Treadmill Testing

Treadmill Testing

Basic treadmill exercise testing involves EKG monitoring at rest and continuously while walking on a treadmill, which starts at a slow rate and with a mild incline, increases every three minutes until a person has reached their target heart rate or has one of several clinical indications for stopping. An EKG may be normal at rest but with exercise show changes that indicate a likely presence of blockages or narrowing of the coronary arteries. With exercise and increased heart rate, the heart needs more oxygen and therefore more blood flow. If there is a fixed narrowing in one of the coronary arteries, blood flow will be unable to increase in that region and that area of the heart will become ischemic (lacking sufficient oxygen). This is what causes angina, which may be experienced on the treadmill, causes EKG changes, and other defects as discussed below. Sometimes stress tests will be performed with a secondary imaging technique; both to give greater information, greater accuracy and especially if the EKG is abnormal at baseline.

We offer Stress Echo, which is an ultrasound of the heart at rest and is then repeated at peak exercise and allows us to see the movement of the walls of the pumping chamber of the heart and compare them at rest and with exercise. This is in addition to the findings on EKG and generally speaking overrules abnormalities in the EKG. Sometimes Stress Echo will be performed with the injection of a special inert contrast, which allows us to see the heart walls better.

We also offer Nuclear Cardiology. This involves injecting a small amount of radioactive tracer into the vein at rest showing the perfusion or blood flow to the heart at rest. Then after exercise or chemical stress testing, the second injection of tracer is performed and pictures obtained. These two views are then compared to see if an area of the heart fails to get enough blood flow during stress conditions, which implies a narrowing in one of the coronary arteries leading to that part of the heart.

Chemical stress testing can be used in place of treadmill exercise testing for either stress echo or stress nuclear studies. With chemical stress testing, no exercise is performed and a short-acting IV medicine is given which dilates the arteries and/or stimulates the heart to simulate exercise. The decision to use exercise or chemical stress testing will be made by you and your physician based on your ability to perform the exercise test, your underlying EKG, and other clinical factors.