Ambasilide, a representative of Class III antiarrhythmics, was reported to prolong the cardiac action potential duration in the dog, with little or no effect on Ca and Na currents. We synthesised a series of ambasilide analogues, having the 3, 8-diazabicyclo-[3.2. 1]-octane moiety instead of the 3, 7-diazabicyclo-[3.3. 1]-nonane present in ambasilide. The compounds were tested both in vitro extracellular electrophysiological assays and by the ...