SYSTEM AND METHOD FOR DETECTING CARDIAC ISCHEMIA BASED ON T-WAVES USING AN IMPLANTABLE MEDICAL DEVICE
First Claim
1. In an implantable medical device for implant within a patient, a system comprising:
- a T-wave detection subsystem operative to detect a plurality of individual T-waves;
a T-wave energy integration subsystem operative to detect a total energy for each of a plurality of the individual T-waves; and
a cardiac ischemia detection subsystem operative to process a total energy of one of the individual T-waves, an average of the total energies of a plurality of the T-waves and an energy threshold value, to detect cardiac ischemia.
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Abstract
A technique is provided for detecting episodes of cardiac ischemia based on an examination of the total energy of T-waves. Since cardiac ischemia is often a precursor to acute myocardial infarction (AMI) or ventricular fibrillation (VF), the technique thereby provides a method for predicting the possible onset of AMI or VF. Briefly, the technique integrates internal electrical cardiac signals occurring during T-waves and then compares the result against a running average. If the result exceeds the average by some predetermined amount, ischemia is thereby detected and a warning signal is provided to the patient. The maximum slope of the T-wave is also exploited. Techniques are also set forth herein for reliably detecting T-waves, which help prevent P-waves from being misinterpreted as T-waves on unipolar sensing channels. The T-wave detection technique may be used in conjunction with ischemia detection or for other purposes.
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Citations
20 Claims
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1. In an implantable medical device for implant within a patient, a system comprising:
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a T-wave detection subsystem operative to detect a plurality of individual T-waves;
a T-wave energy integration subsystem operative to detect a total energy for each of a plurality of the individual T-waves; and
a cardiac ischemia detection subsystem operative to process a total energy of one of the individual T-waves, an average of the total energies of a plurality of the T-waves and an energy threshold value, to detect cardiac ischemia. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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detecting a plurality of individual T-waves;
calculating a total energy for each of a plurality of the individual T-waves; and
detecting cardiac ischemia based on the total energy of one of the individual T-waves, an average of the total energies of a plurality of the other T-waves and an energy threshold value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification