Objective: To compare the safety, sensitivity, specificity and accuracy of low dose dobutamine (Dob), isosorbide dinitrate and their combination in stress echocardiography to predict regional movement recovery after coronary revascularization (CRV) in patients with old myocardial infarction (OMI) and severe left ventricular dysfunction.
Methods: Fourty patients (mean age 52 +/- 8 years, male 39, female 1) with OMI waiting for CRV with mean left ventricular ejection fraction (LVEF) (39.4 +/- 5.1)%, underwent Dob (3, 5 and 10 microg.kg(-1).min(-1)), isosorbide dinitrate (270 +/- 56) microg/min and their combination (nitrate plus Dob 3, 5 microg.kg(-1).min(-1)) stress echocardiography. Twenty-six patients completed follow-up rest two dimension echocardiography (2DE) (6.8 +/- 2.9) months after CRV.
Results: During Dob 2DE, side effects rates increased by dosage, the drug even induced ischemia at a dosage of 10 microg.kg(-1).min(-1). When Dob was combined with nitrate, no ischemia happened. Among 272 abnormal segments in 26 patients after CRV, 156 segments showed contractile improvement. In Dob 2DE, both the sensitivity (46.8% to 88.6%) and accuracy (64.1% to 77.9%) increased by dosage gradient, while the specificities decreased from 87.1% to 64.2%. When combined with nitrate, the sensitivities and accuracy were higher than either drugs used alone (P < 0.05). The detecting effect in isosorbide dinitrate + Dob 5 microg 2DE was comparable to that of Dob 10 microg.kg(-1).min(-1) 2DE.
Conclusions: In identifying myocardial viability in patients with OMI and severe left ventricular dysfunction, Dob 5-10 microg.kg(-1).min(-1) 2DE have good detecting effects, but could induce ischemia. When nitrate was combined with Dob, no ischemia happened, and the sensitivity and accuracy improved significantly. Isosorbide dinitrate + Dob 5 microg.kg(-1).min(-1) 2DE has identifying effect comparable to Dob 10 microg.kg(-1).min(-1) 2DE.