Liposome-encapsulated hemoglobin (HbV) can serve as blood substitutes of oxygen-carrying capacity comparable to human blood. To investigate the resuscitation effect of HbV on lethal hemorrhage and its efficacy on myocardial arrhythmogenesis, optical mapping analysis (OMP) and electrophysiological study (EPS) were performed in graded blood exchange up to 85% blood loss in rats. Six rats were gradually exchanged blood with 5% albumin (Alb-group) while 4 rats exchanged with washed rat erythrocyte (washed RBC-group) and 5 rats with HbV (HbV-group). Survival effects over 24 hours were examined in 5 rats in each group. After excising the heart, OMP and EPS were performed. All rats died in Alb-group whereas all survived for following 24-hours in washed RBC-group and HbV-group (Figure 1). OMP revealed impaired (prolonged) action potential duration (APD) dispersion in LV in Alb-group. In contrast, myocardial APD dispersions in LV were substantially attenuated in HbV-group and washed RBC-group (Figure 2). Lethal arrhythmias (VT/VF) were provoked by EPS in Alb-group. No VT/VF was induced in both HbV-group and washed RBC-group.
Conclusions: Lethal hemorrhage causes VT/VF in the presence with impaired APD dispersion. HbV could rescue acute-phase lethal hemorrhage partially through preventing lethal arrhythmias with preserved APD dispersion and improve prognosis.