Figure 1. Reversal of Arm Electrodes

At first pass, the ECG is notable for sinus rhythm with T wave inversion in leads I, aVL, and II. Closer scrutiny reveals an inverted P wave, QRS complex, and T wave in lead I, as well as a �normal� appearing complex in lead aVR. These findings, together with normal precordial lead complexes, signify RA/LA electrode reversal. Dextrocardia is excluded due to the normal R wave progression across the precordium.