Exercise ECG

Question 1

How would you recognise atrial fibrillation (AF) on the ECG trace?

Answer 1

No discernible P waves

irregular and erratic RR intervals - ventricular contractions are irregularly irregular

Question 2

Describe the normal ECG changes during exercise (based on Hill and Timmis, 2002).

Answer 2

P wave increases in height
R wave and T wave decreases in height
J point becomes depressed
ST segment is shortly upsloping
QT interval shortens

Question 3

Describe the electrocardiographic criteria for myocardial ischaemia during an exercise test.

Answer 3

ST segment depression of > or equal to 1mm horizontal/downsloping at 80ms post J point
T wave is inverted
Premature ventricular contractions

Question 4

Which findings (during a CPET) are suggestive of a high probability of ischaemic heart disease? (Hill and Timmis, 2002)

Answer 4

Horizontal ST segment depression of > or equal to 2mm
Downsloping ST segment depression
Early positive response 6 minutes into test
Persistence of ST segment depression more than 6 minutes into recovery
ST segment depression in 5 or more leads
Exertional hypotension

Question 5

Describe normal sinus rhythm

Answer 5

HR 60 - 100 bpm
rhythm is regular
P waves before each QRS
PR between 0.12s and 0.20s
QRS is less than 0.12s

Question 6

Describe ST elevation myocardial infarction (STEMI)

Answer 6

ST segment is raised and T wave is high lifting

A Q wave appears and stays after heart attack

Question 7

Describe normal variant of ST waves

Answer 7

J point is raised

Early take off of T waves

Question 8

Describe myocardial ischaemia

Answer 8

Inadequate oxygen supply to myocardium
Myocardium becomes anaerobic and ion permeability is altered
Ischaemic areas have slower depolarisation rate

Question 9

Name 3 other positive ETT changes for ischaemia

Answer 9

Abnormal haemodynamic response
Ventricular arrhythmias
Ischaemic symptoms during exercise

Question 10

Describe a premature ventricular contraction

Answer 10

There are no P waves
Ventricular tachycardia - all PVCs
Can deteriorate to ventricular fibrillation - death

Question 11

1 MET represents what?

Answer 11

3.5ml O2/kg/min which is the oxygen consumption of an average person at rest

Question 12

Why is ischamia more likely to be detected during exercise?

Answer 12

increase in HR and SBP
therefore the rate pressure product increases reflecting myocardial requirements
increase in HR causes a shortened diastolic phase and decrease myocardial perfusion