Retrograde Conduction in Complete Heart Block

ABSTRACT

A 45 year old man with a history of syncopal attacks of 3 days' duration showed complete heart block with occasional retrograde P waves following QRS complexes in the electrocardiogram. The site of A-V block seemed to be below A-V node judging from the QRS complexes when occasional capture occured. This may be a case of complete heart block progressing from right bundle branch block plus left posterior hemiblock. There was a rapid improvement of conduction with sublingual isoproterenol in a few days, EKG's showing normal A-V conduction and QRS complexes on discharge. The mechanism of the retrograde conduction in the presence of complete heart block is discussed with a review of literature.