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 individual T-waves;
a T-wave energy integration subsystem operative to determine a total energy for each of the individual T-waves; and
a cardiac ischemia detection subsystem operative to;
a) calculate a running average of the total energies of the detected T-waves;
b) calculate the difference between the total energy of a last detected T-wave and the running average;
c) compare the energy difference to a predetermined energy threshold value;
repeat a), b) and c) for a plurality of cardiac beats; and
detect cardiac ischemia when the difference exceeds the predetermined energy threshold value for a predetermined number of cardiac beats.
0 Assignments
0 Petitions
Accused Products
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.
-
Citations
10 Claims
-
1. In an implantable medical device for implant within a patient, a system comprising:
-
a T-wave detection subsystem operative to detect individual T-waves; a T-wave energy integration subsystem operative to determine a total energy for each of the individual T-waves; and a cardiac ischemia detection subsystem operative to; a) calculate a running average of the total energies of the detected T-waves; b) calculate the difference between the total energy of a last detected T-wave and the running average; c) compare the energy difference to a predetermined energy threshold value; repeat a), b) and c) for a plurality of cardiac beats; and detect cardiac ischemia when the difference exceeds the predetermined energy threshold value for a predetermined number of cardiac beats. - View Dependent Claims (2, 3, 4)
-
-
5. A method comprising:
-
detecting a plurality of individual T-waves; calculating a total energy for each of the individual T-waves; a) calculating a running average of the total energies of the detected T-waves; b) calculating the difference between the total energy of a last detected T-wave and the running average; c) comparing the energy difference to a predetermined energy threshold value; repeating a), b) and c) for a plurality of cardiac beats; and indicating cardiac ischemia when the energy difference exceeds the predetermined energy threshold value for a predetermined number of cardiac beats. - View Dependent Claims (6, 7, 8, 9, 10)
-
Specification