Identification of viable myocardium in patients with chronic coronary

Abstract

Low-dose dobutamine stress echocardiography (LDDSE) is one of the methods most used to assess myocardial viability. Glucose-insulin-potassium (GIK) has been shown to increase contraction of the ischernic zone. The aim of this study was to compare LDDSE and echocardiography during GIK infusion for detection of myocardial viability in patients with chronic coronary artery disease (CAD) and myocardial dysfunction. Twenty-one patients who had chronic CAD and myocardial dysfunction were included in the study. Glucose-insulin-potassium protocol consisted of a fixed dose of insulin (100 muU/kg/hour IV) and a variable glucose/potassium infusion rate. GIK echocardiography was made at baseline and after 60 minutes of GIK infusion. During continuous electrocardiographic, blood pressure, and echocardiographic monitoring, an intravenous infusion of dobutamine (3 mug/kg body weight/min) was started with an infusion pump and continued for 5 minutes and then increased to 5 mug/kg/min and 10 mug/kg/min for another 5 minutes. The detected viable myocardium was defined as I or 2 scores decreasing in at least 2 adjacent abnormal segments during LDDSE and GIK echocardiography. Viability was detected in 19% (52 segments) of the asynergic segments at baseline with GIK echocardiography and 16% (44 segments) of those segments with LDDSE (p > 0.05). Left ventricular wall motion score index at baseline was 2.24 +/- 0.35 and it decreased significantly during both LDDSE (p=0.004 vs 2.11 +/- 0.36) and GIK echocardiography (p=0.001 vs 2.09 +/- 0.32). The agreement between LDDSE and GIK echocardiography for detection of myocardial viability was 95%. This study shows that GIK echocardiography is similar to LDDSE for detection of myocardial viability. With the support of further clinical studies GIK echocardiography can be used to detect myocardial viability in patients with chronic CAD.