Low prostaglandin concentrations cause cardiac rhythm disturbances. Effect reversed by low levels of copper or chloroquine.

In perfused male rat hearts concentrations of prostaglandins (PGs) E2 and F2alpha in the range 1 pg/ml to 10 ng/ml (2.8 X 10(-12) to 2.8 X 10(-8)M) consistently caused rhythm irregularities. Higher concentrations had no effect themselves and stabilized rhythm in hearts made unstable by lower concentrations. Copper ions (as the sulphate) at 2 X 10(-6)M stabilized hearts made unstable by PGs and when present prior to the PGs prevented PG induced disturbances. Chloroquine also reversed PG-induced rhythm changes.