ECG 2

Question 1

role of the ECG in the clinical environment

Answer 1

conduction abnormalities
structural abnormalities
perfusion abnormalities

Question 2

sinus rhythm

Answer 2

each p wave is followed by a QRS wave (1;1)
rate is regular (even R-R intervals) and normal (83 bpm)
otherwise unremarkable

Question 3

sinus bradycardia

- features and due to?

Answer 3

each p wave is followed by a QRS wave (1:1)
rate is regular (even R-R intervals) and slow (56 bpm)
can be healthy, caused by medication or vagal stimulation

Question 4

sinus tachycardia

- features and due to?

Answer 4

each p wave is followed by QRS wave (1:1)
rate is regular (even R-R intervals) and fast (107 bpm)
often a physiological response (ie. secondary)

Question 5

sinus arrhythmia

- features and due to?

Answer 5

each p wave is followed by a QRS wave
rate is irregular (variable R-R intervals) and normal-ish (65 - 100 bpm)
R-R interval varies with breathing cycle

Question 6

atrial fibrillation

Answer 6

oscillating baseline- atria contracting asynchronously
rhythm can be irregular and rate may be slow
turbulent flow pattern increases clot risk
atria not essential for cardiac cycle

Question 7

atrial flutter

Answer 7

regular saw-tooth pattern in baseline (II, III, aVF)
atrial to ventricular beats at a 2:1 ratio, 3:1 ratio or higher
saw-tooth not always visible in all leads

Question 8

first degree heart block

Answer 8

prolonged ST segment/interval caused by slower AV conduction
Regular rhythm: 1:1 ratio of P-waves to QRS complexes
Most benign heart block, but a progressive disease of ageing

Question 9

second degree heart block (mobitz I)

Answer 9

gradual prolongation of the PR interval; until beat skipped
Most p waves followed by QRS; but some P waves are not
regularly irregular: caused by diseased AV node
also called Wenckebach

Question 10

second degree heart block (mobitz II)

Answer 10

p waves are regular, but only some are followed by QRS
No P-R prolongation
Regularly irregular; successes to failure
can rapidly deteriorate into third degree heart block

Question 11

Third degree heart block (complete)

Answer 11

p waves are regular, QRS regular, but no relationship
P waves can be hidden within bigger vectors
a truly non-sinus rhythm- back up pacemaker in action

Question 12

ventricular tachycardia

Answer 12

p waves hidden- dissociated atrial rhythm
rate is regular and fast (100-200 bpm)
at high risk of deteriorating into fibrillation
shockable rhythm- defibrillators widely available

Question 13

ventricular fibrillation

Answer 13

heart rate irregular and 250 bpm and above
heart unable to generate an output
at high risk of deteriorating into fibrillation (cardiac arrest)
shockable rhythm- defibrillators widely available

Question 14

ST elevation

Answer 14

P waves visible and always followed by QRS
Rhythm is regular and rate is normal (85 bpm)
ST segment is elevated 2mm above the isoelectric line
caused by infarction (tissue death caused hypoperfusion)

Question 15

ST depression

Answer 15

P waves visible and always followed by QRS
Rhythm is regular and rate is normal 995 bpm)
St-segment is depressed >2m below the isoelectric line
caused by myocardial ischaemia (coronary insufficiency)