Now this is not the mental stress that you may like to get rid of. This is a test to indirectly assess how the coronaries that supply blood to your heart are faring.

The Principle:

Normally, when you exert yourself physically, your heart starts to work more so that the hard working legs and other body parts get a good blood supply. The heart achieves this by getting stronger contractions and by beating at a faster rate. You must have experienced this when you have had a jog or have climbed a few stair cases. Now when the heart is working overtime, it’s own needs of blood supply also have to be taken care of. The coronaries achieve this by becoming wider or dilating. Now, in case the coronary arteries are thickened or narrowed because of coronary artery disease, this dilatation fails or is suboptimal. Subsequently, the heart is deprived from it’s much needed blood supply during the need hours and it suffers. This suffering can be easily detected by tests which are called Stress tests.

Different types of Stress Test:

ECG Based Exercise Stress Test:

The routinely performed stress test is the Treadmill Test. You must have seen those cardio-walkers in the Gym. In a Treadmill Test, you are made to walk on such a Treadmill so as to give your heart a standardized exertion. It isn’t difficult at all, provided your knees are in shape and you are able to walk at a normal pace. The test starts at a very low speed. Every 3 minutes, the speed and inclination gradually increases. Depending upon your heart rate, symptoms and ECG changes, your attending physician would decide when to stop the test. The changes in the ECG would give a fair indication as to how well your coronaries are performing at peak exercise and after.

Sometimes instead of a Treadmill, a few centers use the bicycle ergometry as a substitute for the treadmill, although the process remains the same.

Stress Echocardiography:

Just as an ECG, an Echo Cardiograph can also be used to see the functioning of the heart during exercise. This is called Stress-Echocardiography. This facility is not very commonly available. The process of exerting the heart remains more or less same; however, the evaluation is done on the basis of 2 D Echocardiograph images of the heart. It rests on the principle that the part of the heart that is suffering normally contracts with a lesser force during exercise and is seen on the Echocardiography. This could give an idea of the area of the heart which is suffering and the possible branch of the artery which is involved.

Stress-Thallium Testing:

Sometimes, because of some abnormalities in the resting ECG, the interpretation of a routine ECG based Stress test could be difficult. In this case a radio-isotope chemical dye is used in addition. This test can be performed at specialized centers which are licensed to use the dye. The radio-isotope dye is injected in the body at the time of peak exercise and at rest. A difference in the uptake of the dye in the heart during these two phases can give a good idea about the part of the heart which is suffering. This test is also useful in those longstanding cases under treatment, to identify the culprit vessel which needs to be handled.

Dobutamine Stress test:

Sometimes, when a stress test is needed and walking is difficult, a Treadmill test cannot be performed. In these cases, the heart rate can be artificially increased under controlled conditions using certain medications. This is especially helpful in those patients who are old or have a walking disability.

When would you be denied of a Stress Test:

1. If you have had had significant angina lasting more than 10 minutes in the last 48 hours.
2. If you are known to have certain heart rhythm disturbances.
3. If ECG and Echo cardiograph shows certain structural problems in the heart.
4. If there is a very high Blood pressure value which remains persistent.

What should you take care of before a Stress Test:

1. Before you fix your appointment for a stress test, you should inform your doctor about your ongoing medications. Medicines for Hypertension like Propranolol , Atenelol, Metaprolol, Verapamil etc. need to be paused for at least 48 hours before the test. The same goes with certain anti-anginal medicines like Isosorbide Nitrite or similar medications. This needs to be done after consultation with your physician.
2. A light breakfast should be consumed before the test. Empty stomach or a heave meal should be avoided.
3. A good pair of sporting shoes would be useful to perform the test to your best efficiency.

It is important to note that a negative stress test is not a certificate that you wouldn’t get a heart attack in the near future. At the same time a positive stress test does not mean that there is a time bomb in your heart. A Stress test is utilized more for evaluating a chronic or a long standing and slow process affecting your heart.