&NA;Tedisamil (KC 8857) is a potassium channel antagonist with bradycardic action and class III antiarrhythmic properties. Under development by Solvay, the drug is in phase III clinical trials in Europe for the treatment of ischaemic heart disorders. Tedisamil is produced as a capsule for oral administration.Studies of the cardiac and haemodynamic effects of tedisamil in patients with heart failure secondary to dilated cardiomyopathy have so far shown it to be unsuitable as a treatment, as tedisamil increased vascular resistance.