You are in your office and your next patient is here. She is a new patient who is here for a "wellness visit" with no chief complaints. She is an 83 year old female whohas a few records with her. Her hysterectomy surgery report, her living will and an old chart from her old doctor. You open the chart before you go into the room and the first thing you see is the EKG below. What is your interpretation and what would you expect to hear when you examine her?

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With a Left Bundle Branch block present you would expect to here a paradoxically split S2. Which means, usually the s2 splits on inspiration when Venous return increases to the RV and the second part of s2 (pulmonic component) comes a little later than the first part (aortic) so you can here the split sound. In a LBBB, s2 is single in inspiration and and split on expiration. This is because now the right side depolerizes first so the pulmonic component comes first than the aortic which makes it split during expiration and on ispiration when venous return increases to the RV the delay created makes the pulmonic compent come later and at the same time when the delayed left side (aortic) making it sound single on inspiration. Hence, paradoxical splitting.

With an LBBB you cant really say much about the ST and T wave changes that are present. So if this patient was symptomatic with chest pain, you still could not comment on the st segments. However is this were a RBBB present you could still use the ST segments if they were symptomatic to say that something was going on.