['The aims of this study were to evaluate myocardial mechanics using pulsed tissue Doppler imaging (TDI), and to determine the relationship between abnormal myocardial performance and plasma brain natriuretic peptide (BNP) levels and oxidative stress in acute Kawasaki disease (KD).', 'Consecutive TDI parameters, including peak systolic velocity (Sw) and early (Ew) and late diastolic excursion of the mitral annuli were obtained in 42 patients with KD (mean age: 2.4+/-0.4 years) in weeks 1, 2, and 3, and during convalescence. Plasma BNP level and urinary 8-isoprostane were also examined during the acute phase. These data were then compared with TDI profiles from 62 healthy children, plasma BNP levels in 38 controls with other febrile illnesses, and urinary 8-isoprostane levels in 13 healthy children. Ew in week 1 was significantly lower than in controls, subsequently normalizing in the convalescent stage. Plasma BNP level in acute KD patients was significantly higher (65+/-9 pg/ml) than in controls (13+/-2 pg/ml). Urinary 8-isoprostane level in acute KD patients was significantly higher as compared with control (596 +/-37 vs 379+/-26 pg/ml Cr, p<0.05). There was a significant negative correlation between week 1 Sw and plasma BNP level (r=-0.55, p=0.0001). Change in Sw velocity in the BNP >/=51 group was significantly greater than in the BNP <51 group. There was a significant negative correlation between week 1 Sw and urinary 8-isoprostane level (r=-0.48, p=0.001).'] Are abnormal tissue doppler images associated with elevated plasma brain natriuretic peptide and increased oxidative stress in acute Kawasaki disease?