What is a Heart Attack in Emergency Medicine?
Published on July 23, 2026
Contact Terrell CV DownloadHeart attack as a medical emergency: what problem is happening
In emergency medicine, a heart attack is a life-threatening medical emergency.
It happens when blood flow to part of your heart muscle becomes severely reduced or blocked, so that area does not get enough oxygen.
Without oxygen, heart muscle cells start to die, and the injured area can grow as time passes.
That is why minutes matter and why clinicians focus on restoring blood flow fast.
Next, it helps to understand how the blockage forms in the first place.
How the blockage happens in coronary arteries (atherosclerosis, plaque rupture, clot) and other less common causes
Most heart attacks start in the coronary arteries, the blood vessels that feed the heart muscle. Over time, fatty deposits made of cholesterol and other substances can build up inside these arteries.
This buildup is called atherosclerosis, and the deposits are called plaque. Plaque can narrow the artery and limit blood flow, especially during activity or stress.
A more sudden problem happens when plaque breaks open. Your body forms a blood clot on that rough surface, and the clot can partly or fully block the artery, cutting off oxygen to the heart muscle.
Less common causes exist. A coronary artery can clamp down from a spasm, which can reduce blood flow even without a large blockage. A tear inside the artery wall, called spontaneous coronary artery dissection, can also block flow.
Some infections, including COVID-19, can damage the heart muscle and contribute to heart attack-like injury. Other non-plaque causes discussed in clinical sources include an embolism, when a clot or air bubble travels to a coronary artery, and problems in smaller heart vessels. With those causes in mind, the next step is recognising what a heart attack can feel like.
What a heart attack can feel like and why symptoms vary
Many people think a heart attack always feels like sudden crushing chest pain, but the experience varies. Chest discomfort often feels like pressure, tightness, squeezing, or aching, and it can spread to the shoulder, arm, back, neck, jaw, teeth, or upper belly.
Some people notice shortness of breath, sweating, nausea or vomiting, lightheadedness, fainting, or an unusual level of fatigue. Others feel indigestion or heartburn-like burning and may not connect it to the heart.
Symptoms vary in severity, and some people have mild symptoms or none at all, sometimes called a silent heart attack.
Women, older adults, and people with diabetes may have less typical warning signs, such as nausea, shortness of breath, or brief pain in the neck or back.
Because symptoms can look different from person to person, it also helps to know what clinicians mean when they classify a heart attack and what complications they watch for.
Clinical implications: heart muscle injury, common classifications, and major complications
When the heart muscle goes without oxygen, the affected tissue becomes injured and can die. During healing, the damaged area can form scar tissue, which does not contract like healthy muscle.
In medical settings, you may hear a heart attack called a myocardial infarction.
You may also hear acute coronary syndrome, which refers to a group of conditions caused by reduced blood flow to the heart, including heart attack and unstable angina.
Clinicians often use an electrocardiogram, also called an ECG or EKG, to help classify heart attacks. A STEMI usually points to a complete blockage of a medium or large heart artery, while an NSTEMI often reflects a partial blockage, though some NSTEMIs involve a total blockage.
Major complications can follow heart muscle damage, including dangerous abnormal heart rhythms that can lead to cardiac arrest, heart failure, cardiogenic shock, and inflammation around the heart called pericarditis, sometimes linked with Dressler syndrome.
Since these risks rise with delay, the next section focuses on what you can do right away.
What to do immediately (patient/bystander actions and emergency response steps)
If you think you are having a heart attack, call 911 right away or your local emergency number.
If you can avoid it, do not drive yourself to the hospital. Emergency responders can start care at your location and alert the hospital that you are coming.
If your clinician prescribed nitroglycerin, take it as directed while you wait for help.
Only take aspirin if a clinician or emergency personnel recommend it, since aspirin can cause problems for some people, including those with an allergy or interactions with certain medicines.
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