System for cardiac status determination
A system improves detection and diagnosis of blood pressure based cardiac function and tissue activities by analyzing and characterizing cardiac blood pressure signals (including non-invasive and invasive blood pressure, discrete values and continuous waveforms) using pressure signal variation and variability calculation and evaluation. The system combines blood pressure analysis with multi clinical related factors and parameters to detect and quantify cardiac health status and arrhythmia severity. The system determines an accurate time, location and severity of cardiac pathology and events by calculating blood pressure variability and statistical variation. The accurately and reliably identifies cardiac disorders, differentiates cardiac arrhythmias, characterizes pathological severity, predicts the life-threatening events, and supports evaluation of drug delivery effects.
1. A system for heart performance characterization and abnormality detection, comprising:
an interface configured to receive a set of raw sampled data values representing patient blood pressure occurring during individual heart cycles of plurality of sequential heart cycles;
a signal processor configured to generate a mathematical distribution directly using the received raw sampled data set and calculate,
(a) a first value substantially comprising an average of the raw sampled data set,
(b) a second value substantially comprising a magnitude value of said distribution at a first deviation point from the average of the raw sampled data set and
(c) a ratio of the first and second values as a representation of blood pressure variation; and
a comparator configured to compare said ratio with a threshold value to provide a comparison indicator; and
a patient monitor configured to, in response to said comparison indicator indicating said ratio exceeds the threshold value, generate an alert message associated with the threshold.
2. A system according to claim 1 , wherein said plurality of sequential heart cycles are successive heart cycles.
3. A system according to claim 1 , wherein said average of the raw sampled data set comprises at least one of, (a) an arithmetic mean, (b) a median, and a (c) a root mean square value.
4. A system according to claim 1 , wherein said first deviation point substantially comprises a standard deviation value of the dataset.
5. A system according to claim 1 , wherein said signal processor generates a third value substantially comprising a distribution value at a second deviation point from the average of the data set.
6. A system according to claim 5 , wherein said signal processor generates a ratio of a difference between the first and second values and a difference between the second and third values as representation of blood pressure variation.
7. A system according to claim 5 , wherein said second deviation point is substantially twice the deviation from the average of the data set as the first deviation point.
8. A system according to claim 1 , wherein said blood pressure comprises at least one of, (a) an intra-cardiac blood pressure, (b) a systolic blood pressure, (c) a diastolic blood pressure, (d) an invasive blood pressure and (e) a non-invasive blood pressure.
9. A system according to claim 1 , wherein
said comparator determines a comparison indicator indicating whether said ratio lies in a predetermined value range and
said patient monitor, in response to said comparison indicator indicating said ratio lies in a predetermined value range, generates an alert message associated with the value range.
10. A system according to claim 1 , wherein said threshold value is derived from recorded blood pressure data for said patient.
11. A system according to claim 1 , wherein said threshold value is derived from recorded blood pressure data for a population of patients having similar demographic characteristics including at least two of, (a) age, (b) weight, (c) gender and (d) height, to those of said patient.
12. A system according to claim 1 , wherein said signal processor dynamically adjusts said threshold value in response to a determined blood pressure variation of said patient.
13. A system according to claim 1 , wherein said mathematical distribution comprises at least one of, (a) a Gaussian distribution, (b) a normal distribution, (c) an Autoregression distribution model and (d) an Autoregression and Moving Average distribution model.
14. A system according to claim 1 , including
a repository of predetermined mapping information, associating ranges of the ratio with corresponding medical conditions and
said comparator compares said ratio with said ranges to provide a comparison indicator identifying a medical condition and
said patient monitor generates an alert message identifying said medical condition.
15. A system according to claim 14 , wherein said predetermined mapping information associates ranges of the ratio with particular patient demographic characteristics and with corresponding medical conditions and said system uses patient demographic data including at least one of, age weight, gender and height in comparing the ratio with said ranges and generating an alert message indicating a potential medical condition.
16. A system according to claim 1 , wherein said first value and said second value comprise amplitude values.
17. A method employed by at least one processing device for heart performance characterization and abnormality detection, comprising:
receiving a set of raw sampled data values representing patient blood pressure occurring during individual heart cycles of plurality of sequential heart cycles;
generating a mathematical distribution directly using the received raw sampled data set and calculating,
(a) a first value substantially comprising an average of the raw sampled data set,
(b) a second value substantially comprising a magnitude value of said distribution at a first deviation point from the average of the raw sampled data set and
(c) a ratio of the first and second values as a representation of blood pressure variation; and
comparing said ratio with a threshold value to provide a comparison indicator; and
in response to said comparison indicator indicating said ratio exceeds the threshold value, generating an alert message associated with the threshold.
18. A method employed by at least one processing device for heart performance characterization and abnormality detection, comprising the activities of:
receiving a set of sampled data values representing patient blood pressure occurring during individual heart cycles of a plurality of sequential heart cycles;
generating, from the received sampled data set, a spectrum comprising spectral value against frequency and calculating,
(a) a first local maximum peak value of the spectrum,
(b) a second local maximum peak value of the spectrum,
(c) a third local maximum peak value of the spectrum,
(d) a first value substantially comprising a difference between the first and the second local maximum peak values,
(e) a second value substantially comprising a difference between the second and the third local maximum peak values,
(f) a ratio of the first and second values as a representation of blood pressure variation; and
comparing said ratio with a threshold value to provide a comparison indicator; and
in response to said comparison indicator indicating said ratio exceeds the threshold value, generating an alert message associated with the threshold.