Low Dose Dobutamine And Isoket Stress Echocardiography For Identifying Viable Myocardium In Patients With Old Myocardial Infarction And Severe Left Ventricular Dysfunction

Objective: (1) This study was sought to compare the detection rate, accuracy and safety of low dose dobutamine (LDD) and its combination with Isoket stress echocardiography (SE) with ^99mTc-MIBI / ¹⁸FDG myocardial SPECT image for identifying viable myocardium and predicting its functional improvement after coronary revascularization (CRV) in patients with old myocardial infarction (OMI) and severe left ventricular dysfunction; (2) to evaluate the characteristics of and the relationship among the blood perfusion, celluar metabolism and contractile reserve of viable and nonviable myocardium in patients with OMI and severe left ventricular dysfunction; (3) to evaluate the effects of CRV on left ventricular remodeling attenuation and its global function recovery sa well as the related affecting factors. Methods: Forty patients with OMI and severe left ventricular dysfunction (mean left ventricular ejection fraction, LVEF 39.4%±5.1%) were enrolled in this study. All the patients underwent LDD, Isoket and their combination SE and DISA SPECT within one week.(1) Isoket and its combination with LDDSE. Before the test, beta-adrenergic blockades, calcium antagonists, nitrates and inotropic drugs were discontinued at least 18 hours. Heart rate (HR), blood pressure (BP) and electrocardiogram (ECG) were recorded at rest and monitored during the whole test. On Hewlett-Packard sonos 100 CF, Image Point and 5500 imaging systems, the standard long-axis, short-axis in three levels and three apical 2DE views (BASE 1) were aquired and recorded in videotapes. Then Isoket was infused intravenously with intitial dose of 60μg/min and increased every 3 minutes at the same dosage until the systolic BP decreased by 5-10 mmHg,...