A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to operate in three different modes according to relative frequency of different beat types. If beats of a first beat type, such as ventricularly paced beats, are predominant, the processor ignores other beat types and performs ischemia detection only on ventricularly paced beats. Conversely, if beats of a second beat type, such as sinus or atrially paced beats, are predominant, the processor ignores ventricularly paced beats and performs ischemia detection only on sinus or atrially paced beats. If there is a mixture of beat types such that neither predominates, the processor performs ischemia detection on both beat types.
