Norfolk County Cardiologist Association

Silent Ischemia

Cardiac ischemia happens when an artery becomes narrowed or blocked for a short time, preventing oxygen-rich blood from reaching the heart. If ischemia is severe or lasts too long, it can cause a heart attack (myocardial infarction) and can lead to the death of heart tissue. In most cases, a temporary blood shortage to the heart causes angina pectoris. But in certain other cases, there is no pain. These cases are called silent ischemia.

Silent ischemia may also disturb the heart's rhythm. Abnormal rhythms such as ventricular tachycardia or ventricular fibrillation can interfere with the heart's pumping ability and can cause fainting or even sudden cardiac death.

How common is silent ischemia, and who is at risk?

An estimated four million Americans-mostly men over age 65-have episodes of silent ischemia. People who have had previous heart attacks or those who have diabetes are especially at risk for silent ischemia. Heart muscle disease (cardiomyopathy) that is caused by silent ischemia is among the four most common causes of heart failure in the United States.

Major risk factors include

· Previous heart attacks.

· Coronary artery disease.

· Diabetes.

· High blood pressure (Hypertension).

· Smoking.

· Obesity.

· Cardiomyopathy.

· Alcohol and drug abuse.

What are the symptoms of silent ischemia?

Silent ischemia has no symptoms. But researchers have found that if you have noticeable chest pain, you may also have episodes of silent ischemia.

How is silent ischemia diagnosed?

The following tests can be used to diagnose silent ischemia:

· An exercise stress test can show blood flow through your coronary arteries in response to exercise, usually walking on a treadmill.

· Holter monitoring records your heart rate and rhythm over a 24-hour period (or more). You wear a recording device (the Holter monitor), which is connected to disks on your chest. Doctors can then look at the printout of the recording to find out if you have had episodes of silent ischemia.

How is ischemia treated?

Treatment for ischemia is similar to that for any form of cardiovascular disease and usually begins with the following lifestyle changes:

· If you smoke, quit.

· Control high blood pressure, cholesterol, and diabetes.

· Limit how much alcohol you drink.

· Adopt healthy eating habits.

· Start an exercise program that has been approved by your doctor.

Medicines and Surgery

Treatment focuses on improving blood flow to your heart and on reducing your heart's oxygen demands. You may receive aspirin, blood-thinning medicines (anticoagulants), or other blood-thinning agents to prevent blood clots from forming. Oxygen may be given to increase the oxygen content of the blood still flowing through your heart. Painkillers may be used for pain.

Some patients receive drugs aimed at slowing their heart rate, opening and relaxing their blood vessels, and otherwise reducing the burden on the heart. Most patients respond well to these medicines. Those who do not respond well may need a transcatheter intervention (such as balloon angioplasty), coronary artery bypass surgery, or a related procedure.

Updated May 2000