Prediction of recovery of left ventricular dysfunction after acute myocardial infarction: Comparison between Tc-99m-sestamibi cardiac tomography and low-dose dobutamine echocardiography

The aim of this study was to evaluate the role of Tc-99m-sestamibi cardiac imaging and dobutamine echocardiography in detecting myocardial viability e arly after acute myocardial infarction. Methods: Forty-nine patients (mean age 52 +/- 10 y) underwent coronary angiography, low-dose dobutamine echoca rdiography, radionuclide angiography and rest Tc-99m-sestamibi imaging with in 10 d after myocardial infarction. Of these patients, 19 were revasculari zed and 30 were treated medically. Resting echocardiogram and radionuclide angiography were repeated 8 mo later to evaluate segmental functional recov ery and changes in left ventricular (LV) ejection fraction, respectively. R esults: In revascularized patients, 61 of 108 akinetic or dyskinetic segmen ts showed functional recovery. In these patients, sensitivity in predicting segmental functional recovery was 87% for sestamibi imaging and 66% for do butamine echocardiography (P < 0.001), whereas specificity and accuracy wer e comparable. Sestamibi activity (greater than or equal to 55% of peak) was the strongest predictor of segmental functional recovery (P < 0.001) and o f LV ejection fraction improvement greater than or equal to 5% (P < 0.01) a fter revascularization. In medically treated patients, 60 of 149 akinetic o r dyskinetic segments showed functional recovery. In these patients, the ma jority (94%) of segments with contractile reserve on dobutamine were viable on sestamibi imaging and 86% of them improved function at follow-up. Funct ional recovery was poor in segments without contractile reserve either with (38%) or without (62%) preserved sestamibi uptake. Inotropic response was the best predictor of segmental (P < 0.001) and global (P < 0.01) LV functi onal improvement in medically treated patients. Conclusion: Dobutamine echo cardiography predicts spontaneous functional recovery after acute myocardia l infarction. However, sestamibi imaging is useful to identify patients wit h dysfunctional myocardium without contractile reserve who may benefit from coronary revascularization.