The invention relates to a novel tension-dependent potassium channel protein Kv6.2 (SEQ ID NO:1). The Kv6.2 gene is expressed preferably in the myocardium or in the hippocampus. Novel functional heteromultimeric potassium channels having high affinity with propafenone are formed in conjunction with subunit Kv2.1. According to the invention, said novel potassium channels are used in test systems which are suitable of identifying substances modulating, opening or closing the Kv2,1/Kv6.2 channels and which can be used as therapeutic agents.