arrhythimias

Cardiac Arrhythmias in Cardiac Arrhythmias in children & viral children & viral

myocarditismyocarditis

Dr Aly MA EL-Mohsen, MDDr Aly MA EL-Mohsen, MDLecturer in PediatricsLecturer in Pediatrics,,Alexandria UniversityAlexandria University

Impulse formation & Impulse formation & conductionconduction

Impulse propagation through the conductive system

Electromechanical Electromechanical couplingcoupling

Recording the electrical Recording the electrical activity of the heartactivity of the heart

The electrical activity The electrical activity of the heart is of the heart is recorded by recorded by electrodes connected electrodes connected to a machine to to a machine to measure the measure the electrical currentelectrical current

The positive electrode The positive electrode is the recording is the recording electrode while the electrode while the negative one is an negative one is an indifferent electrode.indifferent electrode.

Recording ECGRecording ECG

Limb Leads (I , II, III)Limb Leads (I , II, III) Augmented leads (avL, avR, Augmented leads (avL, avR,

avF)avF) Chest (precordial) leads (V1 Chest (precordial) leads (V1

–– V6) V6)

Limb leadsLimb leads

Augmented leadsAugmented leads

Precordial LeadsPrecordial Leads

Precordial leadsPrecordial leads

++++++++++++++++++++++++++++++++++++++

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ++++++++++++++++++++++++++++++++++++++

I, II, III,avL, avFV3-6

avRV 1-2 Na+

K+

Wave generationWave generation

Wave GenerationWave Generation

Wave generation continuedWave generation continued

Depolarization/Depolarization/RepolarizationRepolarization

Repolarization Repolarization starts at last area starts at last area to depolarizeto depolarize

Repolarization Repolarization starts at first area starts at first area to depolarizeto depolarize

ECG PaperECG Paper

Estimation of the HREstimation of the HR

300

Number of large squares

HR=

Irregular HRIrregular HR

Use long strip lead IIUse long strip lead II Count R waves in 6 seconds (30 Count R waves in 6 seconds (30

large squares) X 10large squares) X 10

Finding the P-waveFinding the P-wave

Criteria of normal sinus Criteria of normal sinus rhythmrhythm

Normal heart rate for age.Normal heart rate for age.Normal P-wave axis & Normal P-wave axis &

morphologymorphologyOne P-wave before each One P-wave before each

QRSQRS

Normal Sinus RhythmNormal Sinus Rhythm

Aetiology of arrhythmiasAetiology of arrhythmias

Congenital heart diseases.Congenital heart diseases. Myocarditis (e.g. viral myocarditis)Myocarditis (e.g. viral myocarditis) Cardiomyopathy. Cardiomyopathy. Post-operatively.Post-operatively. Drug-induced (e.g. digitalis).Drug-induced (e.g. digitalis). Electrolyte disturbances.Electrolyte disturbances. Endocrinal & metabolic diseases.Endocrinal & metabolic diseases. Cardiac tumours (rhabdomyoma or Cardiac tumours (rhabdomyoma or

myxoma)myxoma)

Arrhythmia

Abnormal impulse formation

Abnormal impulse conduction

Abnormal impulse Abnormal impulse formationformation

Supraventricular

• Sinus tachycadia.

• Sinus bradycardia.

• Premature atrial complexes

• Supraventricular tachycardia

•Atrial flutter & fibrillation.

Ventricular

• Premature ventricular complexes.

• Ventricular tachycardia.

• Ventricular fibrillation.

Sinus TachycardiaSinus Tachycardia

Sinus tachycardiaSinus tachycardia

Sinus BradycardiaSinus Bradycardia

Premature atrial Premature atrial complexescomplexes

APCs continuedAPCs continued

Blocked PACs

Supraventricular Tachycardia

Automatic Reentry

Ectopic atrial tachy.

AV node

Accessory pathway

Reentry TachycardiaReentry Tachycardia

Reentry TachycardiaReentry Tachycardia

Nodal Accessory Pathway

Accessory PathwayAccessory Pathway

WPWWPW

Accessory Pathway Accessory Pathway TachycardiaTachycardia

Accessory Pathway

AV nodal Re-entry AV nodal Re-entry TachycardiaTachycardia

Supraventricular Supraventricular TachycardiaTachycardia

The most frequent sustained The most frequent sustained arrhythmia in pediatrics.arrhythmia in pediatrics.

May start to occur in-utero, neonatal, May start to occur in-utero, neonatal, infancy or childhood.infancy or childhood.

HR is regular & rapid 240-300 bpm.HR is regular & rapid 240-300 bpm. Attacks starts suddenly & last for Attacks starts suddenly & last for

period of few seconds up to several period of few seconds up to several weeks.weeks.

Heart failure may eventually occur.Heart failure may eventually occur.

Multifocal atrial Multifocal atrial tachycardiatachycardia

1212--lead ECG (SVT)lead ECG (SVT)

Clinical features of SVTClinical features of SVT

In newborn & infants:In newborn & infants: Sudden pallor, tachyapnea & refusal of Sudden pallor, tachyapnea & refusal of

feeding.feeding. Baby is usually restless & very irritable.Baby is usually restless & very irritable. Very rapid HR with cardiomegaly & Very rapid HR with cardiomegaly &

hepatomegaly.hepatomegaly. In older children:In older children:

Child may be aware of the onset of the fast Child may be aware of the onset of the fast heart rate & become anxious & heart rate & become anxious & apprehensive. apprehensive.

Treatment of SVTTreatment of SVT Vagal stimulation.Vagal stimulation.

Adenosine: (adenocor 3mg/ml)Adenosine: (adenocor 3mg/ml) IV 50 IV 50 –– 100 mcg/kg , can be repeated/2min 100 mcg/kg , can be repeated/2min

with 50 mcg/kg increase in dose up to 3 with 50 mcg/kg increase in dose up to 3 times. times.

Digitalis: Digitalis: Digitalization at 0.02 Digitalization at 0.02 –– 0.035 mg/kg/day 0.035 mg/kg/day ÷ 3 ÷ 3

doses IV.doses IV. maintenance : 0.01 mg/kg/day ÷ maintenance : 0.01 mg/kg/day ÷ 2 dose orally2 dose orally

(for 1 year)(for 1 year)

NOT in WPW

Treatment of SVT continuedTreatment of SVT continued

Beta blockers:Beta blockers: Inderal (propranolol)Inderal (propranolol)

IV slowly 0.02 - 0.05 mg/kg can be IV slowly 0.02 - 0.05 mg/kg can be repeated/ 6-8 hrs.repeated/ 6-8 hrs.

Orally 0.2 Orally 0.2 –– 0.5 mg/kg t.d.s for 0.5 mg/kg t.d.s for maintenance. maintenance.

Esmolol : (brevibloc)Esmolol : (brevibloc) IV bolus 0.5 mg/kg then 50 mcg/kg/min IV bolus 0.5 mg/kg then 50 mcg/kg/min

IV infusion.IV infusion.

AmiodaroneAmiodarone: (cordarone): (cordarone) IV 5mg/kg over 20 minutes followed by IV 5mg/kg over 20 minutes followed by

IV infusion of 0.3 IV infusion of 0.3 –– 0.9 mg /kg/hr. 0.9 mg /kg/hr. Orally 5 mg /kg twice daily for 7-10 Orally 5 mg /kg twice daily for 7-10

days then 5-10 /kg daily.days then 5-10 /kg daily. FlecainideFlecainide::

IV 2 mg/kg over 10 -30 mins then 0.1 -IV 2 mg/kg over 10 -30 mins then 0.1 -0.2 mg/kg/hr until arrhythmia stops.0.2 mg/kg/hr until arrhythmia stops.

Orally 2 mg /kg 2-3 times daily.Orally 2 mg /kg 2-3 times daily.


VerapamilVerapamil : (in older children) : (in older children) IV: IV: Given over 2Given over 2––3 minutes in dose of 0.13 minutes in dose of 0.1––

0.3 mg/kg, using continuous ECG 0.3 mg/kg, using continuous ECG monitoring. May repeat once after 30 mins. monitoring. May repeat once after 30 mins. max dose:max dose: 5 mg. 5 mg.

PO: Children: PO: Children: 44––8 mg/kg/24 hr ÷ TID8 mg/kg/24 hr ÷ TID DC shock:DC shock:

For unresponsive hemodynamically For unresponsive hemodynamically compromised infants & children with SVT.compromised infants & children with SVT.

0.50.5––2 watt-sec/kg. 2 watt-sec/kg.


Twenty-four hour electrocardiographic Twenty-four hour electrocardiographic (Holter) recordings(Holter) recordings are useful in are useful in monitoring the course of therapy and in monitoring the course of therapy and in detecting brief runs of asymptomatic detecting brief runs of asymptomatic tachycardia .tachycardia .

Radiofrequency ablationRadiofrequency ablation of an accessory of an accessory pathway : 1- multiple agents are pathway : 1- multiple agents are required or required or

2- drug side effects are intolerable 2- drug side effects are intolerable 3- arrhythmia control is poor. 3- arrhythmia control is poor. The overall initial success rate ranges from The overall initial success rate ranges from

approximately 80% to 95%, depending on approximately 80% to 95%, depending on the location of the bypass tract or tracts. the location of the bypass tract or tracts.


Atrial flutterAtrial flutter

Atrial fibrillationAtrial fibrillation

Atrial fibrillation examplesAtrial fibrillation examples

Premature Ventricular Premature Ventricular ComplexesComplexes

Dangerous types :

(1 )two or more ventricular premature beats in a row.

(2 )multifocal origin.

(3 )increased ventricular ectopic activity with exercise.

(4 )R on T phenomenon (PVC occurs on the T wave of the preceding beat) .

(5 )Presence of underlying heart disease

Premature Ventricular Premature Ventricular ComplexesComplexes

Ventricular TachycardiaVentricular Tachycardia

Ventricular tachycardia

SVT

1212--lead ECG (VT)lead ECG (VT)

VT

SVT

Treatment of Vent Treatment of Vent arrhythmiasarrhythmias

Lidocaine: Lidocaine: IV 0.5 IV 0.5 –– 1 mg /kg then 0.6 1 mg /kg then 0.6 –– 3 mg/kg/hr 3 mg/kg/hr

by infusion.by infusion. Amiodarone intravenously.Amiodarone intravenously. DC shock (0.5DC shock (0.5––2 watt-sec/kg) .2 watt-sec/kg) .

11stst degree HB degree HB

22ndnd degree HB degree HB

22ndnd degree HB (types) degree HB (types)

Type I

Type II

First degree HBFirst degree HB

Second degree Heart Second degree Heart BlockBlock

33rdrd degree HB degree HB

Viral MyocarditisViral Myocarditis EtiologyEtiology::

Coxsackie B virus.Coxsackie B virus. Adenovirus Adenovirus

ClinicallyClinically:: Breathlessness on exertion & feeding.Breathlessness on exertion & feeding. Excessive sweating.Excessive sweating. Irritability & weak cry.Irritability & weak cry. Tachycardia Tachycardia Tachyapnea.Tachyapnea. Gallop rhythm.Gallop rhythm.

Enlarged tender liver.Enlarged tender liver. Edema.Edema.

CXRCXR:: Cardiomegaly.Cardiomegaly. Congested lung fields.Congested lung fields.

ECGECG:: Low voltage ECG.Low voltage ECG. ST segment changes.ST segment changes.

TreatmentTreatment:: Diuretics.Diuretics. Digitalis.Digitalis. Captopril.Captopril.

arrhythimias

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