Paediatric ECG Abnormalities

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Paediatric ECG Abnormalities

• Supraventricular Tachycardia (SVT):

  • Narrow complex tachycardia originating above the ventricles.
  • Classified by atrial or AV nodal origin.
  • Crucial to identify P wave position (relative to the QRS complex) during tachycardia ("P wave hunting").
  • Common causes include AV nodal reentrant tachycardia and atrioventricular reciprocating tachycardia. Early recognition and management are vital.

• Supraventricular Tachycardia (SVT):

  • Narrow complex tachycardia originating above the ventricles.
  • Classified by atrial or AV nodal origin.
  • Crucial to identify P wave position (relative to QRS complex) during tachycardia ("P wave hunting").
  • Common causes include AV nodal re-entrant tachycardia (AVNRT), atrioventricular re-entrant tachycardia (AVRT, including Wolff-Parkinson-White Syndrome), permanent junctional reciprocating tachycardia (PJRT).
  • AVRT: Accessory pathway connects atria and ventricles, creating a re-entrant circuit.
    • Impulses can travel down AV node and up accessory pathway (orthodromic) or vice versa (antidromic).
    • Retrograde P wave may be seen at end of QRS.
  • AVNRT: Micro-reentrant circuit in or near AV node.
    • P waves difficult to see, often hidden in QRS.
  • PJRT: Type of orthodromic AVRT with concealed accessory pathway near coronary sinus.
    • Characterized by long RP interval tachycardia.
    • Inverted P wave(s) in inferior leads (not in sinus rhythm).
    • RP interval longer than PR interval in sinus rhythm. Misdiagnosis as sinus tachycardia is common. Requires cardiology intervention, as adenosine is often ineffective.

• Wolff-Parkinson-White Syndrome (WPW):

  • Conduction abnormality with accessory pathway connecting atria and ventricles.
  • Accessory pathway (anterogradely) conduction faster than AV node leading to pre-excitation.
  • Can lead to SVT (AVRT).
  • ECG findings: Short PR interval (<100ms) and delta wave (fusion of accessory pathway and normal QRS).

• Complete Heart Block:

  • Impulse not conducted from atria to ventricles.
  • Usually due to AV node pathology, often congenital (structural disease or maternal antibodies, e.g., in neonatal lupus).
  • SA node controls atrial rate; ventricle rate is a ventricular escape rhythm (much slower).
  • Atria and ventricles contract independently.
  • Narrow QRS in AV block, wide QRS in infranodal block.
  • Infranodal block generally less stable and increased risk of asystole.
  • ECG findings: Regular P waves and regular QRS complexes, but they are unrelated.

• Myocarditis:

  • Myocardium inflammation.
  • Caused by various infections (viruses, bacteria, spirochetes, fungi, etc) with a toxic effect on the myocardium.
  • Systemic illness (e.g., Coxsackie) or certain drugs (e.g., anthracyclines, alcohol) are implicated.
  • Often occurs alongside pericarditis.
  • ECG findings: Usually exhibits sinus tachycardia and non-specific T-wave and ST-segment changes (eg, T-wave inversion)

• Dilated Cardiomyopathy (DCM):

  • Weak and floppy myocardium.
  • Inherited or developed result of myocarditis (secondary infection or drugs).

• Hypertrophic Cardiomyopathy (HOCM):

  • Genetic condition affecting heart sarcomeres.
  • Leads to Left Ventricular Hypertrophy (LVH), unexplained by other causes.
  • Highly significant due to its association with sudden cardiac death.

Explore the key concepts of Supraventricular Tachycardia (SVT) in pediatric patients. This quiz covers types of SVT, including AV nodal re-entrant and atrioventricular re-entrant tachycardias. Learn to identify P wave positions and the clinical significance of these ECG abnormalities.