A massive heart attack


Mild and Massive Heart Attacks: What’s the Difference?


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When you think about a massive heart attack, you probably imagine someone who suddenly clutches their chest and collapses. This is not always the scenario, even with a large heart attack. Although some heart attacks are more dramatic than others, a heart attack is always serious. Whether a heart attack is mild or severe, you can improve your odds of living the longest, healthiest life possible if you know what to do.

What causes heart attacks?

All heart attacks occur when circulation of blood to the heart is blocked. If the blockage is not rapidly opened, heart tissue will die from a lack of oxygen.

Most often, a heart attack, also called myocardial infarction (MI), is a result of coronary heart disease (CHD).Coronary heart disease is a narrowing of the coronary arteries, which bring blood into the heart muscle. Coronary heart disease is most often caused by atherosclerosis, a buildup of fatty plaque on the artery walls.

Narrowed coronary arteries reduce blood flow to the heart muscle and can cause chest pain (angina), especially during exercise or stress. In addition, blood clots form more easily in a narrowed artery damaged by fatty plaques. A blood clot can completely block blood flow, causing a heart attack and life-threatening heart damage. Angina is not a heart attack, but if it does not go away with rest or after taking nitroglycerin, it is a sign of a developing heart attack.

What is a mild heart attack?

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A mild heart attack affects a relatively small portion of the heart muscle, or does not cause much permanent heart damage. This is because the blockage in a coronary artery occurs in a small artery that supplies a small portion of the heart muscle; does not completely block blood flow to the heart; or lasts briefly.

It is a common misconception that a mild heart attack is not serious. Even if the area of the heart affected is small, a heart attack can result in permanent heart damage and life-threatening problems that affect you for the rest of your life, including heart failure, an abnormal heart beat (arrhythmia), and a higher risk of a second heart attack.

What is a massive heart attack?

A massive heart attack affects a large portion of the heart muscle, or causes a large amount of heart damage. This can happen if the blockage in a coronary artery occurs in a large artery that supplies a large portion of the heart; completely blocks blood flow to the heart; or lasts for a long period of time.

A massive heart attack can result in collapse, cardiac arrest (when your heart stops beating), and rapid death or permanent heart damage. A massive heart attack can also lead to heart failure, arrhythmia, and a higher risk of a second heart attack.

What do I do if I have a heart attack?

Chest pain with a heart attack can spread into the arms, neck, jaw or stomach. Another major heart attack symptom is shortness of breath, even without chest pain. Other symptoms include feeling nauseous, sweaty and dizzy.

If you experience heart attack symptoms, call 911 for the fastest medical help. While waiting for emergency personnel to arrive, remain as calm as possible and loosen tight clothing. The 911 operator may ask if you have aspirin available because it can help prevent a blood clot. The 911 operator will keep you on the phone until help arrives.

The danger of “silent” heart attacks

About half of all heart attacks are mistaken for less serious problems and can increase your risk of dying from coronary artery disease.

Image: goir/Getty Images

Updated: October 22, 2019Published: January, 2017

You can have a heart attack and not even know it. A silent heart attack, known as a silent myocardial infarction (SMI), account for 45% of heart attacks and strike men more than women.

They are described as “silent” because when they occur, their symptoms lack the intensity of a classic heart attack, such as extreme chest pain and pressure; stabbing pain in the arm, neck, or jaw; sudden shortness of breath; sweating, and dizziness.

“SMI symptoms can feel so mild, and be so brief, they often get confused for regular discomfort or another less serious problem, and thus men ignore them,” says Dr. Jorge Plutzky, director of the vascular disease prevention program at Harvard-affiliated Brigham and Women’s Hospital.

For instance, men may feel fatigue or physical discomfort and chalk it up to overwork, poor sleep, or some general age-related ache or pain. Other typical symptoms like mild pain in the throat or chest can be confused with gastric reflux, indigestion, and heartburn.

Also, the location of pain is sometimes misunderstood. With SMI, you may feel discomfort in the center of the chest and not a sharp pain on the left side of the chest, which many people associate with a heart attack. “People can even feel completely normal during an SMI and afterward, too, which further adds to the chance of missing the warning signs,” says Dr. Plutzky.

SMI: Unaware of possible danger

The number of people who suffer an SMI and don’t realize it is alarming. A study in the Nov. 10, 2015, Journal of the American Medical Association looked at almost 2,000 people ages 45 to 84 (half of whom were men) who were free of cardiovascular disease.

After 10 years, 8% had myocardial scars, which are evidence of a heart attack. Most surprising was that 80% of these people were unaware of their condition. Overall, the prevalence of myocardial scars was five times higher in men than in women.

SMI and regular heart attacks share the same risk factors: smoking, being overweight, lack of exercise, high blood pressure, high cholesterol levels, and diabetes. They can be just as dangerous, too. “SMI often leaves scarring and damage to the heart, which, combined with the fact that many people who have an SMI don’t seek immediate care, can further raise a person’s risk of a second and potentially more harmful heart attack,” says Dr. Plutzky. In fact, people who have an SMI and don’t get treatment have a three times greater risk of dying from coronary artery disease. “A silent heart attack is a loud signal your body sends that you have some kind of underlying health issue that needs attention,” says Dr. Plutzky.

How to get checked out

Men may not be aware they had an SMI until weeks or even months later when they see their doctor for a regular visit, or because of persistent symptoms like fatigue, shortness of breath, or heartburn.

SMI is usually detected from an electrocardiogram (EKG) or echocardiogram, which can highlight heart muscle damage. Another method is a blood test for the molecular footprints of troponin T, a protein released by injured heart cells. That test is often used in emergency departments for patients with heart attack symptoms.

Once an SMI is diagnosed, your doctor can identify your main risk factors and help design a treatment strategy, such as changing your diet, exercising regularly, or taking statins, if needed, as well as other medication to help prevent a second heart attack .

“If you do notice any symptoms of a SMI, do not brush them aside, even if you do not think they are serious,” says Dr. Plutzky. “Playing it safe is always a better move than risking the potential harmful downside.”

SMI warning signs

SMI symptoms are often mild and brief. Seek immediate medical attention if you experience one or more of the following:

  • Discomfort in the center of the chest that lasts several minutes, or goes away and comes back. It can feel like an uncomfortable pressure, squeezing, or pain.
  • Discomfort in other upper-body areas, such as one or both arms, the back, the neck, the jaw, or the stomach.
  • Shortness of breath before or during chest discomfort.
  • Breaking out in a cold sweat, or feeling nauseated or lightheaded.

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Heart attack


The underlying cause of a heart attack is coronary heart disease.

Some people may not know they have coronary heart disease until they have a heart attack. For others, a heart attack can happen after weeks, months or years of having coronary heart disease.


Heart attack warning signs can vary from person to person, and they may not always be sudden or severe. Read about heart attack warning signs


If you are rushed to hospital with a suspected heart attack, your health care team will do some tests to find out if you are having a heart attack. They may include:

  • electrocardiogram (ECG)
  • blood tests
  • chest X-ray
  • coronary angiogram.

These tests will help them to decide the best treatment for you. Find out more about medical tests


Emergency treatment

If you think you’re having a heart attack, call Triple Zero (000). Don’t hang up. Ask the operator for an ambulance. Too many people lose their lives because they wait too long to get treatment for heart attack.

You may be given medicines to help dissolve clots.

There is a high risk of dangerous changes to your heartbeat after the start of a heart attack. The most serious changes stop your heart beating and cause a cardiac arrest. Ambulance or hospital staff may use a defibrillator to give your heart a controlled electric shock that may make it start beating again.

In hospital

In hospital, you will receive treatments that help to reduce damage to your heart, and to help prevent future problems. You may need to have a procedure like:

  • angioplasty and stent implantation
  • bypass surgery (also known as coronary artery bypass grafts or CABG).

Read more about heart procedures and devices

Preventing further problems

Medical treatments and healthy lifestyle choices can help your heart attack recovery, greatly reduce your risk of further heart problems, and relieve or control symptoms such as angina. Read about living with heart disease

Cardiac rehabilitation

If you’ve had a heart attack or a procedure, you should be given information about a cardiac rehabilitation program which is another really important step in your recovery.

As the name suggests, a massive heart attack is the most severe form of heart attack one can experience. The symptoms may be so great that victims may become unconscious, suffer permanent heat damage, or simply drop dead on the spot.

Heart attacks, in general, are a serious health issue. The medical term for a heart attack is myocardial infarction, which means that the heart tissue experienced cell death due to lack of blood supply. If a large portion of heart muscle dies, this is referred to as a massive heart attack.

Heart attacks strike nearly 600,000 people each year, with the survival rate of these individuals not being so great, with massive heart attack survival rates estimated at less than six percent. Heart attacks, also known as cardiac arrest, are considered the third leading cause of death in the U.S. behind cancer and heart disease.

Massive Heart Attack vs Heart Attack: What Is the Difference?

You may not think there is a difference between a heart attack and a massive heart attack, but the two are distinct.

A mild heart attack affects a smaller area of the heart and typically doesn’t lead to too much permanent damage. Regardless, even a mild heart attack is still a medical emergency and without proper treatment, there is a higher risk of a more serious heart attack occurring in the future.

A massive heart attack affects a larger portion of the heart, contributing to greater damage. A massive heart attack can lead to collapse, cardiac arrest, rapid death, or permanent heart damage.

Symptoms in both types of heart attack include coughing, nausea, vomiting, chest pain, dizziness, shortness of breath, restlessness, feeling clammy and sweaty, and shortness of breath.

Massive heart attack causes

Atherosclerosis: Considered the main cause of heart attacks, leading to a condition called coronary artery disease. Atherosclerosis leads arteries to become blocked due to an accumulation of cholesterol plaques that accumulate and line the blood vessels. When significant plaque accumulation does occur, especially in the blood vessels that supply the heart muscles, blood cannot circulate efficiently due to impaired expansion and contraction of the blood vessels.

The most worrisome issue, however, is the sudden formation of a thrombus or blood clot at atherosclerotic choke points. When this occurs in the heart vessels, a heart attack will shortly ensue.

Coronary artery spasms: A sudden and transient narrowing of the arteries of the heart called coronary artery spasm can cause an obstruction of blood flow. When this occurs, it deprives the tissues that it normally supplies from oxygen-rich blood. Spasms tend to occur in arteries that have already hardened or arteries with accumulating plaque buildup. Artery spasms can be felt as chest pain and tightness under the sternum or on the left side of the chest. Spasms may be triggered by high blood pressure or high cholesterol states. Emotional stress, alcohol withdrawal, and exposure to cold environments are also known causes.

Coronary microvascular disease: A disease of the small arteries in the body leading to their damage. Like atherosclerosis, this condition is commonly found in those with high cholesterol levels as well as those with high blood sugar, high blood pressure, and those who smoke. Sedentary lifestyles and obesity are also risk factors.

Massive heart attack symptoms

Some of the common symptoms of major heart attack include:

  • Chest pain is a cardinal symptom of a massive heart attack. Severe and excruciating chest pain which can radiate to the left arm, jaws, back, and neck.
  • The feeling of tightness in the chest. Patient may also feel an “elephant is sitting on their chest”
  • Difficulty in breathing.
  • Perfuse sweating
  • Nausea/vomiting
  • Limbs feeling cold and clammy.
  • Dizziness.
  • Cyanosis (lips, nails, and tongue turn blue for few minute)
  • Face turns pale.
  • Irregular pulse and heart beat with low blood pressure.
  • Fainting

Survival chances of a massive heart attack

Time is of the essence when dealing with a massive heart attack. The more time that is taken before the initiation of treatment, the higher the chance of death. Getting to the emergency room within the first couple of hours will give you the best chance of survival when suffering from a massive heart attack.

Overall survival rates will depend on the extent of damage to cardiac tissue, how fast treatment can be given to the patient, and if the patient has any pre-existing conditions that affect overall survival rates.

Massive heart attack diagnosis

When arriving at the emergency department, one of the first things to be done is hooking you up to an electrocardiogram (ECG). It is the main diagnostic tool used for all cases of heart attack. ECG records electrical responses of the heart and outputs them in the form of a wave graph.

Impaired heart muscles have difficulty conducting electrical waves and can easily be interpreted on an ECG graph. Along with symptom presentation, an ECG is a great tool to use when diagnosing any sort of problem with heart function.

Another test that will be done to provide evidence of a heart attack is a blood test to look for specific cardiac markers. During a heart attack, certain enzymes are released into the blood stream because of tissue damage. These enzymes can be detected, helping to confirm a heart attack has occurred.

Treatment to follow after a massive heart attack

Suffering a massive heart attack is a medical emergency and requires immediate attention. When reaching the emergency room, the following will likely occur:

  • The patient will be given a sub-lingual aspirin to prevent further clotting of the blood. If necessary, nitroglycerine will be provided if there is chest pain. Oxygen will also be provided. Morphine or another pain killer may be utilized as well.
  • If the patient has already fainted, emergency cardiopulmonary resuscitation will be done. The purpose is to maintain blood flow to the brain and other organs.
  • Once any emergency intervention has been taken care of, an ECG will be hooked up to get a better picture of how the heart is functioning.
  • In cases of arrhythmia (irregular heart beating), cardioversion or a defibrillator will be used to help re-sync the heart to a normal rhythm.
  • When no heart beat is detected, a combination of CRP and chemical cardioversion will be used.
  • Once the worst has passed and procedures such as angioplasty have been done, cardiac arrest patients will likely be given a combination of thrombolytics, statins, beta-blockers, and ACE inhibitor medications to help reduce any future chance of a repeat heart attack.

Related: Silent heart attack (silent ischemia): Symptoms, causes, and treatments

Cardiac survival rates around 6 percent for those occurring outside of a hospital

Following a cardiac arrest, each minute without treatment decreases the likelihood of surviving without disability, and survival rates depend greatly on where the cardiac arrest occurs, said the committee that carried out the study and wrote the report. In addition, there are wide variations in survival rates among communities and hospitals across the U.S. The committee recommended a series of strategies and actions to improve survival and quality of life following cardiac arrest.

“Cardiac arrest survival rates are unacceptably low,” said Robert Graham, chair of the study committee and director of the national program office for Aligning Forces for Quality at George Washington University, Washington, D.C. “Although breakthroughs in understanding and treating cardiac arrest are promising, the ability to deliver timely interventions and high-quality care is inconsistent. Cardiac arrest treatment is a community issue, requiring a wide range of people to be prepared to act, including bystanders, family members, first responders, emergency medical personnel, and health care providers.”

Although the terms are often used interchangeably, cardiac arrest is different and medically distinct from a heart attack. A heart attack occurs when blood flow to an area of the heart is blocked by a narrowed or completely obstructed coronary artery, resulting in damage of heart muscle. Heart attack symptoms may include pain, dizziness, and shortness of breath, among others. Cardiac arrest results from a disturbance in the electrical activity of the heart that causes it to stop beating. The electrical disturbance can occur suddenly due to a heart attack, severe imbalance of electrolytes, or an inherited genetic mutation that predisposes to electric abnormalities. Symptoms include an almost instantaneous loss of consciousness. The treatment goal for a cardiac arrest is to facilitate the return of circulation and restore the electric rhythm, while for a heart attack, it is to reopen blocked arteries and restore blood flow.

Wide disparities in cardiac arrest outcomes have been documented — many due to variations in patient demographics and health status, geographic chacteristics, and system-level factors affecting the quality and availability of care, such as rates of CPR knowledge among bystanders. For example, the committee found that more than 8 out of 10 cardiac arrests occur in a home setting, and 46 percent of in-home cardiac arrests are witnessed by another person. In addition, one study found that survival rates of cardiac arrests that occurred outside the hospital ranged from 7.7 percent to 39.9 percent across 10 North American sites. Risk-adjusted survival rates for cardiac arrests that occur in the hospital also vary 10.3 percent between bottom- and top-decile hospitals.

Effective treatment for cardiac arrest demands an immediate response from an individual to recognize cardiac arrest, call 911, start CPR, and use an automated external defibrillator (AED), the committee said. Decreasing the time between cardiac arrest onset and the first chest compression is critical. The likelihood of surviving decreases by 10 percent with every passing minute between collapse and return of spontaneous circulation, although new research offers hope in extending this time.

Although evidence indicates that bystander CPR and AED use can significantly improve survival and outcomes from cardiac arrest, each year less than 3 percent of the U.S. population receives CPR training, leaving many bystanders unprepared to respond to cardiac arrest. Furthermore, EMS systems vary in capacities and resources to respond to complex medical needs, such as cardiac arrests. National EMS-system oversight contributes to fragmentation and lack of coordination and planning in response to cardiac arrest, but some communities have demonstrated that focused leadership and accountability can overcome these barriers, the committee said. Educating and training EMS providers to administer “high-performance CPR” — which emphasizes team-related factors such as communication and collaboration to attain high-quality CPR — and provide dispatcher-assisted CPR can help increase the likelihood of positive outcomes.

To improve survival and quality of life following cardiac arrest, the committee recommended several actions:

  • Establish a national registry of cardiac arrest to monitor performance, identify problems, and track progress.
  • Educate and train the public on how to recognize cardiac arrest, contact emergency responders, administer CPR, and use AEDs, as well as facilitate state and local education departments to include CPR and AED training as middle- and high-school graduation requirements.
  • Enhance performance of EMS systems with emphasis on dispatcher-assisted CPR and high-performance CPR.
  • Develop strategies to improve systems of care within hospital settings, including setting national accreditation standards related to cardiac arrest for hospitals and health care systems.
  • Adopt continuous quality improvement programs for cardiac arrest to promote accountability, encourage training and continued competency, and facilitate performance comparisons within hospitals and EMS and health care systems.
  • Expand research in cardiac arrest resuscitation and promote innovative technologies and treatments.
  • Create a national cardiac arrest collaborative to unify the field and identify common goals.

“There are complex challenges and barriers to successfully treat cardiac arrests, both in communities and hospitals,” said Victor Dzau, president of the Institute of Medicine. “However, if existing and developing capabilities are leveraged, the system of cardiac arrest response can be strengthened throughout the U.S.”

Explore and embrace your options

You had a heart attack. Now what?

It’s no surprise that many people feel scared, confused and overwhelmed after a heart attack. A heart attack represents a life-changing event.

After your treatment for heart attack, you likely received instructions and a lot of information from your doctor. With time to reflect, you may be trying to understand what happened. You’re sure to want to know what you can do to avoid heart problems in the future.

Navigating the road to recovery isn’t easy. Questions, confusion, uncertainty and even fear are common. Get answers to your questions and learn more about what to expect.

5 ways to prevent another heart attack

Make prevention your priority

After a first heart attack, most people go on to live a long, productive life. However, around 20 percent of patients age 45 and older will have another heart attack within five years of their first.

Make preventing another heart attack your first priority. Here are five things you can do:

Take your medications as prescribed. Certain medicines can greatly lower your risk of another cardiac event. That’s why it’s important for you to understand your medicines and take them correctly. Learn about managing your medications.

Attend your follow-up appointments. Attending your follow-up appointments will help your doctors keep track of your condition and recovery. You can make the most of your time with your doctor by preparing for your appointment.

Participate in cardiac rehabilitation. Cardiac rehabilitation is a medically supervised program designed to help you recover after a heart attack. You should have received a referral to cardiac rehab when you were discharged from the hospital – if you didn’t, ask your doctor about it. Learn more about cardiac rehab.

Get support. It’s normal to feel scared, overwhelmed or confused after a heart attack. Getting support from loved ones or from people who have also experienced a heart attack can help you cope. Connect with other heart attack survivors and caregivers through our Support Network.

Manage your risk factors. After a heart attack, it’s important to manage risk factors (such as high blood pressure, high cholesterol and diabetes) by taking medications, quitting smoking, eating healthy food and getting active. Find out more about managing your risk factors.

Learn about other lifestyle changes.

Everything You Need to Know About Heart Attacks

The Difference Between Heart Attacks and Cardiac Arrest

The term “heart attack” is often incorrectly used to describe cardiac arrest — when your heart suddenly stops beating.

Cardiac arrest is caused by an electrical disturbance (ventricular tachycardia or ventricular fibrillation). It is often fatal if steps aren’t taken immediately to restore and stabilize the heart rhythm and pumping function.

While a heart attack can lead to cardiac arrest, your heart doesn’t always stop beating during a heart attack. (2)

Heart Attack Statistics

Someone in the United States has a heart attack every 40 seconds, according to the Centers for Disease Control and Prevention (CDC). (3)

According to the CDC, 1 in 5 heart attacks are silent, meaning that the person isn’t aware of it and doesn’t seek immediate medical attention. (3)

About 1 million people in the United States have a heart attack each year, according to a report from the American Heart Association (AHA) published in January 2018 in its journal, Circulation. (4)

This includes an estimated 720,000 first-time heart attacks and 335,000 recurrent heart attacks.

The average age for a first heart attack is 65.6 for men and 72.0 for women, according to the AHA. (4)

Fewer than 10 percent of heart attacks are fatal, according to Harvard Medical School. Most of the drop in heart attack fatalities in recent decades is due to wider use of treatments in the early stages of a myocardial infarction. (5)

Still, the broader category of cardiovascular disease is the leading cause of death among adults in the United States, accounting for 1 in 3 deaths overall.

Coronary artery disease is the deadliest form of cardiovascular disease, followed by stroke, heart failure, high blood pressure, other artery diseases, and other cardiovascular diseases.

Worldwide, cardiovascular disease is also the leading cause of death, accounting for more than 17.9 million deaths in 2015. (4)

Cardiovascular disease doesn’t affect all racial and ethnic groups equally. According to the AHA, the cardiovascular disease death rate for African-Americans is about one-third higher than for the overall U.S. population.

American Indians and Alaska Natives are also at higher risk for death from cardiovascular disease, with 36 percent dying from it before age 65, compared with only 17 percent of the overall U.S. population. (6)

The Degree of Blockage of a Coronary Artery Determines the Type of Heart Attack

Heart attacks are divided into types based on severity:

STEMI Heart Attack

This is the deadliest type of heart attack. It happens when a coronary artery is completely blocked.

STEMI is short for ST segment elevation myocardial infarction. This refers to changes that can be seen on an electrocardiogram (ECG or EKG).

Sometimes called a massive heart attack or a “widowmaker” heart attack, a STEMI heart attack causes significantly reduced blood flow to the heart.

As a result, areas of the heart muscle quickly begin to die.

NSTEMI Heart Attack

This type of heart attack happens when blood flow to your heart through a coronary artery is severely restricted but not entirely blocked.

NSTEMI stands for non-ST segment elevation myocardial infarction.

Sometimes called a mini heart attack or a mild heart attack, an NSTEMI heart attack usually causes less damage to the heart than a STEMI heart attack. (7)

Silent Heart Attack

Some people have a heart attack with mild symptoms or even none at all, known as a silent heart attack.

Although they don’t involve severe symptoms, silent heart attacks are far from harmless. They can cause permanent damage to the heart muscle.

Silent heart attacks account for about 45 percent of all heart attacks, according to Harvard Medical School. They affect women more often than men. (8)

Heart Attack Complications

Certain complications may arise after a heart attack, depending on the location and extent of damage to your heart.

Common heart attack complications include:


Arrhythmias happen when the electrical signals that control heartbeats become abnormal or disorganized.

An arrhythmia may cause heart palpitations or irregular heartbeat.

An electrical disturbance can cause your heart to stop beating altogether. This condition can be fatal without immediate treatment. (9)

Heart Failure

Damage to your heart from a heart attack or coronary heart disease can lead to problems with the pumping function of your heart.

Heart failure happens when your heart’s pumping action becomes weaker, and it can’t pump enough blood to meet your body’s needs.

Valve Problems

A heart attack may damage one of the four valves that keep blood flowing in the correct direction through your heart.

Valve problems can lead to an abnormal heart murmur when a doctor listens to your heart, as well as fatigue, dizziness, shortness of breath, and swelling in your ankles and feet. (10)


A heart attack can be a scary, stressful, life-changing event.

As many as one-third of people who survive a heart attack will develop depression following the incident, according to the American Heart Association.

If you find that your mood or eating or sleeping habits have changed, or you no longer enjoy certain activities after your heart attack, see your doctor to discuss treatment options, which may include counseling or medication. (11)

Sudden Cardiac Arrest

Sudden cardiac arrest (SCA) is also called sudden cardiac death

Sudden cardiac arrest occurs when the heart suddenly stops beating, which stops oxygen-rich blood from reaching the brain and other organs. A person can die from SCA in minutes if it is not treated right away.

Sudden cardiac arrest is not a heart attack, even though you may hear the terms “heart attack” or “massive heart attack” used to describe it. A heart attack happens when blood flow to a part of the heart is slowed or stopped, usually because of plaque rupture in one of the coronary arteries. This causes death of the heart muscle. But a heart attack does not always mean that the heart stops beating. A heart attack may cause SCA, but the two terms do not mean the same thing.

What causes SCA?

According to the National Heart, Lung, and Blood Institute, between 250,000 and 450,000 Americans have SCA each year. Almost 95% of these people die within minutes.

Sudden cardiac arrest happens most often in adults in their mid 30s to mid 40s. It affects men twice as often as it affects women. It hardly ever affects children, unless they have an inherited problem that increases their risk.

People with heart disease have a greater chance of SCA, but it can happen in people who appear healthy and do not know they have any heart problems.

Most cases of SCA are caused by a very fast heartbeat (ventricular tachycardia) or a very chaotic heartbeat (ventricular fibrillation). These irregular heart rhythms, called arrhythmias, may cause the heart to stop beating. Another type of arrhythmia, called bradycardia, which is a very slow heart rate, can also cause SCA.

Other causes of SCA are

  • Coronary artery disease (CAD), which results from a condition called atherosclerosis. Atherosclerosis is a condition where a waxy substance (plaque) forms inside the arteries that supply blood to your heart. If that plaque builds up in the arteries that supply blood to your heart, the blood flow slows or stops. This decreases the amount of oxygen that gets to the heart, which can lead to a heart attack. Any scarring or damage to the heart after a heart attack increases the risk of arrhythmia and SCA.
  • Physical stress, which can cause the heart’s electrical system to stop working. In people who already have heart problems, intense physical activity or exercise can lead to SCA because the release of the hormone adrenalin acts as a trigger for SCA.
  • Inherited disorders, which are disorders that run in families. Some types of arrhythmias tend to run in families. Also, people born with heart defects, a coronary artery anomaly (CAA), or Brugada Syndrome may be at greater risk of SCA.
  • Medicines for heart disease, which can sometimes increase the risk of arrhythmias.
  • Illegal or illicit drug use (like cocaine).
  • Changes to the size or shape of the heart, which can be caused by high blood pressure or heart disease. Changes to the heart’s structure may cause problems with its electrical system, increasing the risk of arrhythmias.

What are the signs and symptoms of SCA?

For most people, the first sign of SCA is fainting or a loss of consciousness, which happens when the heart stops beating. Breathing may also stop at this time. Some people may experience dizziness or lightheadedness just before they faint.

How is SCA diagnosed?

Because SCA happens quickly and without warning, it usually cannot be diagnosed when it is happening. But there are tests that doctors use to determine if patients are at risk of SCA:

  • Electrocardiography (ECG or EKG), which is used to look at the electrical activity of the heart. An electrocardiogram can tell your doctor a lot about your heart and how it is working. This test can help your doctor learn more about your heart rhythm, the size and function of the chambers of your heart, and your heart muscle.
  • Echocardiography, which uses sound waves to produce an image of the heart to see how it is working.
  • Cardiac catheterization, which involves threading a long, thin tube (called a catheter) through an artery or vein in the leg or arm and into the heart. Depending on the type of test your doctor has ordered, different things may happen during cardiac catheterization. For example, a dye may be injected through the catheter to see the heart and its arteries (a test called coronary angiography or coronary arteriography).
  • Electrophysiology studies (EPS), which use cardiac catheterization techniques to study patients with arrhythmias. EPS shows how the heart reacts to controlled electrical signals.
  • Gated blood pool scan, or MUGA, which shows how well your heart is pumping blood.
  • Magnetic resonance imaging (MRI) which gives doctors detailed pictures of your heart.

How is SCA treated?

Sudden cardiac arrest should be treated right away with a defibrillator, which is a device that sends an electrical shock to the heart to restore its normal rhythm. If you think someone is having SCA, you should dial 9-1-1 right away.

Defibrillators are now available in many public places, such as shopping malls and airports. But if someone is having SCA and there is no defibrillator available, then cardiopulmonary resuscitation (CPR) should be performed until an ambulance or other help arrives. The chest compressions given during CPR move a small amount of blood to the heart and brain, “buying time” until a normal heartbeat can be restored. Patients with known heart problems who are at risk of SCA should be under the care of a doctor.

Patients who have already had SCA are at greater risk of having it again. These patients may be treated with antiarrhythmic medicines or an implantable cardioverter defibrillator (ICD) to stop the arrhythmias that can lead to SCA. An ICD is a device that applies electric impulses or, if needed, a shock to restore a normal heartbeat.

In some patients, balloon angioplasty or coronary artery bypass surgery may be performed to treat their CAD and prevent the heart damage that can lead to arrhythmias and SCA.

Heart Attack (Myocardial Infarction)

What is a heart attack?

A heart attack, or myocardial infarction (MI), is permanent damage to the heart muscle. “Myo” means muscle, “cardial” refers to the heart, and “infarction” means death of tissue due to lack of blood supply.

A closer look inside your coronary arteries

Your heart muscle needs to receive a good supply of blood at all times to function properly. Your heart muscle gets the blood it needs to do its job from the coronary arteries.

What is coronary artery disease?

Coronary artery disease is the narrowing or blockage of the coronary arteries caused by atherosclerosis. Atherosclerosis (sometimes called “hardening” or “clogging” of the arteries) is the buildup of cholesterol and fatty deposits (called plaque) on the inner walls of the arteries that restricts blood flow to the heart.

Without adequate blood, the heart becomes starved of oxygen and the vital nutrients it needs to work properly. This can cause chest pain called angina. When one or more of the coronary arteries are completely blocked, a heart attack (injury to the heart muscle) may occur.

What happens during a heart attack?

A network of blood vessels known as coronary arteries surround the heart muscle and supply it with blood that is rich in oxygen and nutrients. The heart muscle needs this continuous supply of oxygen and nutrients to function.

A heart attack occurs when a coronary artery becomes suddenly blocked, stopping the flow of blood to the heart muscle and damaging it.

Types of Heart Attacks

When fat builds up inside your arteries it causes slight injury to your blood vessel walls. In an attempt to heal the blood vessel walls, the cells release chemicals that make the blood vessel walls stickier. Other substances traveling through your blood stream, such as inflammatory cells, cellular waste products, proteins and calcium, begin to stick to the vessel walls. The fat and other substances combine to form a material called plaque.

Over time, the inside of the arteries develop plaques of different sizes. Many of the plaque deposits are soft on the inside with a hard fibrous “cap” covering the outside. If the hard surface cracks or tears, the soft, fatty inside is exposed. Platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque.

If a blood clot totally blocks the blood supply to the heart muscle, called a coronary thrombus or coronary occlusion, the heart muscle becomes “starved” for oxygen and nutrients (called ischemia) in the region below the blockage. Within a short time, an acute coronary syndrome can occur.

Acute Coronary Syndrome is a name given to three types of coronary artery disease that are associated with sudden rupture of plaque inside the coronary artery: unstable angina, Non-ST segment elevation myocardial infarction or heart attack (NSTEMI), or ST segment elevation myocardial infarction or heart attack (STEMI).

Circumflex Occlusion (Back of heart)

Left Anterior Descending (LAD) Occlusion (Front of heart)

Right Coronary Artery Occlusion (Front of heart)

Dark red = artery

Blue = outlines region of heart affected by blockage

Each coronary artery supplies blood to a region of the heart muscle. If an artery is occluded (blocked) there is no blood supply to that region.

The amount of damage to the heart muscle depends on the size of the area supplied by the blocked artery and the time between injury and treatment.

What is a Coronary Spasm?


A heart attack can also occur less frequently by a spasm of a coronary artery. During coronary spasm, the coronary arteries constrict or spasm on and off, causing lack of blood supply to the heart muscle (ischemia). It may occur at rest and can even occur in people without significant coronary artery disease. If coronary artery spasm occurs for a long period of time, a heart attack can occur.

What are the symptoms of a heart attack?

If you are having any one of the symptoms described below that lasts for more than 5 minutes, SEEK EMERGENCY TREATMENT (CALL 911) WITHOUT DELAY. These symptoms could be the signs of a heart attack (also called myocardial infarction or MI) and immediate treatment is essential.

Symptoms of a heart attack include:

  • Angina: Chest pain or discomfort in the center of the chest; also described as a heaviness, tightness, pressure, aching, burning, numbness, fullness or squeezing feeling that lasts for more than a few minutes or goes away and comes back. It is sometimes mistakenly thought to be indigestion or heartburn.
  • Pain or discomfort in other areas of the upper body including the arms, left shoulder, back, neck, jaw, or stomach
  • Difficulty breathing or shortness of breath
  • Sweating or “cold sweat”
  • Fullness, indigestion, or choking feeling (may feel like “heartburn”)
  • Nausea or vomiting
  • Light-headedness, dizziness, extreme weakness or anxiety
  • Rapid or irregular heart beats

Women’s Symptoms Sometimes Differ

Although most women and men report symptoms of chest pain with a heart attack, women are slightly more likely than men to report unusual symptoms. Those who have more vague or less typical “heart” symptoms have reported the following:

  • Upper back or shoulder pain
  • Jaw pain or pain spreading to the jaw
  • Pressure or pain in the center of the chest
  • Light headedness
  • Pain that spreads to the arm
  • Unusual fatigue for several days

In a multi-center study of 515 women who had an acute myocardial infarction (MI), the most frequently reported symptoms were unusual fatigue, sleep disturbances, shortness of breath, indigestion and anxiety. The majority of women (78%) reported at least one symptom for more than one month before their heart attack.

Lessons learned:

  1. If you have chest pain or other symptoms of heart attack that last longer than 5 minutes – do not ignore it – seek emergency care to rule out a heart attack.
  2. Learn to identify the common symptoms of heart disease. They may be warning signs of a heart attack.
  3. Get a physical exam that includes screening for heart disease risk factors.
  4. If you have questions and symptoms persist, seek a second opinion.

Learn more about women and heart attack.

Silent MI

Some people have a heart attack without having any symptoms (a “silent” myocardial infarction). A silent MI can occur among all patients, though it is more common among women or people with diabetes. A silent MI may be diagnosed during a routine doctor’s exam.

If You Take Nitroglycerin

If you have been prescribed nitroglycerin and you experience angina, stop what you are doing and rest. Take one nitroglycerin tablet and let it dissolve under your tongue, or if using the spray form, spray it under your tongue. Wait 5 minutes. If you still have angina after 5 minutes, call 911 to get emergency help.

For patients diagnosed with chronic stable angina:

If you experience angina, take one nitroglycerin (NTG) tablet and let it dissolve under your tongue. If chest discomfort or pain is not improved or getting worse 5 min after one dose, call 9-1-1 immediately to get emergency help before taking additional NTG. If symptoms are much improved by 1 dose of NTG, you may repeat the dose every 5 min for up to 3 tablets over 15 minutes. If you still have angina after taking 3 doses of nitroglycerin, call 911 to get emergency help.

Do not wait to get help: Time is Muscle

At the first signs of a heart attack, call for emergency treatment (911). Do not wait for your symptoms to “go away.” Early recognition and treatment of heart attack symptoms can reduce the risk of heart damage and allow treatment to be started immediately. Even if you’re not sure your symptoms are those of a heart attack, you should still be evaluated.

The best time to treat a heart attack is within one hour of the onset of the first symptoms. When a heart attack occurs, there’s a limited amount of time before significant and long-lasting damage occurs to the heart muscle. If a large area of the heart is injured during the heart attack, full recovery becomes much more difficult.

Studies show that the people who have symptoms of a heart attack often delay, or wait to seek treatment, for longer than seven hours.

Reasons why people wait to get help:

People who delay tend to be older, female, African-American and to have a history of angina, high blood pressure or diabetes. People who delay also consult their family members or try to treat themselves first before seeking treatment.

Reasons people delay:

  • They are young and don’t believe a heart attack could happen to them
  • Symptoms are not what they expected
  • They may deny the symptoms are serious and wait until they go away
  • They may ask the advice of others, especially family members
  • They may first try to treat the symptoms them-selves, using aspirin or antacids
  • They may think the symptoms are related to other health problems (upset stomach, arthritis)
  • They may put the care of others first (take care of children or other family members) and not want to worry them

Waiting just a couple hours for medical help may limit your treatment options, increase the amount of damage to your heart muscle, and reduce your chance of survival.

Call 911 — Not a Friend

Calling 911 is almost always the fastest way to get life-saving treatment. When you call, emergency personnel may tell you to chew an aspirin to break up a possible blood clot, if there is not a medical reason for you to avoid aspirin. When emergency help arrives, they can promptly begin treatment, and they are trained to revive someone whose heart has stopped. Also, you’re likelier to get treated faster at the hospital if you arrive by ambulance. If you are having symptoms, do not drive yourself unless there is absolutely no other option.

If you’ve had prior heart treatments

Even if you’ve been treated for a prior heart attack or if you’ve had other treatments for coronary artery disease, a heart attack CAN happen again. Treatments such as medications, open heart surgery and interventional procedures DO NOT cure coronary artery disease, so it is still important to lead a healthy lifestyle.

Action Plan

  • Ask your doctor whether you are at risk for a heart attack and what you can do to reduce your risk factors. Be sure to ask about aspirin and nitroglycerin.
  • Learn the signs and symptoms of a heart attack.
  • Learn what to do if you have symptoms: Call 911 after five minutes – do not call a friend or family member for help.
  • Talk with your family members, friends and coworkers about the heart attack warning signs and the importance of acting quickly.

Importance of a heart-healthy lifestyle

It is important for you to be committed to leading a heart-healthy lifestyle to reduce your risk of a heart attack. Your health care team can help you achieve your goals, but it is up to you to take your medications as prescribed, make dietary changes, quit smoking, exercise regularly, keep your follow-up appointments and be an active member of the treatment team.

Share this information with your family members and caregivers so they learn to recognize the symptoms of a heart attack and when to help you seek emergency treatment.

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