Abnormal myocardial mechanics in Kawasaki disease: Rapid response to gamma-globulin

Background The time course and rate of recovery of myocardial dysfunction i n association with Kawasaki disease inl response to intravenous gamma-globu lin is unknown and may provide mechanistic clues. Methods and Results The acute changes in myocardial contractility in 25 pat ients with Kawasaki disease were evaluated by noninvasive stress-shortening and stress-velocity analysis. Echocardiograms were performed before and th en daily for 4 days during which the patients received gamma-globulin 1.6 t o2 g/kg, Before treatment, contractility was abnormally low (<2 SD) in 14 p atients (56%). Contractility increased significantly (SD-increase) in 17 (6 8%), including 13 of 14 with depressed contractility and 4 whose initial co ntractility fell within normal limits. Of the 14 patients with depressed co ntractility, 8 (57%) normalized within 24 hours and a further 5 (35.7%) nor malized within 6 months. A clinical response to treatment (fall in C-reacti ve protein by 50% and/or resolution of fever within 4 days) was seen in 22 patients (88%). Contractility increased in 17 of the 22 clinical responders and was normal before therapy in the other 5. The 3 patients who did not r espond clinically also had no change in contractility with gamma-globulin t herapy. Long-term (more than 12 months) follow-up was available in 19 patie nts. All patients had normal contractility at late follow-up. Conclusions More than half the patients with Kawasaki disease have abnormal contractility at presentation. Myocardial response to gamma-globulin thera py is associated with rapid improvement in myocardial mechanics, with a hig h concordance between the clinical and myocardial response to therapy. The speed of recovery suggests that depressed contractility in patients with Ka wasaki disease is caused by a rapidly reversible process such as circulatin g toxins or activated cytokines, long-term outcome is good even in those pa tients with slow recovery of myocardial function.