SUMMARY
BACKGROUND: Tachycardia-induced cardiomyopathy (TIC) is a rare cause of dilated cardiomyopathy (DCMP). The diagnosis can be missed because tachycardia is a common symptom in DCMP. CASE REPORT: We reviewed a case 5-year-old with palpitation and dyspnea with symptoms and signs of heart failure that diagnosed as DCMP initially. Then, in the evaluation for cause of tachycardia, atrial tachycardia was detected. Hence, treatment with flecainide was started and after 3 months, left ventricular (LV) systolic function and symptoms of the patient was relieved. CONCLUSION: TIC should be suspected in all patients with unexplained LV dysfunctions in the setting of a persistent tachyarrhythmia. Keywords: Dilated Cardiomyopathy, Heart Failure, Tachyarrhythmia