In the ABCs of cardiology, which component is addressed first?

• A. Airway
• B. Breathing
• C. Circulation
• D. Defibrillation

Answer: (A)

Securing the airway is the first priority because nothing else matters if oxygen cannot reach the lungs. If the airway is blocked or inadequate, ventilation cannot occur effectively, so tissues become hypoxic regardless of what you do next with breathing support or circulation. The first step is to open and maintain a patent airway, clear obstructions if present, and provide ventilation as needed (for example with a bag‑valve‑mask or an advanced airway). Once the airway is patent and ventilation is supported, you move on to assessing and optimizing breathing, and then address circulation (such as chest compressions and defibrillation when indicated). Defibrillation targets the heart rhythm itself and is not the immediate first action because without a patent airway and adequate ventilation, you can’t achieve proper oxygenation to sustain any resuscitation effort.