Pediatric Tachycardia Algorithm 🔥🔥

Initial Assessment and Categorization

• The evaluation of a child presenting with a rhythm disturbance hinges on two primary considerations: the child's typical heart rate/rhythm for their age and the patient's hemodynamic status (clinical condition).
• Tachycardia is defined as a heart rate that is abnormally fast compared to the normal physiological heart rate for the patient's age.
• The rhythm is clinically categorized as "unstable" if the tachycardia produces signs of poor tissue perfusion, such as weak pulses, hypotensive shock, respiratory distress, or altered consciousness.
• Once a pulse is confirmed to be present, tachyarrhythmias are classified based on the width of the QRS complex on the electrocardiogram (ECG).
• Narrow Complex Tachycardia (QRS $\le$ 0.09 seconds): Includes Sinus Tachycardia (ST), Supraventricular Tachycardia (SVT), and Atrial Flutter.
• Wide Complex Tachycardia (QRS > 0.09 seconds): Includes Ventricular Tachycardia (VT) and SVT with aberrant intraventricular conduction.

Differentiating Narrow Complex Tachycardias (ST vs. SVT)

• Distinguishing between Sinus Tachycardia (ST) and Supraventricular Tachycardia (SVT) is a critical step in the narrow-complex algorithm, guided by clinical history and ECG characteristics.

Management of Hemodynamically Unstable Tachycardia (Poor Perfusion)

• Immediate intervention is mandated for any tachyarrhythmia presenting with signs of hemodynamic instability and compromised perfusion.
• Narrow Complex (Unstable SVT): Synchronized cardioversion is the definitive therapy of choice and must be administered as soon as possible.
• The initial dose for synchronized cardioversion is 0.5 to 1 J/kg.
• If the first shock is unsuccessful, the subsequent dose is escalated to 2 J/kg.
• A rapid dose of Adenosine may be attempted first to determine if the rhythm is SVT, provided that its administration does not delay the electrical cardioversion.
• Wide Complex (Unstable VT with Pulse): Unstable wide-complex tachycardia is treated identically with synchronized cardioversion (0.5 to 1 J/kg, escalating to 2 J/kg).
• If the wide-complex tachycardia is refractory to synchronized shocks, or if it recurs quickly, pharmacological therapy with intravenous Amiodarone or Lidocaine should be administered.
• If at any point the patient loses their pulse, the provider must immediately commence cardiopulmonary resuscitation (CPR) and shift to the pulseless arrest (defibrillation) algorithm.

Management of Hemodynamically Stable Tachycardia (Adequate Perfusion)

• For patients maintaining adequate perfusion and blood pressure, the approach is stepwise and pharmacological, guided by the QRS width.
• Stable Narrow Complex (Probable ST): Identify and aggressively treat the underlying reversible causes, such as hypovolemia, fever, or pain (the "Hs and Ts").
• Stable Narrow Complex (Probable SVT):
  • Vagal maneuvers should be attempted first, provided they do not unduly delay chemical cardioversion.
  • For infants and young children, ice applied to the face (without occluding the airway) is utilized.
  • For older children, Valsalva maneuvers (e.g., blowing through an obstructed straw) or carotid sinus massage are safe and effective.
  • If vagal maneuvers fail, Adenosine is the pharmacological drug of choice.
• Stable Wide Complex (Probable VT):
  • An expert cardiology consultation is highly recommended.
  • Pharmacological cardioversion is achieved using an infusion of Amiodarone.
  • Alternative agents include Procainamide or a Lidocaine bolus followed by an infusion.

Pharmacological Agents and Dosages

• Adenosine: Administered via rapid intravenous push using a 'two-syringe' technique (drug followed immediately by a rapid $\ge$ 5 ml normal saline flush). The initial dose is 0.1 mg/kg (maximum first dose 6 mg). If there is no response, the dose is doubled to 0.2 mg/kg (maximum second dose 12 mg).
• Amiodarone: Administered as an intravenous infusion of 5 mg/kg given slowly over 20 to 60 minutes (maximum 300 mg per dose). It can be repeated up to a total daily dose of 15 mg/kg (maximum 2.2 g in 24 hours).
• Procainamide: Administered as an intravenous infusion of 15 mg/kg slowly over 30 to 60 minutes. Note: Extreme caution must be exercised if administering both Amiodarone and Procainamide due to the compounded risk of severe QTc prolongation.
• Lidocaine: Administered as a 1 mg/kg intravenous bolus, which can be followed by a continuous infusion of 20 to 50 $\mu$g/kg/min.