The impact of Kawasaki-related coronary injury on the myocardium was evaluated in 13 patients with persistent coronary aneurysm after a follow-up period of 7.92 ± 3.97 years (range 1.8 to 14.3). Myocardial segmental perfusion and contractility integrity were assessed by resting and exercise echocardiography and technetium-99 (Tc-99m) sestamibi scan. Eight patients (61.5%) had giant aneurysms (≥8 mm) and 9 had multivessel involvement; the mean diameter of the largest aneurysm was 8.6 ± 2.5 mm (range 5 to 14). During the acute phase, myocardial infarction occurred in 1 patient and coronary thrombosis in another. At the latest echocardiographic evaluation, the mean aneurysm diameter was 6.8 ± 2.4 mm (range 4.5 to 12), there was persistent giant aneurysms in 5 of 8 patients, and 3 of 9 patients had multivessel involvment. Coronary angiography demonstrated stenosis in 7 of 10 patients, with multiple levels in 2. At sestamibi scan, all 13 patients had perfusion anomalies at rest, whereas only 7 had detectable hypokinesia on echocardiography. With exercise, perfusion returned to near normal in 3 patients, improved in 3, remained unchanged in 4, and worsened in 3 patients. Segmental contractility similarly deteriorated in the latter 3 patients but also in 2 patients whose perfusion scan had improved with exercise. Three patients, normal at rest, developed segmental hypokinesia during exercise. When present, the location of observed changes in contractility on stress echocardiography corresponded to that of perfusion defect. In conclusion, abnormal myocardial perfusion is present long term after complicated Kawasaki disease, the worst anomalies accompanying persistent giant aneurysms. Unfavorable perfusion response was coupled with abnormal contractility; however, enhanced perfusion with exercise correlated poorly with segmental contractility response.