Biophysical Analysis of Biosignals (1) PDF

Biophysical Analysis of Biosignals (1) Theoretical Background Instructions for practical exercises on Medical Biophysics do c. RN D r. Mg r. Ka t a rína Ko zlíko vá, CSc. IMPh BPh I&TM FM CU UK in Bratislava T h e p r e s entation i s p a r t o f t h e p r o j ect K E G A 0 4 0 U K -4 /20 22...

Biophysical Analysis of Biosignals (1) Theoretical Background Instructions for practical exercises on Medical Biophysics do c. RN D r. Mg r. Ka t a rína Ko zlíko vá, CSc. IMPh BPh I&TM FM CU UK in Bratislava T h e p r e s entation i s p a r t o f t h e p r o j ect K E G A 0 4 0 U K -4 /20 22 & Disclaimer This material is intended exclusively for the educational purposes of the subject Medical Biophysics in the 1st year of General Medicine and Dentistry of the Medical Faculty of Comenius University in Bratislava in the academic year 2022/23. Resources are provided for materials used to better visualize the topic. The individual educational use of this material does not authorize its further distribution as a whole or in parts. Citing of this presentation is possible according the norm ISO 690 (STN 01 0197). Contact: doc. RNDr. Mgr. Katarína Kozlíková, CSc. Mail: katarina.kozlikova (at) fmed.uniba.sk Workplace of FM CU in v Bratislava: Institute of Medical Physics, Biophysics, Informatics and Telemedicine Web: https://www.fmed.uniba.sk/en/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 2 Contents (1) o Introduction o Aim o Basic information about biological signals o Biophysical analysis of biosignals o Biophysical principle of electrocardiogram o Electrocardiographic leads o ECG curve nomenclature o Graphic record calibration Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 3 Contents (2) o Heart rate o Electrical axis of the heart o ECG ruler o Selected physiological values required for biophysical analysis of the electrocardiogram o Summary o Conclusion o Literature Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 4 Introduction Ilav foras o Biophysical analysis of biosignals - a group of presentations for the purposes of practical exercises from the subject Medical Biophysics 1) Theoretical background 2) ECG recording of limb leads 3) Biophysical analysis of an ECG recording 4) Construction of the electrical axis of the heart Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 5 Aim o The aim of the presentation Biophysical analysis of biosignals (1) Theoretical background is a brief explanation of the concepts, principles and procedures that are needed to master successfully two topics from practical exercises o Further necessary information can be found by students in the study literature, in the literature listed at the end of the presentation and in lectures on the MEFANET portal FM CU in Bratislava (https://portal.fmed.uniba.sk/) in the medical discipline Biophysics, especially ◦ Overview of biological signals ◦ Active electric biosignals II Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 6 Biosignal > - nearly all diagnostic nethoos are based on this o Information on the patient's condition should be obtained during the diagnosis process o Information about the state of the organism is encoded in its analogue manifestations o The material manifestation (material carrier) of information is the signal o A biological signal (biosignal) is any material manifestation of information about an investigated biological system o Biosignals specify the characteristics of the system, therefore, they form the basis of all diagnostic methods Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 7 Display and Storage of Measured Values ◦ Process of biosignal processing ◦ Registration of biosignals ◦ Amplification and pre-processing of signals ◦ Display and storage of measured values of a biosignal ◦ In terms of form ◦ Graphical (pictorial) ◦ Digital ◦ In terms of archiving time ◦ Temporary ◦ Permanent Earlier, biosignal registration could be like this. [Cit. 4. 4. 2011] Available at: https://www.tumblr.com/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 8  resting membrane : Analysis of Biosignals su --- - ◦ In terms of output travels - ◦ Qualitative ◦ Visual n e r e nembrane ◦ The output is a verbal description (text) ◦ Quantitative ↓ ◦ Measurement of physical quantities - ◦ The output is numbers ◦ In terms of signal complexity **I ◦ Automatic dipolarisation : ---- ↓ ◦ Especially irregular, complex, non-repetitive signals ◦ Manual ◦ Simple, repetitive signals repolarisation ↓ --- ◦ Therefore, in practical training, analysis of an ECG recording ++ 7 # --- Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 9 Biophysical Analysis of an Electrocardiogram (1) Electrocardiographic curve ◦ Graphical record of electric heart activity (permanent) ◦ Relatively simple graph of voltage versus time ◦ Quasiperiodic (almost periodic) curve ◦ A certain section of the record is repeated regularly (possibly only with small changes) A Voltage S Example of an ECG recording from one lead. time Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 10 Biophysical Analysis of an Electrocardiogram (2) Biophysical analysis of an ECG curve ◦ Simple ◦ Amplitude ◦ Measuring the height and depth of individual deflections Z ◦ Time ◦ Measuring the duration of individual parts of the ECG curve ◦ Determination of (average) heart rate ◦ More complicated ◦ It is based on values obtained by simple analysis ◦ Construction of the electrical axis of the heart ◦ Analysis of heart rate variability ◦ Using special software ◦ Spectral (frequency) analysis of the ECG Diagram of height and depth (left) and duration (right) of a deviation. Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 11  baste stop bere ; oherwis gairal "nov o mon o Biophysical Principle of the Electrocardiogram (1) o The heart works like a pump - under pressure it pushes blood through the circulatory system o The function of the piston is represented by the contracting muscle of the ventricles o The coordination of contraction is ensured by the sequence of action potentials of individual heart cells - the source of electric current - the electric field of the heart is created o The electric impulse precedes the contraction Animation of cardiac muscle contraction after electrical impulse transition (red colour) and related electrocardiographic curve scheme. [Cit. 4. 4. 2018] Available at: https://en.wikipedia.org/wiki/Electrocardiography Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 12 Biophysical Principle of the Electrocardiogram (2) o The heart as a source of electric current is stored in the human body - an electrically conductive medium - in a three-dimensional volume conductor that modifies the electric field of the heart o We register the electric field of the heart on the surface of the body as electric voltage - potential difference - in the form of electrocardiographic curves A model of a chest as a volume conductor with the heart and lungs. [Cit. 4. 4. 2018] ] Available at: https://www.epfl.ch/labs/aspg/page-55579-en-html/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 13 Physical Comment - Electric Voltage ◦ Electric voltage ◦ Physical quantity ◦ Expresses the difference of the electric potential between two points ◦ Represents the energy needed to move an electric charge between these two points in a certain electric field ◦ Symbol: U ◦ SI unit: volt [V] ◦ Is related to the electric current I [A] (movement of electric charges) in accordance with Ohm´s law U=R·I R: electric resistance [Ω] An example of a simple electric circuit to measure the electric voltage using a voltmeter. Source: Author's archive.. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 14 Electrocardiography – Basic Terminology Electrocardiography ◦ Method ◦ Detection, registration and analysis of action potentials of the heart Electrocardiogram ◦ Graphic output of an electrocardiograph, which records the electric activity (changes of electric voltage) in the heart versus time Electrocardiograph ◦ Device used to record the electric activity of the heart Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 15 Electrocardiographic Leads ◦ Lead ◦ A combination of two conductors and their electrodes, forming a closed electric circuit with the measuring device (electrocardiograph) ◦ A bipolar lead ◦ Two active (equivalent) electrodes ◦ A unipolar lead ◦ An active (different) and a reference (indifferent) electrode Example of an electrocardiograph and common used electrodes for the standard examination. [Cit. 3. 1. 2020] ] Available at: : http://www.zdravotnicka-technika.com/zdravotnicky-material/elektrokardiograf-ekg/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 16  massure difference in potential 1 Bipolar Leads – Einthoven Triangle ◦ Electric activity of the heart ◦ Electric dipole (about 90 %) ◦ Heart position ◦ In the frontal plane ◦ In the middle of an equilateral triangle ◦ Position of electrodes ◦ Right hand (R) ◦ Left hand (L) ◦ Left foot (F) ◦ Names of leads (bipolar) grounding ◦ ◦ I: II: V I =  L – R VII = F – R ◦ III: VIII = F – L Einthoven triangle.  i : electric potential on the ith electrode [Cit. 30. 3. 2020] ] Available at: http://www.bem.fi/book/index.htm ◦ For the voltage in every instant holds the Einthoven formula VI + VIII = VII Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 17  Wilson´s Central Terminal (WCT) ◦ Reference electrode for unipolar leads ◦ Connected through large electric resistances (R  5 k) ◦ Total current in the WCT has to be zero ◦ 1st Kirchhoff´s law 𝐼𝑅 + 𝐼𝐿 + 𝐼𝐹 = 0 ◦ After substitution Φ𝑊𝑆 − Φ𝑅 Φ𝑊𝑆 − Φ𝐿 Φ𝑊𝑆 − Φ𝐹 + + =0 5000 5000 5000 ◦ i: potential on ith electrode ◦ Potential on WCT Φ𝑅 + Φ𝐿 + Φ𝐹 ◦ Average of limb potentials Φ𝑊𝐶𝑇 = Wilson´s Central Terminal. 3 [Cit. 30. 3. 2020] ] Available at: http://www.bem.fi/book/index.htm Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 18  Unipolar Limb Leads compare voltage ◦ Formation ◦ One different electrode uncoupled from the Wilson’s central terminal ◦ Names and symbols of unipolar limb leads ◦ Augmented („amplified“) – aVR, aVL, aVF ◦ According to the disconnected electrode ◦ Goldberger leads Wiring diagram of augmented leads. [Cit. 30. 3. 2020] ] Available at: http://www.bem.fi/book/index.htm Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 19 Unipolar Chest Leads Standard locations - six leads ◦ V1, V2, V3, V4, V5, V6 ◦ Standard exactly defined locations in the 4th and the 5th intercostal spaces Additional used locations ◦ V7 ◦ Posterior axillary line ◦ V3R, V4R, V5R, V6R Unipolar chest leads and their typical locations. ◦ „Mirror image“ V 3, V4, V5, V6 [Cit. 30. 3. 2011] ] Available at: http://www.bem.fi/book/index.htm Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 20  contractions A Standard 12-lead Electrocardiogram (1) I Example of a standard 12-lead electrocardiogram. Leads I, II, III, aVR, aVL, aVF (left) and leads V 1 to V 6 (right) are shown. There is a calibration deviation at the beginning of each lead. Below the curves are the the paper speed, voltage calibration, signal frequency band, and heart rate. Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 21 A Standard 12-lead Electrocardiogram (2) Example of a standard 12-lead electrocardiogram. Leads I, II, III, aVR, aVL, aVF (left) and leads V 1 to V6 (right) are shown. There is a calibration deviation at the beginning of each limb lead valid also for the chest lead. Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 22 Schematic Representation of an ECG Curve printed ⑧ paper > - on > conected to ventricals ? - -learn heart TP segment by ⑳ OVoltage (V) ⑧⑳ ⑳ Nomenclature of individual parts of the electrocardiogram. [Cit. 30. 3. 2020] ] Available at: http://nursingpub.com/12-lead-ekg-explained-part-1 Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 23 Nomenclature of ECG Curves (1) ◦ Zero isoelectric line, baseline ◦ Horizontal record line representing zero voltage ◦ It is determined over 2 consecutive TP segments ◦ Segment ◦ A section of the record that contains only a zero isoelectric line ◦ Theoretically horizontal ◦ PQ segment (PR segment) ◦ From the end of the P wave to the beginning of the QRS complex, i. e. Q wave or R wave (if Q is missing) ◦ ST segment ◦ From the end of the QRS complex to the beginning of the T wave ◦ TP segment ◦ From the end of T wave (U wave) of the previous beat to the beginning of wave P of the next beat ◦ It is used as a reference (zero) value for voltage measurement Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 24 Nomenclature of ECG Curves (2) Wave ◦ A section of the record where the voltage deviates from the zero isoelectric line upwards (positive deflection) or downwards (negative deflection) ◦ Waves with „a slow" change in voltage, usually round in shape ◦ P wave ◦ T wave ◦ U wave ◦ Waves with „a fast" change in voltage, usually pointed ◦ Q wave ◦ R wave ◦ S wave ◦ Together they form the QRS complex Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 25 Nomenclature of ECG Curves(3) ◦ Interval ◦ A section of the record that contains more waves or segments ◦ PQ interval (PR interval) ◦ From the beginning of the P wave to the beginning of the QRS complex, i. e. Q wave or R wave (if Q is missing) ◦ ST interval ◦ From the end of the QRS complex to the end of the T wave RR ◦ QT interval ◦ From the beginning of the QRS complex to the end of the T wave r ◦ QRS interval ◦ Alternative name for QRS complex ◦ RR interval ◦ The distance between the peaks of two adjacent R waves ◦ Used to assess heart rate Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 26  Polarity and Height of Deflection ◦ Polarity of deflection ◦ It depends on the mutual position (angle) of the depolarization wave and the sensing electrode ◦ Depolarization wave ◦ Border between polarized and depolarized regions, direction of depolarization process ◦ Height of deflection ◦ It depends on the mutual distance of the depolarization wave and the sensing electrode Basic shapes of QRS complex in terms of polarity of deflection. ◦ The closer they are, the higher it is [Cit. 30. 8. 2020] ] Available at: https://www.slideshare.net/ynabubbles/ ecg-lecture Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 27 Positive and Negative Waves ◦ During QRS comples ◦ Positive deflection negativese positive ◦ R wave ◦ They may be more (R, R´) ◦ Negative deflection ◦ Q wave ◦ It precedes the R wave ◦ There can be at most one ◦ S wave ◦ It follows the R wave ◦ They may be more (S, S´) ◦ P wave and T wave Nomenclature of selected shapes of he QRS complex. ◦ Positive or negative [Cit. 30. 8. 2020] After: https://litfl.com/qrs-interval-ecg-library/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 28 Calibration of the Graphic Record (1) ◦ The electrocardiographic curve is written on a special registration paper with a grid resembling graph paper ◦ Small square 1 mm x 1 mm ◦ Large square 5 mm x 5 mm printed ◦ Time calibration – paper speed ◦ Standard speed ◦ 25 mm/s ◦ 1 mm  0.04 s; 5 mm  0.2 s ◦ Faster speed (for detailed analysis) ◦ 50 mm/s ◦ 1 mm  0.02 s; 5 mm  0.1 s ◦ Slower speed (for heart rate analysis) ◦ 10 mm/s Demonstration of standard calibration on a typical ECG paper. Source: Author's archive. ◦ 1 mm  0.1 s; 5 mm  0.5 s Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 29 Calibration of the Graphic Record (2) o Voltage calibration o Standard o 1 mV  10 mm o 1 mm  0.1 mV o For low deflections o 1 mV  20 mm o 1 mm  0.05 mV o For high deflections o 1 mV  5 mm o 1 mm  0.2 mV Example of different voltage calibration for limb leads (10 mm / mV) and for chest leads (5 mm / mV). Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 30 Heart Rate (1) ◦ Heart rate (HR, pulse) ◦ The number of heart beats that are recorded in one minute ◦ A heart beat ◦ Contraction of the heart and expulsion of blood from the heart into the blood vessels, systole ◦ Heart rate -how the ◦ Physiological offen heart beats ◦ 60/min < SF < 100/min ◦ Decreased (bradycardia) ◦ SF < 60/min ◦ Increased (tachycardia) ◦ SF > 100/min Animation of cardiac muscle contraction.. [Cit. 9. 9. 2020] ] Available at: https://tenor.com/view/beating-heart-veins-heart-gif-9565723 Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 31 Heart Rate (2) ◦ The pulse is usually examined by palpation ◦ The fingertip of the 2nd to 4th fingers is gently placed on the artery, most often on the wrist (arteria radialis) ◦ Because mechanical systole (contraction of the heart muscle) is related to its electrical activity, we can also determine the heart rate from an electrocardiographic record. ◦ Measurement of RR intervals is used Example of different duration of RR intervals and the corresponding hert rate at paper speed 25 mm/s. Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 32 Electrical Heart Axis (1) ◦ Refers to the general direction of the heart's depolarization wave front (not the position of the heart) ◦ Electric vector (dipole) ◦ Projection into leads (lead vectors) ◦ Can be evaluated e ◦ In a certain time moment ◦ An instantaneous electric vector ◦ During a certain time interval ◦ The mean electric vector ◦ During the whole QRS complex ◦ During the whole T wave Einthoven´s triangle and the electrical heart axis. [Cit. 30. 8. 2020] ] Available at: ◦ During the whole P wave https://litfl.com/qrs-interval-ecg-library/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 33 Electrical Heart Axis (2) ◦ It is usually determined in the frontal plane ◦ The determination ◦ Is based on Einthoven's triangle ◦ Uses an axial coordinate system ◦ The sides of Einthoven's triangle move to its centre ◦ Bailey system Hexaxial reference system in the frontal plane. [Cit. 30. 8. 2020] ] Available at: https://sk.pinterest.com/pin/5207355794493913/ ; https://en.wikipedia.org/wiki/Hexaxial_reference_system Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 34 Electrical Heart Axis (3) ◦ It is expressed in degrees as the deviation from the horizontal axis directed from right to left ◦ The horizontal axis is parallel to the lead I ◦ It can also be determined in the horizontal plane Axial reference systems in the frontal plane (triaxial top left, hexaxial top right) and in the horizontal plane (bottom right). [Cit. 30. 3. 2011] ] Available at: https://thoracickey.com/surface-electrocardiography/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 35 Electrical Heart Axis Interpretation - Deviation ◦ Normal axis ◦ From 0° to +110° (children and young adults) ◦ From -30° to +90° (older adults) ◦ Left axis deviation (LAD) ◦ From -90° to -30° ◦ Right axis deviation (RAD) ◦ From +110° to  180° ◦ Extreme axis deviation ◦ From -90° to 180° ◦ With high probability, the axis was incorrectly constructed or an error occurred during registration (interchanged cables) ◦ However, it may occur in some pathologies ◦ Indeterminate axis The deviation of the electrical heart axis of the QRS ◦ Cannot be determined complex in the frontal plane shown by the axial ◦ Very rare reference system. [Cit. 30. 3. 2011] ] Available at: https://thoracickey.com/electrocardiography-5/ Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 36 Electrical Heart Axis Interpretation - Position ◦ Intermediate (middle) position ◦ From +30° to +60° ◦ Horizontal position ◦ From -30° to +30° ◦ Vertical position ◦ From +60° to +110° The division of the frontal plane into different regions depending on the orientation of the mean QRS vector. Source: MACFARLANE et al., 2010. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 37  An ECG ruler – a Tool for ECG Analysis ◦ Different versions ◦ Always contain ◦ Scale [mm] ◦ Deflections ◦ Time intervals ◦ Heart rate scale ◦ Time calibration (paper speed) ◦ May contain ◦ Conversion of values ◦ Hexaxial coordinate system for electrical heart axis evaluation ◦ Protractor ◦ ECG curve diagram ◦ Other data Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 38 Selected Physiological Values (1) Table 1: Selected physiological values of men and women aged 18 – 29 years to perform time analysis of an ECG curve Parameter Males Females P wave – duration [ms] 103  14 99  13 QRS complex – duration [ms] 96  9 88  8 PR interval – duration [ms] 153  23 146  20 QT interval – duration [ms] 386  29 380  28 Heart rate [1/min] 70  12 76  12 Data are presented as mean  standard deviation. Processed after: MACFARLANE et al., 2010. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 39 Selected Physiological Values (2) Table 2: Selected physiological values of men and women aged 18 – 29 years to perform amplitude analysis of an ECG curve Amplitude Lead I Lead II Lead III [mV] Males Females Males Females Males Females P wave 0.10  0.03 0.10  0.03 0.15  0.06 0.15  0.06 0.09  0.05 0.08  0.05 Q wave* -0.07  0.05 -0.07  0.05 -0.09  0.06 -0.08  0.05 -0.13  0.11 -0.11  0.09 R wave** 0.76  0.33 0.70  0.28 1.36  0.43 1.13  0.34 0.78  0.56 0.56  0.39 S wave -0.23  0.14 -0.16  0.10 -0.21  0.13 -0.17  0.10 -0.22  0.23 -0.21  0.18 T wave 0.34  0.12 0.28  0.09 0.42  0.14 0.33  0.11 0.14  0.10 0.09  0.06 Data are presented as mean  standard deviation * Q wave amplitude under physiological conditions has to be less or equal to 25 % of the R wave amplitude: Q≤ R/4. ** In bipolar limb leads, the amplitude of the R wave should not exceed 2 mV: R ≤ 2 mV. Processed after: MACFARLANE et al., 2010. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 40 Literature o KADLEC O. (Ed.) Encyklopédia medicíny VI. diel E – F. Bratislava: Asklepios, 1997. 393 s. o KOZLÍKOVÁ K., MARTINKA J. Theory and Tasks for Practicals on Medical Biophysics. Brno : Tribun, 2010. 248 pp. ISBN 978-80-7399-881-3 o KOZLÍKOVÁ K., TRNKA M. Úvod do spracovania a prezentovania dát v medicíne. Košice : Equilibria, 2018. 226 s. ISBN 978-80-8143-234-7 o MACFARLANE P. W., VAN OOSTEROM, A., PAHLM, O., KLIGFIELD, P. (Eds) Comprehensive Electrocardiology (4 Volume Set) (2nd edition). Springer 2010. 2291 pp. ISBN 978-1-84882-047-0 o MORNSTEIN V. a kol. Lékařská fyzika a biofyzika. Brno : Masarykova univerzita, 2018. 340 s. ISBN 978-80-210-8984-6 o NAVRÁTIL L., ROSINA J. a kol. Medicínská biofyzika. 2. vydanie. Praha : Grada Publishing, 2019. 432 s. ISBN 978-80-271-0209-9 o Electronic sources on the MEFANET FM CU portal (http://portal.fmed.uniba.sk/) o Electronic sources listed directly in the text. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 41 Summary (1) Introduction Heart rate Aim Electrical axis of the heart Basic information about biological ECG ruler signals Selected physiological values required Biophysical analysis of biosignals for biophysical analysis of the electrocardiogram Biophysical principle of electrocardiogram Literature Electrocardiographic leads Summary ECG curve nomenclature Conclusion Graphic record calibration Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 42 Summary (2) Heart rate Electrical axis of the heart ECG ruler Selected physiological values required for biophysical analysis of the electrocardiogram Summary Conclusion Literature Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 43 Conclusions o The task continues on the basis of instructions o Biophysical analysis of biosignals (2): ECG recording of limb leads Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 44 Thank you for attention Electrocardiograph, electrodes and next tools to measure an ECG. Source: Author's archive. Biophysical Analysis of Biosignals (1) © K. Kozlíková, 2022 45