ECG

Question 1

PR interval?

Answer 1

Question 2

QRS complex/segment?

Answer 2

Question 3

PR segment?

Answer 3

Question 4

QT interval?

Answer 4

Question 5

ST segment

Answer 5

Question 6

Dr Sandilands “very basic ECG algorithm”

Answer 6

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

Question 7

Visualise the normal progression of R waves from V1 to V6:

r wave and s wave together still called QRS

Answer 7

Question 8

With regular rhythm is there equal spacing between QRS complexes and a p wave before each QRS?

Answer 8

Yes

Question 9

What does Sinus arrhythmia look like? And what causes it?

Answer 9

Its a normal variation, often as a result of a patient breathing deeply.

Question 10

What does AFib look like

Answer 10

Rhythm: irregular so spacing between each QRS is different (irregularly irregular)

No p waves

Often V1 wavy line

Look on slides

Question 11

Which axis of deviation, if leads I and II are the most +ve?

Answer 11

Normal

Question 12

Which axis of deviation, if lead aVL is most +ve?

Answer 12

Left axis deviation

Question 13

WHich axis of deviation, if lead III is most +ve?

Answer 13

RIght axis deviation

Question 14

If theres a very short PR interval, what sign on the ECG should you consider? And if present which condition would this be?

Answer 14

Delta wave

WPW

Question 15

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

Answer 15

LBBB

Question 16

LBBB is associated with which axis deviation?

Answer 16

Left axis devisation

Question 17

If QRS is prolonged (broadened). And V1 has +ve QRS deflection (with “bunny ears”). What condition is this?

Answer 17

RBBB

Question 18

How can we confirm RBBB on an ECG?

Answer 18

Look for “slurred S wave” in aVL

Question 19

What would the chest leads (V1-V6) look like in someone with Left Ventricular Hypertrophy?

Answer 19

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”

Question 20

In late chest leads the R waves are small and alter in height (amplitude). This signifies what around the heart?

Answer 20

Fluid

Pericardial Effusion

Question 21

Post MI theres dead myocardium in the left ventricle. How would Lead I look and why?

Answer 21

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

Question 22

ECG look like in a STEMI

Answer 22

ST elevation

Question 23

ECG normal ST segment?

Answer 23

Question 24

ECG NSTEMI appearance?

Answer 24

Question 25

What reduces QT interval?

Answer 25

HyperCA