OBJECTIVES We explored the association of noncoronary cardiac abnormalities with coronary artery dilation and with laboratory inflammatory markers early after Kawasaki disease (KD) diagnosis. BACKGROUND Left ventricular (LV) dysfunction, mitral regurgitation (MR), and aortic root dilation occur early after diagnosis; their associations with coronary artery dilation and inflammatory markers have not been well-described. METHODS Centrally interpreted echocardiograms were obtained at KD diagnosis and 1 and 5 weeks after diagnosis on 198 subjects in the National Institutes of Health-sponsored Pediatric Heart Network KD pulsed steroid trial. Regression models were constructed to investigate the relationships among early LV dysfunction, MR, and aortic root dilation with coronary artery dilation and laboratory inflammatory markers. RESULTS At diagnosis, LV systolic dysfunction was present in 20% of subjects and was associated with coronary artery dilation, seen in 29% (p = 0.004). Although LV dysfunction improved rapidly, LV dysfunction at diagnosis predicted greater odds of coronary artery dilation at 1 and 5 weeks after diagnosis (5-week odds ratio: 2.7, 95% confidence interval: 1.2 to 6.3). At diagnosis, MR was present in 27% of subjects and aortic root dilation was present in 8%; each was associated with larger coronary artery size at diagnosis. Left ventricular dysfunction was associated with higher erythrocyte sedimentation rate and, at diagnosis only, lower serum albumin; MR was associated with higher erythrocyte sedimentation rate and lower albumin at all times. Aortic root size had little association with inflammatory markers. CONCLUSIONS Noncoronary cardiac abnormalities are associated with coronary artery dilation and laboratory evidence of inflammation in the first 5 weeks after KD, suggesting a shared inflammatory mechanism. (Trial of Pulse Steroid Therapy in Kawasaki Disease [A Trial Conducted by the Pediatric Heart Network]; NCT00132080).