Myocardial infarction : causes, symptoms , diagnosis and treatment
Cardiovascular Diseases / / April 27, 2016
Heart - the hardest working organ of the human body.Throughout human it continuously pumps blood through the arteries of the network life, enriching the oxygen and vital nutrients to all tissues of the body.To perform this task tense, the heart muscle itself needs an abundance of oxygen-rich blood through the coronary network.These arteries carry oxygen-rich blood to the heart muscle wall - the myocardium.
Myocardial infarction, or heart attack occurs when blood flow to the heart muscle is blocked, comes necrosis (death) of tissue from loss of oxygen and seriously damaged portion of the heart.
Coronary heart disease (CHD) causes almost all heart attacks.CHD is the end result of a complex process called "atherosclerosis".This leads to blockage of artery (ischemia) and gives oxygen-rich blood to reach the heart.
Causes and risk factors for myocardial infarction
Risk factors for myocardial infarction - are the same as the risk factors of coronary heart disease.These include:
- Age. increase risk of coronary arteries increases with age.About 85% of people die of heart disease at the age of 65 years.For men, the average age of a first heart attack - 66 years;
- Paul. Men have a higher risk of coronary artery disease, and more likely to have heart attacks at an earlier age than women.The risk of developing heart disease in females increases after menopause, and it is likely, angina pectoris;
- Genetic factors and family history. Some genetic factors increase the likelihood of the development of important risk factors - such as diabetes, high cholesterol and high blood pressure;
- race and ethnicity. African-Americans have the highest risk of cardiovascular disease, in particular, due to high rates of high blood pressure as well as diabetes and obesity;
- Obesity and the metabolic syndrome. excess body fat, especially around the waist, can increase the risk of developing heart disease.Obesity increases the risk of other conditions (e.g., high blood pressure and diabetes), which are associated with heart disease.Obesity is especially dangerous when it is part of the metabolic syndrome - a pre-diabetic condition that is strongly associated with heart disease.This syndrome is diagnosed when there are:
- abdominal obesity;
- low cholesterol (HDL);
- high levels of triglycerides;
- high blood pressure;
- insulin resistance (diabetes or pre-diabetes).
- lack of physical activity. Exercises provide a number of effects that benefit the heart and circulation.This, including - improving healthy cholesterol and blood pressure and maintain a normal weight.People who are mostly sedentary, almost twice as likely to suffer heart attacks than those who regularly engaged in physical culture and sports.
- Smoking. Smoking is the most important risk factor for heart disease.Smoking can cause high blood pressure, lipids, and it degrades very sticky makes platelets, which increases the risk of blood clots.Although heavy smokers of cigarettes are at high risk, people who smoke only three cigarettes a day have a higher risk of blood vessel abnormalities that greatly endangers the heart.And regular exposure to smoking outside ( "passive smoking" smoking) also increases the risk of cardiovascular disease.
- Alcohol. Moderate alcohol consumption in small doses, can increase the level of HDL - the "good" cholesterol.Alcohol in small doses can also prevent the formation of thrombi and inflammation.In contrast, heavy drinking is very harmful to the heart.In fact, heart disease is the leading cause of death in alcoholics.
- Power. Diet plays an important role in protecting the heart, especially by reducing dietary sources of trans fats, saturated fats and "bad" cholesterol and limiting salt intake, which contributes to high blood pressure.
- NSAIDs and COX-2 (cyclooxygenase enzyme type 2). All nonsteroidal anti-inflammatory drugs (NSAIDs), except aspirin, carry risks for the heart.NSAIDs and COX-2 inhibitors may increase the risk of death in patients who have had a heart attack.The highest risk - at higher doses, but some studies have shown that even low doses of NSAIDs taken for short periods of time, are not safe after a heart attack.NSAIDs include nonprescription drugs, such as ibuprofen and prescription drugs like Diclofenac.Patients who have had a heart attack should talk to their doctors before taking any of these medications.
Symptoms of myocardial infarction
symptoms of myocardial infarction can be very different.They can appear suddenly and heavily, or may progress slowly, ranging from mild pain.Symptoms may also differ in men and women.Women are less likely than men to have classic chest pain, but they are more likely to experience shortness of breath, nausea or vomiting, pain in the jaw, or back.
Common signs and symptoms of heart attack include:
- Chest pain. Pain or discomfort in the chest (angina pectoris) is the main sign of a heart attack.It may feel like pressure, squeezing, enlargement of the heart or chest pain center.Patients with coronary artery disease who have stable angina often experience chest pain that lasts a few minutes and then goes out.When a heart attack pain usually lasts longer than a few minutes, and this feeling may go away, but then it may return;
- Discomfort in the upper body. People who have a heart attack may feel discomfort in the arms, neck, back, jaw or stomach;
- Shortness of breath. Shortness of breath may occur with pain in the chest or without it;
- Nausea and vomiting ;
- Cold sweat ;
- dizziness or fainting.
following symptoms may be less associated with myocardial infarction or heart attack:
- acute pain caused by breathing or coughing;
- pressure in the chest;
- pain that occurs mainly or only in the middle or in the lower abdomen;
- pain that can be played by moving your fingers on the body and pressing the chest wall or arm;
- pain that is constant and lasts for a few hours (in this case, no one has to wait a few hours, if the suspects had a heart attack);
- sharp pain, which is very short, lasting only a few seconds;
- pain that spreads to the feet.
However, the absence of these symptoms does not always rule out serious heart disease.
Some people with severe coronary artery disease and angina do not have pain.This condition is known as "silent ischemia".This is a dangerous condition, because the pain - an indicator of disease, and these patients did not receive from his body disturbing warning signs of heart disease.Some studies show that people with "silent ischemia" have higher morbidity and mortality than those with pain symptoms.
What if a heart attack
People showing symptoms who were heart attack symptoms, do the following:
- angina patients need to take one dose of nitroglycerin under the tongue (tablet) or in the form of a spray atthe appearance of symptoms.It is necessary to take another dose every 5 minutes (up to three doses) or up until the pain is reduced;
- should immediately call the number of the local emergency medical services.This should be the first action taken, if angina patients continue to experience pain in the chest after taking three doses of nitroglycerin.However, only 20% of heart attacks occur in patients previously diagnosed with angina pectoris.Therefore, anyone who develop symptoms of heart attack, should immediately call the "fast";
- the patient should chew and swallow aspirin for adults (325 mg) is uncoated and the doctors say that they did not give him an extra dose of nitroglycerin;
- patients with chest pain should not tire themselves, they should go to hospital.
Diagnostics myocardial infarction
When a patient comes to the hospital with chest pain, through the diagnostic steps are usually taken to determine any heart problems, if they are present, and their degree of severity.The patient must inform the doctor about any symptoms that doctors could not rule out heart problems and suggest possible other causes of serious illness.
test images, including echocardiography and perfusion scintigraphy, help eliminate heart attack, if there are any questions and doubts.
- Electrocardiogram (ECG). ECG measures and records the electrical activity of the heart.Wave measured on an electrocardiogram measured corresponding contraction and relaxation of different parts of the heart.
Doctors use the terms «PQ» and «PR-interval" - this is the time it takes to move an electrical impulse from the atria to the ventricles.
most important wave patterns in the diagnosis and determination of treatment of heart attack called «S-t» and «Q-wave."
- Elevated segments S-t: a heart attack. Elevated segments S-t are convincing evidence of a heart attack in patients with symptoms of myocardial infarction.It is assumed that the artery leading to the heart are blocked, and that the total thickness of the heart muscle is damaged.Kind of heart attack associated with these findings, called a «Q-myocardial infarction (MI)" or "with the rise of IM S-t» (S-t-segment elevation myocardial infarction).However, the increase
S-t segment does not necessarily mean the patient has a heart attack.For example, inflammation in the sack around the heart (pericarditis) is another reason height S-t-segment.
- Stable angina (when the results of blood tests or other tests do not indicate a serious problem and does not eliminate the pain in the chest).Between 25-50% of people who have angina or silent ischemia, normal EKG readings.
- Acute coronary syndrome (ACS) - includes sudden and severe heart disease that requires serious treatment, but the disease that has not yet become a full-blown heart attack.
- Echocardiogram - noninvasive test that uses ultrasound images of the heart.The doctor is important to know whether a part of the heart muscle has been damaged.Echocardiography can also be used as part of the load test to detect the location and extent of damage to the heart muscle at the time of discharge or shortly after discharge from the hospital after a heart attack.
- Radionuclide imaging (thallium stress test). Radionuclide procedures using imaging techniques and computer analysis to build and detect the passage of radioactive isotopes through the heart.Such elements are usually administered intravenously.Radionuclide imaging used for the diagnosis and:
- the severity of unstable angina, when less expensive diagnostic approaches are unavailable or unreliable;
- the severity of chronic ischemic heart disease;
- success of the operation in ischemic heart disease;
- if you had a heart attack;
- the location and extent of damage to the heart muscle at the time of discharge or shortly after discharge from the hospital after a heart attack.
procedure is non-invasive (no intervention into the body).If there is damage to a heart attack, a radioactive isotope (technetium or thallium) is introduced into the patient's vein.The radioactive isotope passes through the blood circulating in the heart.The isotope can be traced through the heart by means of special cameras or scanners.The images can be combined with an electrocardiogram.The patient is tested during the holidays, and then re-test passes during a load test.Damage as a result of a heart attack last will be saved when the heart scan is repeated.Trauma caused by angina, however, the time will appear.
- Angiography. Angiography is an invasive test.It is used for patients who show strong evidence of severe obstruction (obstacle normal operation) due to stress and other tests, as well as for patients with acute coronary syndrome.
The procedure: the narrow tube is inserted into an artery - usually in the leg or arm and then threaded up the moving body to the coronary arteries.Dye is injected into the tube, and an X-ray records for the dye through the arteries.This process provides a map of the coronary circulation, revealing the blocked area.
- Biological markers.When heart cells are damaged, they release a variety of enzymes and other substances into the bloodstream.Elevated levels of these markers of cardiac damage in the blood or urine may help predict heart attacks in patients with severe chest pain, and help determine treatment methods.Tests for these markers are often performed in the machine "emergency" or in the hospital when a heart attack is suspected.Some markers include troponins;myocardial creatine kinase (CK-MB), etc.
myocardial infarction Treatment
Treatment options include myocardial infarction:
- oxygen therapy;
- Nitroglycerin or morphine - to relieve pain and discomfort;
- control any arrhythmia (heart rhythm disturbances);
- blocking further blood clotting (if possible);
- opening blocked arteries as soon as possible - by performing angioplasty or medications that thin the blood clots;
- beta-blockers, calcium channel blockers or ACE inhibitors - to help the muscles of the heart and arteries work better.
first help the patient with myocardial infarkom
In early support procedures are similar for patients who have suffered myocardial infarction.Needed, especially oxygen, aspirin, nitroglycerin, morphine, opening the artery through emergency angioplasty or thrombolytics.
Standard general medical and surgical care to open arteries:
- angioplasty (percutaneous coronary intervention - PCI) - the preferred emergency procedure to open the arteries;
- thrombolytics (drugs) - the standard drugs that are used to open the artery.Thrombolytic drug must be given within 3 hours after onset of symptoms;
- coronary bypass surgery - is sometimes used as an alternative to angioplasty.
- Thrombolytics. Thrombolytics - drugs that are recommended as an alternative to angioplasty.These drugs dissolve a blood clot blocking an artery and leading heart muscle tissue to die.
Thrombolysis is considered a good option for patients with heart attacks, in which the symptoms are less than 3 hours.Ideally, these drugs must be given within 30 minutes after arrival at the hospital, when angioplasty is not a viable option.
other situation where you can use the drug:
- continuous transport of the patient;
- too long waiting for catheterization;
- if the procedure of coronary bypass surgery is not successful, or if anatomically too complicated.
thrombolytics should be avoided or used with caution for the following groups of patients after a heart attack:
- over 75 years;
- those whose symptoms persist more than 12 hours;
- pregnant women;Art.