Cardiac Emergencies

Cardiac Emergencies
Luba Komar
Introduction
  • Congenital cardiac diseases often present in the newborn period and may require emergency management (see Chapter 11)
  • Other cardiac emergencies include arrhythmias, myocarditis, and pericarditis
  • Chest pain is uncommonly due to cardiac disease in children (< 5%)
Dysrhythmias
  • Tachyarrhythmias: heart rate faster than accepted normal range
  • Heart Rates in Normal Ranges

    Age

    Normal Range (bpm)

    Mean (bpm)

    0-3 mos.

    90-180

    140

    3-6 mos.

    80-160

    130

    6 mos to 1 yr

    80-140

    115

    1-3 yrs

    75-130

    105

    6 yrs

    70-110

    95

    10 yrs

    60-90

    80

  • Narrow vs wide complex
  • Mechanisms: reentry, automaticity, or triggers
Narrow Complex Tachyarrhythmia
  • Most common tachyarrhythmia
Sinus Tachycardia
  • Most common tachycardia in children
Electrocardiographic Features
  • Heart rate above normal range for age
  • Heart rate
    • Usually < 220 bpm in infants
    • < 180 bpm in children
  • Normal P wave axis
  • Normal AV conduction
  • Normal QRS duration
  • Beat to beat variability
  • Variable RR interval BUT constant PR interval
Causes of Sinus Tachycardia
  • Fever, hypovolemia (dehydration, blood loss), pain, sepsis, stress, poisoning, anemia, hyperthyroidism
Treatment of Sinus Tachycardia
  • Treat underlying cause—antipyretic, fluids, pain medication, etc.
Supraventricular Tachycardia (SVT)
Rapid, regular rhythm
  • Often sudden onset
  • Most often caused by reentry mechanism that involves an accessory pathway
  • Usually well tolerated in most infants and children
  • May lead to congestive heart failure and cardiovascular collapse
Figure 21.1 Supraventricular Tachycardia (SVT)
Electrocardiographic Features
  • Heart rate > 220 in 60% of infants
  • Heart rate > 180 in children
  • P waves may be difficult to identify, P wave axis is abnormal
  • No beat to beat variability
Causes of Supraventicular Tachycardia
  • Wolff-Parkinson-White (22%)
  • Congenital heart disease (23%): corrected TGA, Ebstein’s anomaly, mitral valve prolapse, asplenia-polysplenia syndromes, post Mustard, Fontan, or ASD repair
  • Hyperthyroidism
  • Myocarditis
  • Drugs: sympathomimetics, caffeine, digitalis toxicity
Treatment of Hemodynamically Stable SVT
  • Resuscitation room, cardiac and saturation monitors
  • Initial 12-lead ECG, and continuous 12-lead ECG during cardiac conversion
  • Vagal maneuvers (62% successful, less successful in infants and younger children):
    • Ice (diving reflex): ice/water mixture in bag applied over forehead and eyes only for 15-20 seconds
    • Gag, carotid sinus massage, abdominal pressure, or Valsalva: ask older child to blow through straw, rectal stimulus (do not apply pressure to eyeballs)
  • IV access
  • Adenosine: 0.05-0.25 mg/kg IV/IO quick push, increase by 0.05 mg/kg q 2 min or 6 mg max first dose
  • Cardiology consultation to consider other medications including phenylephrine, neostigmine, verapamil, propranolol, esmolol, procainamide, digoxin
  • Esophageal overdrive pacing
  • ECG post conversion
Treatment of Hemodynamically Unstable SVT
  • ABCs
  • Synchronized cardioversion 0.25-1 J/kg, then 0.5-2 J/kg, max 10 J/kg
    Note: cardioversion may not be successful in presence of hypoxia or acid-base imbalance
Cardioversion
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Jun 22, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Cardiac Emergencies

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