PMID- 18310522
OWN - NLM
STAT- MEDLINE
DCOM- 20080529
LR  - 20200930
IS  - 0363-6135 (Print)
IS  - 0363-6135 (Linking)
VI  - 294
IP  - 4
DP  - 2008 Apr
TI  - Moderate hypothermia increases the chance of spiral wave collision in favor of 
      self-termination of ventricular tachycardia/fibrillation.
PG  - H1896-905
LID - 10.1152/ajpheart.00986.2007 [doi]
AB  - In cardiac arrest due to ventricular fibrillation (VF), moderate hypothermia (MH, 
      33 degrees C) has been shown to improve defibrillation success compared with 
      normothermia (NR, 37 degrees C) and severe hypothermia (SH, 30 degrees C). The 
      underlying mechanisms remain unclear. We hypothesized that MH might prevent 
      reentrant excitations rotating around functional obstacles (rotors) that are 
      responsible for the genesis of VF. In two-dimensional Langendorff-perfused rabbit 
      hearts prepared by cryoablation (n = 13), action potential signals were recorded 
      by a high-resolution optical mapping system. During basic stimulation (2.5-5.0 
      Hz), MH and SH caused significant prolongation of action potential duration and 
      significant reduction of conduction velocity. Wavelength was unchanged at MH, 
      whereas it was shortened significantly at SH at higher stimulation frequencies 
      (4.0-5.0 Hz). The duration of direct current stimulation-induced ventricular 
      tachycardia (VT)/VF was reduced dramatically at MH compared with NR and SH. The 
      spiral wave (SW) excitations documented during VT at NR were by and large 
      organized, whereas those during VT/VF at MH and SH were characterized by 
      disorganization with frequent breakup. Phase maps during VT/VF at MH showed a 
      higher incidence of SW collision (mutual annihilation or exit from the anatomical 
      boundaries), which caused a temporal disappearance of phase singularity points 
      (PS-0), compared with that at NR and SH. There was an inverse relation between 
      PS-0 period in the observation area and VT/VF duration. MH data points were 
      located in a longer PS-0 period and a shorter VT/VF duration zone compared with 
      SH. MH causes a modification of SW dynamics, leading to an increase in the chance 
      of SW collision in favor of self-termination of VT/VF.
FAU - Harada, Masahide
AU  - Harada M
AD  - Dept. of Cardiovascular Research, Research Inst. of Environmental Medicine, 
      Nagoya University,Nagoya, 464-8601, Japan.
FAU - Honjo, Haruo
AU  - Honjo H
FAU - Yamazaki, Masatoshi
AU  - Yamazaki M
FAU - Nakagawa, Harumichi
AU  - Nakagawa H
FAU - Ishiguro, Yuko S
AU  - Ishiguro YS
FAU - Okuno, Yusuke
AU  - Okuno Y
FAU - Ashihara, Takashi
AU  - Ashihara T
FAU - Sakuma, Ichiro
AU  - Sakuma I
FAU - Kamiya, Kaichiro
AU  - Kamiya K
FAU - Kodama, Itsuo
AU  - Kodama I
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080229
PL  - United States
TA  - Am J Physiol Heart Circ Physiol
JT  - American journal of physiology. Heart and circulatory physiology
JID - 100901228
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - Cardiac Pacing, Artificial
MH  - Cryosurgery
MH  - Disease Models, Animal
MH  - Electrocardiography
MH  - Female
MH  - Heart Conduction System/*physiopathology
MH  - *Hypothermia, Induced
MH  - In Vitro Techniques
MH  - Male
MH  - Optics and Photonics
MH  - Perfusion
MH  - Rabbits
MH  - Research Design
MH  - Signal Processing, Computer-Assisted
MH  - Tachycardia, Ventricular/physiopathology/*prevention & control
MH  - Thermography
MH  - Time Factors
MH  - Ventricular Fibrillation/physiopathology/*prevention & control
EDAT- 2008/03/04 09:00
MHDA- 2008/05/30 09:00
CRDT- 2008/03/04 09:00
PHST- 2008/03/04 09:00 [pubmed]
PHST- 2008/05/30 09:00 [medline]
PHST- 2008/03/04 09:00 [entrez]
AID - 00986.2007 [pii]
AID - 10.1152/ajpheart.00986.2007 [doi]
PST - ppublish
SO  - Am J Physiol Heart Circ Physiol. 2008 Apr;294(4):H1896-905. doi: 
      10.1152/ajpheart.00986.2007. Epub 2008 Feb 29.