Chemical stress test is a medical procedure meant to measure the response of the heart to an increased flow of blood through the arteries that lead to it. Generally, this increase is achieved by means of making the patient engage in physical conditions under closely monitored and controlled conditions. In most cases, the patient is asked to walk on a treadmill to the point that s/he reaches an optimum level of physical exertion. The doctor would then measure the rate of blood flow through the coronary arteries and the corresponding reaction of the heart muscles with the help of an electrocardiogram. These results are then compared with the activity of the heart in a resting state.
The Stress test is also used to diagnose any obstructions in the blood vessels, to assess the body's response to previous medical treatment for unclogging blood vessels and to calculate the risk of cardiac complications in the future. However, in certain cases it is not viable to make the patient undergo physical stress to achieve the requisite increase in the rate of blood flow through the arteries. This is due to conditions like debility resulting from chronic illnesses or age, severe arthritis, problems relating to the spine, past history of cardiac arrest or stroke, surgery or major injury, or conditions like obesity and asthma. In such cases, instead of making the patient exercise, a small amount of medicine is introduced intravenously into the bloodstream in order to make the arteries dilate and the blood flow through them at a faster rate.
Since the increase in the flow of blood through the coronary arteries is achieved within a matter of seconds, it could lead to a few side effects that you should be prepared for. Patients commonly complain of headache, nausea and vomiting, trembling and fluttering of the limbs, hot flashes, perspiration, irregular or skipped heartbeats and breathlessness. Following the test, the patient may feel fatigued in spite of the fact that s/he has not engaged in any physical exercise. In a few rare cases, this test may lead to serious complications like cardiac arrest. It is, therefore, extremely important that you inform your doctor beforehand of your medical history and strictly follow all the instructions that s/he asks you to. This generally involves discontinuing the intake of blood-thinning medicines and refraining from consuming food or drink a few hours before the test is conducted. You should ideally also have a friend or a family member accompany you to the clinic on the day of the test.
Submitted by M H on March 5, 2010 at 12:52