Echocardiography is ultrasound imaging of the heart. Stress echocardiogram is echocardiography done during some form of stress, either by exercise or with medications. It can be done soon after a person exercises on a treadmill. It is possible to use arm bicycle to give stress during actual procedure. But all these are technically difficult to arrange in the echo room. Most often stress echocardiography is done while medications are given as drip to increase the workload of heart. This is known as pharmacological stress testing. Usual medication used is dobutamine, which stimulates the heart. Hence it is called dobutamine stress echocardiography.
When do you recommend dobutamine stress echocardiography instead of treadmill stress test?
There are two situations when it is recommended instead of a treadmill test (TMT):
- When the person is unable to exercise on a treadmill either due disability or weakness of legs or is too sick to undergo an exercise test
- When the baseline ECG is abnormal so that changes occurring during exercise cannot be interpreted well
What additional equipment is needed for doing a stress echocardiography?
The echocardiograph should be a higher end one with a computer package for stress echocardiography. This would mean that split screen facility to compare before and after exercise images is available. The machine should have good clarity to interpret images in a person with increasing heart rate. The requirement if more demanding if exercise stress is used as the person will be breathing fast after exercise and lung will overlap the heart while breathing in. The operator should be well trained in interpreting changes in a fast beating heart.
All measures to handle an emergency situation should be made available. Heart rhythm, blood pressure and oxygen level of blood should be continuously monitored. Occasionally patient’s condition may worsen during the test if there is severe underlying heart disease.