What does it mean if you badly on a nuclear stress test?

March 5, 2010

A nuclear stress test is conducted to detect obstructions in the coronary arteries that may lead to cardiac ailments. It also helps calculate the risk of heart diseases if you have a family history of such problems and to assess the condition of the cardiac muscles and blood vessels if you have already had a heart surgery or are on medication for cardiac complications. Those who suffer from ailments like hypertension and diabetes also belong to the high-risk group for cardiac diseases and are therefore recommended to undergo a cardiac stress test. Unlike the traditional cardiac stress test, in which the patient is made to exercise on a treadmill till his/heart begins of beat fast due to increased flow of blood through its arteries, the nuclear stress test does not require the patient to engage in physical exercise.

Rather, a small amount of a radioactive isotope is injected through a vein in the arm to induce the coronary arteries to dilate and thereby achieve the requisite increase in the rate of blood flow into the heart. This method is especially useful in those cases where the patient is unable to withstand the physical stress of exercise, due to old age, chronic illness, spinal problems, respiratory disorders or excessive body weight. Once the radioactive substance reaches the heart through the blood flowing into it, a scanner is used to expose the area to a minimal amount of radiation in order to obtain electrographic images of the cardiac muscles, especially of the left ventricle, as it experiences the maximum degree of pressure in pumping blood. These images are compared with the readings that are taken before the flow of blood into the chambers of the heart is artificially increased akin to a state of vigorous physical exercise.

The two sets of readings are compared to arrive at an accurate assessment of the performance of the heart. The nuclear substance present in the bloodstream shows up in the scanned images according to its concentration in various parts of the organ. If a certain portion of the heart or the coronary artery appears lighter than the surrounding areas, it indicates that those parts are not getting adequate supply of blood. Also, if a certain artery is clogged, it obstructs the flow of blood and pushes it into other arteries that are unobstructed. Thus, variation in the color of the arteries in the scanned image could also point to the risk of coronary complications. Based on the results, your doctor will prescribe appropriate treatment for you.

Submitted by M H on March 5, 2010 at 01:27

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