CHAPTER 63 ■ PALPITATIONS STEVEN C ROGERS, ANDREW T HEGGLAND INTRODUCTION Heart palpitations can most easily be characterized by the perception of an abnormal heartbeat or heart rate (HR) by the patient Descriptions commonly given include heart “racing,” “pounding,” “fluttering,” “beating irregularly,” or a sensation of the heart “stopping” intermittently In children, most etiologies of palpitations are benign but are often accompanied by significant anxiety Pediatric patients demonstrate great variability in sensitivity to changes in HR or rhythm A child who has trivial cardiac events may express severe symptoms while one with a significant arrhythmia may remain asymptomatic The challenge is to determine which complaint can be managed in the emergency department (ED) and which merits urgent consultation and/or further evaluation by a cardiologist PATHOPHYSIOLOGY The heart is innervated by the vagus nerve (cranial nerve X) and the sympathetic ganglia Cardiovascular reflexes (e.g., vasovagal bradycardia) are transmitted by the vagus nerve Pain sensation (e.g., related to myocardial ischemia) travels through afferent fibers associated with the sympathetic ganglia In most patients, the sensation of the heartbeat is not felt Children with documented arrhythmias, such as supraventricular tachycardia (SVT) and stable ventricular tachycardia (VT), may not complain of any symptoms Even patients with heart murmurs audible to the unassisted ear can learn to ignore this obvious cue Patients with palpitations often report a perception of increased force of cardiac contraction, tachycardia, or irregular heartbeat Increased force of the contraction is better detected when the patient is supine At times, it may be described as a rushing or pounding in the ears, particularly when the ear is pressed against a pillow Caffeine or alcohol consumption, illicit drug use, exercise, and emotional excitement can produce this same sensation Patients with premature contractions and a compensatory pause may