open access

Vol 67, No 9 (2009)
Other
Published online: 2009-10-12
Submitted: 2012-12-28
Get Citation

Electrocardiogram of the month
Supernormal excitability and conduction in the human heart – electrocardiographic myth or reality?

Marek Jastrzębski
Kardiol Pol 2009;67(9):1030-1035.

open access

Vol 67, No 9 (2009)
Other
Published online: 2009-10-12
Submitted: 2012-12-28

Abstract

Three cases of possible supernormal conduction and excitability are described. Case one: subthreshold stimulation with ventricular capture occurring only at the end of the T wave. Case two: advanced atrioventricular block with conduction present only when P waves fell at the downsloping part of the T wave of ventricular escape beats. Case three: 2 : 1 atrioventricular block at atrial pacing rate of 115 bpm with improvement of conduction during higher pacing rates (3 : 2 block at 130 bpm and above; with negligible PR prolongation). Possible alternative mechanisms: gap phenomenon, ventriculophasic modulation of vagal discharge, ventriculophasic pacing lead movement and concealed 2 : 1 atrioventricular block due to superimposed ventricular escape rhythm, are discussed and considered either impossible or unlikely.

Abstract

Three cases of possible supernormal conduction and excitability are described. Case one: subthreshold stimulation with ventricular capture occurring only at the end of the T wave. Case two: advanced atrioventricular block with conduction present only when P waves fell at the downsloping part of the T wave of ventricular escape beats. Case three: 2 : 1 atrioventricular block at atrial pacing rate of 115 bpm with improvement of conduction during higher pacing rates (3 : 2 block at 130 bpm and above; with negligible PR prolongation). Possible alternative mechanisms: gap phenomenon, ventriculophasic modulation of vagal discharge, ventriculophasic pacing lead movement and concealed 2 : 1 atrioventricular block due to superimposed ventricular escape rhythm, are discussed and considered either impossible or unlikely.
Get Citation

Keywords

supernormality; supernormal conduction; atrioventricular block; electrocardiogram

About this article
Title

Electrocardiogram of the month
Supernormal excitability and conduction in the human heart – electrocardiographic myth or reality?

Journal

Kardiologia Polska (Polish Heart Journal)

Issue

Vol 67, No 9 (2009)

Pages

1030-1035

Published online

2009-10-12

Bibliographic record

Kardiol Pol 2009;67(9):1030-1035.

Keywords

supernormality
supernormal conduction
atrioventricular block
electrocardiogram

Authors

Marek Jastrzębski

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By "Via Medica sp. z o.o." sp.k., Świętokrzyska 73 street, 80–180 Gdańsk, Poland

tel.:+48 58 320 94 94, faks:+48 58 320 94 60, e-mail: viamedica@viamedica.pl