Why does hypokalaemia increase the risk of digitalis-induced cardiac arrhythmias during treatment with Hemosol B0?

The supplied information states that hypokalaemia increases the risk of digitalis-induced cardiac arrhythmias but does not explain the mechanism; Hemosol B0 is potassium-free, so serum potassium must be monitored before and during haemofiltration and/or haemodialysis.