This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Spilkin, S. Articles by Chesler, E. Search for Related Content PubMed PubMed Citation Articles by Spilkin, S. Articles by Chesler, E.

Circulation, Vol 55, 418-422, Copyright © 1977 by American Heart Association

ARTICLES

Complete heart block in a case of idiopathic hypertrophic subaortic stenosis: noninvasive correlates with the timing of atrial systole

S Spilkin, AS Mitha, RE Matisonn and E Chesler

A young man with IHSS who developed complete heart block was successfully treated with a permanent pacemaker. Echocardiography and other noninvasive techniques showed marked cycle-to-cycle variation in the evidence of subvalvular obstruction which decreased markedly when atrial systole preceded the ensuing paced complex by an appropriate interval. Because cycle length and therefore afterload were constant, it is concluded that diminished obstruction resulted from augmented ventricular end-diastolic volume produced by atrial contraction. The mitral valve echocardiogram showed unusual movements in diastole dependent upon the timing of atrial systole. Early reopening of the leaflets was a direct result of atrial contraction when the P waves were appropriately timed in presystole, whereas late reopening was passive and a result of ventricular filling in mid-diastole. Variations in intensity of the first heart sound correlated with the position of the mitral valve leaflets at the onset of ventricular systole.