Pediatric Dysrhythmias Board Review

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Pediatric DysrhythmiasBoard Review

• February 11, 2008
• Brad Rodrigue, M.D.

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Pediatric dysrhythmias
Reproduced from Zitellis Atlas of Pediatric
physical diagnosis, 2007, pg 140.
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Pediatric dysrhythmias

• Vital to be aware of arrhythmias that occur in
  otherwise healthy children
• Management is individualized
• Does child have history of heart disease?
• Are symptoms present?

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Sinus arrhythmia

• Most common irregularity of heart rhythm seen in
  children
• Normal variant
• Reflects healthy interaction between autonomic
  respiratory and cardiac control activity in CNS
• Heart rate increases during inspiration and
  decreases during respiration

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Sinus arrhythmia
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Wandering atrial pacemaker

• Atrial pacemaker shifts from sinus node to
  another atrial site
• Normal variant, irregular rhythm

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Isolated PACs

• Premature atrial contractions
• Benign in absence of underlying heart dz
• Common in newborn period
• Early p wave, sometimes with different morphology
  than a sinus p wave
• Can be either
• Not conducted to ventricle, apparent pause
• Conducted to ventricle with aberrant or widened
  QRS complex ( careful not to mix up with PVCs)

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Isolated PACs
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Premature Ventricular Contractions (PVCs)

• Not very commonly seen in children
• Incidence of 0.3 to 2.2
• Early, wide QRS complexes
• T waves in opposite direction of QRS
• Unifocal PVCs are most encountered type
• Bigeminy, sinus beat followed by PVC, repeating
  as a pattern, also frequently seen

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PVCs

• If unifocal, disappear with exercise, and
  associated with structurally and functionally
  normal heart, then considered benign, no therapy
  needed

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PVCs evaluation

• 12 lead EKG, Echocardiogram
• Perhaps Holter monitoring
• Brief exercise in office to see if ectopy
  suppressed or more frequent
• Multifocal or paired PVCs more worrisome
• Medications usually not needed
• Advise patients to avoid caffeine and other
  stimulants

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First degree AV block

• Commonly seen (up to 6 normal neonates)
• PR interval is greater than upper limits of
  normal for a given age
• PR interval is age and rate dependent
• 70-170 msec in newborns is normal
• 80-220 msec in young children and adults
• Generally does not cause bradycardia since AV
  conduction remains intact

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First degree AV block

• Diseases that can be associated with first degree
  AV block rheumatic fever, rubella, mumps,
  hypothermia, cardiomyopathy, electrolyte
  disturbances

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Third degree AV block

• AKA complete heart block
• Most common cause of abnormal bradycardia in
  infants and children
• Complete disassociation between P waves and QRS
  complexes

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Third degree AV block

• Can be congenital in this case it is strongly
  associated with maternal SLE
• Mom of an infant should be worked up
• Most common structural heart defect associated is
  corrected transposition of great vessels

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Third degree AV block

• May be asymptomatic follow clinically
• Slower the heart rate, and wide QRS escape
  rhythms place into high risk group
• May need implantable pacemaker significant
  bradycardias, syncope, exercise intolerance,
  ventricular dysrhythmias, or ventricular
  arrhythmias, structural disease
• Possible acute treatment isoproterenol

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Supraventricular tachycardia

• Most common abnormal tachycardia seen in
  pediatric practice
• Most common arrhythmia requiring treatment in
  pediatric population
• Most frequent age presentation 1st 3 months of
  life, 2nd peaks _at_ 8-10 and in adolescense
• Rapid, regular, usually narrow QRS rhythm,
  originating above the ventricles

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SVT
Figure 5-42 Supraventricular tachycardia. Note a
normal QRS complex tachycardia at a rate of 214
beats/minute without visible P waves.
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SVT

• Paroxysmal, sudden onset offset
• Rates of SVT vary with age
• Overall average rate for all ages 235 bpm
• 1st 9 months of life avg rate is 270 bpm
• Older children avg rate is 210 bpm( 180-250)
• P waves difficult to define, but 11 with QRS
• Important to differentiate from sinus tach

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SVT

• Older kids can describe a sensation of a fast
  heart rate, palpitations, or chest tightness
• Hemodynamic compromise in newborns and those with
  structural heart disease
• Those with typical symptoms would benefit from
  cardiac consultation

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SVT - Treatment

• Goal identify unstable patients, differentiate
  from sinus tachycardia, and terminate the rhythm
• Vagal maneuvers in stable patients
• Adenosine if IV access readily available
• Stop conduction through AV node
• Helps to define p waves if unsure of etiology
• 0.1 mg/kg (max 6 mg), repeat 0.2 mg/kg ( max 12
  mg) in line closest to central circulation
• Need continuous ECG and BP monitoring
• Synchronized cardioversion
• Amiodarone, Procainamide if above unsuccessful
• Transesophageal atrial pacing can also be
  performed

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SVT - Treatment

• Need post conversion EKG identify those with
  WPW syndrome ( 25 pts with SVT)
• Will also need an echo identify structural
  problems
• Radiofrequency catheter ablation
• Frontline treatment
• Very effective
• Cutoff points usually are 5 y.o. and 15 kg,
  unless severe SVT
• Observation and expectant management
• Medications
• Digoxin and beta blockers as first line
• Flecainide, sotalol, amiodarone

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Other SVTs

• A flutter, A fib, ectopic atrial tachycardia,
  junctional tachycardias
• Not commonly seen in pediatric patients
• Adenosine does not terminate these rhythms,
  originate above AV node
• Treatments procainamide, amiodarone,
  cardioversion, or ablation

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SVT - WPW
Figure 5-43 Wolff-Parkinson-White syndrome. Note
the characteristic findings of a short P-R
interval, slurred upstroke of QRS (delta wave),
and prolongation of the QRS interval.
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Ventricular tachycardia

• Sustained V-tach is uncommon, needs workup
• Regular wide complex tachycardia
• Atrioventricular dissociation
• Life threatening arryhthmia
• Often presents in those who have had open heart
  surgical repair, or those with cardiomyopathies,
  myocarditis, or tumors

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V-Tach

• Treatment IV lidocaine, procainamide, amiodarone
• If critically ill synchronized cardioversion
• Long term meds, ablation, or defibrillator

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Ventricular fibrillation

• Seen in children with EKG abnormalities such as
  long QT syndrome, or Brugada syndrome
• Cardiomyopathies, structural heart disease
  causing ventricular dysfunction
• Treatment immediate defibrillation, CPR

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V-fib

• Brugada syndrome inherited arrhythmia,
  autosomal dominant person goes into v-fib,
  faints, dies suddenly
• Treatment defibrillator, careful screening

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Thats all!