Although computerized electrocardiogram (ECG) interpretation is a valuable and widespread clinical aid, it can be imperfect.1,2 The case of a 47-year-old man who presented to our emergency department with increasing dyspnea illustrates why an expert in electrocardiography must confirm all computer ECG analyses. The patient’s medical history included nonischemic cardiomyopathy and atrial fibrillation. He denied chest pain, palpitations, nausea, and diaphoresis.