Cardiac arrest” and “heart attack” are often confused, but they are distinct medical emergencies. Both require immediate attention, but their causes and effects differ significantly. Understanding these differences helps in recognizing symptoms and responding effectively.
Understanding a Heart Attack
A heart attack, medically known as a myocardial infarction, is primarily a “circulation” problem. It occurs when blood flow to a part of the heart muscle is severely reduced or blocked. This blockage is most often caused by a buildup of plaque, a waxy substance, in the coronary arteries, which supply blood to the heart. When a piece of this plaque breaks away, a blood clot can form, obstructing blood flow and depriving the heart muscle of oxygen and nutrients.
This lack of oxygen can cause damage or even death to the affected heart muscle tissue. Symptoms commonly include chest pain or discomfort, often described as pressure, squeezing, or aching. This discomfort can spread to the arm, back, neck, jaw, or stomach. Shortness of breath, cold sweats, nausea, vomiting, or lightheadedness are also common. The person remains conscious during a heart attack.
Understanding Cardiac Arrest
In contrast, cardiac arrest is an “electrical” problem, signifying a sudden malfunction in the heart’s electrical system. This malfunction leads to an irregular heart rhythm (arrhythmia), often ventricular fibrillation, causing the heart to quiver instead of pumping blood effectively. When the heart stops pumping, blood flow to the brain and other vital organs ceases abruptly.
Symptoms are immediate. An individual will suddenly collapse, become unresponsive, and either stop breathing or exhibit abnormal, gasping breaths. There will be no pulse. This condition is life-threatening and can result in death within minutes without immediate intervention.
Comparing the Two Conditions
A heart attack is a “plumbing” issue affecting blood flow, while cardiac arrest is an “electrical” issue affecting the heart’s rhythm. During a heart attack, heart muscle damage occurs due to lack of blood, but the heart continues to beat. Symptoms develop over time, and the person remains conscious.
While a heart attack damages heart tissue, cardiac arrest results in a complete lack of blood flow to the brain and other organs, causing rapid brain damage and death. A heart attack can sometimes trigger cardiac arrest, but not all heart attacks lead to it. Cardiac arrest can also occur due to other electrical abnormalities. Survival rates for cardiac arrest are lower without immediate intervention, while heart attack survival is higher with prompt medical treatment.
Responding to a Cardiac Emergency
Responding quickly to a cardiac emergency is crucial. For a suspected heart attack, immediately call emergency services (e.g., 911). While waiting, keep the person calm, loosen tight clothing, and if advised by emergency services and without contraindications, aspirin may be given to chew.
If someone suddenly collapses, becomes unresponsive, and is not breathing normally, suspect cardiac arrest and immediately call emergency services. Begin cardiopulmonary resuscitation (CPR). For untrained bystanders, hands-only CPR, involving continuous hard and fast chest compressions (100-120 per minute), is recommended until medical help arrives. If an automated external defibrillator (AED) is available, use it as soon as possible; it can deliver an electrical shock to restore a normal heart rhythm, increasing survival chances.