Duke Treadmill Score Calculator

Coronary artery disease (CAD) is the most common type of heart disease in the United States. Its other names include coronary heart disease or ischemic heart disease. For some people, the first sign of CAD can be a heart attack; however, many patients experience various symptoms of this illness beforehand.

Coronary artery disease is caused by plaque buildup in the walls of the arteries, which supply blood to the heart, and other parts of the human body. The plaque, built from cholesterol and other substances, successively narrows the arteries, which limits the blood flow or can block it entirely.

The symptoms and complications of CAD include:

• Angina;
• Chest pain and discomfort;
• Heart attack (weakness, nausea, angina, chest pain, cold sweat, and shortness of breath); and
• Heart failure (dyspnea, fatigue, shortness of breath, swelling in the legs, rapid and irregular heartbeat).

The risk factors for CAD include:

• Being overweight;
• Physical inactivity;
• Unhealthy diet;
• Smoking — it's never too late to quit smoking and save!; and
• Family history of CAD.

If a patient is at a high risk of heart disease or already has symptoms, the doctor can use several tests to diagnose CAD. One of the coronary artery disease tests is an exercise stress test. Use the Duke treadmill score calculator to obtain the information required to assess the patient's health.

The Duke Treadmill Score is a weighted index using treadmill exercise time (performed according to the standard Bruce protocol), maximum netST-segment deviation (depression or elevation), and exercise-induced angina. It was developed to provide diagnostic and prognostic information to help evaluate patients with suspected coronary heart disease.

The typical observed range for Duke treadmill score starts from -25 (the highest risk) up to +15 (the lowest risk).

The Duke score equation is as follows:

Duke score = exercise – 5 × ST-segment dev. – 4 × TAI

where:

• exercise is the duration of exercise expressed in minutes;

• ST-segment dev. is the maximal net ST-segment deviation expressed in millimeters. ST deviation refers to maximum ST change (elevation or depression) in any lead except lead aVR; and

• TAI is the Treadmill Angina Index, that we can describe as follows:

If you're interested in ECG interpretation, check out our QTc calculator.

According to the Duke treadmill score, patients are categorized as low-risk, intermediate-risk, or high-risk.

Let's use a practical example to show how the Duke treadmill score calculator works.

The patient, named Susan, took a Duke treadmill test. She was exercising for 8 minutes, and didn't experience any pain during the test. Her maximal net ST-segment deviation was equal to 0.6 mm.

The Duke score will be calculated as follows:

1. Duke score = exercise – 5 × ST-segment dev. – 4 × TAI

2. Duke score = 8 min – 5 × 0.6 mm – 4 × 0

3. Duke score = 8 − 3

4. Duke score = 5

Interpretation: Susan is a low-risk patient.