Acute coronary syndrome
Acute coronary syndrome (ACS) describes conditions in which the heart suddenly stops receiving adequate blood supply. Sometimes doctors use the term interchangeably with heart attack (myocardial infarction) though it can also refer to unstable angina or chest pain.
Definition & Facts
Any time the blood supply to the heart is blocked it is referred to as an acute coronary event. Both a heart attack and chest pain that comes and goes are considered to be acute coronary events because of the suddenness with which they appear.
Doctors refer to chest pain that comes and goes as unstable angina. It could mean that clots are forming, breaking up and then re-forming. The alarming part of this is that every time it happens, a part of the heart muscle dies, even if only a few cells.
Symptoms & Complaints
Nausea often accompanies a heart attack. People sometimes misdiagnose themselves as having severe heartburn, especially if they have a history of heartburn. Other symptoms may be sudden, heavy sweating or clammy skin and a lightheaded or dizziness. In women, unexplained severe fatigue may be a sign that an acute cardiac event is taking place.
Shortness of breath is another sign of heart attack, as is a fast or irregular heart beat. Some people report feeling extremely anxious and apprehensive, with a feeling of impending doom. Lesser known symptoms that may appear are vomiting, abdominal pain and pressure or pain in the back or neck.
Acute coronary syndrome is often caused by a buildup of plaque in the coronary arteries. This plaque buildup limits the heart's effectiveness at supplying blood to the rest of the body. Sometimes the plaque can form into a blood clot and this causes the blood flow to the heart to be blocked. Without blood and the oxygen it delivers, the heart will start to die.
The buildup of plaque is called coronary atherosclerosis or heart disease. One warning sign of heart disease is pain in the middle of the chest or on the left side (angina). It shows up during stressful activities like exercising and goes away when the activities stop. Some people, especially women, may experience this pain in the neck, arm or back instead of the chest.
Coronary artery disease begins when the inner walls of the arteries are damaged and platelets form to repair the harm. Ongoing stress can damage coronary arteries as can simply growing older. The platelets might clump, causing arteries to narrow, and they can even break off into blood clots.
There are seven major known red flags for heart disease:
- high blood pressure
- High cholesterol
- Sedentary lifestyle
- Family history of heart attack or stroke
Diagnosis & Tests
A complete checkup by a medical professional is the first step in diagnosing coronary artery disease and/or identifying acute cardiac syndrome. During an acute episode, a monitor will be attached to the patient to take an electrocardiogram (ECG). The machine uses twelve electrodes to measure the electrical activity of the heart and can show whether there has already been damage.
Blood will also be drawn to look for cardiac enzymes that indicate damage to the heart. A cardiac perfusion scan may be administered to measure the amount of blood flow to different areas of the heart. This is a test that requires radioactive markers to be injected intravenously. If the markers do not show up in some parts of the heart, this is an indication that they may not be getting an adequate blood supply. It can also indicate areas that have already been damaged by a heart attack.
A cardiac catheterization can include an angiogram and will show in detail which areas of the arteries are damaged or blocked. A long, thin catheter is inserted into a major artery and dye is injected to help identify the problems. Sometimes a balloon catheter can be inserted to clear blocked areas of the arteries. A mesh tube called a stent is then inserted to make sure that the artery stays open. This procedure is called balloon angioplasty.
Treatment & Therapy
Balloon angioplasty and coronary artery bypass graft surgery are both treatments for acute coronary syndrome. Because bypass surgery is open heart surgery, it is usually only used for cases in which there are multiple narrowed arteries. The surgeon bypasses the blocked arteries using pieces of artery from elsewhere in the body.
Medications can help the heart by reducing the amount of cholesterol in the body. Statins work with the liver to block cholesterol from being formed. Cholesterol absorption inhibitors reduce the amount of cholesterol absorbed from food. Niacin, which is a form of vitamin B, has also been shown to help reduce cholesterol.
Some blood pressure control medicines also provide benefits for those with heart disease. Beta blockers slow the heart rate and decrease blood pressure, which can provide protection from future heart attacks. Nitroglycerine is a drug that can temporarily dilate the arteries leading to the heart, allowing oxygen-rich blood to reach it.
After a heart attack patient has stabilized, a stress test for heart disease can determine how a person's heart and arteries perform when under the stress of exercise. Patients walk on a treadmill and their heart rate is measured at varying degrees of exertion. A stress test combined with blood testing and imaging is an important tool for designing the right treatment for the patient.
Prevention & Prophylaxis
Obesity, smoking and a sedentary lifestyle contribute to the possibility of future heart problems. Happily, all of these can be improved upon, giving patients a great deal of control over their heart health.