PMID- 19808461
OWN - NLM
STAT- MEDLINE
DCOM- 20091029
LR  - 20091007
IS  - 1941-3084 (Electronic)
IS  - 1941-3084 (Linking)
VI  - 2
IP  - 2
DP  - 2009 Apr
TI  - Interaction of activation-repolarization coupling and restitution properties in 
      humans.
PG  - 162-70
LID - 10.1161/CIRCEP.108.785352 [doi]
AB  - BACKGROUND: Dynamic modulation of repolarization is important in 
      arrhythmogenesis. An inverse relation exists in myocardium between activation 
      time (AT) and action potential duration (APD). We hypothesized that resulting 
      gradients of APD and diastolic interval (DI) interact with restitution properties 
      and modulate the timing of repolarization. METHODS AND RESULTS: 
      Activation-recovery intervals (ARI) were acquired from reconstructed noncontact 
      unipolar electrograms from the left ventricular endocardium in 9 patients (7 
      male) with normal ventricles. At a basic paced cycle length (median, 450 ms), 
      ARIs shortened along the path of activation, with a mandatory reciprocal increase 
      of DIs. In the median patient, this range of DIs started at 230 ms at the site of 
      earliest activation and increased to 279 ms at the site of latest activation at a 
      basic cycle length of 450 ms. Four consecutive standard S1 to S2 restitution 
      curves were performed. At sites with a longer ARI (and therefore shorter DI) 
      close to the site of stimulation, premature stimulation produced more shortening 
      of ARIs; therefore, the time course of restitution was steeper than at more 
      distal sites. At normal heart rate, the decrease in ARIs along the conduction 
      pathway compensated for later activation. Thus, dispersion in repolarization time 
      (RT) is smaller than dispersion in ARI in a heart with a steep negative AT-ARI 
      relationship. This protective effect is lost in hearts without such a 
      relationship. In the patients with a steep AT-ARI relationship at basic cycle 
      length, this relation is lost after premature stimulation and is a function of 
      prematurity. Thus, dispersion in RT is larger after shortly coupled extra stimuli 
      in patients with a steep AT-ARI relationship. CONCLUSIONS: A complex interplay 
      exists between activation-repolarization coupling and restitution properties, 
      largely driven by ARI and DI gradients. This plays a significant role in the 
      dynamics of repolarization in humans.
FAU - Hanson, Ben
AU  - Hanson B
AD  - Department of Mechanical Engineering, University College London, London, WC1E 
      6DB, United Kingdom.
FAU - Sutton, Peter
AU  - Sutton P
FAU - Elameri, Nasser
AU  - Elameri N
FAU - Gray, Marcus
AU  - Gray M
FAU - Critchley, Hugo
AU  - Critchley H
FAU - Gill, Jaswinder S
AU  - Gill JS
FAU - Taggart, Peter
AU  - Taggart P
LA  - eng
GR  - Wellcome Trust/United Kingdom
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20090218
PL  - United States
TA  - Circ Arrhythm Electrophysiol
JT  - Circulation. Arrhythmia and electrophysiology
JID - 101474365
SB  - IM
CIN - Circ Arrhythm Electrophysiol. 2009 Apr;2(2):100-1. PMID: 19808452
MH  - Action Potentials/*physiology
MH  - Adult
MH  - Aged
MH  - Catheter Ablation
MH  - Diastole/*physiology
MH  - Female
MH  - Heart Conduction System/*physiopathology
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Refractory Period, Electrophysiological/*physiology
MH  - Tachycardia, Supraventricular/*physiopathology/surgery
MH  - Young Adult
EDAT- 2009/10/08 06:00
MHDA- 2009/10/30 06:00
CRDT- 2009/10/08 06:00
PHST- 2009/10/08 06:00 [entrez]
PHST- 2009/10/08 06:00 [pubmed]
PHST- 2009/10/30 06:00 [medline]
AID - CIRCEP.108.785352 [pii]
AID - 10.1161/CIRCEP.108.785352 [doi]
PST - ppublish
SO  - Circ Arrhythm Electrophysiol. 2009 Apr;2(2):162-70. doi: 
      10.1161/CIRCEP.108.785352. Epub 2009 Feb 18.