Hi Docs. I had my first post MI Nuclear Stress test. My Rest LVEF: 68% Post-stress LVEF: 53%. I am specifically interested in understanding the distinction and/or implications of the difference between Rest and Post-stress percentages. I’ve been looking at the literature but it is beyond my capacity to interpret. The report says that overall function was normal, and myocardial perfusion was normal. Of course, I am not asking for specific medical advice, just some understanding of what I am looking at. Thank you,
Left ventricular ejection fraction refers to the proportion of blood that is pumped out of the left ventricle with each contraction of the heart muscle. A typical normal ejection fraction is >55% or so.
After injury to this muscle (e.g. after an MI), its contractility may be reduced, which can sometimes be reflected by a reduced ejection fraction.
When the heart is “stressed” (e.g., via exercise or using certain drugs), the heart muscle demands more oxygen, which demands more coronary blood flow (i.e., “perfusion”).
If there are hemodynamically significant coronary blockages (e.g., due to plaque), the distribution of blood flow can be altered during the “stressed” state relative to the “rest” state, such that perfusion defects can be visualized. In other words, this can reveal a section of the myocardial muscle tissue that is not receiving adequate blood flow during “stress” and is thus at risk for infarction. Such a reduction in blood flow to a particular area can also cause local dysfunction of the muscle, causing it to contract more poorly (which can manifest as wall motion abnormalities under stress echocardiography, for example) as evidence of cardiac ischemia.
It sounds like the myocardial perfusion scan you underwent revealed that mild change in LVEF during stress (though still generally considered within normal), but otherwise showed normal perfusion of the heart muscle. Hopefully this makes sense.
Thanks! Very helpful
My rest lvef was > 65% and my post stress lvef was > 77% . is that normal