What is the best approach to resuscitate a man with a history of heart disease who collapsed from a myocardial infarction (heart attack) and is now unresponsive?

Immediate Resuscitation of a Man Who Collapsed from a Heart Attack

Begin high-quality chest compressions immediately at a rate of 100-120 per minute with a depth of at least 2 inches (5 cm), as this is the single most critical intervention for survival from cardiac arrest. 1, 2

Initial Recognition and Activation

• Assume cardiac arrest in any collapsed, unresponsive individual who is not breathing normally or only gasping—agonal gasps are common early after cardiac arrest and must not be mistaken for normal breathing 3, 1
• Immediately activate the emergency response system (call 911) and send someone to retrieve an automated external defibrillator (AED) while you begin CPR 3
• Do not waste time checking for a pulse—if you cannot definitively feel a pulse within 10 seconds, start compressions immediately, as pulse checks are unreliable even among trained providers 2

High-Quality CPR Technique

• Push hard and push fast: Compress at least 2 inches (5 cm) deep at a rate of 100-120 compressions per minute 3, 1, 2
• Allow complete chest recoil between compressions to permit venous return and cardiac refilling 1, 4
• Minimize interruptions in chest compressions—any pause reduces coronary and cerebral perfusion pressure 1, 4
• Use a 30:2 compression-to-ventilation ratio if you are trained in rescue breathing; otherwise, perform continuous hands-only (compression-only) CPR 1, 2
• Switch compressors every 2 minutes or sooner if fatigued to maintain effective compression quality 1, 2

Defibrillation

• Apply the AED as soon as it arrives and turn it on without stopping chest compressions 3, 1
• Stop CPR only for rhythm analysis and shock delivery if the AED advises it 1
• If a shock is indicated (ventricular fibrillation or pulseless ventricular tachycardia), deliver one shock and immediately resume CPR for 2 minutes before reassessing the rhythm 3, 2
• For manual defibrillators, use 120-200 Joules for biphasic or 360 Joules for monophasic waveforms 3, 2

Advanced Life Support (When Available)

• Establish IV or intraosseous (IO) access without interrupting compressions 3, 2
• Administer epinephrine 1 mg IV/IO every 3-5 minutes throughout the resuscitation to increase coronary and cerebral perfusion 3, 2
• For shock-refractory ventricular fibrillation/pulseless ventricular tachycardia, consider amiodarone (300 mg IV/IO first dose, then 150 mg) or lidocaine (1-1.5 mg/kg first dose, then 0.5-0.75 mg/kg) 3, 1
• Place an advanced airway (endotracheal tube or supraglottic airway) and confirm placement with waveform capnography 1, 2
• After advanced airway placement, provide 1 breath every 6 seconds (10 breaths/minute) with continuous chest compressions—do not pause compressions for ventilation 1, 2

Identify and Treat Reversible Causes

Search for the "H's and T's" during each 2-minute CPR cycle, as myocardial infarction is a common cause of cardiac arrest 3, 1:

• Hypoxia, Hypovolemia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, Hypothermia
• Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis (coronary or pulmonary) 1

In the context of a heart attack, acute coronary occlusion is the likely culprit—early coronary angiography and percutaneous coronary intervention may be life-saving after return of spontaneous circulation 3

Recognition of Return of Spontaneous Circulation (ROSC)

Watch for these indicators that circulation has been restored 1, 2:

• Palpable pulse and measurable blood pressure
• Abrupt sustained increase in end-tidal CO2 (PETCO2) to ≥40 mmHg on capnography
• Spontaneous arterial pressure waves if invasive monitoring is in place

Post-Cardiac Arrest Care

Once ROSC is achieved 1:

• Transport immediately to a hospital with comprehensive post-cardiac arrest care capabilities, including cardiac catheterization
• Optimize oxygenation: Titrate inspired oxygen to achieve arterial oxygen saturation of 94% to avoid oxygen toxicity
• Control ventilation: Target PETCO2 of 35-40 mmHg or PaCO2 of 40-45 mmHg using 10-12 breaths per minute
• Maintain blood pressure: Target mean arterial pressure >80 mmHg or systolic blood pressure >100 mmHg
• Consider therapeutic hypothermia (32-34°C) for comatose survivors to optimize neurological recovery 3, 1
• Identify and treat ST-elevation myocardial infarction (STEMI) with urgent coronary angiography 3

Critical Pitfalls to Avoid

• Do not delay CPR to check for a pulse or wait for equipment—every second without compressions reduces survival 3
• Do not hyperventilate—excessive ventilation impedes venous return and decreases cardiac output 1
• Do not stop compressions for rhythm checks except when the AED is analyzing or delivering a shock 1, 4
• Do not assume gasping is normal breathing—it is a sign of cardiac arrest requiring immediate CPR 3, 1

The evidence strongly supports that immediate, high-quality chest compressions combined with early defibrillation are the most critical determinants of survival from cardiac arrest due to myocardial infarction 3, 1, 4, 5. While advanced interventions like medications and airway management are important, they should never delay or interrupt the delivery of effective chest compressions 3, 4.