Abstract 14820: Action Potential Duration Dispersion is Still Significant Determinant in Lethal Arrhythmias Even After Successful Resuscitation by Artificial Oxygen Carrier in Hemorrhagic Shock Heart
Prolonged low mean systemic blood pressure<40 mmHg in hemorrhagic shock causes irreversible heart dysfunction. This “Shock Heart Syndrome” (SHS) associates with lethal arrhythmias (VT/VF) leading to adverse prognosis. In 30% repetitive bleeding of Sprague-Dawley rat’s model, we previously reported that the oxygenated liposome-encapsulated human hemoglobin (HbV) is almost comparably effective with washed red blood cell (wRBC) to improve prognosis and prevent VT/VF in SHS using optical mapping analysis (OM) with electrophysiological burst pacing (EP). However, still about 20% of rats resuscitated by HbV had VT/VF by EP. To investigate the mechanisms of lethal arrhythmogenesis in HbV resuscitation, we measured conduction time (CT) and pattern, as well as action potential duration dispersion (APDd) defined as maximum APD - minimum APD in each right and left ventricle (RV/LV) in 29 SHS rats resuscitated by HbV, and compared them with normal rats (n=6, NL-Group) using OM and EP. The SHS by HbV were divided into two groups of none-VT/VF-Group (n=22) and VT/VF-Group (n=7) according to VT/VF induction by EP. Pathological findings including the connexin43 (Cx43) immunehistochemistry were also compared. As results, CT and patterns were not different among three groups while APDds in RV and LV were significantly prolonged in VT/VF-Group (VT/VF-Group vs. none-VT/VF-Group and NL-Group: RV, 19±7 vs. 12±6, 12±2 ms, p<0.05; LV, 32±7 vs. 14±7, 13±7 ms, p<0.05). Myocardium and Cx43 were more damaged in VT/VF-Group. In conclusions: The repolarization property expressed as APDd is significant index to identify VT/VF induction and myocardial damage in HbV-resuscitated SHS. This information could contribute to improve the efficacy of HbV.
Author Disclosures: B. Takase: None. K. Hashimoto: None.
- © 2016 by American Heart Association, Inc.