The abnormal function of the posteromedial wall of the left ventricle on gated myocardial SPECT is associated with ischemic mitral regurgitation after acute myocardial infarction

Objectives: The findings of gated myocardial SPECT (GM-SPECT) according to the presence of ischemic mitral regurgitation (IMR) after acute myocardial infarction (AMI) have not been well studied. The purpose of this study was to find GM-SPECT findings that were associated with IMR after AMI. Methods: The subjects were 51 patients with first AMI and without valvular heart disease who underwent both echocardiography (Echo) and adenosine stress 99mTc-tetrofosmin GM-SPECT within 3 days. IMR was present in 13 (25.5%) of the patients. Demographics, presence of risk factors, findings of Echo, coronary angiography, laboratory examinations, and GM-SPECT were compared according to the presence or absence of IMR using univariate and multivariate analyses. Results: There was no difference of demographics, risk factors, coronary angiographic or laboratory findings in two of the groups. Left ventricular (LV) ejection fraction and LV volume were the same in both groups. Abnormal systolic function of the posteromedial wall of the LV where posterior papillary muscles insert was more frequent in the IMR group as compared to the non-IMR group (92.3% vs 44.7%, p=0.003). Abnormal perfusion to the posteromedial LV wall (84.6% vs 52.6%, p=0.04), and abnormal systolic function of the anterolateral LV wall where the anterior papillary muscles insert (69.2% vs 31.6%, p=0.02) were also associated with IMR. In a multivariate analysis, the presence of IMR was significantly associated with the abnormal systolic function of PMW (p=0.043). Conclusion: The presence of IMR is associated with an abnormal systolic function of the posteromedial LV wall where posterior papillary muscles insert