Electrocardiogram changes pre- and post-ablation (Patient 1). Baseline surface 12-lead resting electrocardiogram prior to ablation (A). There is a short PR interval and delta wave suggesting an accessory pathway; however, no ST-segment abnormalities. B demonstrates the absence of pre-excitation on the 12-lead surface electrocardiogram; however, there is acute ST-segment elevation in leads II, III, and aVF with reciprocal ST-depression in lead aVL, potentially indicating an acute inferior myocardial infarction affecting the right coronary artery territory.