The sudden stopping of the heart, known as sudden cardiac arrest (SCA), is an electrical malfunction, unlike a heart attack, which is a circulation problem caused by a blocked artery. SCA occurs when the heart’s electrical system fails, causing it to quiver chaotically or stop beating entirely. This immediately halts blood flow to the brain and other organs. Survival rates drop significantly with every minute that passes without intervention. Prompt action from bystanders is the most important factor until professional medical help arrives.
Identifying the Signs of Sudden Cardiac Arrest
The collapse associated with sudden cardiac arrest is typically immediate and without warning. The person will be unconscious and unresponsive to shouting or shaking. They will not be breathing normally, which may manifest as no breathing or merely gasping breaths, often described as agonal breathing. This gasping should be treated as a lack of normal breathing. Once these signs are confirmed, the first step is to call for emergency medical services (EMS), such as 911, and begin the chain of survival.
Executing Hands-Only Cardiopulmonary Resuscitation
Hands-Only Cardiopulmonary Resuscitation (CPR) involves providing continuous, high-quality chest compressions to manually circulate blood and oxygen to the brain and heart. To begin, place the person on their back on a firm, flat surface and kneel beside them. Position the heel of one hand in the center of the chest, between the nipples, and place the heel of your other hand on top, interlacing your fingers. This ensures the force is applied to the breastbone (sternum) rather than the ribs.
The quality of the compression requires you to push hard and push fast, minimizing interruptions. For an adult, compress the chest to a depth of at least 2 inches (5 centimeters) but no more than 2.4 inches (6 centimeters). The speed should be maintained at a rate of 100 to 120 compressions per minute, which can be timed to the beat of the song “Stayin’ Alive.” Allow the chest to fully recoil after each compression to ensure the heart chambers can refill with blood. Continue this manual circulation until a trained responder or an automated external defibrillator (AED) is ready for use.
The Role of Automated External Defibrillators
The Automated External Defibrillator (AED) is a user-friendly device designed to deliver an electrical shock to reset the heart’s electrical system. This shock corrects ventricular fibrillation (V-Fib), the most common cause of sudden cardiac arrest. V-Fib is a life-threatening arrhythmia where the ventricles quiver chaotically instead of contracting, making the heart incapable of pumping blood. The AED acts as a temporary “reset button” for the heart’s natural pacemaker.
To use the device, simply turn it on and follow the automated voice and visual prompts. Attach two electrode pads to the person’s bare chest in the locations indicated on the pads. Once connected, the AED automatically analyzes the heart’s electrical rhythm to determine if a shockable rhythm is present. If shockable, the machine will charge and prompt the user to press a button to deliver the electrical current. This temporarily stops all electrical activity to allow the heart’s natural pacemaker to potentially take over.
Hospital Resuscitation and Recovery Care
Once emergency medical services take over, they provide advanced cardiac life support (ACLS) interventions. These procedures include administering resuscitation medications such as epinephrine, a potent vasoconstrictor that helps increase blood flow to the heart and brain during CPR. Epinephrine is typically administered intravenously or intraosseously (into the bone marrow) every three to five minutes to improve the likelihood of restoring a spontaneous heart rhythm.
Advanced airway management, such as endotracheal intubation, is also performed to secure the person’s airway and ensure effective oxygen delivery. Following the successful restart of the heart, a post-resuscitation intervention is Targeted Temperature Management (TTM). TTM involves actively cooling the body temperature to a controlled range for at least 24 hours. This cooling helps protect the brain from injury that commonly occurs after blood flow is restored.