Evaluation of myocardial ischemia in Kawasaki disease by dobutamine stress signal-averaged ventricular late potentials.

OBJECTIVE To determine the possibility of diagnosing myocardial ischemia from signal-averaged electrocardiographic late potentials (LPs) in patients with Kawasaki disease. METHODS Dobutamine stress LPs were obtained in 85 children with a history of Kawasaki disease (48 without coronary artery lesions, 19 with coronary artery lesions without myocardial ischemia, and 18 with myocardial ischemia). The infusion of dobutamine was started at 5 micrograms/kg/min, increased to 30 micrograms/kg/min. The presence of LPs was determined by the filtered QRS duration, the root mean square voltage during the last 40 ms, and the duration of the signal under 40 microV. RESULTS Among the children without coronary lesions, LPs were detected in 4.2% at rest and in 2.1% with dobutamine stress. Among the group with coronary lesions but without ischemia, LPs were found in 5.3% at rest and in 5.3% with stress. In the group with ischemia, LPs were present in 44.4% at rest and in 77.8% with stress. The sensitivity for myocardial ischemia was 72.7% at rest and 87.5% with stress (p < 0.05), and the specificity was 86.5% at rest and 94.2% with stress. CONCLUSION LPs associated with dobutamine stress testing are useful for identifying myocardial ischemia in children with Kawasaki disease, especially in those who cannot tolerate testing involving physical exercise.