Heart Attack or Myocardial Infarction (MI): Causes, Risk Factors, Symptoms, Treatment

Heart attack, also known as myocardial infarction (MI), is a condition which occurs when a blood clot obstructs the coronary artery thus blocking the blood flow to the heart. Coronary artery is a vital blood vessel which supplies blood to the heart muscle.^[1] Any hindrance in the blood flow to the heart can damage or destroy the heart muscle. A heart attack can be dangerous if ignored. This happens when people confuse their symptoms with other minor illnesses such as indigestion and delay their treatment. Nowadays, treatment for heart attack has become more advanced. It is important that patients promptly recognize their symptoms and seek medical help immediately or call 911 if they suspect they are having a heart attack.

Recovering from a heart attack depends on the patient’s lifestyle, frequency and duration of exercise, stress handling, diet etc. Patient should follow a healthy lifestyle to prevent a heart attack and control risk factors which contribute to the narrowing of the coronary arteries which supply blood to the heart.

The cause of a Heart Attack or Myocardial Infarction (MI) is blockage in one or more of the coronary arteries supplying the heart muscle. The cause of the blockage could be a clot which separates when a plaque ruptures. Other causes include accumulation of cholesterol which leads to narrowing of the coronary artery. The accumulation of cholesterol is known as plaques and this condition is known as atherosclerosis. When a heart attack occurs, one of these plaques may rupture leading to formation of a blood clot at the site of the rupture. If the clot is large, then it can completely block the blood flow. Atherosclerosis causes narrowing of the coronary arteries and this results in a condition known as coronary artery disease. The cause of majority of the heart attacks is coronary artery disease. Other uncommon cause of a heart attack is spasm of the coronary artery which causes hindrance in the blood flow to a part of the heart muscle. Certain drugs, such as cocaine, may cause life-threatening spasm of the coronary artery. Heart attack can also occur due to coronary artery dissection (tear in the coronary artery).^[2]

Other uncommon causes of heart attack include coronary embolism where small blood clots or tumors travel from other parts of the body and get lodged in the artery.

A Heart Attack or Myocardial Infarction (MI) is the culmination of a process which usually progresses over several hours. As each minute passes, the heart tissue is deprived of blood and can deteriorate or die.^[3] However, if there is reestablishment of the blood flow in time, then the damage done to the heart can be limited or prevented.

• Age: Men aged 45 or more and women aged 55 or more are at higher risk for having a heart attack.
• Tobacco: Individuals who smoke and those who are exposed to secondhand smoke continuously are at higher risk for having a heart attack. Smoking increases the risk of formation of deadly blood clots which cause heart attack.
• Diabetes: Diabetes greatly increases the risk of a heart attack.
• High Blood Pressure (Hypertension): High blood pressure gradually damages the coronary arteries by speeding up atherosclerosis thus increasing the risk for heart attack.
• Hypercholesterolemia: Individuals who have high blood cholesterol or triglyceride levels are at higher risk for having a heart attack.
• Family History of Heart Attack: Individuals with a family history of heart attack (siblings, parents or grandparents who have had heart attacks) are at increased risk.
• Lack of Exercise: Individuals who don’t do any exercise or physical activity are at increased risk for having a heart attack as an inactive lifestyle leads to obesity and high blood cholesterol levels. People who do regular aerobic exercise have good cardiovascular fitness, which in turn decreases their overall risk of heart attack. Exercise also helps in lowering hypertension.
• Obesity: Individuals who are obese, i.e. having a body mass index of 30 or higher, are at increased risk of heart disease, as it’s associated with diabetes, high blood cholesterol levels and high blood pressure.
• Stress: Excessive stress, anger and other negative emotions increases the blood pressure along with increasing the risk for heart attack.
• Illegal use of drugs: Stimulant drugs, such as cocaine or amphetamines, causes spasm in the coronary arteries which leads to heart attack.^[4]

• A feeling of pressure, fullness or a squeezing pain in the center of the chest which lasts for some time.
• Radiating pain outside the chest to the shoulder, arm, back and even teeth and jaw.
• Increasing spells of chest pain.
• Continuous pain in the upper abdomen.
• Shortness of breath.
• Sweating.
• Anxiety.
• Fainting.
• Nausea.
• Vomiting.
• Heartburn.
• Pain in the abdomen.
• Damp skin.
• Dizziness or lightheadedness.
• Fatigue.^[5]

If you come across an individual who is unconscious and you suspect a heart attack, then immediately call for medical help. If you are trained in emergency procedures, start doing cardiopulmonary resuscitation (CPR), which involves chest compressions and rescue breaths. Check the person’s airway and if it is clear, then deliver rescue breaths after every 30 compressions. If you aren’t trained, then continue doing compressions only.

• Aspirin is given by emergency medical personnel immediately after the patient arrives at the hospital. Aspirin helps in reduction of blood clotting and thereby helps in maintaining blood flow through the narrowed artery.
• Thrombolytics, also known as clot busters, help in dissolving the blood clot which is blocking the blood flow to the heart. The earlier a thrombolytic is given after a heart attack, the greater the chances of surviving and decreasing the damage to the heart.^[6]
• Super aspirins are similar to aspirin and help in preventing the formation of new clots. Super aspirins include clopidogrel (Plavix) and platelet aggregation inhibitors.
• Blood-thinning medications such as heparin help in making the patient’s blood less “sticky” and decrease the risk of forming more dangerous clots. Heparin can be given intravenously or via an injection under the skin. Heparin is usually given during the initial days after a heart attack.
• Pain relievers, such as morphine, are given for relieving chest discomfort and chest pain.
• Nitroglycerin is used for treating angina (chest pain). This medication temporarily opens up arterial blood vessels thereby, increasing the blood flow to and from the heart.
• Beta blockers are those medications which help in relaxing the heart muscle, slowing the heartbeat and decreasing the blood pressure. All this helps in taking the load off of the heart. Beta blockers restrict the amount of damage to the heart muscle and help in preventing future heart attacks.
• Cholesterol-lowering medications such as statins, niacin, fibrates and bile acid sequestrants help in lowering the levels of unwanted cholesterol in the blood. These medications are best useful when given immediately after a heart attack for increasing survival rate.
• Surgical procedures for treating heart attack include coronary angioplasty and stenting; and coronary artery bypass surgery.^[7]

• Quitting smoking.
• Avoiding secondhand smoke.
• Getting cholesterol levels checked regularly.
• Getting regular medical checkups.
• Keeping your blood pressure under control.
• Exercising regularly.
• Losing the excess weight.
• Following a heart-healthy diet.
• Reducing stress levels.
• Avoid drinking alcohol, if you do, drink in moderation.

Regular physical exams should be done to screen for risk factors which may result in a heart attack. Vital signs, such as blood pressure, pulse and temperature etc, are checked in the emergency room. Doctor will listen to heart and lung sounds using a stethoscope. Health history and family history of heart disease will be taken. Other than this, tests which will be taken include:

• Electrocardiogram (ECG).
• Blood tests to check for specific heart enzymes which slowly leak into blood if there has been any damage to the heart.
• Chest x-ray to check the size of heart, its blood vessels and also to look for any fluid in the lungs.
• Echocardiogram.
• Angiogram (Coronary Catheterization).
• Exercise Stress Test.
• Cardiac Computerized Tomography (CT)
• Magnetic Resonance Imaging (MRI)^[8]

References:

Also Read:

• Symptoms of False Heart Attack: Conditions That Mimic Heart Attack Symptoms
• Can You Have Symptoms of a Heart Attack for Days?
• What Does It Feel Like When You are Having a Heart Attack?
• Is Belching a Sign of Heart Attack?