Cardiology - ECG interpretation

Question 1

How do you calculate rate on an ECG?

Answer 1

rate = 300 / (number of large squares in R-R interval)

Question 2

How would LAD appear on ECG? Causes?

Answer 2

Positive in lead I
Negative in lead II, aVF
Causes - inferior MI, VT, WPW, L ant hemiblock

Question 3

How would RAD appear on ECG? Causes?

Answer 3

Negative in lead I
Positive in aVF
Causes - PE, cor pulmonale, lateral MI, L posterior hemiblock

Question 4

What ECG change is seen in TCA overdose?

Answer 4

QRS prolongation

Question 5

Causes of QTc prolongation?

Answer 5

acute MI
hypothermia
hypocalcaemia
drugs (TCAs, quinidine)

Question 6

Causes of chest pain?

Answer 6

CVS - ACS, aortic dissection
Resp - pneumothorax, pneumonia, PE
MSK - costochondritis
GI - oesophagitis, cholecystitis, pancreatitis

Question 7

Secondary symptoms to ask about in chest pain history?

Answer 7

N&V, sweating, SOB, cough, haemoptysis, LOC, palpitations, dizziness

Question 8

acute mx of STEMI/NSTEMI

Answer 8

12 lead ECG + MONA + GRACE
Aspirin 300mg + clopidogrel
Cannula - bloods (FBC, U&Es, TnT, VBG, cholesterol) + IV morphine
Nitrates
O2 if sats <90
CXR
Calculate GRACE risk score, start enoxaparin unless CI
If STEMI early referral for PCI in cathlab (or thrombolysis)

Question 9

Changes in ECG leads V1-3 indicate an MI in which location?

Answer 9

Anteroseptal

Question 10

Changes in ECG leads V5-6, all indicate an MI in which location?

Answer 10

anterolateral

Question 11

Changes in ECG leads V2-4 indicate an MI in which location?

Answer 11

anterior

Question 12

Changes in ECG leads V1-6 indicate an MI in which location?

Answer 12

extensive anterior

Question 13

Changes in ECG leads I, II, aVL, V6 indicate an MI in which location?

Answer 13

lateral

Question 14

Changes in ECG leads II, III, aVF indicate an MI in which location?

Answer 14

inferior

Question 15

Changes in ECG leads V1, V4R indicate an MI in which location?

Answer 15

RV

Question 16

Causes of AF?

Answer 16

IHD, heart failure, htn, valvular disease, sepsis, PE, thyrotoxicosis, drug abuse, lung/pleural disease, low K/volume/temp

Question 17

What is torsades de pointes and what causes it?

Answer 17

Polymorphic VT assoc with low Mg/K, and long QTc.

Question 18

How is SVT treated?

Answer 18

Unstable - electrical cardioversion

Stable - valsalva, carotid sinus massage, adenosine or verapamil

Question 19

Sudden severe chest/back pain and a history of htn - must rule out what diagnosis?

Answer 19

aortic dissection - can resemble MI, may also see aortic regurg, asymmetrical pulses, htn, tamponade, neurological signs