This 42-year-old man presents to the Emergency Department with atypical pleuritic chest pain, on and off for a few seconds at a time:

Negative P-waves in lead I are initially suggestive of Right Arm-Left Arm lead reversal, but the unusual P-wave axis in leads V1 and V2 coupled with the unusual QRS progression from V2 to V6 with decreasing voltage are all compatible with dextrocardia.

Following confirmation of dextrocardia with a CXR (see next tab), an ECG tracing with reversal of Right Arm-Left Arm and recording of right sided chest leads should be performed:

His chest x-ray went on to confirm the diagnosis of dextrocardia.