Question

Figure shows two electrocardiogram records from a patient. Record B was taken one year after record A was obtained. In these records: 

a. The QRS axis in A is directed to the left rather than to the right of vertical. 

b. The QRS complexes V₁, V₄ and V₆ in A suggest left, rather than right, ventricular hypertrophy. 

c. The change from A to B suggests a return towards normality. 

d. The QRS axis in B is directed downwards rather than upwards. e. The inversion of T in leads III and V₁ in record A indicates myocardial is chaemia.

Answer 1

a. False The net QRS in lead I is negative, indicating an axis to the right rather than the left; this is confirmed by lead III having a large positive deflection. 

b. False The R dominance in V₁ and the prominent S wave in V₄ suggest an abnormally great contribution from the right ventricle in these leads. 

c. True In record B, V₁ now shows a normal S wave; V₄ has lost its S wave to show only a normal R wave. 

d. True It is roughly 60^o below the horizontal (close to the axis of lead II). The swing from right (A) to left (B) indicates return of left ventricular dominance, as do the V lead changes. 

e. False Occasional T wave inversion is common and usually has no sinister significance.