Myocardial infarction

It consists of the death of heart tissue (myocardium) due to the obstruction, for various reasons, of the coronary arteries that supply it with oxygen. Currently, the age-standardized incidence is estimated at 276 cases per 100,000 individuals, making it the leading cause of death and disability in the general population.

The acute temporary occlusion of one or more coronary arteries that supply blood and nutrients to the heart can cause an acute myocardial infarction due to the lack of oxygen supply (ischemia). Depending on the affected area, cardiac function may be more or less compromised. This arterial occlusion can have different origins.

• Most heart attacks are triggered by the rupture of cholesterol deposits or plaques on the walls of the arteries that progressively narrow their diameter, a process known as atherosclerosis. During a heart attack, a plaque can rupture, spilling cholesterol and other substances into the bloodstream, forming a clot at the rupture site that can block blood flow.
• This obstruction of the coronary arteries can also be caused by an air bubble (embolism) that becomes trapped in a coronary artery.
• Another triggering cause is a spasm or contraction of the coronary arteries that closes off blood flow to part of the heart muscle. Smoking or substance abuse can cause a potentially fatal spasm.

A family history of myocardial infarction, especially at an early age of risk (before 55 or 65 years for men and women respectively), represents a relevant genetic factor for myocardial infarction. However, there are other factors that contribute to the appearance of one of these causes:

• Age. Men over 45 and women over 55.
• Smoking and long-term exposure to secondhand smoke.
• High blood pressure can damage the coronary arteries. When accompanied by obesity, high cholesterol, or diabetes, known as metabolic syndrome, the risk is even greater.
• High total cholesterol or LDL levels or triglycerides increase the risk of heart attack, while high HDL levels may reduce it.
• Obesity is associated with high blood cholesterol levels, high triglycerides, high blood pressure, and diabetes.
• Having type I or type II diabetes increases the risk of a heart attack.
• An inactive lifestyle contributes to high blood cholesterol levels, obesity, and even high blood pressure.
• Stress.
• The use of illegal stimulant drugs such as cocaine or amphetamines can cause a spasm of the coronary arteries.

Not everyone who has a heart attack experiences the same symptoms or with the same severity, and some may have no symptoms at all. Additionally, while a heart attack can sometimes occur suddenly, it is often associated with warning signs and symptoms in the hours, days, or weeks beforehand. The following are the most common symptoms of a myocardial infarction:

• Pressure, fullness, tightness, severe pain, or discomfort in the center of the chest that lasts more than a few minutes and may extend to the shoulders, neck, arms, or jaw.
• Chest pain that worsens or does not improve with rest, and may be accompanied by sweating, cold and clammy skin, paleness, shortness of breath, nausea or vomiting, dizziness or fainting, unexplained weakness or fatigue, rapid or irregular pulse.

While chest pain is the main sign, it can be confused with other conditions such as indigestion, pleurisy, pneumonia, or heartburn.

Reducing or limiting risk factors can delay the onset of a myocardial infarction and reduce its severity if it occurs:

• Quit smoking. Smoking damages and narrows blood vessels, increasing the risk of coronary heart disease. Avoid passive tobacco smoke exposure.
• Follow a diet low in fat, cholesterol, salt, and sugars, including fruits, vegetables, fish, and omega-3 fatty acids.
• Lose weight, exercise regularly, and maintain an active lifestyle.
• Limit alcohol intake.
• Avoid stress.
• Regularly monitor and prevent high blood pressure, elevated cholesterol levels, and diabetes.