Ventricular fibrillation masked by the implanted unipolar pacemaker.
D000818:Animals; D002648:Child; D004285:Dogs; D004562:Electrocardiography; D004566:Electrodes; D005260:Female; D006327:Heart Block / Q000628:therapy*; D006801:Humans; D008991:Monitoring, Physiologic; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D014693:Ventricular Fibrillation / Q000175:diagnosis*