SCA and Heart Attack: Understanding the Difference

It’s a common misconception that sudden cardiac arrest (SCA) and heart attack are the same thing. In reality, they are quite different.

Understanding the difference could save your life—or the life of someone you love.

HEART ATTACK: A "PLUMBING PROBLEM”

The Person is Awake and the Heart is Beating

Heart attack (the medical term is myocardial infarction or MI) occurs when part of the heart’s blood supply is reduced or blocked, causing the heart muscle to become injured or die. The person is awake (conscious) and may complain of one or more of the signs and symptoms of heart attack.

Signs and Symptoms of Heart Attack

Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes or that goes away and comes back.

Some heart attack victims experience mild intermittent chest discomfort that comes and goes over a period of days. These are early “warning signs” that may precede a heart attack. (Some victims, however, do not experience any warning signs.)

Chest discomfort can feel like uncomfortable pressure, squeezing or fullness. It can evolve into crushing pain if nothing is done.

Other symptoms of heart attack include:

• Pain or discomfort in one or both arms, spreading to the shoulder, upper back, neck or jaw
• Shortness of breath
• Nausea, sweating, lightheadedness
• A general sense of anxiety
• A tendency to deny that anything serious is happening.

It’s important to act right away if these symptoms occur to maximize the odds of survival and minimize potential permanent damage to the heart.

Signs and Symptoms of Heart Attack in Women

The most common symptom of heart attack in women is the same as it is for men: chest discomfort or pain. Women are more likely than men, however, to experience other common symptoms such as:

• Shortness of breath
• Fainting, nausea, vomiting
• Back or jaw pain
• Cold, sweaty skin, paleness.

Sometimes women experience additional symptoms including:

• Stomach or abdominal pain
• Weakness and/ or overwhelming fatigue
• Swelling of the ankles and/ or lower legs.

Lifesaving Actions

When someone experiences a heart attack, he or she is awake and the heart is beating. There is no need to give cardiopulmonary resuscitation (CPR) or to use an automated external defibrillator (AED). Instead, the correct action is to call 9-1-1 immediately to get emergency medical services (EMS) on the way to help. The sooner the person is treated, the better the outcome.

How You Can Save a Life: Heart Attack

What to do:

• Call 9-1-1 immediately
• Have the person rest or lie down while waiting for EMS

What not to do:

• Refrain from driving the person experiencing symptoms of heart attack to the hospital. The only rare exception might be when the hospital is very close by and you expect EMS to be delayed significantly in getting an ambulance to the scene.
• Never drive yourself to the hospital if you are experiencing heart attack symptoms.
• Do not delay more than five minutes from the onset of symptoms to call 9-1-1.
• Do not hesitate to call 9-1-1 because you are embarrassed or don’t want to bother anyone. EMS is there for you. And, it is better to be safe than sorry.

Are You at Risk for Heart Attack?

The risk factors for heart attack include:

• A family history of heart disease
• Smoking
• High blood pressure
• High cholesterol
• Obesity
• Diabetes
• A sedentary lifestyle
• Stress.

SUDDEN CARDIAC ARREST: “AN ELECTRICAL PROBLEM”

The Person is Not Awake and the Heart is Not Beating

Sudden cardiac arrest (SCA) is different from heart attack. While heart attack is described as a “plumbing problem,” SCA is more of an “electrical problem” that prevents the heart from functioning effectively. Heart attack can lead to SCA, but there are many other causes, such as congenital abnormalities, severe heart failure, electrocution and drug overdose.

Signs and Symptoms

When SCA occurs, the heart stops beating altogether. As a result, blood no longer is pumped throughout the body, including the brain. The person suddenly passes out, loses consciousness, and appears lifeless—except for abnormal “gasping” which may last for several minutes.

Occasionally, SCA victims will experience 10-20 seconds of seizure activity (shaking of the arms and legs) at the onset of the event as the brain stops receiving blood and oxygen from the heart.

The SCA victim is never awake and needs immediate help. If nothing is done, the victim will die within minutes.

Lifesaving Actions

When SCA occurs, it is critically important that whoever is near the victim calls 9-1-1 immediately, checks for signs of life, and if there are none, gives CPR and uses the nearest automated external defibrillator (AED).

This is lifesaving care that any layperson can provide. It is best to be trained in CPR and the use of AEDs, but even without formal training, the rescuer can push hard and fast on the victim’s chest and follow the directions on the AED, while waiting for EMS to arrive.

How You Can Save a Life: Sudden Cardiac Arrest

What to do:

• Call 9-1-1 immediately
• Give CPR or at the very least chest compressions
• Use AED

What not to do:

The worst thing for an SCA victim is to do nothing. Sometimes people hesitate to help because they are afraid they might do the wrong thing and hurt the victim. But the SCA victim is clinically dead and cannot get worse. Your actions can only help.

Are You at Risk for SCA?

How do you know whether you are at risk for SCA? Here are some risk factors:

• A previous heart attack
• A previous episode of cardiac arrest
• A low (<35%) ejection fraction or EF (the heart’s ability to pump blood)
• Underlying heart conditions such as coronary artery disease, congenital heart disease (e.g., hypertrophic cardiomyopathy), electrophysiological abnormalities (e.g., Long QT syndrome, Wolff-Parkinson-White disease, Brugada syndrome)
• Severe heart failure
• Marked changes in electrolytes in the blood
• A tendency to faint
• Hyperthyroidism
• Electrocution
• Drug abuse
• A family history of heart disease or stroke.

If you have one or more of these risk factors, you may be a candidate for SCA. If you think may be at risk, you should see a cardiologist or heart rhythm specialist (e.g., electrophysiologist, or EP) for an evaluation. The specialist may recommend implantable cardioverter defibrillator (ICD) therapy, medications, or other measures to prevent sudden death.

Summary

Take action today. Share this information with everyone you care about. Lives are at stake and your actions can mean the difference between life and death.

By Mary Newman, Sudden Cardiac Arrest Foundation

Reviewed by Norman S. Abramson, MD, FACEP, FCCM, Joseph P. Ornato, MD, FACC, and Allan Braslow, PhD