Reperfusion-induced arrhythmias and lethality are reduced by a 2KDa heparin fragment

The influence of a low molecular weight heparin (Oligo-H, m.w. 2KDa) on ventricular arrhythmias and lethality induced by heart reperfusion following a 5 min coronary occlusion was studied in anesthetized rats. Both intravenous (i.v.) and subcutaneous (s.c.) injection of the compound dose- and time-dependently prevented the reperfusion syndrome: in all saline-pretreated animals post-ischemic reperfusion induced ventricular tachycardia (VT), which degenerated into ventricular fibrillation (VF) in 25 out of 30 rats, with a mortality rate of 73%; on the other hand, in rats i.v. or s.c. pretreated with Oligo-H (20 mg/kg, 30 and 90 min, respectively, before coronary occlusion), VT occurred in 4 out of 10-11 animals and degenerated into VF in 2-3 out of 10-11 animals, with a mortality rate of 18-20%. Even more effective was a low molecular weight dermatan sulfate (Oligo-DS, m.w. 2.1KDa). In rats treated with lidocaine, used as reference compound, at the dose of 5 mg/kg i.v. 10 min before coronary occlusion, VT occurred in 2 out of 10 animals and degenerated into VF in 1 out of 10 animals, with a mortality rate of 10%. It is concluded that low molecular weight glycosaminoglycans significantly reduce the consequences of heart reperfusion.