What is a stress echocardiogram?
A stress echocardiogram combines an ultrasound of the heart with exercise or a medication that makes the heart work harder. Ultrasound pictures are taken while you are at rest and then again at peak stress, and the two are compared. A narrowed coronary artery may supply enough blood while you rest but not when the heart is working hard, and when that happens the affected part of the heart wall does not squeeze as strongly, which can be seen on the ultrasound. It is also used to assess how a heart valve behaves under stress.
Why is it done?
It helps to establish whether chest pain or breathlessness is caused by narrowed coronary arteries, and how much of the heart muscle is affected, which guides whether you need medication only or an angiogram. Because it looks at the movement of the heart walls rather than at the electrical tracing alone, it is more accurate than a plain treadmill test, and it is particularly useful when the resting ECG is abnormal. It is also used to assess valve disease, to check the pressure in the lung arteries with exercise, and to judge risk before major surgery.
How do I prepare?
Please do not eat for about three hours before the test, and avoid coffee, tea, cola, energy drinks and chocolate for at least twelve hours if a medication-based test is planned, because caffeine interferes with the medicine. Bring a list of your medication; you will usually be told to leave out beta-blockers and certain other tablets for a day or two, but never stop medication unless we have instructed you to. Wear comfortable clothing and walking shoes if you will be exercising, and bring your inhaler if you use one. The whole visit takes about an hour, and you should arrange for someone to drive you home if you are having the medication version.
What happens on the day?
ECG dots are placed on your chest and resting ultrasound pictures are recorded while you lie on your left side. If you are able to exercise, you then walk on a treadmill or cycle with the workload increasing every few minutes until your heart rate target is reached or symptoms stop you, and you are moved quickly back to the couch so that pictures can be taken while the heart is still working hard. If you cannot exercise, a medicine called dobutamine is given through a drip in increasing doses to make the heart beat faster and stronger; this can cause a pounding heartbeat, flushing, headache or mild nausea, which pass within minutes of stopping the infusion. Your ECG, blood pressure and symptoms are monitored closely throughout by a doctor and a nurse.
Possible complications
Stress echocardiography is safe and is performed under continuous medical supervision, with resuscitation equipment always at hand. Common and temporary effects are breathlessness, tiredness, a pounding heart, flushing, headache, nausea or mild chest discomfort during the stress phase. Uncommonly the test provokes a significant fall in blood pressure or an abnormal heart rhythm, and the test is stopped and treated. Serious events such as a heart attack, a dangerous rhythm or death are very rare, in the order of one in a few thousand tests. With exercise there is also a small risk of a muscle or joint injury. Tell us beforehand if you have asthma, glaucoma or a rhythm problem, as this influences which type of stress is used.
This information does not replace a consultation. Please discuss your own risks and options with your cardiologist.