Synergistic interaction of tri- and tetra-chloroethylene, hypoxia, and ethanol on the atrioventricular conduction of the perfused rat heart.

Abstract

The interactions of trichloroethylene (TCEL) or tetrachloroethylene (perchloroethylene ; PCEL) with hypoxia and/or ethanol on the conduction system of the isolated perfused rat heart were investigated by recording the direct elec-trocardiogram (ECG). The coadministration of TCEL (0.05 mM), hypoxia (45% oxygen decrease), and ethanol (0.3%) produced the significant prolongation of atrioventricular conduction time (PQ interval) (p<0.01), whereas none of TCEL (0.05 mM) alone, hypoxia alone, ethanol alone, hypoxia with ethanol, TCEL with hypoxia, and TCEL with ethanol caused significant change in ECG findings. In TCEL of 0.1 mM, the coadministration with hypoxia and/or ethanol produced the significant prolongation of PQ interval (p<0.01). In PCEL of 0.1 mM, only when hypoxia and ethanol were coadministered simultaneously, PQ prolongation observed was significant (p<0.01). It is concluded that (1) TCEL and PCEL have the direct and local effect on the heart conduction system ; (2) the effect on the heart con-duction system is stronger in TCEL than in PCEL ; (3) hypoxia and ethanol synergistically enhance the effect of TCEL and PCEL on the atrioventricular conduction system at the observed concentrations.