ECGs Flashcards
What are juvenile T waves?
Precordial Twaves normally inverted at birth. After childhood become upright, but some stay inverted.
What are possible signs of early repolarisation?
J point notching
Concavity of ST segment
No evidence of reciprocal changes
Rare over 50y
What are the ECG changes for a Type 1, 2nd degree AV block, and where does it originate?
‘I’ncreasing PR interval.
Originates in AV node.
What is the quick axis deviation method?
Norm: 1 positive & aVF positive
LAD: 1 positive & aVF negative
RAD: 1 negative & aVF positive
What are the ECG changes for a Type 2, 2nd degree AV block, and where does it originate?
Every x beat dropped.
Originates in His-Purkinje system.
What is the pathophysiology behind SVTs?
AV node has a fast & a slow pathway. Normally impulse travels down fast & half up slow, stopping slow impulse. PAC causes early slow impulse which then goes up fast path & down slow again.
What are the ECG changes for a 3rd degree block?
Complete dissociation.
A rate > V rate.
Bradycardia.
What is the Brugada Criteria?
Concordance = VT OR
Brugada Sign = VT OR
AV dissociation = VT OR
BBB Criteria
Brugada Sign = Start of R to deepest part of S > 0.1s
Define pathological Q waves…
Pathological if greater than 0.03s duration or 1/3 amplitude of R wave
What are the ECG criteria for pathological Q waves?
Pathological if greater than 0.03s duration or
1/3 amplitude of R wave
What are the ECG changes for a LBBB?
QRS > 0.12s
Negative monophonic V1 (can have small r)
Positive monophonic V6 (& I)
Always due to pathology
What is the intrinsicoid deflection and what does it represent?
Beginning of QRS to beginning of R downslope. Represents time taken for electrical impulse to travel from purkinje system in endocardium to surface of epicardium near electrode.
What is the J point?
End of QRS, beginning of ST segment
What is the ECG criteria for a normal P wave?
2-3 squares (0.08-0.12s). Symmetrical & monomorphic.
What is the ECG criteria for a normal PR interval?
3-5 squares (0.12-0.2s).
What is the ECG criteria for a normal QRS duration?
1.5-3 squares (0.06-0.12s).
Describe T waves deflection…
Positive deflection as repolarises in opposite direction (unlike Tp wave) due to increased pressure on endocardium during contraction reducing blood supply. Like Tp is negative charge.
What leads are unipolar?
V1-V6, aVL, aVF & aVR. Unipolar uses one physical & one calculated lead.
Why does the T wave have a positive deflection?
Positive deflection as repolarises in opposite direction to repolarisation (unlike Tp wave) due to increased pressure on endocardium during contraction reducing blood supply. Like Tp, is negative charge.
What leads are bipolar?
I, II & III. Bipolar uses 2 physical leads.
What is the triplicate method of rate calculation?
300-150-100-75-60-50
What is the R-R method of rhythm rate calculation?
300 / # large squares between Rs
What is the 6s method of rhythm rate calculation?
10x number of R waves in 30s strip
What are the ECG criteria for pathological T waves?
Twave 2/3 height Rwave V2-V4
What is IACD and what are the ECG changes seen?
Intratrial Conduction Delay.
Biphasic P wave in V1.
What are the ECG signs of a possible pericardial effusion?
.
What are the ECG changes in pregnancy?
.
How do you calculate QT interval and what is a normal QTc?
QT = 1/2 RR
QTc < 0.45s (male)
QTc < 0.47s (female)
What are the ECG changes seen in a RBBB?
QRS > 0.12
Terminal R wave in V1
Slurred S wave in V6 (& I)
