Acute coronary syndrome involves a sudden obstruction of blood flow to the heart. The condition may result in unstable angina (chest pain that occurs when a person is at rest, as opposed to chest pain with exertion); if severe enough, it can lead to myocardial infarction.
When blood supply is reduced or cut off to the heart, it is usually due to a blood clot. In many cases, an individual will already have some degree of narrowing of the artery due to a buildup of fatty materials. The material, known as an atheroma, may rupture. When an atheroma ruptures, it causes the platelets to become stickier, which may lead to clot formation.
Depending on the severity of the obstruction, damage to the tissue may occur. Acute coronary syndrome is usually classified based on serum markers present when heart tissue is damaged and electrocardiogram changes. In patients who do not have signs of heart damage, such as ST changes or the presence of elevated serum makers, acute coronary syndrome may be classified as unstable angina.
Because acute coronary syndrome is potentially life-threatening, prompt recognition of symptoms is essential. Symptoms for acute coronary syndrome may be the same whether heart damage has occurred or not, so it is important to evaluate each case closely.
Chest pain which comes on suddenly is one of the most common symptoms of acute coronary syndrome. However, it is difficult for medical professionals to distinguish between angina pectoris and unstable angina by chest pain alone.
One way to differentiate symptoms of stable angina from acute coronary syndrome is to determine whether there has been a change in the pattern of the pain. For example, patients who have experienced stable angina may have had chest pain in the past which occurred after physical exertion. In people who are experiencing acute coronary syndrome, the pain may be different in that it occurred at rest, is more severe or it lasts longer than it has in the past. Pain associated with ACS may also be unresponsive to nitroglycerin.
Acute coronary syndrome which results in a myocardial infarction may cause chest pain; however, it is important to note that not all people who have a myocardial infarction have chest pain. When chest pain or discomfort develops it may be described as pressure, fullness or tightness.
In addition, pain suggestive of acute coronary syndrome may also radiate to the back, jaw and arms. According to the University of Maryland Medical Center, when chest pain is associated with a myocardial infarction it often lasts longer than a few minutes and may vary in intensity.
When determining the quality of the pain, it is important to avoid leading the patient. Avoid asking yes or no questions if possible. Ask how the patient would describe the pain, what they were doing when it started and if it was relieved by anything. Understanding the characteristics and patterns of pain can play a role in making a diagnosis; however, it is important to note that an electrocardiogram and blood tests are needed in order to make a definitive diagnosis.
According to the American Heart Association, most patients will present with chest discomfort and shortness of breath as their predominant symptoms, but additional symptoms may occur. Although they may vary in intensity, some people experience lightheadedness, nausea and vomiting. Clinical presentation for patients with acute coronary syndrome may also include diaphoresis in the form of cold, clammy skin.
Most patients with acute coronary syndrome will not present with isolated symptoms, such as diaphoresis or lightheadedness, although it is not impossible. Atypical presentations can occur, but they are more common in the elderly and in women. Individuals with diabetes sometimes also have atypical symptoms.
According to the American Heart Association, women sometimes present with pain in the abdominal area, shortness of breath and fatigue. Similarly, the elderly may also present without chest pain- instead, shortness of breath, pain in the back or arms and fatigue may be present. The exact reason for the differences in presentation is not fully understood.