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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Lehmann, M. H. Articles by Akhtar, M. Search for Related Content PubMed PubMed Citation Articles by Lehmann, M. H. Articles by Akhtar, M.

Circulation, Vol 69, 1096-1102, Copyright © 1984 by American Heart Association

ARTICLES

Postextrasystolic alterations in refractoriness of the His-Purkinje system and ventricular myocardium in man

MH Lehmann, S Denker, R Mahmud and M Akhtar

The changes in refractoriness of the His-Purkinje system (HPS) and ventricular myocardium (VM) that are associated with the occurrence of postextrasystolic beats in man are unknown. Accordingly, using a pacing model of the cycle length changes created by a ventricular extrasystole- postextrasystole sequence, we measured retrograde HPS and VM relative and effective refractory periods (RRP and ERP) in 15 patients with the use of ventricular test extrastimuli during preextrasystolic basic control drive (method I) and after programmed extrasystolic (method II) and postextrasystolic (method III) beats. The basic cycle length (same for all three methods) ranged from 500 to 700 msec (mean 613 +/- 74 msec) and the extrasystolic coupling interval (identical for methods II and III) comprised 68 +/- 4% of the basic cycle length. In method III the postextrasystolic pause was programmed to equal the basic cycle length (i.e., noncompensatory) so that method I could serve as control for method III. RRP-HPS decreased from 331 +/- 37 msec in method I to 245 +/- 37 msec or less during the extrasystolic beat (p less than .001). A less dramatic corresponding shortening of ERP-VM and RRP-VM was observed, i.e., from 245 +/- 21 and 264 +/- 23 msec (method I) to 233 +/- 23 and 251 +/- 22 msec (method II), respectively (p less than .001). With the postextrasystolic beat, however, RRP-HPS increased to exceed the control value of method I by 23 +/- 11 msec (p less than .001). This greater-than-expected RP prolongation was also associated with significantly increased retrograde HPS conduction times (in method III vs method I) at both long and short test stimulus coupling intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				M. O. Sweeney, L. L. Ruetz, P. Belk, T. J. Mullen, J. W. Johnson, and T. Sheldon Bradycardia Pacing-Induced Short-Long-Short Sequences at the Onset of Ventricular Tachyarrhythmias: A Possible Mechanism of Proarrhythmia? J. Am. Coll. Cardiol., August 14, 2007; 50(7): 614 - 622. [Abstract] [Full Text] [PDF]

				M. A. Watanabe and M. L. Koller Mathematical analysis of dynamics of cardiac memory and accommodation: theory and experiment Am J Physiol Heart Circ Physiol, April 1, 2002; 282(4): H1534 - H1547. [Abstract] [Full Text] [PDF]