- Dysrhythmias in children are classified according to rate, QRS width, and clinical stability.
- Sinus bradycardia in the neonate always requires aggressive investigation and prompt resuscitation.
- Infants with paroxysmal supraventricular tachycardia (PSVT) may present in a low output state with irritability, poor feeding, tachypnea, and diaphoresis.
- Vagal maneuvers and adenosine convert most episodes of PSVT. Verapamil is contraindicated in children <2 years of age.
- Accessory pathway is the most common mechanism for PSVT in the child, but is difficult to appreciate during PSVT. Digoxin may precipitate ventricular tachycardia (VT) and is only used under the supervision of a pediatric cardiologist.
- Atrial fibrillation or flutter associated with accessory pathway disease or hypertrophic cardiomyopathy puts a child at high risk for 1:1 conduction, ventricular tachycardia, and sudden death.
- The electrocardiogram (ECG) is important in the evaluation of the syncopal patient, looking for wide complex tachycardia, long QT syndrome (QTc > 0.46s), or hypertrophic myocardopathy (LVH).
Disorders of rate and rhythm are fortunately rare in the pediatric population. Supraventricular tachycardias (SVTs) have predictable etiologies based on age. Rhythm disturbances, such as sinus bradycardia, can be life-threatening in the neonate.
Dysrhythmias in children are usually the result of cardiac lesions with a poorer prognosis than patients with structurally normal heart. Noncardiac causes, such as hypoxia, electrolyte imbalance, toxins, and inflammatory disease, must be considered in the child, as should cardioactive drugs, such as digoxin or over-the-counter cold remedies. Initial evaluation of the child with idiopathic or unexplained dysrhythmia includes an echocardiogram.
Age is an important consideration in the child with dysrhythmia. Some ventricular dysrhythmias disappear with age. Other conditions associated with an escape pacemaker worsen with age. The ventricular rate in third-degree heart block may be adequate for the 2-month-old child but will not provide an adequate cardiac output for the child at age 12. Age is also a factor in the clinical presentation of the dysrhythmia. The infant may present with poor feeding, tachypnea, irritability, or signs of a low output state. Caregivers often note that their baby is “not acting right.” The older child presents with specific symptoms, such as syncope from decreased cerebral blood flow, chest pain from decreased coronary blood flow, or palpitations. Adolescents involved in competitive athletics with syncope, palpitations, or worrisome chest pain should be investigated promptly. Normal ranges for heart rate and blood pressure are listed in Tables 50–1 and 50–2.
Table 50-1. Expected Heart Rates According to Age2 |Favorite Table|Download (.pdf)
Table 50-1. Expected Heart Rates According to Age2
3 mo–2 y
> 10 y
Table 50-2. Expected Systolic and Diastolic Blood Pressures According to Age |Favorite Table|Download (.pdf)
Table 50-2. Expected Systolic and Diastolic Blood Pressures According to Age
Systolic BP (mm Hg)
Diastolic BP (mm Hg)