular Care guidelines.

Assess the patient and identify threats

The heart and blood vessels deliver oxygenated blood to tissues. When cardiac output or circulation falls, signs may include altered mental status, pale or cyanotic skin, cool or clammy skin, weak pulses, delayed capillary refill, dizziness, or hypotension. A normal initial blood pressure does not rule out a serious problem; assess the whole patient and watch for trends.

A focused assessment

1. Check scene safety and form a general impression. Note work of breathing, skin signs, ability to speak, and level of alertness.

2. Assess airway, breathing, and circulation, and identify immediate threats. Treat life threats before obtaining a detailed history. If the patient is unresponsive and not breathing normally, occasional gasps count as abnormal breathing.

3. Obtain and repeat vital signs. Assess pulse rate and quality, blood pressure, respiratory rate and effort, skin, and oxygen saturation when available. Do not let a device reading delay urgent care.

4. Ask focused questions. Use OPQRST for symptoms and SAMPLE for history. Ask about onset, exertion, radiation, associated shortness of breath, nausea, sweating, fainting, prior heart disease, medications, allergies, and any aspirin or nitroglycerin already taken.

5. Provide appropriate care and transport. Keep the patient at rest, use a position of comfort, manage oxygenation and ventilation according to need and protocol, request additional resources when indicated, and reassess after interventions and during transport.

Recognize cardiac emergencies

Cardiac ischemia may feel like pressure, tightness, heaviness, or discomfort rather than sharp chest pain. Symptoms can radiate to the arm, back, jaw, neck, or upper abdomen, and may include shortness of breath, nausea, sweating, weakness, or lightheadedness. Older adults, people with diabetes, and women may have less typical symptoms. Treat suspected acute coronary syndrome (ACS) as time-sensitive; EMTs cannot rule it out in the field.

Common emergencies and priorities

• Suspected ACS or myocardial infarction: Recognize possible ischemia, minimize exertion, obtain and trend vital signs, request appropriate resources, and transport promptly. Give aspirin only when authorized by protocol and when there is no relevant contraindication or prior dose. Assist with the patient’s prescribed nitroglycerin only when permitted by protocol and after checking the required safety criteria. Do not delay transport or assume symptom improvement excludes a heart attack.

• Heart failure or pulmonary edema: Look for respiratory distress, difficulty breathing when lying flat, crackles if assessed, and possible dependent swelling. Support breathing and oxygenation as indicated, position the patient for comfort, and arrange prompt transport. Severe respiratory distress is an immediate priority.

• Shock or poor perfusion: Treat the underlying life threat within EMT scope, support airway and breathing, keep the patient warm, and transport rapidly. Shock may occur before hypotension appears.

• Possible aortic aneurysm or dissection: Sudden severe chest, back, or abdominal pain, sometimes with fainting or signs of shock, warrants urgent transport and minimal scene delay. Do not dismiss it as routine indigestion or uncomplicated chest pain.

• Syncope or palpitations: Assess for injury, abnormal breathing, poor perfusion, chest discomfort, and ongoing altered mental status. A brief loss of consciousness can signal a serious cardiac cause even if the patient feels better afterward.

Medication authority and details vary by jurisdiction. Do not exceed EMT scope or local protocol.

Perform adult CPR and use an AED

An unresponsive patient who is not breathing normally, including one who is only gasping, may be in cardiac arrest. For a healthcare professional, check for a definite pulse for no more than $10$ seconds; if no definite pulse is felt, begin CPR. Avoid prolonged or repeated checks that delay compressions.

Adult CPR

Start high-quality cardiopulmonary resuscitation (CPR), and have another rescuer activate EMS support and obtain an automated external defibrillator (AED) when available. Compress at $100\text{–}120$ per minute, to a depth of at least $2$ inches ($5\text{ cm}$), while avoiding depths over $2.4$ inches ($6\text{ cm}$) for an average adult.

Allow full chest recoil, minimize interruptions, and avoid excessive ventilation. Without an advanced airway, use $30:2$ compressions to breaths. Give each breath over about $1$ second, with visible chest rise. If two trained rescuers are present, change compressors about every $2$ minutes, with minimal interruption.

AED sequence

1. Turn on the AED and follow its prompts. Expose and dry the chest, then attach pads as shown.

2. Keep everyone clear during rhythm analysis and shock delivery. Make sure no one is touching the patient.

3. If a shock is advised, deliver it as directed, then immediately resume CPR, starting with compressions. If no shock is advised, immediately resume CPR.

4. Continue CPR and follow AED prompts until the patient shows signs of life, care is transferred, the scene becomes unsafe, or you are physically unable to continue.

Use pediatric pads or an energy-attenuating setting for a child or infant when available, but do not delay defibrillation if only an adult AED is available. Follow its prompts and local protocol. Prompt CPR and defibrillation are priorities in shockable arrest.

Adapt resuscitation for children and infants

Pediatric arrest often follows respiratory failure or shock, so effective ventilations matter. Use age-appropriate compression technique and depth—about $\frac{1}{3}$ of the chest’s front-to-back diameter—at $100\text{–}120$ compressions per minute. For CPR without an advanced airway, use $30:2$ with one rescuer; with two rescuers for a prepubertal child, use $15:2$. Follow pediatric BLS guidance and local protocol for pulse assessment, ventilation, and AED use.

If a patient has a pulse but is not breathing adequately, provide ventilations and frequently reassess the pulse and breathing. Do not perform chest compressions unless cardiac arrest develops. Follow the current age-specific BLS algorithm and local protocol.

Manage special resuscitation situations

For suspected opioid poisoning, support airway and breathing, activate EMS, and give naloxone when authorized and available. If the patient is in cardiac arrest, CPR and AED care take priority; naloxone must not interrupt or delay resuscitation.

After return of spontaneous circulation (ROSC), reassess airway, breathing, pulse, mental status, and vital signs. Provide supportive care, monitor for deterioration, and transport with an appropriate handoff.

For advance directives, termination criteria, and scene safety, follow applicable law and protocol. Do not independently withhold or stop resuscitation outside those rules.

Apply priorities to common presentations

An adult collapses, is unresponsive, and makes occasional gasping sounds. A pulse is not definitely felt within $10$ seconds. Begin CPR and apply an AED as soon as possible: gasping is not normal breathing.

A patient reports new chest pressure and nausea but has a normal first blood pressure. Treat suspected ACS seriously, perform a focused assessment, repeat vital signs, provide authorized care, and arrange prompt transport. One normal measurement does not rule out a life-threatening cardiac problem.