Myocardial Infarction and ECG diagnosis

Question 1

Describe the limb and chest leads and the anatomical relations for each

Answer 1

II, III and aVF - Inferior surface V1 to V4 - anterior surface I, aVL, V5 and V6 - lateral surface V1 and aVR - Right atrium and cavity of left ventricle

Question 2

Order these ECG features in the sequence you would see during an MI: Q-wave formation Peaked T-waves T-wave inversion ST-elevation

Answer 2

The correct sequence is: Peaked T-wave ST - elevation Q-wave formation T-wave inversion

Question 3

Describe the leads in which you would see ST elevation in the case of a left coronary artery infarct and the leads in which you would see reciprocal changes.

Answer 3

ST elevation would typically occur in I, aVL, V5 and V6. You would see ST-depression in V1-V3.

Question 4

Describe the ECG you are likely to see given a right ventricular infarction

Answer 4

ST-Elevation in II, III, aVF, V1 and possibly V2. Reciprocal ST-depression is likely in aVL and I.

Question 5

A patient presents with chest pain and ST-elevation in all leads except for aVR and V1 and depression of the PR segment. What is the likely condition?

Answer 5

Acute pericarditis. Produces a diffuse rather than localised ST-elevation.

Question 6

Describe the similarities in the chest leads for a posterior infarct and ischemia to the anterior wall of the left ventricle and how you could differentiate the two.

Answer 6

Both produce ST-deression in leads V1 to V3. To make a diagnosis of posterior infarction you can use the posterior leads V7-V9 which will show ST-elevation

Question 7

Lead V4 can give you the information you need to make a diagnosis of benign early take off. What are these features?

Answer 7

Concave ST- segment Notch or slurring at the J-point (i.e. the junction of the R and S waves) High take off of the ST-segment Symmetrical, upright T-waves of large amplitude