A heart attack, also known as myocardial infarction (MI) in medical terminology, is a serious medical emergency in which the supply of blood to the heart is suddenly blocked, usually by a blood clot. A lack of blood to the heart may seriously damage the heart muscle and can be life threatening. (https://www.nhs.uk/conditions/heart-attack/)
Heart attacks are very common. According to the Centers for Disease Control and Prevention, more than 800,000 people in the United States have a heart attack each year. A heart attack is not the same as cardiac arrest, which happens when your heart suddenly and unexpectedly stops beating. A heart attack can cause sudden cardiac arrest. (https://www.nhlbi.nih.gov/health/heart-attack)
What causes a heart attack?
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 atherosclerotic buildup in the blood vessels to your heart, this is called coronary artery disease.
Sometimes, plaque deposits inside the coronary (heart) arteries can break open or rupture, and a blood clot can get stuck where the rupture happened. If the clot blocks the artery, this can deprive the heart muscle of blood and cause a heart attack.
Heart attacks are possible without ruptured plaque, but this is rare and only accounts for about 5% of all heart attacks. This kind of heart attack can occur for the following reasons:
A heart attack may be caused by a complete or partial blockage of a heart (coronary) artery. One way to classify heart attacks is whether an electrocardiogram (ECG or EKG) shows some specific changes (ST elevation) that require emergency invasive treatment. Your health care provider may use electrocardiogram (ECG) results to describe these types of heart attacks.
An acute complete blockage of a medium or large heart artery usually means you've had an ST elevation myocardial infarction (STEMI).
Rare medical conditions, like any disease that causes unusual narrowing or spasm of blood vessels, for e.g. Prinzmetal's angina, vasospastic angina or variant angina.
Trauma that causes tears or ruptures in your coronary arteries, e.g. spontaneous coronary artery dissection (SCAD).
Obstruction that came from somewhere else in your body, like a blood clot or air bubble (embolism) that ends up in a coronary artery.
Eating disorders over time, can damage your heart and ultimately result in a heart attack.
Anomalous coronary arteries are a congenital condition where the coronary arteries are in abnormal positions from birth. Compression of these causes a heart attack.
Other conditions that can cause your heart not to receive as much blood as it should for a prolonged period of time, such as when blood pressure is too low, oxygen is too low or your heart rate is too fast.
Age: Men age 45 and older and women age 55 and older are more likely to have a heart attack than are younger men and women.
Tobacco use: This includes smoking and long-term exposure to second-hand smoke. If you smoke, quit.
High blood pressure: Over time, high blood pressure can damage arteries that lead to the heart. High blood pressure that occurs with other conditions, such as obesity, high cholesterol or diabetes, increases the risk even more.
Obesity: Obesity is linked with high blood pressure, diabetes, high levels of triglycerides and bad cholesterol, and low levels of good cholesterol.
Diabetes: Blood sugar rises when the body doesn't make a hormone called insulin or can't use it correctly. High blood sugar increases the risk of a heart attack.
Metabolic syndrome: This is a combination of at least three of the following things: enlarged waist (central obesity), high blood pressure, low good cholesterol, high triglycerides and high blood sugar. Having metabolic syndrome makes you twice as likely to develop heart disease than if you don't have it.
Family history of heart attacks: If a brother, sister, parent or grandparent had an early heart attack (by age 55 for males and by age 65 for females), you might be at increased risk.
Not enough exercises: A lack of physical activity (sedentary lifestyle) is linked to a higher risk of heart attacks. Regular exercise improves heart health.
Unhealthy diet: A diet high in sugars, animal fats, processed foods, trans fats and salt increases the risk of heart attacks. Eat plenty of fruits, vegetables, fiber and healthy oils.
Stress: Emotional stress, such as extreme anger, may increase the risk of a heart attack.
Illegal drug use: Cocaine and amphetamines are stimulants. They can trigger a coronary artery spasm that can cause a heart attack.
A history of preeclampsia: This condition causes high blood pressure during pregnancy. It increases the lifetime risk of heart disease.
High cholesterol or triglycerides: A high level of low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol) is most likely to narrow arteries. A high level of certain blood fats called triglycerides also increases heart attack risk. Your heart attack risk may drop if levels of high-density lipoprotein (HDL) cholesterol — the "good" cholesterol — are in the standard range.
