Balanced myocardial ischaemia

Balanced myocardial ischaemia If all three major coronary branches have similar degree of stenosis, the radionuclide used for perfusion study will have equal uptake in all regions of the myocardium. Thus a balanced three vessel coronary artery disease can produce a false negative myocardial perfusion scan. This situation is called balanced myocardial ischemia. In most cases this is picked up by the treadmill ECG usually done along with stress myocardial perfusion imaging. Since the ECG findings of myocardial ischemia does not depend on the relative perfusion in the coronary tree, ischemic changes will be noted in treadmill ECG even when nuclear perfusion study shows false negative due to balanced myocardial ischemia. In a case reported in Heart [1], adenosine technetium (Tc99) setamibi scan showed no resting or stress induced perfusion defects in an elderly person with stable exertional chest pain. But ST segment depression was noted on the ECG. Coronary computed tomography (CT) angiogram showed severe calcified ostial left main lesion, which was further confirmed by invasive coronary angiography. The patient underwent successful coronary artery bypass surgery. In another case report published in Heart International, there was triple vessel coronary artery disease including 95% distal left main stenosis, with markedly positive stress ECG and a negative SPECT 99m-sestamibi scintigram [2]. This patient also underwent successful coronary artery bypass surgery. Other potenti...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: Nuclear Cardiology Source Type: blogs