Coronary Artery Disease Basics

How the heart works

The heart has four chambers, divided by a muscular wall. Oxygen-rich blood from the lungs passes through the left atrium to the left ventricle, which pumps this blood to the rest of the body. After the body has used the oxygen in the blood, the now oxygen-poor blood flows through the right atrium to the right ventricle. From there, it’s pumped to the lungs to pick up more oxygen. The coronary arteries supply oxygen and nutrients to the heart so it can do its work.

How the heart works
What is coronary artery disease?

Coronary artery disease (CAD) is the most common form of heart disease. CAD develops when the arteries that supply blood to the heart—called the coronary arteries—become damaged or diseased. This can happen when a material called plaque, made up of fat, cholesterol, and other substances found in the blood, builds up over time in the coronary arteries, resulting in a condition called atherosclerosis. A buildup of plaque can narrow the arteries, reducing or blocking blood flow to the heart. If the coronary arteries stay blocked, the heart muscle may become permanently damaged.

Coronary artery disease

Enlarged view of coronary artery

Causes of CAD

Many factors can contribute to CAD. Some can’t be changed, including your age, gender, and heredity. More people over age 65 develop CAD, as do those with a family history of heart disease. Women are diagnosed with CAD less often than men, but women may not recognize their symptoms because they can be different from men's, and they may not be correctly diagnosed when they do see a doctor.

Many risk factors for CAD can be controlled with lifestyle changes, medication, or medical procedures. Some risk factors include the following:

Medical Risk Factors
Lifestyle Risk Factors
  • Smoking
  • Being overweight or obese
  • Physical inactivity
  • Drinking too much alcohol
  • Stress
Symptoms of CAD

Some people with CAD have no symptoms until the disease has progressed, earning it the name of the "silent" disease. Having CAD that goes undiagnosed can lead to serious complications, including heart attack and stroke. That's why it's important to pay attention to any unusual symptoms and talk to your doctor about them.

When people do experience symptoms, they can include:

  • Angina—chest pain that feels like pressure, heaviness, or squeezing in your chest. You may also feel it in your left shoulder, arms, back, neck, or jaw. Angina is sometimes mistaken for indigestion
  • Shortness of breath—may be caused by physical activity or stress
  • Sweating—may also be a "cold sweat"
  • Nausea—can lead to vomiting
  • Irregular heartbeats—may feel like your heart is pounding
  • Weakness—may also include dizziness or anxiety

Women's symptoms can be different from men's, and may include:

  • A burning feeling in the chest or upper abdomen
  • Pain or pressure in the chest that travels to the arm or the jaw
  • Shortness of breath
  • Irregular heartbeat
  • Sweating
  • Dizziness
  • Fatigue
  • Nausea
When to See Your Doctor

It's important to call your doctor if you develop new symptoms of CAD or if your symptoms become more severe or more frequent. It's also a good idea to set up an appointment if you have risk factors for CAD even if you don't have any symptoms. CAD that goes undiagnosed and untreated can lead to serious complications, including:

  • Heart failure, when your heart can't pump enough blood to your body
  • Heart attack, when plaque in a coronary artery breaks apart, forming a blood clot that can cut off blood to the heart and damage the heart muscle
  • Stroke, caused by a blood clot in an artery to the brain, which cuts off oxygen and blood to the brain

If you have CAD, the sooner you are diagnosed, the sooner you and your doctor can decide on a treatment plan and lifestyle modifications that are right for you.

To learn more about getting diagnosed for CAD, see Stress Tests for CAD.


Read Lexiscan® (regadenoson) injection Full Prescribing Information (PDF - 193 KB)

ADOBE Reader is needed to view the PDF file. To download ADOBE Reader, click on the get ADOBE Reader icon.


Lexiscan (regadenoson) injection is a prescription drug given through an IV line that increases blood flow through the arteries of the heart during a cardiac nuclear stress test. Lexiscan is given to patients when they are unable to exercise adequately for a stress test.

Important Safety Information
  • Lexiscan should not be given to patients who have certain abnormal heart rhythms unless they have a pacemaker.
  • Lexiscan can cause serious or fatal cardiac arrest, abnormal heart rhythms or heart attack.
  • Allergic reactions can occur after Lexiscan injection.
  • Drugs such as Lexiscan may cause an increase or decrease in blood pressure, especially in patients with certain heart and blood vessel disorders.
  • Lexiscan can cause breathing difficulties. Before receiving Lexiscan, tell your doctor if you have respiratory diseases, such as COPD (chronic obstructive pulmonary disease) or asthma. Tell your doctor about all medications you use to manage these conditions.
  • Lexiscan can increase the risk of seizures. Before receiving Lexiscan, tell your doctor if you have a history of seizures.
  • Lexiscan can cause stroke, which may be a result of an increase or decrease in blood pressure.
  • The most common side effects that occurred in clinical trials of Lexiscan were shortness of breath, headache, flushing, chest discomfort or chest pain, dizziness, nausea, abdominal discomfort, a metallic taste in the mouth, and feeling hot. Most common side effects began soon after receiving Lexiscan and went away within 15 minutes except for headache, which resolved in most patients within 30 minutes.
  • Avoid consuming any caffeine-containing foods and beverages or medicines containing caffeine, aminophylline or theophylline in the 12 hours before your scheduled heart scan.
  • Ask your doctor if you should stop taking any medications you usually take before the day of the test.
  • For women who are nursing, pump and discard breast milk for 10 hours after receiving Lexiscan.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088.