11 - ECG 2

Question 1

What abnormalities are recognised by an ECG?

Answer 1

• conduction abnormalities
• structural abnormalities
• perfusion abnormalities

Question 2

What are the normal ranges for an ECG waveform?

Answer 2

• P wave: <0.11 s
• PR interval: 0.12-0.2 s
• QRS complex: <0.12s
• Q wave: <0.04 s
• QT interval: 0.38-0.42 s

Question 3

What are the features of a normal sinus rhythm?

Answer 3

• 1:1 ratio for p wave and qrs complex
• regular rate (even r-r intervals)
• normal heart rate

Question 4

What is the name of this ECG and its features?

Answer 4

SINUS BRADYCARDIA

• regular rate
• slow
• caused by medication or vagal stimulation

Question 5

What is the name of this ECG and its features?

Answer 5

SINUS TACHYCARDIA

• regular rate
• fast
• physiological response

Question 6

What is the name of this ECG and its features?

Answer 6

SINUS ARRYTHMIA

• irregular rate
• normal HR
• R-R interval varies with breathing cycle

Question 7

What is the name of this ECG and its features?

Answer 7

ATRIAL FIBRILLATION

• oscillating baseline
• irregular rate
• slow
• turbulent flow pattern increases clot risk

Question 8

What is the name of this ECG and its features?

Answer 8

ATRIAL FLUTTER

• regular saw-tooth patterin in baseline
• atrial to ventricular beats higher than 1:1 ratio
• pattern in leads ii, iii and aVF

Question 9

What is the name of this ECG and its features?

Answer 9

FIRST DEGREE HEART BLOCK

• prolonged PR segment
• regular rate
• progressive disease of ageing

Question 10

bWhat is the name of this ECG and its features?

Answer 10

SECOND DEGREE HEART BLOCK: MOBITZ I

• gradual prolongation of PR interval until beat skipped
• regularly irregular
• disease AV node

Question 11

What is the name of this ECG and its features?

Answer 11

SECOND DEGREE HEART BLOCK: MOBITZ II

• regular p waves, not always followed by QRS complex
• regularly irregular
• no P-R elongation
• can rapidly turn into third degree heart block

Question 12

What is the name of this ECG and its features?

Answer 12

THIRD DEGREE HEART BLOCK

• no relationship between p wave and QRS complex
• both regular
• p waves can be hidden in bigger vector
• non-sinus rhythm

Question 13

What is the name of this ECG and its features?

Answer 13

VENTRICULAR TACHYCARDIA

• hidden p waves
• regular rate
• fast
• high risk of deteriorating into fibrillation
• shockable rhythm

Question 14

What is the name of this ECG and its features?

Answer 14

VENTRICULAR FIBRILLATION

• irregular rate
• >250bpm
• heart unable to generate output
• shockable rhythm

Question 15

What is the name of this ECG and its features?

Answer 15

ST ELEVATION

• regular rate and rhythm
• ST segment raised >2mm above baseline
• caused by infarction

Question 16

What is the name of this ECG and its features?

Answer 16

ST DEPRESSION

• regular rate and rhythm
• ST segment depressed >2mm below baseline
• caused by ischaemia

Question 17

What is the process of measuring blood pressure?

Answer 17

• measure pressure in brachial artery in upper arm with cuff, sphygmomanometer and stethoscope
• inflate arm to obstruct blood flow by increasing pressure until cuff exceeds arterial pressure
• release cuff slowly while placing stethoscope distal to cuff on brachial artery
• blood squirts into artery and sets up turbulent flow: first korotkoff sound indicates SBP
• eventually artery no longer occluded and flow returns to normal, silent, laminar flow
• disappearance of sounds indicates DBP

Question 18

What are the two blood pressure equations?

Answer 18

• pulse pressure = SBP - DBP
• MAP = DBP + 1/3PP

(= 2/3DBP + 1/3SBP)