Acute coronary syndrome


Acute coronary syndrome (ACS) is a term used to describe three types of coronary artery diseases that can have life-threatening consequences. These conditions occur when a blockage suddenly slows down or completely stops blood flow to the heart.

The three types of ACS are:

  • Unstable angina: This condition involves the onset of sudden and unexpected chest pain or pressure, even while at rest. It serves as a warning sign of a potential heart attack and usually occurs when stable angina worsens.
  • Non-ST-elevation myocardial infarction (NSTEMI): NSTEMI is a type of heart attack that can be detected through blood tests but not necessarily through an electrocardiogram (EKG). It indicates that the coronary arteries are partially blocked or were blocked for a short period.
  • ST-elevation myocardial infarction (STEMI): STEMI is a more severe form of heart attack that can be detected through both blood tests and EKG. It occurs when blood flow to the heart is completely blocked for an extended period, causing significant damage to a large portion of the heart.

A heart attack, also known as a myocardial infarction, occurs when the death of heart tissue is caused by inadequate blood supply. People with ACS can experience unstable angina or a heart attack. Unstable angina occurs when blood flow to the heart is reduced, but it is not severe enough to cause cell death or a full-blown heart attack. However, it still increases the risk of a heart attack. Common symptoms of unstable angina include chest pain or pressure (angina), shortness of breath (dyspnea), or dizziness.

ACS is a medical emergency that requires immediate diagnosis and care. The treatment goals include improving blood flow, managing complications, and preventing future problems. If you suspect you are having a heart attack, it is crucial to take an aspirin and call emergency services right away.


The symptoms of acute coronary syndrome can differ depending on the extent and position of the blockage, as well as individual factors such as age, gender, and concurrent medical conditions like diabetes. Typically, signs of ACS manifest unexpectedly, even during periods of rest. This syndrome commonly presents as chest pain or discomfort, resembling angina, which may be described as:

  • Chest pain or discomfort, which can be characterized as aching, pressure, tightness, or a burning sensation. This sensation may extend to the left shoulder, arms, neck, back, or jaw. It is also known as angina.
  • Feeling dizzy, lightheaded, or experiencing fainting spells.
  • Sudden and excessive sweating, also known as diaphoresis.
  • Fatigue.
  • Sensation of a racing or pounding heart, also referred to as heart palpitations.
  • Pain in the upper abdomen, which can sometimes be mistaken for indigestion or heartburn.

While chest pain or discomfort is the most common symptom, it is important to note that symptoms of acute coronary syndrome can vary significantly depending on factors such as age, sex, and existing medical conditions. Specifically, women, older adults, and individuals with diabetes are more likely to experience symptoms without chest pain or discomfort. It is crucial to recognize that acute coronary syndrome is a medical emergency, and chest pain or discomfort can indicate various life-threatening conditions. Seeking immediate emergency assistance is vital for an accurate diagnosis and appropriate care. It is strongly advised not to drive yourself to the hospital.


The heart muscle requires a continuous supply of oxygenated blood to function properly. It receives this blood through coronary arteries and their smaller vessels. Over time, a buildup of fat and cholesterol called plaque can narrow and harden these arteries, a condition known as atherosclerosis. Sometimes, the plaque can rupture suddenly, leading to a medical condition called acute coronary syndrome.

When the plaque ruptures, a blood clot forms over the damaged area, further obstructing or completely blocking the blood flow to a specific part of the heart called the myocardium. As a result, the heart muscle does not receive enough oxygen, leading to ischemia. This lack of oxygen can cause damage to the heart muscle, resulting in unstable angina or a heart attack.

In rare cases, acute coronary syndrome may be caused by different factors such as a blockage in the coronary artery due to a blood clot, air bubble, fat, or other materials (known as coronary artery embolism), a sudden constriction of the coronary artery (known as coronary artery spasm), or a spontaneous tearing of the coronary artery wall (known as spontaneous coronary artery dissection or SCAD).

Risk factors

The risk factors for acute coronary syndrome are similar to those associated with other types of heart disease. These risk factors encompass:

  • Advancing age.
  • Hypertension (high blood pressure).
  • Elevated levels of cholesterol in the blood.
  • Smoking.
  • Sedentary lifestyle with insufficient physical activity.
  • Unhealthy dietary habits.
  • Obesity or being overweight.
  • Diabetes.
  • Personal or family history of chest pain, heart attacks, or stroke.
  • Previous occurrence of high blood pressure, preeclampsia, or diabetes during pregnancy, as well as early menopause.
  • COVID-19.