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CS-100 (Cardio Scan– 100) 5/5/2015Copyright, Trigon Medical Inc., 20081 An ECG Acquisition and FCG (Frequency CardioGram) Spectrum Analysis Systems A Preliminary.

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Presentation on theme: "CS-100 (Cardio Scan– 100) 5/5/2015Copyright, Trigon Medical Inc., 20081 An ECG Acquisition and FCG (Frequency CardioGram) Spectrum Analysis Systems A Preliminary."— Presentation transcript:

1 CS-100 (Cardio Scan– 100) 5/5/2015Copyright, Trigon Medical Inc., 20081 An ECG Acquisition and FCG (Frequency CardioGram) Spectrum Analysis Systems A Preliminary Screening Tool To Detect Coronary Artery Diseases (CAD) Early Ischemia to Myocardial Infarction Theoretical Principle

2 Schematic Flow Chart of CS-100 Copyright, Trigon Medical Inc., 20082 Electrodes Time Domain Cardiac Electrical Currents Time Domain Cardiac Electrical Currents Complied and Recorded Complied and Recorded ECG Electrocardiogram ECG Electrocardiogram FFT (Fast Fourier Transformation) Into Frequency Components FFT (Fast Fourier Transformation) Into Frequency Components Digital Signal Analysis (1) Energy Spectrum (2) Phase Shift (3) Impulse Response (4) Cross-Correlation (5) Coherence Digital Signal Analysis (1) Energy Spectrum (2) Phase Shift (3) Impulse Response (4) Cross-Correlation (5) Coherence FCG Frequency Cardiogram and Diagnostic Indexes FCG Frequency Cardiogram and Diagnostic Indexes Index Value - Data Base (30,000 tests) Index Value - Data Base (30,000 tests) 5/5/2015

3 HUMAN HEART A dual functioning self-regulatory electrical engineering system (1) A human heart is able to self generate the electrical currents in a regular time Intervals which cause the heart muscle to contract and relax; and (2) With the contraction and relaxation of the heart muscle, a heart becomes a mechanical pump that pumps blood throughout the body. (3) The mechanical movement and electrical activity of the heart system are mutually coupled and mutually influenced. (4) The frequency of heartbeat per minute coincides with the frequency of Electrical charge and discharge cycle of the electrical system of the heart. Copyright, Trigon Medical Inc., 200835/5/2015

4 Electrocardiograph (ECG) 1.ECG is a measurement of the cardio electrical signal, the physiologic events occurring within a human heart, in the time domain; 2.Any change in the physiology of a human heart will cause a unique corresponding change in the cardio electrical signal; 3. ECG waveform can display some, but not all the changes, specially the subtle or slight change; 4. From those changes in the ECG waveform to detect the presence of heart diseases with an average of 50% accuracy. Copyright, Trigon Medical Inc., 200845/5/2015

5 Copyright, Trigon Medical Inc., 20085 Dynamics of the Human Heart Blood is non-Newtonian fluid Cardiac muscle is a viscous and elastic solid mass that exhibits a lagging effect during its relaxation. It’s behavior is path-dependence, or has rate-independent Memory, and mathematically forms a hysteresis loop. As the heart beats with the increase of cycling, this lagging effect becomes stable, and the area of the hysteresis loop diminishes and the curves that form the loop become a straight line, thus can be looked upon as a system with no hysteresis. In a system with no hysteresis, it is possible to predict the system’s output at an instant in time, given only it input at that instant in time. This kind of predication is not possible for a system with hysteresis.

6 5/5/2015Copyright, Trigon Medical Inc., 20086 FCG FIRST HYPOTHESIS (1) Human Heart possesses a linear time-invariant (LTI) property in a finite short segment of time of less than 2 minutes; (2) ECG is a complex continuous periodic time dependent signal and by ways of FFT (Fast Fourier Transformation) can be mathematically decomposed, digitized, and transformed into a series of frequency components. FFT does not physically create nor destroy any cardio electrical signal. (3) Apply the DIGITAL SIGNAL PROCESS (DSP), a difference approach, and the use of a computer to probability assess the changes in the ECG.

7 Copyright, Trigon Medical Inc., 20087 DIGITAL SIGNAL PROCESS (DSP) LTI (Linear Time-Invariant) System: (1) Linear System - a signal detected is the sum of the Individual outputs of several individual inputs signal; and (2) Time-Invariant System - wherever there is a time delay (or shift) in the input sequence, it will have an equivalent time delay in the output sequence. DSP (Digital Signal Processing) Mathematic Equations - (1) FFT (Fast Fourier Transformation) (2) Evaluation – (1) Power Spectrum, (2) Phase Shift and (3) Impulse Response 5/5/2015

8 Copyright, Trigon Medical Inc., 20088 DIGITAL SIGNAL PROCESS (DSP) APPLICATION IN FCG FFT (Fast Fourier Transformation) To mathematically convert the time-domain ECG into its frequency components by means of decomposition, digitization and transformation. Evaluation Equations – Power Spectrum, Phase Shift and Impulse Response - Use these equations to mathematically calculate all the frequency data of an ECG detected from a patient; and - from the result of each calculation, to probability assess how well the patient’s heart is performing mechanically, and any presence of abnormality within the cardiovascular system.

9 Copyright, Trigon Medical Inc., 20089 Power Spectrum An power spectrum is a plot of power uV verse frequency Hz. It is used to describe how the energy of a time domain signal is distributed in frequency. The tip Sx(f) is the energy reading at frequency point (f) in uV/Hz. ↑ ↑ uV Hz → Sx(f) is the amplitude of energy in uV for a frequency at (f) Hz point. 5/5/2015

10 Normal Power Spectrum - Six (6) Distinctive Characteristics (1)Same distance between two energy peaks with ascertain peak height ratio among the peaks; (2)First peak usually appears at 1.2 Hz, a number relates to heart beats per minute; (3)There are 26-50 peaks within 0 – 25 Hz frequency range; (4) Combined energy of the 1st to 5th peaks is 50% - 60% of the total energy; (5)The first peak (related to the T wave) takes up 1/3 of the total energy; and (6) Peak height relationship among peaks having diagnostic value: (a)1 st peak is higher then 2 nd peak; (b) 3 rd peak is higher than 4 th peak; (c)5 th peak and peaks thereafter are all lower than the 1 st peak Copyright, Trigon Medical Inc., 2008105/5/2015

11 Copyright, Trigon Medical Inc., 200811 Diagnostic Index Selection and Value (1) Differential Diagnosis - It is a systematic method used to identify unknowns. It essentially is a process of elimination used by physicians or other clinicians to diagnose the specific disease in a patient. (2) Probability Assessment – the probability of event is a number lying in the interval 0 1 with 0 corresponding to an event that never occurs, and 1 to an event that is certain to occur. From (1) and (2), a number of indexes and their respective value were determined and selected. 239 persons with Coronary Heart Disease were tested, and 210 were correctly diagnosed which gives an accuracy rate of 88%.

12 5/5/2015Copyright, Trigon Medical Inc., 200812 Power Spectrum - “+” index diagnostic Suggestion H - 2 nd / 1 st > normal ratio - Insufficient myocardial power due to insufficient blood supply - Early warning of development of myocardial ischemia. N - Low or no 1 st peak and low or no 3 rd or 4 th peak - myocardium injuries (recent or old). B - 1 st and/or 2 nd peak is too high - Cardiomyopathy (Ischemic) or Ventricular Hypertrophy A - 5 th / 1 st > normal ratio - Possible ischemia with compensation already set in, if H is “-“. However, if H is “+”, then a more advanced ischemia E - Any one or two peaks after 5 th peak / 1 st peak > normal ratio. - myocardial compensation has already set in for one or more years. - ischemic damages to myocardium.

13 FCG 2 nd Hypothesis (Further Evaluation of left ventrical) 1.Following the first hypothesis; 2.Designate Lead V5 ECG current as the Input (exciting) current; 3. Designate Lead II ECG current as the Output Current. 4.Reasons for using these two currents are: (a) These two ECG currents under a normal condition travel at the same direction with a phase angle of 90 degree, and (b) through the left ventricular area, this allows further evaluation of the left ventrical of a human heart. Copyright, Trogon Medical Inc., 2008135/5/2015

14 Copyright, Trigon Medical Inc., 200814 DSP Application of Lead II and Lead V5 1. Applying the digital signal processing evaluation equations of (1) transfer function in phase angle shift; and (2) impulse response. 2.With differential diagnosis and probability assessment, FCG has identified a total of five (5) indexes: one for the phase shift index (P) and a set of four indexes for the impulse response (M, f, R, C) to have diagnostic significance.

15 Transfer Function in Phase Shift Phase angle shifts spectrum – angle shift between +180 degree to -180 degree Measured in every 2 Hz increment from 0Hz to 25Hz. + one unit zone - a rectangular zone starting from frequency 6Hz to 20Hz and phase angle shift + 90 degree, the applicable measuring area. Copyright, Trigon Medical Inc., 2008155/5/2015 A normal Phase Shift with the PS line traveling smoothly and close to the “0” line

16 5/5/2015Copyright, Trigon Medical Inc., 200816 Phase Shift - Indexes P (-) index - the phase shift line shall be relatively smooth traveling closely to the middle zero degree line and within this + one unit zone – Normal condition. Two types of (+) Index (+) index - The Phase Shift line travels over and above the zero degree line (time lead,) and/or below the zero degree line (time lag) – abnormal condition indicative of early ischemia. (+) index - When the phase shift line exhibits great deviation or oscillation, it is indicative of conduction blockage and/or CAD. See next page for (+) Phase Shift.

17 5/5/2015Copyright, Trigon Medical Inc., 200817 A (+) P index - Phase shift line travels over and below the zero unit zone Abnormal Phase Shift Response A (+) P index – Phase Shift line exhibits great oscillation

18 Phase Shift Mathematic Calculation A phase shift between the input current and output current is called a “Transfer Function in Phase Angle Shift” and can be measured by the following equation: Өxy(f) = tan -1 {Image Hxy(f) / Real Hxy(f)} Whereas Өxy(f) is the phase shift of the electrical currant in degree. It can be positive or negative within the range of +180 degree to -180 degree. Where as Hxy(f) = Gxy(W)/Gxx(W). (Transfer Function in Amplitude ratio between the amplitude of one lead x and that of the other lead y at (f) Hz frequency point. Gxy(W) = Sx(f) x Sy(f). (Cross power of the amplitude of one lead x at (f) frequency and that of the other lead y at the same frequency point.) Gxx(W) = Sx(f) x Sx(f). (The power at (f) frequency point of lead x.) Image Hxy(f) is a Hxy from an imaginary new heart Real Hxy(f) is the measured value. Copyright, Trigon Medical Inc., 2008185/5/2015

19 FCG - Impulse Response In the DSP, for a machine, when an electrical signal is excited at one point, its output response for that point can be measured: IHxy(f) = F -1 [Hxy(f)], an inverse Fourier Transformation. By measuring and observing the difference between the exciting current and its output response, the engineer can evaluate the mechanical performance and in turn locate the problem within the system. FCG applies the same DSP principle to treats the electrical current from Lead-V5 as the input (excited) current and that of Lead-II as the output current and measure the Impulse Response of IHxy(f) and Hxy(f) at frequency point (f) from 0 Hz to 26 Hz. Copyright, Trigon Medical Inc., 2008195/5/2015

20 Copyright, Trigon Medical Inc., 200820 a normal Impulse Response Impulse Response Diagnostic Indexes FCG identified four (4) indexes for diagnostic purpose – M, f, R, C. All four diagnostic indexes are (-). A normal Impulse response spectrum displays a narrow sharp tall main peak pointing up above the base line at the middle zero point with no sub-response ( a smooth line) on either side of the middle zero point.

21 5/5/2015Copyright, Trigon Medical Inc., 200821 Positive (+) Impulse Response Diagnostic Index f - A significant negative reflected (inverted) main peak. - Suggests a decreased compliance or conduction block or disturbance of reaction function of the heart, usually caused by CAD, MI, ischemia or conduction blockage. M - Double or multi inverted main peak. - Suggest poor conduction, increased in compliance, left ventricular malfunction. R - Regular Sub-Response (RSR) peaks with one peak on each side of the main peak. - Suggest unstable cardio electricity prior to the formation of MI caused by the narrow arteries or existence of plaques deposit in the arteries. - When there is an increase in RSR peak height, the possibility of re-occurrence MI increases. - R provides preventive diagnostic value in early detection of MI.

22 5/5/2015Copyright, Trigon Medical Inc., 200822 Positive (+) Impulse Response Diagnostic Index Multiple peak (some inversed) at the center with RSR peaks on each side Multiple peaks (some inversed) at the center with several CSR peaks on each side C - Causal Sub-Response(CSR) peaks - one or more peaks on each side of the main peak. - Suggest unstable cardio electrical activities at the beginning of contraction, possible existence of the latent arrhythmia.

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