The frontal plane vector loop in this patient is complicated and difficult to visualize. There is a small initial inferiorly directed vector (vector #1), reflecting the small narrow R wave in III and AVF that is associated with the left anterior fascicular block. The loop then swings superiorly (vector #2) reflecting the QS complex in lead II, the manifestation of the inferior wall infarction. The loop then remains directed superiorly and to the left (vector #3) with an axis of -60 degrees. This reflects the S waves in leads III and aVF and the R wave in lead aVL, the result of the left anterior fascicular block. Note the figure-of-eight shape of the vector loop.