Pattern classification techniques are provided for use with an implantable medical device for detecting cardiac ischemia substantially in real-time. Values representative of morphological features of electrical cardiac signals are detected by the implantable medical device. Then, a determination is made as to whether the patient is subject to an on-going episode of cardiac ischemia by applying the values to a pattern classifier configured to identify patterns representative of cardiac ischemia. In one example, the determination is made substantially in real-time by the device itself based on the IEGM signals it detects. In other examples, the IEGM signals are relayed promptly to a bedside monitor or other external device, which analyzes the signals using the pattern classifier to detect ischemia. Therapy may be applied in response to cardiac ischemia. For example, if the implanted device is equipped with a drug pump, appropriate medications may be administered such as anti-thrombolytics.