BACKGROUND AND OBJECTIVES: Cardiac troponin I (cTnI) is a sensitive and specific marker of myocardial injury. Although myocardial infarction due to coronary artery occlusion is the most common cause of cTnI elevation, its rise has been reported in non-coronary artery diseases such as paroxysmal tachycardia. This study was conducted to determine the incidence of cTnI elevation in supraventricular tachycardia and to identify the factors associated with the rise in cTnI. SUBJECTS AND METHODS: We studied sixty-nine patients (35 males and 34 females, average age: 59+/-14 years) who were admitted for supraventricular tachycardia without evidence of coronary artery disease between January 2001 and December 2004. Coronary artery disease was excluded on the basis of clinical examinations, non-invasive techniques or coronary angiography. The subjects comprised 31 patients with paroxysmal supraventricular tachycardia, 36 patients with atrial fibrillation and 2 patients with atrial flutter. RESULTS: Serum cTnI elevation was observed in 22 of the 69 patients (31.9%) with supraventricular tachycardia. Multiple regression analysis revealed interventricular septal thickness (p<0.0001), the diastolic left ventricular internal dimension (p=0.0416) and hypertension (p=0.0460) as the significant factors related to cTnI elevation. However, the type or duration of tachycardia, the heart rate during tachycardia and patient's age were not related to cTnI elevation. CONCLUSION: This study showed that cTnI elevation may occur not infrequently in the patients with supraventricular tachycardia even in the absence of coronary artery disease. Myocardial hypertrophy and hypertension were the important factors related to cTnI elevation in this setting.