Cardiac Health Questions

Commonly Asked Questions

“My doctor did an exercise test on me recently and said it was normal. Now you did an angiogram and tell me that I have four blockages. Why is that?”

An exercise test is a good screening test to identify critical exercise-induced, flow-limiting blockages in the coronary system. If a patient has tight (more than 75%) blockage in one or more of the coronaries, an exercise test can induce some chest pain and/or EKG changes in about 25%-65% of the patients. A nuclear stress test or a stress echocardiography will improve the sensitivity of detecting coronary artery disease by 80%. In about 30% of the patients, even with critical blockages of the coronary arteries, an exercise test will not be very useful and may even be misleading by demonstrating a “normal” result. If a patient has one or more subcritical blockages, i.e., blockages less than 70%, an ETT may read entirely normal also.

A coronary angiogram is the one and only diagnostic test, which will absolutely identify the exact location and degree of coronary stenosis. In rare instances, one might even need an intravascular ultrasound examination for the most accurate evaluation of the degree, nature, and extent of coronary stenosis.

It is reasonable to say that an exercise test is not a test to identify buildup of cholesterol in the coronary system. Even in those patients with very severe three-vessel coronary artery disease, a treadmill test could be read as normal. This happens particularly when there is collateral circulation.

Case Study

A 58-year-old physically very active and totally asymptomatic dentist had a minor EKG change (mild T wave inversion in the inferior leads) on the resting 12-lead EKG during annual physical examination. His life insurance policy was denied due to this change. He had a perfectly normal treadmill exercise test, as well as stress echocardiography with no evidence of exercise-induced chest pain, anginal equivalent symptoms, or additional EKG changes. Still his policy was denied. Subsequently, a nuclear exercise test showed multiple small reversible perfusion abnormalities in the myocardium.

Fig 11
Fig. 11: Coronary angiogram from this patient. The angiogram showed normal systolic function of the left ventricle. The right coronary artery was totally occluded with collaterals from the left coronary artery. There were multiple 60-95% stenoses on the left coronary system, as shown in the figure. He underwent five- vessel CABG. He had some, if not, more T wave changes on the EKG postoperatively.

Caveat – New EKG changes, even if minor, must be evaluated thoroughly.

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