ECG Flashcards
PR interval?
QRS complex/segment?
PR segment?
QT interval?
ST segment
Dr Sandilands “very basic ECG algorithm”
RATE Each 12 lead ecg=10 secs. Count number of QRS * 6 =HR per min. Or divide 300 by the number of big squares between two consecutive R waves.
RHYTHM regular, sinus arrhythmia, irregular. (if irregular iregular (ie has no pattern at all) and no P waves then its AFib)
AXIS If lead aVL becomes most postive then Left axis deviation. If lead III becomes most positive then right axis deviation.
Intervals
PR 0.12-.2s if short look for delta waves, this is then WPW
QRS less than 0.12s, if broad think BBB. If tall R waves in late V1-V6 leads with deep S waves in early V1-V6 leads think LVH.
R wave progression
ST/T wave changes Look for elevation, depression or inversion
*QTc * around 2 large boxes, or 400-440ms
Visualise the normal progression of R waves from V1 to V6:
r wave and s wave together still called QRS
With regular rhythm is there equal spacing between QRS complexes and a p wave before each QRS?
Yes
What does Sinus arrhythmia look like? And what causes it?
Its a normal variation, often as a result of a patient breathing deeply.
What does AFib look like
Rhythm: irregular so spacing between each QRS is different (irregularly irregular)
No p waves
Often V1 wavy line
Look on slides
Which axis of deviation, if leads I and II are the most +ve?
Normal
Which axis of deviation, if lead aVL is most +ve?
Left axis deviation
WHich axis of deviation, if lead III is most +ve?
RIght axis deviation
If theres a very short PR interval, what sign on the ECG should you consider? And if present which condition would this be?
Delta wave
WPW
If QRS is prolonged (broadened). And theres P waves. If theres dominant S waves (very negative) in V1. If QRS (r waves) doesnt become +ve until V5/V6. What condition is this?
M pattern can also be seen in V5 V6
LBBB
LBBB is associated with which axis deviation?
Left axis devisation
If QRS is prolonged (broadened). And V1 has +ve QRS deflection (with “bunny ears”). What condition is this?
RBBB
How can we confirm RBBB on an ECG?
Look for “slurred S wave” in aVL
What would the chest leads (V1-V6) look like in someone with Left Ventricular Hypertrophy?
Deep S waves in early chest leads. Tall R waves in late chest leads. T wave inversions may be apparent
“More muscle in heart taller R waves”
In late chest leads the R waves are small and alter in height (amplitude). This signifies what around the heart?
Fluid
Pericardial Effusion
Post MI theres dead myocardium in the left ventricle. How would Lead I look and why?
Significant Q wave in Lead 1.
Q wave in this case = >25% amplitude of R wave
>0.04 seconds of duration
This is because the dead tissue cant conduct the AP, therefore electrical forces are directed towards the opposite slide of heart.
look at slides
ECG look like in a STEMI
ST elevation
ECG normal ST segment?
ECG NSTEMI appearance?
What reduces QT interval?
HyperCA
