Valvular heart disease in Kawasaki syndrome: incidence and natural history.

To elucidate the incidence and natural history of valvular heart disease in Kawasaki syndrome, we analyzed patients who were found to have a new heart murmur after the onset of the disease. Among 1215 patients we found 13 (1.1%) with valvular disease (12 with mitral regurgitation and one with aortic regurgitation). We compared these patients with 30 who did not have valvular lesions. The duration of fever was longer and the incidence of coronary artery lesions significantly higher than in those without valvular disease. Heart murmurs disappeared within 2 months after the onset of valvular heart disease in five patients, whereas in another six, all involving valve prolapse, they persisted for 2 years or more. We postulate that two different mechanisms may be responsible for the variation in the duration of valvular heart disease: one, which disappeared spontaneously, was attributed to pancarditis; the other, which persisted, was due to dysfunction in valve and papillary muscles as a result of ischemia.