Basic Paediatric Ecg

8/13/2019 Basic Paediatric Ecg

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INSTITUT JANTUNG NEGARANational Heart Institute

Dr Marhisham Che Mood

PCHC IJN





The Anatomy of the Heart

The Coronary Circulation





The Heartbeat

Heartbeat Needs two Types of Cardiac Cells – Contractile cells

• Provide the pumping action

– Cells of the conducting system • Generate and spread the action potential





The Heartbeat

The Conducting System – Initiates and spreads electrical impulses in heart – Two types of cells

• Nodal cells – Pacemaker cells

» Reach threshold first» Set heart rate

• Conducting cells

– Distributes stimuli to myocardium



Click to edit Master title styleINSTITUT JANTUNG NEGARA

National Heart Institute

The Heartbeat

The Conducting System (cont’d) – Heart is self-exciting

• Pacemaker cells establish heart rate – Normal pacemaker is sinoatrial (SA) node

• Impulse spreads from SA node: – Across atria – To atrioventricular (AV) node – To AV bundle and bundle branches

– Via Purkinje fibers to ventricles





The Heartbeat

The ConductingSystem of the Heart





SA node activity and atrialactivation begin.

Stimulus spreads across the atrialsurfaces and reaches the AV node.

There is a 100-msec delay at theAV node. Atrial contraction begins.

The impulse travels along the interventricularseptum within the AV bundle and the bundlebranches to the Purkinje fibers.

The impulse is distributed by Purkinje fibersand relayed throughout the ventricularmyocardium. Atrial contraction is completed,and ventricular contraction begins.

Time = 0

SA node

AV node

Elapsed time = 50 msec


AV bundle

Bundle branches


Elapsed time = 225 msec Purkinje fibers






Time = 0

SA node







Time = 0

SA node

AV node









Time = 0

SA node

AV node



AV bundle

Bundle branches








The impulse travels along the interventricularseptum within the AV bundle and the bundlebranches to the Purkinje fibers.

The impulse is distributed by Purkinje fibersand relayed throughout the ventricularmyocardium. Atrial contraction is completed,and ventricular contraction begins.

Time = 0

SA node

AV node



AV bundle

Bundle branches


Elapsed time = 225 msec Purkinje fibers





The Heartbeat

The Electrocardiogram (ECG or EKG) – A recording of the electrical activity of the heart – Three main components

• P wave

– Atrial depolarization• QRS complex

– Ventricular depolarization• T wave

– Ventricular repolarization





ECG Paper





The Heartbeat

Key Note

The heart rate is established by the SA node, as

modified by autonomic activity, hormones, ions,etc. From there, the stimulus is conductedthrough the atrium to the AV node, the AV bundle,the bundle branches, and Purkinje fibers to theventricular myocardium. The ECG shows theelectrical events associated with the heartbeat.





Lead Placement

The right arm or RA lead- directly below the clavicle & near the rightshoulderThe left arm or LA lead- directly below the clavicle & near the leftshoulderThe left leg or LL lead- on the left lower abdomen




National Heart InstituteSteps to Interpreting Rhythm Strips

1. Evaluate the P wave Are the P wave present? Indicates atrialdepolarizationNormal shape? Upright and round

Are all the P wave the same shape?Do you see one P wave for each QRS complex?





2. Evaluate the Atrial RhythmMeasure the interval between two consecutive Pwaves (P to P interval)

Is the rate regular or irregular

Steps to Interpreting Rhythm Strips





3. Calculate the Heart RateCount the number of QRS complexes in a 6 secondrhythm strip and multiply by 10


6 X 10 = 60





4. Calculate the duration of the PR intervalCount the number of small boxes from thebeginning of the P wave to the beginning of theQRS complex and multiply by 0.04 secondsDoes the PR interval fall within normal limits?Is the PR interval constant in each QRS cycle?






5. Evaluate the ventricular rhythmMeasure the interval between two consecutive Rwaves. This is the R to R interval

Are the R to R intervals consistently the same?If the intervals are not the same, then the rhythm isconsidered irregular






6. Calculate the duration of the QRS complexCount the number of small boxes from thebeginning of the Q wave to the end of the S waveand multiply by 0.04 seconds

Are the complexes all the same size and shape?Do any of the QRS complexes appear different fromeach other?Is there one QRS complex for each P wave?






7. Evaluate the ST SegmentThe normal ST segment is flat or isoelectricThere can be an elevation or depression of 2mm or2 small boxes. This can be considered normal in

pediatrics. Abnormal changes are seen in pericarditis,myocardial ischemia or infarction






History:-Does the fast or slow heart rate start and stopsuddenly?Does it get worse with exercise?

Are there other symptoms? – difficulty breathing,pallor, cyanosis, dizziness, or poor feeding?What is the child’s activity level?

Family history

General Principles of EvaluatingChildren with Arrhythmias





How does the patient look?Is the patient breathing?Is there a pulse present?

General Principles of EvaluatingChildren with Arrhythmias

h h h d





Rhythms originating in the sinus nodeSA node)

Rhythms originating in the sinus node (SA node)are:Normal Sinus RhythmSinus TachycardiaSinus Bradycardia





Characteristics of Sinus Rhythms

The characteristics are:

There is a P wave preceding each QRS complexThere is a regular PR interval

And the P wave is upright in lead II





Normal Sinus Rhythm

The normal rhythm for any age is sinus rhythm.

The average heart rate for infants is 90 to 160beats per minute and for children and teenagers,it is 65 to 100 beats per minute.





Average Heart Rate per minute)

Basic Paediatric Ecg

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