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A 60 y/o man on the cardiology ward presents with a hx of myocardial Infarction.ECG shows a broaden QRS complex, no R wave in V1, and a tall, wide R wave in V6.Splitting of the S2 heart sound increases upon expiration and decreases upon inspiration.What underlying pathology would explain these clinical findings ?

A-AV nodal re-entry
B-Damage to the left bundle branch
C-Damage to the right bundle branch
D- First degree AV block
E- Pre-excitation syndrome

B is the answer

C..?

B.

bb. I think because increases during expiration--> left-sided

yes,expiration causes inc.S2.....so left heart side problem,

very well

What happen to S2 splitting in "Mitral Regurgitation" ? and how ?

ouch, I always have hard time with Qs like that. I would assume that there is a delay in a closure of aortic valves.

so, the closure of pulmonic valves would be first, followed by aortic valves closure.

I think there is no direct change on S2 splitting in MR...because S2 splitting due to the closure of Aortic and Pulmonic valve and if there is stenosis of these 2 valves.....the S2 spliting changes significantly.