1) The document provides guidance on rapidly assessing and diagnosing arrhythmias in pediatric intensive care patients. Key steps include excluding hypoxia, electrolyte abnormalities, and drug causes. 2) It describes approaches to diagnosing specific arrhythmias like sinus tachycardia, junctional ectopic tachycardia, atrial flutter, and ventricular tachycardia based on ECG findings and the effect of adenosine. 3) Initial management focuses on stabilizing the patient and treating reversible causes before considering rhythm-specific treatments like medications, pacing, or cardioversion. The document emphasizes identifying and correcting any contributing factors to arrhythmias.

1. A brief approach to arrhythmias
Shubhadeep Das
MD
Fellowship in Pediatric Critical Care and Cardiac Critical Care (University of Toronto, Sickkids Hospital, Canada)
RCPCH Fellowship in Pediatric Critical and Cardiac Critical Care (London, UK)
European Board Certified in Pediatric Intensive Care (EPIC)
Consultant and in charge, Pediatric Cardiac ICU
NH Narayana Superspeciality Hospital, Howrah

2. • Dysrhythmia resultant of
– Global hypoxia/ electrolyte imbalance
– Isolated conduction system pathology
• Assess and identify rapidly
– Prevents hemodynamic deterioration

3. Rapid assessment
• Exclude hypoxia and hypercapnia: Check ventilation and oxygenation
adequacy with arterial blood gas review.
• Assess for hemodynamic instability: Check vital signs (HR, BP, capillary
refill time, lactate).
• Exclude electrolyte abnormalities : Check Ca, Mg, K
• Exclude iatrogenic drug causes: check chronotropes (positive and negative),
K+ infusion
• 12-lead ECG and atrial ECG (if atrial pacing wire available)

4. To assist in DIAGNOSIS of the
dysrhythmia:
•  Tempo of ONSET: gradual (automatic mechanism: warm-up phenomenon) or sudden (re-
entry mechanism)
•  P waves : yes or no, upright or inverted, antegrade, regularity, PR interval
•  QRS: wide or narrow
•  P to QRS relation : 1 to 1; regular ratio, associated or dissociated
•  ADENOSINE TEST
(Run an ECG continuously during the test; resuscitation plan on standby; ensure vein close to the heart for drug
administration): Rapid administration of 100-300 mcg/kg will temporarily block the AV node unmasking an atrial arrhythmia
(atrial ectopic tachycardia, atrial flutter, etc) or terminate AV re-entry tachycardia.

5. TYPE OF SURGERY:
• Some dysrhythmias are strongly associated with type of operations
(suture lines, myocardial condition)

6. Rapid Initial Management:
 If LCOS, resuscitate appropriately (A-B-C)
 Exclude reversible causes:
1. Correct hypoxemia / hypo – or hypercarbia
2. Optimise electrolytes: magnesium 1-1.5 mmol/L, potassium 4-5 mmol/L and ionised calcium
above 1.2 mmol/L.
3. Correct hypovolemia
4. Ensure effective analgesia
5. Correct metabolic acidosis or alkalosis.
 Exclude cardiac tamponade (urgent echo) and/or surgically redeemable cause.

7. QRS
<0.08
secs
QRS
>0.08
secs

8. Junctional Ectopic Tachycardia
Atrial Ectopic Tachycardia with
symptoms
Atrial Flutter/ Fibrillation

9. Sinus Arrhythmia
expiration

11. Sinus Tachycardia

12. Causes:
Common:
• sympathetic surge (pain, fever, hypovolemia, chrono-inotrope sensitivity),
• low cardiac output
• Hypoxia
• hypercarbia
Uncommon:
• Sepsis
• Seizures
• anemia.
Treat the underlying cause

14. • JET
• Supraventricular tachycardia

15. Atrial Flutter
Adenosine
Mechanism: Macro Re-entrant pathway within atrium

16. Treatment:
Stable patient:
• Amiodarone or Flecainide combined with an av nodal blocking drug (beta-
blockers or digoxin) if no ventricular dysfunction:.
• Overdrive pacing
Unstable patient:
• Synchronized cardioversion (1J/kg) if patient unstable, unresponsive to medication
or even as a first option before antiarrhythmic drugs.
• Consider anticoagulation if persistent beyond 48hrs (increase in stroke risk)

17. Atrial Ectopic Tachycardia
Mechanism: Automatic

18. Treatment
• Difficult to control pharmacologically
• Usually unresponsive to adenosine but adenosine can reveal
diagnosis with transient increase degree of AV nodal block
• Amiodarone or beta-blockers to control heart rate.
• Sometimes responds to cardioversion.

19. Broad complex tachycardia

20. Ventricular Tachycardia

21. Ventricular fibrillation

22. Causes:
• Often related to myocardial disease
– ischemia or dysfunction (prompt investigation for coronary
problems).
• Secondary to antiarrhythmic drugs (Class I, Class III, and Digitalis
toxicity)

23. Ventricular Tachycardia with a pulse
Stable:
• If regular monomorphic:
– Adenosine
– Amiodarone
– Procainamide
Unstable:
• Consider synchronized cardioversion
– 1st Cardioversion: 0.5-1.0 J/kg.
– Following Cardioversions: 2 J/kg
Correct any contributing factor (metabolic acidosis, electrolytes disturbances
(Ca,Mg,K), check intracardiac lines displacements).

24. Pulseless Ventricular Tachycardia / Refractory Ventricular
Fibrillation
• CPR
• Electrical therapy:
– Initiate electrical therapy as soon as possible!
– 1st Defibrillate: Defibrillate at 2j/kg
– If 1st Defibrillate unsuccessful: 2nd Defibrillate at 4j/kg
– If 2nd Defibrillate unsuccessful: following Defibrillations at 4 j/kg

25. Bradyarrythmias

26. • Arrhythmias are not very uncommon in PICU
• Sometimes daunting task to identify a rhythm
• As an intensivist it is important to be familiar with rhythm
disturbances, their diagnoses and rhythm specific
management