Paediatric ECG Flashcards
(19 cards)
Give some background info for paed ECG’s
-at birth the RV is larger and thicker than the LV, so there is a greater physiological stress placed upon it in utero ( pumping blood through the relatively high resistance pulmonary circulation)
-produces an ECG reminiscent of RV hypertrophy in the adult: marked right axis, dominant R wave in V1 and T wave inversions in V1-3
conduction intervals (PR interval, QRS duration) shorter than adults due to smaller cardiac size
Describe the placement of ECG leads for Paeds patients
V1- 4th intercostal RSE
V2- 4th intercostal LSE
V3- use this lead for V4R, must label as such on ECG
V4R- 5th intercostal right midclavicular line
V5- anterior axillary line, same horizontal plane as V4
V6-midaxillary line, same horizontal line as V4
How do you determine the heart rate and rhythm of a paed ECG?
-use lead II or the lead with the least artifacts
-count the number of large boxes between 2 QRSs
-Rate=300/number of large boxes between QRSs
What are the average resting HRs with Paeds ages?
-newborn-110-150bpm
-2yrs-85-125bpm
-4yrs-75-115bpm
-6yrs-60-100bpm
-14yrs-60-120bpm
When is sinus rhythm present in a paed ECG?
-PR interval is consistent throughout
-P wave deflection is positive in leads II and aVF but negative in aVR
What is sinus arrhythmia?
-normal variation in sinus rhythm that occurs with respiration
-HR rises and falls with insp and expir
-The variation is more pronounced in young children and less pronounced in infants and adolescents
What is sinus tachycardia?
fast sinus rhythm that is consistent with anxiety, crying, fever and occasional hyperthyroidism
What is sinus bradycardia?
slow sinus rhythm seen normally in aerobically trained individuals
Describe the QRS axis change with age
1week-1month +110( range +30 to +180)
1 month-3months +70 ( range +10 to +125)
3months-3years +60 (range +10 to +110)
over 3 years +60 ( ramge +20 to +120)
Adult +50 (range -30 to 105)
What is the normal P wave amplitude and duration in paeds?
amp- <3mm
duration - <0.09 sec in children and <0.07 sec in infants
What is the normal QRS complex in a paeds?
normal QRS- 1 small box wide- .04sec or 40msec
A wide QRS - 2 small boxes or more >/.08 or >/8-msec
Describe a normal paed Q wave
-narrow( 0.02sec and less than 0.03 sec)
-less than 5mm deep in left precordial leads and aVF
-may be as deep as 8mm in lead III in children younger than 3
Describe normal QT and T waves in paeds
-use lead II or lead with least artifact
-QTc is calc-Bazett formula to correct QT for HR
-Normal QTc:
infants- <0.49s
older than 6months- <0.44s
normal is 0.40+/- 0.014
Describe T wave config changes over time
-1st week of life- T waves are upright through precordial leads
-after 1st week T waves become inverted in V1-3= juvenile T wave pattern
-Juvenile T waves stay until 8yrs then become upright in V1-3
-However juvenile T waves can persist into adolescence= persistnat Juvenile waves
Describe ST segments in Paeds
elevation od depression of ST segment up to 1mm in limb leads and 2mm in precordial leads is within limits in infants and children
Describe normal Paeds T waves
-Dome shaped wave with assymetrical limbs
-upright except in leads aVR,aVL, V1 and V2
Describe normal U waves in paeds
-repolarization of his-purkinje fibres
-positive deflection comes after T waves and preceeds the P wave of next cycle
-Amplitude of 5mm or less in leads I, II, III, 10mm or less in precordial leads V1-V6 duration not usually measured
Summarise a normal paed ECG
-heart rate>100bpm
-Rightward QRS axis >+90
-T wave inversion in V1-3 (Juvenile T waves)
-Dominanat R wave in V1
-RSR pattern in V1
-marked sinus arrhythmia
-short PR interval <120ms and QRS duration <80ms
-slightly peaked P waves < 3mm in heart is normal for </6 months
-slightly long QTc </490ms in infants </6 months
-Q waves in the inferior and left precordial leads
Why do peads patients have v4R?
their Rv usually extends to the right side sternum, used to see ventricle potentials
