lecture 9: electrocardiography 2

Question 1

what are the three types of arrhythmias?

Answer 1

• supraventrivcular arrhythmias eg. atrial fibrillation atrial flutter atri ventricular nodal reentrant tachycardia - junctional arrhythmias - ventricular arrhythmias eg. ventricular tachycardia - ventricular fibrillation

Question 2

what abnormalities can the ECG pick up on?

Answer 2

• conduction abnormalities - structural abnormalities - perfusion abnormalities

Question 3

what is the way to approach an ECG?

Answer 3

• check if it is the correct recording (name + DOB) - review the signal quality and the leads - verify the voltage and the paper speed - review the patients background - look at the rate and the rhythm of the ECG - look at the p wave and the PR interval - look at the QRS axis - look at the QRS axis - look at the ST segment 9is it high low or isoelectric) - look at QT interval - look at the T wave

Question 4

* what is normal sinus rhythm of a PQRS wave?

Answer 4

• each P is followed by QRS - the rate regular - unremarkable insert pic (normal)

Question 5

* what is a sinus bradycardia

Answer 5

• each P wave is still followed by QRS - the rate is regular but SLOW - it can be healthy

Question 6

* what is a sinus tachycardia

Answer 6

• each P wave is still followed by QRS - rate is regular but fast - normally a physiological response

Question 7

* what is a sinus arrhythmia?

Answer 7

• each P wave is still followed by QRS - the rate is irregular - the RR interval varies with the breathing cycle

Question 8

* whats atrial fibrillation?

Answer 8

• oscillating baseline - when the atria are contracting asynchronously - the rhythm might be irregular and the rate is slow - there is turbulent flow which increases the clot risk - the atria are not essential for the cardiac cycle

Question 9

* what is atrial flutter?

Answer 9

• regular saw tooth pattern is baseline (specific to the atrial flutter) - atrial to ventricular beats at 2:1 ratio - the saw tooth was not always visible in all leads

Question 10

* what is first degree heart block?

Answer 10

• regular 1:1 (P:QRS ) - there is a prolonged ST segment caused by slower atrioventricular conduction - most benign heart block - it happens with progressive ageing

Question 11

* what is second degree heart block? (mobitz i)

Answer 11

• gradual prolongation of PR interval until the beat is skipped - most P waves are followed by QRS (not always though) - regularly irregular - called Wenckebach

Question 12

* what is second degree heart block? (mobitz ii)

Answer 12

• P waves are regular but only some are followed by QRS - there is no P- R prolongation - regularly irregular - can rapidly change into third degree heart block

Question 13

* what is third degree heart block?

Answer 13

• the P waves are regular - the QRS waves are regular but there is no relationship - P waves might be hidden - completely non sinus rhythm

Question 14

* what is ventricular tachycardia ?

Answer 14

• P waves are hidden - the rate is regular and fast - high risk of deteriorating into fibrillation - shockable rhythm

Question 15

* what is ventricular fibrillation?

Answer 15

• heart rate is irregular and 250 bpm and above - heart cannot generate an output - cardiac arrest - shockable rhythm

Question 16

* what is ST elevation?

Answer 16

P waves are visible and always followed by QRS - the rhythm is regular - ST segment is elevated - caused by infarction

Question 17

*what is ST depression?

Answer 17

• P waves always visible - rhythm is regular and rate is normal - ST segment is depressed - caused by myocardial ischaemia