Background: Prolonged regional relaxation and delayed endocardial motion precede systolic dysfunction in myocardial ischemia. Color Kinesis (CK) allows direct quantification of the timing of regional endocardial motion. Our aim was to determine whether Color Kinesis could detect regional diastolic dysfunction at rest in patients with coronary artery disease (CAD) and no echocardiographic evidence of regional wall motion abnormality.Methods: We studied 29 normal subjects and 14 patients with CAD. Regional diastolic endocardial motion was quantified using custom software applied to diastolic CK images, which resulted in regional LV filling time-curves. For each segment, curves obtained in normal subjects were averaged to generate a normal range for comparisons with individual patients' data. Regional filling curves were correlated with the findings of coronary angiography on a segmental basis. Significant coronary stenosis was defined as =< 70% luminal narrowing.Results: Delayed early diastolic endocardial motion was detected in 37168 segments, all supplied by stenotic coronary arteries. In 6 patients, 16168 segments showed normal regional filling curves despite significant stenosis. Three of these six patients had evidence of collateral circulation in the affected segments. The remaining 115 segments had normal filling curves and no significant coronary stenosis.Conclusions: Quantitative CK allows objective detection of regional diastolic dysfunction in patients with CAD and no evidence of regional wall motion abnormality at rest.