Myocardial Stunning During Gated Spect Indicates Presence of Severe Coronary Artery Disease. Biswas,G.** Shukkur, A.M.* Sayed, M.** Alsayed, Y.** and Masoud, M.** Department of Nuclear Medicine **and Cardiology*, Chest Hospital, Kuwait.

Transient left ventricular dysfunction is known to occur in patients following stress in coronary artery disease [CAD]. Also known as myocardial stunning, it is a transient phenomenon occurring during myocardial ischemia after treadmill exercise or pharmacological stress. Our aim was to show that myocardial stunning observed during gated SPECT [GSPECT] is a powerful indicator of severe CAD.
Patients and methods: Sixty two patients with chest pain underwent two days stress/rest Tc-99m-Tetrofosmin GSPECT studies. Using a twenty segment, five point scoring model, summed stress score [SSS], summed rest score [SRS] and summed diffence score [SDS] was calculated for severity of perfusion defects. LV function parameters were evaluated by calculating LVEF and performing visual analysis of regional wall motion [RWM] and regional wall thickening [RWT] after stress and rest. Results of perfusion were classified into severely ischemic [SDS>6], mild to moderately ischemic [SDS 2-6] and normal perfusion [SDS0-1] groups.
Results: In the patient group who showed severe ischemia [SDS>6] on the perfusion study also showed significant fall of mean global LVEF values with RWT and RWM abnormalities in ischemic myocardial segments after stress on the GSPECT study when compared to patient groups with mild to moderate ischemia [SDS 2-6] and patients with normal perfusion [SDS 0-1].
Conclusion: Patients with features of myocardial stunning during gated SPECT are likely to have severe coronary artery disease and should be considered for early revascularization.