Intraosseous infusion of liposome-encapsulated hemoglobin (HbV) acutely prevents hemorrhagic anemia-induced lethal arrhythmias, and its efficacy persists with preventing proarrhythmic side effects in the subacute phase of severe hemodilution model

Abstract

Background: Artificial oxygen carriers (HbV) can treat hemorrhagic shock with lethal arrhythmias (VT/VF). No reports exist on subacute HbV's effects.

Methods: Acute and subacute resuscitation effects with anti-arrhythmogenesis of HbV were studied in 85% blood exchange rat model (85%-Model). Lethal 85%-Model was created by bone marrow transfusion and femoral artery bleeding in 80 SD rats in HbV-administered group (HbV-group), washed erythrocyte-administered group (wRBC-group), and 5% albumin-administered group (ALB-group). Survival rates, anti-arrhythmic efficacy by optical mapping system (OMP) with electrophysiological study (EPS) in Langendorff heart, cardiac autonomic activity by heart rate variability (HRV) and ventricular arrhythmias by 24-h electrocardiogram telemetry monitoring (24 h-ECG) in awake, and left ventricular function by echocardiography (left ventricular ejection fraction [LVEF]) were measured.

Results: All rats in HbV- and wRBC-groups survived for 4 weeks, whereas no rats in ALB-group. HbV and wRBC acutely suppressed VT/VF in Langendorff heart through ameliorating action potential duration dispersion (APDd) analyzed by OMP with EPS. For subacute analysis, 50% blood exchange by 5% albumin was used (ALB-group 50). Subacute salutary effect on APDd and VT/VF inducibility was confirmed in HbV- and wRBC-groups. 24 h-ECG showed that HbV and wRBC suppressed none-sustained ventricular tachycardia (NSVT) and sympathetic component of HRV (LF/HF) with preserved LVEF (HbV-group, wRBC-group vs. ALB-group 50; NSVT numbers/days, 0.5 ± 0.3, 0.4 ± 0.3 vs. 3.9 ± 1.2*; LF/HF, 1.1 ± 0.2, 0.8 ± 0.2 vs. 3.5 ± 1.0*; LVEF, 84 ± 5, 83 ± 4, vs. 77 ± 4%*; *p < 0.05).

Conclusions: Collectively, HbV has sustained antiarrhythmic effect in subacute 85%-Model by ameliorating electrical remodeling and improving arrhythmogenic modifying factors (HRV and LVEF). These findings are useful in now continuing clinical trials of HbV.

Keywords: artificial oxygen carrier; heart rate variability; hemorrhage; lethal arrhythmia; resuscitation.