Cardiac stress testing or exercise electrocardiogram (ECG or EKG) as it's also known, is a test used to measure the heart's ability to respond to external stress in a controlled clinical environment. In many instances cardiac abnormalities may become apparent only when the heart must perform at increased workloads.
The stress response is induced by exercise or drug stimulation. Cardiac stress tests compare coronary circulation while at rest and during maximum physical exertion, showing any abnormal blood flow to the heart's muscle tissue (the myocardium).
What to Expect During an Exercise Electrocardiogram
You may be asked to walk on a treadmill or exercise will be simulated using medications while you are lying still. Ultrasound or nuclear images may be taken of your heart before and after the exercise portion is completed.
In addition to the equipment used to perform the exercise EKG, a blood pressure cuff is placed on your arm for continuous monitoring. A baseline EKG and blood pressure reading are taken before exercise begins, then at regular intervals during and after the exercise.
The exercise continues until one of the following endpoints:
- Your target heart rate is achieved
- You experience chest pain
- The technician or nurse detects EKG abnormalities
- There is a significant change, especially a drop in blood pressure
- You become exhausted and are unable to continue
What We Learn from Stress Testing
The results of your exercise EKG may be useful in the following situations:
- To evaluate exercise tolerance and capacity
- To distinguish chest pain that is cardiac in origin from pain caused by other problems
- To evaluate heart rhythm at increased heart rates
- To evaluate the effectiveness of medications used to manage chest pain associated with heart disease