Technique to evaluate myocardial ischemia from ECG parameters
First Claim
1. A method of evaluating a patient for ischemia by evaluation of an electrocardiogram of that patient and specifically an ST segment thereof, comprising the steps of taking an electrocardiogram of the patient, digitizing the electrocardiogram, determine length of said ST segment, estimating a critical threshold value in said electrocardiogram as a function of the length of the ST-segment of said electrocardiogram, calculating a value representing ST-segment depression relative to a fixed baseline based on signal information representing said baseline and said ST-segment to transform signals representing the ST-segment morphology into signals representing an equivalent horizontal morphology, and comparing said signals representing said equivalent horizontal morphology to said threshold value, where morphologies exceeding said threshold are labelled ischemic.
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Abstract
As a method of diagnosing ischemia non-invasively, the effective component of the ST-segment depression (STe) of an electrocardiogram is measured. A precise mathematical relationship between the values of the ST-segment depression, slope, and length of the ST-segment was defined and implemented, making it possible to compare any ST-segment morphology against a standard reference of horizontal depression.
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Citations
12 Claims
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1. A method of evaluating a patient for ischemia by evaluation of an electrocardiogram of that patient and specifically an ST segment thereof, comprising the steps of taking an electrocardiogram of the patient, digitizing the electrocardiogram, determine length of said ST segment, estimating a critical threshold value in said electrocardiogram as a function of the length of the ST-segment of said electrocardiogram, calculating a value representing ST-segment depression relative to a fixed baseline based on signal information representing said baseline and said ST-segment to transform signals representing the ST-segment morphology into signals representing an equivalent horizontal morphology, and comparing said signals representing said equivalent horizontal morphology to said threshold value, where morphologies exceeding said threshold are labelled ischemic.
- 2. A signal processing system for evaluating and assigning a patient to normal or ischemic categories comprising means for generating a digital representation of an electrocardiogram of said patient, means for analyzing said electrocardiogram and calculating a critical threshold value for said electrocardiogram as a function of the length of the ST-segment of said electrocardiogram, means for calculating a value representing ST-segment depression relative to a fixed baseline based on said digitized signal information representing said baseline and said ST-segment to transform signals representing the ST-segment morphology into signals representing an equivalent horizontal morphology, comparison means for comparing said signals representing said horizontal morphology to signals representing said threshold value and assigning said patient to a normal or ischemic classification based on the result of said comparison.
Specification