• 18 days ago

    RE: Stress test on heart showed a slight "darkening"

    As applicable, on a nuclear stress test, a darkened area typically indicates either a reversible perfusion defect (ischemia) or an infarction (heart attack).

    An angiogram (heart catheterization, X-ray angiography) is currently the "gold standard" in imaging the coronary arteries, indicating exactly where blockages are located and the degree/percentage of stenosis (narrowing).

    Non-invasive cardiac CT with contrast media has improved vastly over the years, though still lacks the precise overall accuracy of an invasive angiogram.


    After stress myocardial perfusion imaging (stress MPI, gated-SPECT scan with Cardiolite or Myoview), the patient's cardiologist may take some time to study the results of the scan before discussing the findings.

    The patient can typically expect one of the following four results -


    No perfusion defect after exercise or at rest

    The heart muscle and blood flow to the heart muscle appear to be normal.


    Perfusion defect after exercise, but not at rest (reversible defect)

    There is some degree of blockage in a coronary artery that interferes with the blood flow to the heart muscle. In someone with significant heart disease, when the heart works hard, it does not get the blood supply and oxygen that it needs (a supply 'n demand mismatch).

    At rest, however, the blood adequately reaches these areas or regions; ANTERIOR/ANTERO (front wall), INFERIOR/INFERO (lower area/lower wall area), POSTERIOR/POSTERO (back wall), SEPTAL/Septum (dividing wall), APICAL/APEX (bottom tip of the heart) and LATERAL (side wall).

    The heart muscle has living cells/tissue in these areas. This indicates that clearing the blockage in the affected artery will be of benefit.


    Perfusion defect AFTER exercise AND at rest (FIXED defect)

    There is one or more totally blocked coronary arteries and one has had damage done to the heart muscle because of a heart attack.

    There is an area/areas of the heart muscle that has become scar tissue (scarring, scarred) because of the heart attack.

    This area would not be able to make functional use of any oxygen even if blood flow to that area of the heart were completely restored.


    Combined reversible and fixed defects

    It is common for individuals with coronary artery disease to have different degrees of blockages in different arteries.

    A heart attack has left a fixed defect in one area of the heart, but there is a reversible defect in another area of the heart due to a less severe blockage.