Myocardial Infarction (Heart Attack)

Myocardial infarction, commonly referred to as a heart attack, occurs when one or more coronary arteries become suddenly blocked, resulting in heart muscle death.
• Myocardial infarction, commonly referred to as a heart attack, occurs when one or more coronary arteries become suddenly blocked, resulting in heart muscle death.
• Typical symptoms of a myocardial infarction include chest pressure or pain, shortness of breath, profound sweating, nausea, vomiting, and/or fainting.
• Myocardial infarction results from coronary artery disease (CAD), which is an accumulation of plaque inside the coronary blood vessels.
• When one of these plaques rupture, a clot forms rapidly at the site and causes a sudden obstruction of blood flow in the coronary artery. 
• Without immediate treatment, a myocardial infarction can cause permanent damage to the heart muscle and chaotic, abnormal heart beating.  Both conditions can cause death.
• Because of the seriousness of a myocardial infarction, seeking immediate medical attention is very important.

Detailed Explanation
Myocardial infarction, also known as MI or heart attack, is a condition when one or more of the coronary arteries which supply oxygen-rich blood to the heart muscle become suddenly blocked, resulting in heart muscle death. 
In general, blockages result from plaques made of cholesterol and fats building up in the coronary arteries.  The accumulation of this plaque is known as coronary artery disease (CAD).  In many cases, the accumulation of plaque is a gradual process and can produce symptoms of chest pain or pressure known as angina pectoris, or angina. 
In contrast to this gradual accumulation of plaque, a myocardial infarction occurs when a plaque suddenly ruptures, causing a rapid accumulation of clotting factors at the rupture site.  This results in a sudden obstruction of blood flow in the coronary artery.  This sudden obstruction prevents any blood from reaching the heart muscle.  Without this vital supply of oxygen-rich blood, the heart muscle begins to die.  The longer the obstruction persists, the greater the amount of heart muscle that dies. 

Myocardial infarction is a medical emergency . Without treatment, substantial portions of the heart can be permanently damaged, preventing efficient pumping of blood to the rest of the body, and resulting in congestive heart failure. In addition, a myocardial infarction can cause ventricular arrhythmias, or rapid and chaotic beating of the lower chambers of the heart.  In many cases, ventricular arrhythmias can cause cardiac arrest, stopping blood flow to the body and brain. If that happens, brain damage and death can result within minutes. 
Because of these serious and potential life-threatening complications of a myocardial infarction, seeking immediate medical attention is very important. 

Symptoms
Myocardial infarction symptoms are typically sudden in nature, and often persist for more than 20 minutes.  Occasionally, symptoms can ‘come and go.’  Typical symptoms include: 
• Chest pain or pressure
• Chest tightness
• Chest pain, pressure, or tightness that extends from the chest to the neck, throat, jaw, shoulder and/or arm
• Chest discomfort just below the breastbone
• Chest burning, similar to heartburn or indigestion
• Shortness of breath 
Because a myocardial infarction usually occurs without warning, it can cause severe anxiety. It can also cause other symptoms such as nausea, lightheadedness, fainting, or profuse sweating.  Many people having symptoms of a myocardial infarction are reluctant to seek medical attention because they think the pain they are feeling is due to something else, are afraid or unwilling to admit that the pain could represent something serious, or are reluctant to ‘cause a scene’ by calling an ambulance, going to the hospital, and then discovering it is a false alarm.  However, by delaying medical attention and treatment, patients are at much higher risk for permanent heart damage and death.  Accordingly, if patients are having symptoms that could represent a myocardial infarction, they should always seek immediate medical attention by dialing 911. 

Risk Factors
Myocardial infarctions result from coronary artery disease (CAD).  Thus, risk factors for the development of CAD are also risk factors for myocardial infarctions: 
• Smoking
• Having high cholesterol levels
• Not exercising regularly
• Having hypertension, or high blood pressure
• Eating a diet high in saturated fat and cholesterol
• Having diabetes mellitus
• Being more than 30 percent over one's ideal weight
• Using stimulant or recreational drugs, such as cocaine or amphetamines
• Having family members (especially parents or siblings) who have had coronary artery disease (CAD), myocardial infarctions, or strokes

Diagnosis
To diagnose a myocardial infarction, a physician will conduct a thorough medical history (including a complete description of a patient’s symptoms), conduct a physical exam, and perform one or more of the following tests: 
Electrocardiogram (ECG): ECG tests monitor the electrical activity of the heart. Physicians look for certain patterns on electrocardiograms that suggest myocardial infarction. In many cases, the ECG can reveal which part of the heart is damaged, the extent of that damage, and whether the heart attack has caused an abnormal heart rhythm. 
Cardiac blood tests: Cardiac blood tests  look for evidence that a myocardial infarction has occurred and that heart muscle has died.  In some cases, several blood tests have to be checked over a period of several hours, since evidence of a myocardial infarction can take some time to appear in the blood.  
Echocardiography: An echocardiogram, or echo, is a test that uses ultrasound, or high-frequency sound waves, to take a moving picture of the heart. The physician uses the echocardiogram to evaluate the structure and function of a patient's heart and surrounding vessels. During a myocardial infarction, echocardiograms can demonstrate the location and extent of heart damage. 
Cardiac catheterization and angiography: Physicians may recommend cardiac catheterization and angiography, especially if the ECG and/or cardiac blood tests indicate the presence of a myocardial infarction.  In this test, a catheter (a very thin, flexible tube) is inserted into an artery in the groin or arm and advanced into the heart. When the catheter is positioned near the arteries that supply blood to the heart, the physician injects a contrast dye. As the dye travels through the arteries, X-ray pictures are taken to see how well blood flows through the arteries, and if there are any blockages that are causing a myocardial infarction.

Treatment
Treatment for myocardial infarction focuses on three goals:  treating the myocardial infarction by interrupting the clotting process and opening blocked coronary arteries, managing any of the complications that can occur with a myocardial infarction, and treating the underlying coronary artery disease (CAD) so as to prevent future myocardial infarctions. 
Treating the myocardial infarction: The most important factor in treating a myocardial infarction is time. A myocardial infarction is a medical emergency, and medical attention is needed as soon as symptoms begin .  Delays in receiving treatment can result in permanent heart damage and death.  Thus, patients experiencing symptoms of a myocardial infarction should call 911 immediately.  Patients should not drive themselves, or have family or friends drive them, to a hospital – it is essential that trained medical personnel and ambulance equipment are available to assist the patient during the transport to the hospital. 
Interrupting the clotting process: Since most myocardial infarctions occur when clotting factors accumulate at the site of a ruptured plaque, medicines are needed to stop the accumulation.  Patients who begin to experience the symptoms of a myocardial infarction and who are not taking aspirin should immediately chew an aspirin, which blocks clotting factors in the blood.  Chewing the aspirin, rather than swallowing it whole, accelerates the body’s process of absorbing the aspirin.  Once the patient is at the hospital, other medicines to block the body’s clotting process may be administered.
Opening blocked coronary arteries: Opening blocked coronary arteries to restore blood flow to the heart as soon as possible can prevent or limit damage to the heart muscle and can also decrease the chance of a repeat myocardial infarction. To open blockages, physicians can either use a medicine to dissolve the clot or use a procedure called coronary angioplasty to open the blocked artery. 

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Recovery
After a myocardial infarction has been treated and the patient is ready to go home from the hospital, the physician may recommend that the patient enroll in a cardiac rehabilitation program.  These programs help patients who have suffered from a myocardial infarction make and commit to the medication and lifestyle changes that can enhance the effects of medical treatment and help prevent further myocardial infarctions. They also oversee a gradual resumption of physical activity, and can be a valuable source of information and support for patients and their families. 

Myocardial infarction is a serious medical event, and it often requires substantial changes in a patient’s life in order to prevent future myocardial infarctions.  Often, patients may become ‘blue’ or depressed during the weeks and months following a myocardial infarction.  If this occurs, it is important to discuss these feelings with a physician to ensure that they do not interfere with taking the necessary steps to prevent future myocardial infarctions. 

Although myocardial infarctions are serious conditions, many therapies are available to minimize heart damage, prevent future myocardial infarctions, and ensure a long and healthy life.  In order to achieve these goals, patients and families should educate themselves about cardiac health, work with their physicians, and adhere to all prescribed medication and lifestyle therapies. 

Sex after a Heart Attack
Many patients who have had a myocardial infarction are concerned about whether sexual activity endangers their heart.  Contrary to a popular belief, sexual activity does not cause myocardial infarctions.  As a general rule, most people can resume sexual activity within 2 weeks after being treated for a heart attack. 

Written by Dr. Mark Steiner, Cardiologist in Orlando