Patients with either bradycardia or tachycardia may present with signs of decreased cardiac output including fatigue, dizziness, syncope, and sudden death Presentation depends on the rate of the rhythm, the patient’s age, how long the patient has been in the abnormal rhythm, and co-existing conditions such as structural heart disease Infants with dysrhythmias may present with increased crying, poor color, decreased responsiveness, poor feeding, vomiting, wheezing, or tachypnea Abnormal heart rates may be picked up on routine well child visit and subsequently referred to the ED There may be a history of tachycardia in utero or earlier in life Older children and adolescents with tachycardia often state their heart is “beeping” fast In addition, they endorse dizziness, palpitations, fatigue, or sudden onset/offset of symptoms Stomach pain, combativeness, or vomiting may be signs of poor cardiac output due to dysrhythmias Some patients with incessant tachycardia may be asymptomatic and have the abnormality discovered incidentally Rarely older children or adolescents with bradycardia endorse the feeling of the heart beating too slowly Rather, they present with irritability, pallor, combativeness, fatigue, or syncope Triage Any patient presenting with a heart rate that is out of the normal range for age and clinical situation should have full vital signs and perfusion checked The emergency physician should evaluate any symptomatic patient giving special consideration to patients with a cardiac history, pacemaker or implantable cardioverter–defibrillator (ICD), syncope, or history of arrhythmias Initial Assessment/H&P The history should focus on the presence of red flags including previous tachycardia, current medications and adherence to medical therapy, prior response to adenosine, length of symptoms, prior heart operation/catheterization/EP procedure, or presence of a pacemaker or ICD Tachycardia in patients with underlying cardiac dysfunction should raise concern, even if the patient looks well Infants, patients with heart transplant, single ventricle or palliated heart disease, and adults with CHD should also raise the provider’s index of concern The focus of the initial examination is to assess the hemodynamic status using heart rate, perfusion, level of consciousness, tachypnea, and hepatomegaly or other signs of CHF Reviewing prior baseline and tachycardia EKGs aids in analyzing the presenting arrhythmia Often treatment that was effective in prior episodes will be effective again; so if time allows, obtain this information from the medical record or the family