Common Name/Other Name
Atake sa puso (Fil.)
Myocardial infarction (MI), more commonly known as heart attack, is the failure of blood to enter the heart causing the heart to experience a lack of oxygen. This is a medical emergency and there could be irreversible damage 30 minutes after the blood supply is cut-off.
Coronary artery disease is considered as the major cause of MI. The coronary arteries can become blocked due to a build-up of fat, cholesterol or other substances. These can form a plaque on the wall of a blood vessel and rupture. This leads to the formation of a clot which can completely block a coronary artery. A heart attack can also happen when a coronary artery experiences a spasm causing the interruption of the blood flow towards the heart. These spasms can be caused by the use of tobacco or illegal drugs.
Types of myocardial infarction:
- ST segment elevation myocardial infarction (STEMI) occurs when the blood supply is completely blocked for too long. This is the most complicated type of MI. The total blockage of a coronary artery leads to a large damage on the heart.
- Non-ST segment elevation myocardial infarction (NSTEMI) occurs when there is only a partial blockage on a coronary artery. Only a small section of the heart is damaged, but NSTEMI can still progress to STEMI.
- Unstable angina is the least serious type because there is no permanent damage on the heart, but the blood flow is still restricted. This can progress to STEMI or NSTEMI.
The heart can be damaged after a heart attack. This can lead to abnormal heart rhythms, failure of the heart to pump enough blood, a hole in the heart or valve problems that can lead to leakage.
The diagnosis of MI is usually done in an emergency setting. Different tests confirm if the signs and symptoms presented are due to a heart attack or another condition. The main tests done include an electrocardiogram (ECG) to monitor the electrical impulses of the heart muscle and blood tests to detect the presence of heart enzymes that increase during a heart attack.
The occurrence and severity of signs and symptoms during a heart attack vary from one person to another. There are heart attacks that occur without prior warning while some have signs and symptoms for several hours to weeks before the actual heart attack. Common signs and symptoms include:
Pressure, tightness, pain or squeezing sensation in the chest or arms, can spread to the neck, jaw or back
Disturbed sleep is usually experienced by women until a month before the heart attack
Nausea, lightheadedness or sudden dizziness
Heartburn, indigestion, abdominal pain
Major non-modifiable risk factors:
- Age. Men who are at least 45 years old and women of at least 55 years old
- Gender. Men are more at risk than women. The risk for women increases after menopause.
- Family history of heart attack. Especially if an immediate family member had an early heart attack (age 55 for males, age 65 for females)
- Race. African Americans and South Asians have a high risk; Hispanics and Latinos have a lower risk
Major modifiable risk factors:
- Smoking. People who smoke two to four times as well as second-hand smoke exposure
- High blood pressure. Blood vessels can become damaged due to a consistently high blood pressure
- High levels of blood cholesterol or triglycerides. Increased levels of the low-density lipoprotein and triglycerides can lead to the narrowing of the coronary arteries
- Lack of physical activity. A sedentary lifestyle contributes to high blood cholesterol and obesity
- Obesity. Association with high blood cholesterol, triglycerides and sugar levels, and high blood pressure
- History of pre-eclampsia. High blood pressure during pregnancy
- History of an autoimmune condition. Conditions like rheumatoid arthritis and lupus
Commonly Prescribed Drugs
- Aspirin is a common drug given once signs and symptoms of heart attack start to present. The first dose is chewed to increase the rate of absorption. Aspirin decreases blood clotting to allow blood flow through the narrowed artery. However, this will not prevent or cure a heart attack. Side effects: stomach pain, vomiting, heartburn
- Fibrinolytics are given to dissolve a clot that has already formed. Receiving a thrombolytic early on reduces the damage on the heart. Examples of this drug class include anistreplase and reteplase. Possible risks: internal bleeding, damage to blood vessel
- Antiplatelets prevent the formation of new clots and development of existing clots into larger clots. Examples of antiplatelet are clopidogrel and dipyridamole. Side effects: GI disturbances, bleeding
- Anticoagulants reduce the viscosity or stickiness of the blood. These drugs prevent the formation of blood clots. Warfarin and heparin are common anticoagulants. Newer anticoagulants include dabigatran and rivaroxaban. Side effects: severe bruising, prolonged nosebleeds, bleeding gums
- Nitroglycerin relieves the chest pain and dilates the blood vessels to improve blood flow. This is given sublingually or placed under the tongue for fast action. Side effects: lightheaded, flushing of face and neck, tingling of hands and feet
- Beta blockers reduce the heart rate and decrease the blood pressure to lessen the work of the heart. This drug class can limit heart damage and prevent future heart attacks. This is recommended for patients diagnosed with STEMI.
- ACE inhibitors increase the rate of survival and reduce the risk of heart enlargement. This is given during the first few days after the heart attack.