pathology, most commonly viruses such as coxsackievirus, Epstein–Barr, and cytomegalovirus Clinical features of myocarditis are fever, tachycardia out of proportion to activity or degree of fever, pallor, cyanosis, respiratory distress secondary to pulmonary edema, muffled heart sounds with gallop, and hepatomegaly caused by passive congestion of the liver EKG findings are nonspecific and include low-voltage QRS complexes (less than 5-mm total amplitude in limb leads), “pseudoinfarction” pattern with deep Q waves and poor R-wave progression in the precordial leads, AV conduction disturbances that range from P-R prolongation to complete AV dissociation, and tachyarrhythmias such as VT and SVT A child with palpitations and clinical findings suggestive of myocarditis requires emergent supportive care (see Chapters A General Approach to the Ill or Injured Child and 10 Shock ), echocardiography, consultation with pediatric infectious disease and cardiology, and admission to a unit capable of intensive monitoring and rapid treatment of cardiac arrhythmias and hemodynamic instability Acute rheumatic fever follows pharyngeal streptococcal infection and is an inflammatory disease that targets the heart, vessels, joints, skin, and central nervous system (CNS) Diagnosis and management of acute rheumatic fever are discussed separately (see Chapter 86 Cardiac Emergencies ) A detailed history of recent medications or precipitating events may reveal the cause of palpitations in some patients Ingestion of highly caffeinated beverages (i.e., coffee, soft drinks, energy drinks), cough and cold preparations, herbal preparations, dietary supplements, “health” drinks with herbal additives, use of illicit drugs, and a smoking/vaping history should be ascertained Similar to cigarettes, e-cigarettes, or vape products may contain highly concentrated nicotine and other substances that may cause palpitations The patient’s emotional state before the onset of palpitations should be discussed to determine the likelihood of anxiety or emotional arousal as the cause of symptoms (see Chapter 126 Behavioral and Psychiatric Emergencies ) The presence of diaphoresis, hypertension, and headache may prompt an assessment for pheochromocytoma, whereas widened pulse pressure and thyroid enlargement suggest hyperthyroidism (see Chapter 89 Endocrine Emergencies ) Anemia may be the cause of symptoms in a patient with pallor (see Chapter 93 Hematologic Emergencies )