Predictive accuracy of dobutamine stress echocardiography for identification of viable myocardium in patients with severely reduced left ventricular ejection fraction

Low dose dobutamine stress echocardiography (LDDE) is an established method for identification of contractile reserve (CR) as a marker of viable myocardium in pts with CAD and LV dysfunction, with excellent positive and negative predictive values. Whether the diagnostic accuracy of LDDE is maintained in pts with severely reduced LVEF is uncertain. We evaluated 20 pts with CAD and LV dysfunction who underwent LDDE before revascularization (RVSC) with follow-up echocardiography after RVSC (mean 89 days). Wall motion at rest, during LDDE (mean dobutamine dose 9.5±2.8 mcg/kg/min), and follow-up was analyzed semi-quantitatively using a 5 point scoring system. Contractile reserve and recovery of function was defined as improvement in resting wall motion score > 1. Pts were divided into 2 groups based on pre-RVSC LVEF > 30% (n=10) and LVEF <30% (n=10). Segments with severe hypokinesis, aldnesis, and dyskinesis under basal condition in the revascularized territory (total 159 segments) were analyzed during LDDE and at follow-up. Age Male CABG LVEF CR PPV NPV (yrs) (0%) (%) (%) (segs/pt) (%) (%) LVEF≥30% 64±10 7(70) 8(80) 34±3 2.3±5.6* 78.3 80.0 LVEF<30% 66±11 8(80) 6(60) 25±4 6.1±19.2 83.6 71.8 *p=0.03 vs LVEF<30%; PPV-positive predictive vajue; NPV=negative predictive value. These data indicate that LDDE retains acceptable predictive accuracy in pts with severely reduced LVEF and is an excellent method for assessing myocardial viability in these pts.