A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between two different heart beats types such as ventricularly paced beats and supraventricular beats. The processor collects separate reference data for a first one of the beat types indicative of the normal values of a cardiac feature. The processor performs an ischemia test to beats of the first type by first checking whether valid reference data exists for that beat type. If so, the ischemia test is based on this reference data. If no valid reference data exists for the first beat type, the processor applies an ischemia test that is not based on reference data for the first beat type.