Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:After introducing IKAS with a relatively low calcium affinity, APD is shortened when Cai transient is large, resulting in negative Cai-Vm coupling and electromechanically discordant alternans (Kennedy et al., 2017).
Category: