Detection of regional temporal abnormalities in left ventricular function during acute myocardial ischemia

Echocardiographic diagnosis of myocardial ischemia is based on visualizing hypokinesis, which occurs late in the ischemic cascade. We hypothesized tha t temporal changes in endocardial motion may constitute sensitive early mar kers of ischemia. Two protocols were performed in 19 anesthetized pigs. Pro tocol 1 included 54 intracoronary balloon occlusions. Transthoracic images were acquired at baseline and every 15 s during 5 min of occlusion and repe rfusion. In protocol 2, ischemia was induced in 12 animals by use of graded dobutamine infusion, after creating significant partial occlusions without a resting wall motion abnormality. Systolic and diastolic endocardial moti on was color encoded using color kinesis and analyzed using custom software . All ischemic episodes caused detectable and reversible changes. The earli est sign of ischemia was tardokinesis in 31/54 occlusions, whereas hypokine sis appeared first in 23/54 cases. Dobutamine-induced ischemia caused tardo kinesis first in 9/12 and hypokinesis in 3/12 animals. Reversible ischemic changes in regional left ventricular performance can be objectively detecte d using analysis of echocardiographic images and will likely improve the ea rly noninvasive diagnosis of acute ischemia.