Dextrocardia as an uncommon cause of inferior ST-segment elevation.

A 36-year-old woman with surgically repaired transposition of the great vessels was admitted with psychiatric symptoms. The 12-lead ECG showed ST-segment elevation in the inferior leads, a positive P wave in aVR, and an absent R wave progression in the precordial leads. The findings were attributed to atrial repolarization (Ta) waves in the setting of dextrocardia and low atrial rhythm, causing ST-segment elevation in the inferior leads. No cardiac symptoms were present, and additional tests ruled out ischemia. Atrial repolarization waves are typically imperceptible on ECG but can become evident in certain conditions, such as low atrial rhythm. This case represents a rare coexistence of dextrocardia and ST-segment elevation due to an inverted atrial repolarization wavefront in the setting of low atrial rhythm. Recognizing this pattern is essential to prevent misdiagnosis and avoid unnecessary procedures.