September 23, 2010

Morning Report

ECG

Rate

Rhythm

What do you think?

What do you want to do?

SA nodeSA node

Cardiac pacemakerUpper wall of the RA

Sinus RhythmNormal heart rhythm controlled by SA nodep-wave before every QRSPR – 120-200 msec

SA nodeSinus Arrhythmia

Healthy childrenDecrease in SA node firing due to activation

of the vagus nerve by exhalationHR varies with respirationNormal sinus rhythm with prolongation of RR

during exhalation

The AtriaPremature Atrial Contractions (PACs)

Ectopic focus stimulates the atria without input from the SA node

CausesDrug use, caffeine, electrolyte imbalance, mostly

unknownSymptoms (Usually asymptomatic)

Skipped beat, pause followed by strong beatECG

Premature, inverted or oddly shaped P waves, sharp inflections in T waves

May have narrow, wide or no QRS depending on focusTreatment

Reassurance, avoidance

The Atria

Atrial Flutter250-400 bpmNewborns or children with

structural heart diseaseReentrant circuit confined to RASymptoms

CHF (infants), dizziness, syncope, CP, SOBECG

Inverted “saw-tooth”Ventricular conduction - 1:1 (300bpm), 1:2 (150-200bpm)

TreatmentUrgent cardiac eval and treatment

The AtriaAtrial fibrillation

Uncommon in young childrenRapid fibrillation of the atrial muscle without

coordinated contractionCauses

Structural heart diseaseStretching of atria

SymptomsPalpitations, CP, syncope

ECG Irregularly irregular rhythmAbsent or low voltage p-waves

TreatmentUrgent referral to cardsClot formation >24h

The AV nodeSupraventricular Tachycardia

Rapid tachycardia originating above the bundle of His

1/250 children

3 categoriesReentrant tachycardia with accessory pathway

WPWReentrant AV nodal tachycardiaAtrial ectopic tachycardia

SVTHeart rates 220-270bpmSymptoms

Infants prolongedPoor feeding, pallor, irritability, lethargy, HD compromise

24-48hSchool age

“beeping in chest”, heart pounding, CP, SOB, sweating, exercise intolerance

HR may be 180ECG

Narrow complex tachycardiaP waves difficult to seeFinding vary with cause

TreatmentCardiac referralEP study and ablation

The VentriclesPremature Ventricular Contractions (PVCs)

Ectopic firings within the ventricle25% of healthy childrenSymptoms

Asymptomatic, chest fullness, dizziness, “heart skips”ECG

Premature, bizarre, wide QRS complex not preceded by a p-wave

Often followed by a compensatory pauseTreatment

Benign if single, suppressed by exercise and no family history of death

Referral to cardiology if history is suspicious

The VentriclesLong QTc Syndrome

Associated with a potentially dangerous arrhythmia, torsades de pointes

QTc = QT/√previous RR QTc >450 msec is suggestive

FH of sudden death, deafnessSymptoms

Syncope, seizures, palpitations, cardiac arrest (10%)Fainting while swimming, playing sports or

exercisingTreatment

Refer if symptoms or if ECG is abnormal

Ventricular Tachycardia Tachycardia of at least 3 successive ventricular

beats<30 sec – nonsustained>30 sec – sustained

CausesDrugs, caffeine, decongestants, electrolyte

imbalances

SymptomsAbnormal hearts, asymptomatic, pallor, fatigue,

palpitations, feeding intolerance

Ventricular TachycardiaECG

Bizarre, wide QRS complex (>120 msec), tachycardia

May or may not see p-wavesT waves are opposite polarization to QRS

TreatmentABCsCardiac Evaluation

Ventricular FibrillationRare cardiac emergencyUncoordinated activity of the cardiac muscle

fibersOften results in cardiac arrest

Nonpalpable pulsesECG

Bizarre, random waveform without clearly identifiable P waves or QRS complexes and a roaming baseline

TreatmentABCsDefibrillation