Background: In 2012, the reported number of dengue fever cases in Indonesia were 90.245, with a mortality rate reached 0.88%. Cardiac complications are uncommon in dengue virus infection, but it can be occurring. Myocarditis is the most common cardiac complication reported worldwide. Case: We report 10 cases of dengue virus infections with ECG abnormalities in normal heart structure. Based on ECG test during the covalescent stage, sinus arrhythmias were present in 3 patients, sinus bradycardia in 3 patients, sinus tachycardia without fever in 1 patient, first-degree AV block in 2 patients and mobitz type I second-degree AV block in 1 patient. The ECG abnormalities which were found in all cases did not cause any clinical symptoms, then no medication were needed. Continues clinical monitoring was done in all of our cases, and ECG evaluation showed improvement after several days. Conclusions: Myocarditis following dengue infection was clinically diagnosed in some asymptomatic children and need a ECG evaluation. Continues monitoring needed in patient who develop cardiac rhythm abnormalities and all the patient completely recovery.