Background: Kawasaki Disease (KD) is a common cause of acquired heart disease in children and may present with life threatening cardiovascular complications. Electrocardiogram (ECG) changes in KD are usually non-specific. Coronary artery (CA) abnormalities may lead to myocardial infarction and manifest as ST segment elevation, T wave inversion or abnormal Q waves.
Methods: We describe 4 children with significant ECG changes during the acute phase of illness but different severity of CA aneurysms. Q wave is considered significant if > 5mm in depth and > 0.04 second, ST segment elevation > 1 mm is significant.
Results: We had 2 infants with KD and bilateral multiple large CA aneurysms (risk level IV) with thrombus in their right CA aneurysms. Both had deep Q wave of 7mm and one also had ST segment elevation in leads II, III, and aVF. Both had raised Troponin T levels and normal creatinine kinase. They received antithrombotic agents in addition to antiplatelet treatment. Thrombi resolved after treatment. Two other patients had bilateral moderate multiple CA aneurysms (risk level III)without thrombosis. Their cardiac enzymes were normal. However, they had significantly deep Q wave or ST segment elevation in leads II, III, and aVF. All 4 patients had normal ventricular function throughout the course of their illness. One patient had myocardial perfusion scan and was normal. Their ECGs normalized on follow-up.
Conclusion: Deep Q waves and mild ST segment elevation in children with KD and moderate to large CA aneurysms are non-specific and may not indicate myocardial infarction.