Effects of low-dose dobutamine on displacement of the atrioventricular plane and assessment of myocardial viability in patients with acute myocardialinfarction treated with thrombolysis

Previous echocardiographic studies have highlighted the usefulness of atrio ventricular (AV) plane displacement (the mitral annular motion) in assessin g left ventricular function, at rest. However, the effects of lour-dose dob utamine on AV plane displacement in thrombolyzed patients with acute myocar dial infarction (AMI) are unknown. Thirty-four patients with AMI treated wi th a thrombolytic agent and having rest wall motion abnormalities at the in farct site were studied with rest and low-dose dobutamine echocardiography before discharge. Thirty-one patients were followed up 18 months later with rest echocardiography. The systolic descent of the AV plane toward the ape x at four different left ventricular sites (i.e., at the septal, anterior, lateral, and inferior walls) was recorded to assess left ventricular functi on. Compared with age-matched healthy subjects, the AV plane displacement w as significantly reduced, especially at the infarct sites, in AMI patients at rest. During Lour-dose dobutamine, the AV plane displacement was increas ed at infarct sites (P < 0.001) in patients with signs of viability. A cuto ff point of art increase in AV plane displacement of greater than or equal to 2 mm at the infarct sites during low-dose dobutamine stress had a sensit ivity of 89% and a specificity of 87% in assessing myocardial viability. Us ing the same cutoff point of a spontaneous increase in the AV plane displac ement of greater than or equal to 2 mm during the follow-up rest echocardio graphy, 87% of the patients with initial signs of viability and only 25% wi thout signs of viability showed a spontaneous late recovery of initially st unned myocardium. Thus, the study shows that changes in the amplitude of th e AV plane displacement during low-dose dobutamine stress echocardiography can, easily be used to detect myocardial viability at an early stage with l ate potential spontaneous recovery.