Investigation of the alterations in cellular electrophysiology underlying ventricular arrhythmia in dogs with the multiple organ dysfunction syndrome.
BACKGROUND
Multiple organ dysfunction syndrome (MODS)-specific cellular electrophysiological changes have so far not been reported and it seemed unlikely that they were related to arrhythmogenesis.


RESULTS
Twelve dogs, weight 12 +/- 2 kg, were divided into a control group (n = 6) and an MODS group (n = 6). MODS lasting for 72 h was induced by the 'two-hit' method in 6 dogs. Ventricular myocytes were enzymatically isolated. Early afterdepolarizations (EADs), action potential duration (APD) and L-type calcium currents (ICa,L) were assessed. Sinus arrhythmias in all MODS dogs (100%; 6 of 6) and premature ventricular beats in 4 MODS dogs (66%; 4 of 6) were recorded, while no arrhythmias were found in the control animals. The prolongation of the APD was associated with a decreased ICa,L, and frequently provoked EADs were the typical electrophysiological alterations in the myocytes of MODS dogs. The action potential prolongation was shortened, the ICa,L blocked and EAD suppressed by using verapamil (100 micromol/l) in the myocytes of MODS dogs (66%; 4 of 6).


CONCLUSIONS
The changes in cellular electrophysiology within 72 h in the heart of MODS dogs are APD prolongation, markedly decreased ICa,L as well as frequently provoked EAD, the most common types of arrhythmia being sinus arrhythmia and premature ventricular beats. This study suggests that verapamil appears to be an effective agent in reversing alterations in cellular electrophysiology at the early stage of MODS.
Department of Cardiac Arrhythmia, Cardiovascular Research Institute, First Affiliated Hospital, Xinjiang Medical University, Xinjiang, China. houyuemei@sina.com
Yue-Mei
YM
Hou
Jian-Guo
JG
Song
Sun
S
Juan
Shuja
S
Ullah
Yang
Y
Bin
Xiao-Qing
XQ
Zang
Fan
F
Ping
Huang
H
Yang
Zheng-Jiang
ZJ
Liu
D000200:Action Potentials; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism; D001794:Blood Pressure; D020746:Calcium Channels, L-Type / Q000378:metabolism; D002478:Cells, Cultured; D004285:Dogs; D022062:Electrophysiologic Techniques, Cardiac; D009102:Multiple Organ Failure / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000502:physiology; D014700:Verapamil / Q000627:therapeutic use
D000889:Anti-Arrhythmia Agents; D020746:Calcium Channels, L-Type; D014700:Verapamil