• Empirical therapy without detecting arrhythmia does not meet the current standard of practice.
• Young children
  • Drug treatment for 6–12 months followed by observation
  • Pacemaker implantation for complete AV block
• Older children and adolescents
  • Depending on clinical and nonclinical factors
    • No therapy
    • Drug therapy
    • Ablation
    • Pacemaker

Premature beats

• PACs
  • Therapy not necessary unless:
    • PACs initiate SVT.
    • PACs block impulses in a newborn infant dependent on heart rate to maintain adequate cardiac output.
  • If suppressive therapy is required:
    • Digoxin
    • Propranolol
• PVCs
  • Neither treatment nor curtailment of exercise is required, even if a bigeminal rhythm is present.
  • If worrisome PVCs are present, the need for therapy should be determined by a pediatric cardiologist.

SVT

• Young children
  • Cardiogenic shock:
    • Direct current synchronized cardioversion
      • 0.5 to 2 watt-seconds or J/kg with the largest paddles allowing effective chest contact
    • Adenosine
      • Administered via IV bolus, if venous access is available
      • Follow with a second doubled if the first dose is ineffective.
      • Should be administered with ECG monitoring
      • Effective in approximately 90% of episodes
    • Procainamide
      • Use if adenosine is ineffective, or if SVT quickly recurs
      • Can be administered IV to infants and young children after appropriate loading, with a subsequent repeat trial of adenosine.
      • If conversion does not ensue, a procainamide level should be obtained 4 hours into the infusion (therapeutic range, 4–8 μg/mL).
  • IV verapamil and propranolol
    • Suppressive therapy with propranolol is appropriate in WPW syndrome.
    • These agents are contraindicated in children < 1 year.
  • Digoxin and verapamil
    • Should be avoided in SVT
    • May shorten the antegrade refractory period of the accessory pathway, allowing more rapid conduction to the ventricles
      • Potentially fatal if atrial fibrillation develops
    • If preexcitation is not present, either agent can be used to prevent recurrence.
  • β-Blockers
    • Should be avoided in the presence of congestive heart failure, sick sinus syndrome, or a history of bronchospasm
  • Other medical therapies
    • Use if the above agents are ineffective.
    • All require hospitalization for drug initiation.
      • Flecainide
      • Sotalol
      • Amiodarone
  • Ablation
    • Not recommended during the first 2 years of life
      • Resultant myocardial scar may grow with the patient and become a subsequent nidus for malignant, often drug-refractory arrhythmias.
• Older children and adolescents
  • Therapeutic choices depend on:
    • Frequency
    • Ease of conversion of episodes
  • No therapy other than self-conversion via a Valsalva maneuver or headstand
  • Drug therapy with consideration of:
    • Duration
    • Compliance
    • Cost
  • Radiofrequency ablation
    • At least 90% successful, but with a chance of a later recurrence
    • If the patient with SVT will undergo surgery for a cardiac defect, preoperative assessment and ablation should be considered to reduce arrhythmia-related postoperative morbidity and potential mortality.

Atrial flutter

• Digoxin
  • One-third of very young patients respond in utero or postnatally.
• Electrical cardioversion
  • Required in about two-thirds of patients
• Long-term therapy
  • Usually unnecessary because recurrences are rare

VT

• Acute management
  • Depends on the patient’s clinical status
    • Rate and duration of VT
    • Presence of structural cardiac lesions
    • Prior myocardial dysfunction
  • Hemodynamic compromise
    • Electrical cardioversion with 1–2 watt-seconds/kg
  • If reasonable clinical stability is present:
    • IV lidocaine
    • Procainamide
    • Magnesium
    • Amiodarone
• Long-term suppressive therapy
  • Predicated on:
    • Risk of recurrence
    • Morbidity and mortality of the type of VT
    • Risk-benefit ratio of treatment
  • Common antiarrhythmic agents to prevent VT recurrence:
    • β-Blockers
    • Sotalol
    • Amiodarone
  • Other treatments:
    • Implantation of an automatic cardioverter-defibrillator
    • VT ablation
• Benign forms of VT
  • Accelerated ventricular rhythm
    • Requires observation only (Figure 7).
  • Right ventricular outflow tract tachycardia

Conduction abnormalities

• First-degree AV block
  • No therapy is required.
• Second-degree AV block
  • Type I
    • No therapy is required in most cases.
  • Type II
    • Ongoing medical surveillance
    • Potential need for pacemaker implantation
• Complete AV block
  • Early pacemaker implantation is advised in infants with:
    • Risk factors
    • Symptoms of inadequate cardiac output
  • Isoproterenol
    • Infuse if necessary to increase the heart rate while awaiting pacemaker therapy
    • Should not delay implantation
  • If not in infancy, pacemaker insertion in adolescence is usually necessary depending on:
    • Symptoms
    • Ventricular rate
    • Stability of the ventricular escape rhythm

Sudden cardiac death

• LQTS
  • For any child or adolescent who collapses suddenly with no discernible cardiac output:
    • Rapid resuscitation
    • Early defibrillation
  • β-Blocker therapy
  • Cardiac pacing
  • Left stellate ganglionectomy
  • Implantation of cardioverter-defibrillator
  • Avoidance of:
    • Competitive sports
    • Drugs capable of prolonging the QTc
    • Sympathomimetics
    • Rapid correction of electrolyte abnormalities

• Arrhythmias associated with presyncope, syncope, chest pain, or a sense of doom
• Underlying heart disease
• Family history of premature (before age 35 years) sudden cardiac death
• Persistent or repetitive bradycardias or tachycardias
• Premature ventricular beats that increase with exercise

• Arrhythmias associated with syncope or low cardiac output
• Symptomatic high-grade AV block
• Difficult-to-control SVT, atrial flutter
• VT
• LQTS with syncope, aborted sudden death