Acute Cardiac Event

When your heart suddenly stops getting enough blood, every minute counts. Understanding what happens during an acute cardiac event and knowing how to respond can make the difference between life and death.

Table of contents

• What is an acute cardiac event?
• Signs and symptoms
• What causes these events?
• What to do in an emergency
• Treatment approaches
• Recovery and prevention

What is an acute cardiac event?

An acute cardiac event is a serious health emergency that happens when something suddenly interrupts your heart’s normal function or blood flow. The term covers several different but related conditions that all require immediate medical attention^[1].

The most common type is called acute coronary syndrome, which includes heart attacks and unstable chest pain. An acute cardiac event occurs when something interrupts your heart’s function or blood flow, which is why having any form of heart disease could be a warning sign^[15]. These events lead to problems with how your heart works, which can then affect your lungs, blood vessels, or nervous system^[15].

In the United States alone, more than 1,000,000 people suffer acute coronary events each year, and more than 400,000 die annually from coronary artery disease^[4]. More than 800,000 people in the U.S. have a heart attack every year^[3].

A heart attack, also called a myocardial infarction, happens when a part of the heart muscle doesn’t get enough blood. The more time that passes without treatment to restore blood flow, the greater the damage to the heart muscle^[5]. When blood flow to a part of your heart stops or is far below normal, it causes injury or death to that part of your heart muscle^[3].

Another type of acute cardiac event is sudden cardiac arrest, which is different from a heart attack. During cardiac arrest, the heart suddenly stops beating, stopping blood flow to the brain and other vital organs^[7]. This happens because of an electrical problem that makes your heart stop beating^[22].

Coronary atherosclerosis is the underlying condition for coronary events with few exceptions. Coronary atherosclerosis is known to develop in childhood and adolescence and progresses throughout adulthood^[4].

Signs and symptoms

The symptoms of acute coronary events usually start suddenly^[1]. Recognizing these warning signs early can save your life or the life of someone else.

The major symptoms of a heart attack include chest pain or discomfort. Most heart attacks involve discomfort in the center or left side of the chest that lasts for more than a few minutes or that goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain^[5].

Many people feel pain in their chest during a heart attack. It can feel like discomfort, squeezing or heaviness, or it can feel like crushing pain. It may start in your chest and spread to other areas like your left arm (or both arms), shoulder, neck, jaw, back or down toward your waist^[3].

Other common symptoms include:

• Pain that starts in the chest and spreads to the shoulders, arms, upper belly area, back, neck or jaw
• Nausea or vomiting
• Shortness of breath, which often comes along with chest discomfort, but can also happen before chest discomfort
• Feeling weak, light-headed, or faint
• Breaking into a cold sweat
• Unusual or unexplained tiredness^[1][5]

While the most common symptom is chest pain, symptoms can vary from person to person. Some people may only experience minor pain, similar to indigestion. People often think they’re having indigestion or heartburn when they’re actually having a heart attack^[3][6].

Women are more likely to have these other symptoms. Women are less likely to have chest pain or discomfort that feels like indigestion. They’re more likely to have shortness of breath, fatigue and sleep problems that started before the heart attack. They also have nausea and vomiting or pain in their back, shoulders, neck, arms or abdomen^[3].

For sudden cardiac arrest, the first sign is usually loss of consciousness (fainting). This happens when the heart stops beating. Some people may have a racing heartbeat or feel dizzy or light-headed just before they faint. And sometimes people have chest pain, shortness of breath, nausea, or vomiting in the hour before they have a sudden cardiac arrest^[7].

What causes these events?

The main cause of heart attacks is coronary artery disease, also called ischemic heart disease. This happens when the arteries of the heart cannot deliver enough oxygen-rich blood to the heart^[7].

Most heart attacks happen because of a blockage in one of the blood vessels that supply your heart. Most often, this occurs because of plaque, a sticky substance that can build up on the insides of your arteries. That buildup is called atherosclerosis. When there’s a large amount of this buildup in the blood vessels to your heart, this is called coronary artery disease^[3].

Before a heart attack, one of the plaques bursts (ruptures), causing a blood clot to develop at the site of the rupture. The clot may block the supply of blood to the heart, triggering a heart attack^[6]. Sometimes, plaque deposits inside the coronary (heart) arteries can break open or rupture, and a blood clot can form^[3].

Several health conditions, your lifestyle, and your age and family history can increase your risk for heart disease and heart attack. About half of all Americans have at least one of these three key risk factors for heart disease: high blood pressure, high blood cholesterol, and smoking^[5].

The most common factors for developing cardiovascular disease include high blood pressure and high cholesterol, so overweight, smoking, and inactive individuals — as well as those with diabetes — are more at risk. Some risk factors (such as age or genetic build) aren’t modifiable^[15].

For sudden cardiac arrest, abnormal heart rhythms (arrhythmias) cause most events. The most common life-threatening arrhythmia is ventricular fibrillation. This is an erratic, disorganized firing of impulses from your heart’s ventricles (lower chambers). When this happens, your heart can’t pump blood^[22].

What to do in an emergency

If you notice the symptoms of a heart attack in yourself or someone else, call 911 immediately. The sooner you get to an emergency room, the sooner you can get treatment to reduce the amount of damage to the heart muscle^[5].

A heart attack is a life-threatening emergency. If you think you or someone you’re with is having a heart attack, call 911 (or your local emergency services phone number). Time is critical in treating a heart attack. A delay of even a few minutes can result in permanent heart damage or death^[3].

Don’t drive yourself to the hospital. Ambulances are equipped with life-saving medical equipment and staffed by trained paramedics who can provide essential care, such as giving medications, performing CPR, and using defibrillators. Don’t risk getting in an accident or stuck in traffic when your life is on the line^[24].

While waiting for an ambulance, it may help to chew and then swallow a tablet of aspirin (ideally 300mg), as long as the person having a heart attack is not allergic to aspirin. Aspirin helps to thin the blood and improves blood flow to the heart^[6].

Stay on the phone with 911 and follow their instructions. Unlock doors and turn on lights to help emergency responders find and access you quickly. Loosen tight clothing. Sit down in a comfortable position, propping yourself against a wall or stable furniture. Avoid physical exertion and keep breathing calmly^[24].

At the hospital, health care professionals can run tests to find out if a heart attack is happening and can decide the best treatment. In some cases, a heart attack requires cardiopulmonary resuscitation (CPR) or an electrical shock (defibrillation) to the heart to get the heart pumping again^[5].

Treatment approaches

In hospital, treatment for a heart attack depends on the type of heart attack, and how serious it is^[6]. Tests to diagnose a heart attack include electrocardiogram (ECG), blood tests to check for certain heart proteins, chest X-ray, and other imaging tests^[9].

The two main treatments are using medicines to dissolve blood clots and surgery to help restore blood to the heart^[6]. Rapid reperfusion with primary percutaneous coronary intervention is the goal with either clinical presentation. Coupled with appropriate medical management, percutaneous coronary intervention can improve short- and long-term outcomes following a heart attack^[12].

If your symptoms started within the past 12 hours, you’ll usually be offered a coronary angiography and primary percutaneous coronary intervention. This is an emergency treatment that involves a procedure to widen any blocked coronary arteries. It’s sometimes called coronary angioplasty^[13].

During coronary angioplasty, a thin tube with a balloon at the end is put into a blood vessel in your groin or arm. The tube is passed through your blood vessels and up to your heart. Once in the narrowed section of your coronary artery, the balloon is inflated to open it. Flexible metal mesh (a stent) is usually inserted into the artery to help keep it open afterwards^[13].

If you cannot be treated urgently with percutaneous coronary intervention, you may be offered medicines to break down blood clots, known as thrombolytics or fibrinolytics. These are usually given by injection^[13]. However, fibrinolysis is not recommended in patients with non-ST elevation acute coronary syndrome^[12].

You may also be given blood-thinning medicines to prevent further clots from forming, such as low-dose aspirin. Both types of medicine usually need to be taken for up to 12 months^[13].

In some circumstances, an alternative operation known as a coronary artery bypass graft may be considered. This involves taking a blood vessel from another part of your body and attaching it to your coronary artery above and below the narrowed area or blockage. The new blood vessel diverts blood around narrowed or clogged parts of your major arteries^[13].

Recovery and prevention

The time it takes to recover from a heart attack will depend on the amount of damage to your heart muscle. Most people can return to work after having a heart attack. How quickly you can go back to work depends on your health, the state of your heart and the type of work you do^[6].

If you’ve had a heart attack, your heart may be damaged. This could affect your heart’s rhythm and its ability to pump blood to the rest of the body. You may also be at risk for another heart attack or conditions such as stroke, kidney disorders, and peripheral arterial disease^[5].

The recovery process aims to reduce your risk of another heart attack through a combination of lifestyle changes (such as eating a healthy diet), and medicines (such as statins), which help to lower blood cholesterol levels, and gradually restore your physical fitness so you can resume normal activities through cardiac rehabilitation^[6].

Your provider may refer you for cardiac rehabilitation, which is a medically supervised exercise program for people recovering from heart problems. Studies show that cardiac rehabilitation lowers the risk of hospitalization and death. It can also improve your quality of life^[25].

After the first acute coronary syndrome event, the goal is to lower LDL-C to less than 1.4 mmol/L (less than 55 mg/dL) and to reduce LDL-C levels 50% or more from baseline^[16]. A combination of medicines called a polypill strategy should be considered to improve how well you stick to taking your medicines and improve cardiovascular outcomes after an acute coronary event^[16].

You can lower your chances of having future health problems following a heart attack with these steps:

• Physical activity: Talk with your health care team about the things you do each day
• Choose heart-healthy foods
• Be physically active
• Quit smoking
• Get enough quality sleep
• Aim for a healthy weight
• Get your blood pressure and cholesterol checked
• Manage your blood sugar^[5][25]

There are some steps you can take to reduce your risk of having a heart attack or having another heart attack. If you smoke, you should quit. If you’re overweight or obese, you should lose weight. You should do regular exercise — adults should do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity activity each week, unless advised otherwise by the doctor in charge of your care^[6].

It is important to get routine medical care and take all medicines regularly, as your healthcare provider prescribed. Follow your provider’s directions. Do not change the amount of your medicine or skip a dose unless your provider tells you to^[25].

The effects of heart disease can go beyond your physical wellbeing, taking a toll on your mental wellness, too. It’s important to recognize that anxiety and depression have been shown to increase the risk of cardiac events in the first place. It is also not uncommon to develop clinical anxiety or depression after sudden cardiac events. The good news is that anxiety and depression are treatable conditions with medications and talk therapies^[19].

• Heart
• Coronary arteries
• Heart muscle
• Blood vessels