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ECGs in the ED.

CASE A 10-year-old boy presents to the Emergency Department for evaluation of palpitations. He began having intermittent palpitations 2 years ago. They initially occurred once every 3 months and terminated spontaneously within 5 to 10 minutes. They now occur at least once per month and last longer. The current episode started 2 hours ago. He initially felt dizzy with the abrupt onset of the episode, but now he feels well other than appreciating a rapid heart rate. There has been no chest pain, shortness of breath, or syncope. The triage nurse reported that the heart rate was Btoo fast to count[, but as he was being brought to an exam room he reported that the episode stopped. The past medical history is noncontributory. There have been no significant intercurrent illnesses. The boy takes no medications and has no significant caffeine intake. He has no known drug allergies. The family history is noncontributory for congenital heart disease, arrhythmias, or sudden death. The patient attends fifth grade and plays football and basketball without limitations. In the Emergency Department, the boy is pink and in no distress. The pulse is 68 bpm and the respiratory rate is 20 per minute. The blood pressure is 108/62 in the right arm. The head and neck exam is unremarkable. The tympanic membranes and oropharynx are clear. The neck is supple. The chest is clear to auscultation. The cardiac exam has a regular rhythm with a normally active precordium. There is a normal first heart sound and soft, physiologically splitting second heart sound. There is no gallop, rub, or murmur. The pulses are full and equal. The abdomen is soft and nontender. There is no organomegaly. The extremities are warm and well-perfused. The neurologic exam is nonfocal. An electrocardiogram was performed (Fig. 1).