PMID- 2805275
OWN - NLM
STAT- MEDLINE
DCOM- 19891218
LR  - 20190623
IS  - 0009-7322 (Print)
IS  - 0009-7322 (Linking)
VI  - 80
IP  - 5
DP  - 1989 Nov
TI  - Slow and long-lasting modulation of myocardial repolarization produced by ectopic 
      activation in isolated rabbit hearts. Evidence for cardiac "memory".
PG  - 1412-20
AB  - Prolonged ventricular pacing induces T wave polarity changes that persist long 
      after cessation of pacing. To examine how ventricular repolarization is modulated 
      by prolonged changes in activation sequence, we studied the effect of ectopic 
      pacing on the distribution of action potential durations (APDs) in nine isolated 
      Langendorff-perfused rabbit hearts. A contact electrode probe was used to map 
      right and left ventricular-epicardial monophasic action potentials during three 
      consecutive changes in stimulus site, that is, 1) during 45 minutes of right 
      atrial pacing, 2) during 120 minutes of right ventricular pacing, and 3) again, 
      during 60 minutes of right atrial pacing. During each of these phases, the effect 
      of activation sequence on repolarization was examined by linear-regression 
      analysis of APD on activation time (AT). Results averaged for all nine hearts 
      showed that during the initial atrial-pacing phase, APD was inversely related to 
      AT (slope [S] = -1.63; r = 0.76), indicating that sites with earlier activation 
      repolarized later. With the onset of ventricular pacing, the inverse correlation 
      between AT and APD disappeared (S = -0.19; r = 0.31). Continuing ventricular 
      pacing, however, produced slow changes in APD that restored the inverse relation 
      (S = -0.71; r = 0.68 at 120 minutes; p less than 0.0002 versus 5 minutes). 
      Switching from ventricular to atrial pacing again perturbed the inverse 
      correlation (S = 0.28; r = 0.35) but at 60 minutes of atrial pacing, a 
      significant inverse correlation was reestablished (S = -1.25; r = 0.53; p less 
      than 0.01 versus 5 minutes). An inverse correlation between AT and APD tends to 
      synchronize repolarization time (RT, the sum of AT and APD).(ABSTRACT TRUNCATED 
      AT 250 WORDS)
FAU - Costard-Jackle, A
AU  - Costard-Jackle A
AD  - Cardiology Division, Stanford University School of Medicine, California.
FAU - Goetsch, B
AU  - Goetsch B
FAU - Antz, M
AU  - Antz M
FAU - Franz, M R
AU  - Franz MR
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Circulation
JT  - Circulation
JID - 0147763
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - *Cardiac Pacing, Artificial
MH  - Electrocardiography
MH  - Female
MH  - Heart Conduction System/*physiology
MH  - Male
MH  - Myocardial Contraction/physiology
MH  - Rabbits
MH  - Time Factors
MH  - Ventricular Function
EDAT- 1989/11/01 00:00
MHDA- 1989/11/01 00:01
CRDT- 1989/11/01 00:00
PHST- 1989/11/01 00:00 [pubmed]
PHST- 1989/11/01 00:01 [medline]
PHST- 1989/11/01 00:00 [entrez]
AID - 10.1161/01.cir.80.5.1412 [doi]
PST - ppublish
SO  - Circulation. 1989 Nov;80(5):1412-20. doi: 10.1161/01.cir.80.5.1412.