Asymmetrically thickened posterior wall is associated with decline of ejection fraction after stress on adenosine stress/rest thallium-201 gated myocardial SPECT

LV parameters (LVEF. ESVI and EDVI) on adenosine stress/rest thallium-201 gated myocardial SPECT (gSPECT) are various from stress to rest. We investigated the reason why they were various in patients without coronary artery disease. Seventy-one patients(M:F=32:39, age 58.1±9.7yrs), who underwent gSPECT and coronary angiography (CAG) due to chest pain or preoperative evaluation were included. CAG results were normal or insignificant. Exclusion criteria were atrial fibrillation, thyroid disease, primary cardiomyopathy, myocardial bridge, LBBB, MI, and valvular heart disease. Patients were calssified into 3 groups by EF difference (ΔEF=rest-stress EF) on gSPECT : group1 (ΔEF≥10), group2 (0 ≤ΔEF<10), and group3 (ΔEF<0). LV parameters on gSPECT and thicknesses of IVS (interventricular septum) and LVPW (left ventricular posterior wall) on echocardiography were compared among the 3 groups. Myocardial perfusion status were normal or mild reversible/persistent perfusion defect in 76.1% (54/71). LVEFs at stress were not different among all 3 groups : 59.3±8.54% in group 1 (61.3±10.22% in group 2 and 64.8±7.58% in group 3 (p>0.05). But LVEF at rest was smaller in group 3 (58.7±8.38%) than the other groups (72.5±8.77% in group1 and 66.7±10.6% in group2) (p<0.01). EDVIs and ESVI at stress were larger than those at rest in all groups (p<0.05) except ESVI in group 3 (16.2±6.21ml at stress and 17.5±6.41ml at rest, p<0.01), and that was attributed to EF<0 in group 3. In echocardiographical analysis, group 3 had significantly increased wall thickness of LVPW (10.7±1.2mm versus 9.4±1.6mm, p=0.01) and decreased wall thickness ratio of IVS/LVPW (0.963±0.102 versus 1.048±0.104, p=0.035) than group 1. In patients without coronary artery disease, LVEF, EDVI and ESVI on gSPECT were various and decline of LVEF from stress to rest was caused by unnormalized ESVI . Asymmetrically thickened LVPW may play a crucial role and further investigation is warranted