Systems and methods for distinguishing cardiac ischemia from systemic influences on IEGM morphology using an implantable medical device

A system, for use with an implantable medical device, for distinguishing cardiac ischemia from other conditions affecting a morphology of electrical cardiac signals sensed within a patient in which the device is implanted, the system comprising:

• a plurality of electrodes configured to monitor electrical cardiac signals from a plurality of spatially-distinct locations within a heart of the patient;
• a morphological feature detecting unit operative to detect changes in morphological features of the electrical cardiac signals indicative of possible cardiac ischemia within the patient;
• and
• a cardiac ischemia discrimination unit configured to:
• determine that the changes in the detected morphological features are global if the changes are detected in signals detected at each of the plurality of spatially-distinct locations;
• determine that the changes in the detected morphological features are local if the changes are detected in signals detected at one or more, but not all, of the plurality of spatially-distinct locations;
• wherein:
• when the changes in the detected morphological features are determined to be global, the cardiac ischemia discrimination unit is configured to determine that the changes in morphological features of the electrical cardiac signals indicate systemic influences;
• and
• when the changes in the detected morphological features are determined to be local, the cardiac ischemia discrimination unit is configured to determine that the changes in the morphological features of the electrical cardiac signals indicate cardiac ischemia.

A system, for use with an implantable medical device, for distinguishing cardiac ischemia from other conditions affecting a morphology of electrical cardiac signals sensed within a patient in which the device is implanted, the system comprising:

• a plurality of electrodes configured to monitor electrical cardiac signals from a plurality of spatially-distinct locations within a heart of the patient;
• a morphological feature detecting unit operative to detect changes in morphological features of the electrical cardiac signals indicative of possible cardiac ischemia within the patient;
• a timing unit operative to track repolarization-based intervals of intervals between the peaks of T-waves and the ends of T-waves within the electrical cardiac signals;
• and
• a cardiac ischemia discrimination unit configured to:
• determine if the T-wave based intervals indicate a cardiac ischemia or systemic influences;
• determine that the changes in the detected morphological features are global if the changes are detected in signals detected at each of the plurality of spatially-distinct locations;
• determine that the changes in the detected morphological features are local if the changes are detected in signals detected at one or more, but not all, of the plurality of spatially-distinct locations;
• wherein:
• when the changes in the detected morphological features are determined to be global and the T-wave based intervals indicate systemic influences, the cardiac ischemia discrimination unit is configured to determine that the changes in morphological features of the electrical cardiac signals indicate systemic influences;
• and
• when the changes in the detected morphological features are determined to be local and the T-wave based intervals indicate cardiac ischemia, the cardiac ischemia discrimination unit is configured to determine that the changes in the morphological features of the electrical cardiac signals indicate cardiac ischemia.