Toggle Main Menu Toggle Search

Open Access padlockePrints

Coupling interval, exit block, and periodicity of ventricular parasystolic rhythm

Lookup NU author(s): Emeritus Professor Alan MurrayORCiD


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Summary: The electrocardiograms in this study of parasystolic rhythm were tape recorded and then analysed with a special purpose hybrid computer. The rate of appearance of specific inter-ectopic intervals was shown to change significantly with small changes in either the sinus or parasystolic pacemaker period. Natural changes in the period of the ectopic pacemakers were observed over several hours. Changes amounting to 14% within 10 min and 18% overall were observed in one patient, and a gradual lengthening of 10% over 3 h in another.A previously undescribed form of exit block has been discovered in one patient where the block remained active for a given time only after propagation from the parasystolic focus. Different interectopic intervals were shown to contribute to specific and restricted coupling interval locations in diastole. Hence this form of exit block, by preventing some inter-ectopic intervals from propagating, limited the locations in diastole in which parasystolic ectopic complexes could appear. In this case later diastolic complexes were inhibited and hence fusion complexes were completely absent. Parasystolic rhythm, with and without the exit block described, was simulated successfully by a digital computer. The simulations aided our understanding of the clinical data.

Publication metadata

Author(s): Vellani CW, Murray A, Neilson JM

Publication type: Review

Publication status: Published

Journal: Cardiovascular Research

Year: 1979

Volume: 13

Issue: 6

Pages: 320-329

Print publication date: 01/06/1979

ISSN (print): 0008-6363

ISSN (electronic): 1755-3245

Publisher: Oxford University Press


DOI: 10.1093/cvr/13.6.320