CARDIOLOGY ECG basic information. ČVUT, March 2011 Jan Daněk, BTL

CARDIOLOGY ECG – basic information ČVUT, March 2011 Jan Daněk, BTL

BTL

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BTL Zdravotnická technika a.s. obchod ČR, servis ČR - www.btl.cz

Medical Technologies CZ a.s. vývojové a výrobní centrum BTL, mezinárodní servis 1992 – založení, obor fyzioterapie, česká společnost 1997 – obor kardiologie 1998 – expanze do zahraničí 2005 – obor estetická medicína 2011 – CZ RO PL BG SK HR UK KZ UZ IT PT MX TH VT IN CY GB US… 2

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BTL 2010 ve světě

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BTL 2011 v Čechách vývojové oddělení, Praha (55 kolegů, zvýšit na 100) výroba elektroniky a prototypových sérií, Benešov (50) vývojové oddělení u výroby, Benešov (5) zahraniční obchod, Praha (25) domácí obchod pro ČR (35) servisní oddělení pro ČR a okolní státy, Praha (5) CÍL: Každý rok uvést nejméně čtyři nové produkty na světový trh – představení na světové výstavě MEDICA Düsseldorf (www.medica.de) Růst společnosti: 30% meziročně 4

BTL – KARDIOLOGIE

Kardiologie 1997 – počítačové EKG 1998 – spolupráce s firmou Aspel, PL 2001 – 1. vlastní přímopíšicí EKG 2004 – kompletní řada EKG 2006 – začátek spolupráce s firmou Spacelabs 2008 – SW BTL-08 MEW „kardiologické pracoviště“ 2009 – SW BTL-08 MEW Spiro 2010 – SW BTL-08 MEW Ergo budoucnost? –> být nejlepší v Evropě!  Schiller Swiss, General Electric, Philips (býv. HP), Mortara 5

VÝVOJ ZDRAVOTNICKÉ TECHNIKY - EKG

Vývoj zdravotnické techniky Mezinárodní řada norem IEC (www.iec.ch): IEC 60601-1 (základní norma o bezpečnosti) IEC 60601-1-2 (EMC, EMI) IEC 60601-2-25 (EKG bezpečnost) IEC 60601-2-47 (EKG Holtery) IEC 60601-2-51 (EKG parametry) v ČR zastoupen ÚNMZ (www.unmz.cz) Certifikace v CB systému (www.iecee.org): v ČR zastoupen EZÚ Praha (www.ezu.cz) CE značka, FDA schválení, systém jakosti ISO 6

VÝVOJ ZDRAVOTNICKÉ TECHNIKY - EKG

EKG – bezpečnost Tzv. příložná část typu CF, odolná defibrilaci: unikající proud do pacienta max. 10 µA (NC) pomocný proud pacientem max. 10 µA (NC) unikající proud do pacienta max. 50 µA (SFC) pomocný proud pacientem max. 50 µA (SFC) NC – Normal Condition, SFC – Single Fault Condition

Pro napájecí napětí 250 Vac: Rizol > 25 MΩ Cparasit < 127 pF 7

CARDIOLOGY – ECG HISTORY

Electrocardiogram - history It is a record of the electrical activity of the heart over time. Alexander Muirhead, St Bartholomew's Hospital, London 1st record of the patient’s heartbeat, 1872 Augustus Waller, St Mary's Hospital, Paddington, London 1st electrocardiograph machine, 1887 ECG signal was projected to a wall Willem Einthoven, Leiden, The Netherlands 1st clinically used machine, 1901 – 1903 signal was recorded on a moving roll of photographic paper 8

• 1st machine weighted 600 lb / 270 kg and required strong water cooling for powerful electromagnets • he assigned the letter P, Q, R, S and T to the deflections of the ECG signal • Nobel Prize 1924

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CARDIOLOGY – ECG HISTORY

Willem Einthoven – early ECG device

CARDIOLOGY – ECG SIGNAL

ECG signal & heart Detail description: http://en.wikipedia.org/wiki/Ecg#Waves_and_intervals

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CODE 1 / EU

CARDIOLOGY – ECG LEAD SYSTEMS

Electrocardiogram – lead systems CODE 2 / US

Right Arm

R

Red

RA White

Left Arm

L

Yellow

LA

Black

Left Leg

F

Green

LL

Red

Right Leg

N

Black

RL

Green

Chest 1

C1

White/Red

V1

Brown/Red

Chest 2

C2

White/Yellow

V2

Brown/Yellow

Chest 3

C3

White/Green

V3

Brown/Green

Chest 4

C4

White/Brown

V4

Brown/Blue

Chest 5

C5

White/Black

V5

Brown/Orange

Chest 6

C6

White/Violet

V6

Brown/Violet 11

Standard ECG 12-lead system is the group of the 3 systems: Einthoven bipolar extremity leads – I, II, III Goldberger unipolar extremity leads – aVR, aVL, aVF Wilson unipolar chest leads – V1, V2, V3, V4, V5, V6 10 electrodes (9 active / 1 neutral) (R L F C1 C2 C3 C4 C5 C6 / N)

12 leads (I II III aVR aVL aVF V1 V2 V3 V4 V5 V6) 12


Electrocardiogram – lead systems

LEADS

ELECTRODES

I

I=L–R

II

II = F – R

III

III = F – L

aVR

aVR = R – (L + F) / 2

aVL

aVL = L – (R + F) / 2

aVF

aVF = F – (L + R) / 2

V1

V1 = C1 – (L + R + F) / 3

V2

V2 = C2 – (L + R + F) / 3

V3

V3 = C3 – (L + R + F) / 3

V4

V4 = C4 – (L + R + F) / 3

V5

V5 = C5 – (L + R + F) / 3

V6

V6 = C6 – (L + R + F) / 3



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Electrocardiogram – Einthoven lead system

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Electrocardiogram – Goldberger lead system

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Electrocardiogram – Wilson lead system

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Electrocardiogram – Wilson lead system

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STANDARD

CABRERA

I

aVL

II

I

III

- aVR

aVR

II

aVL

aVF

aVF

III


Electrocardiogram – Cabrera lead system

The Cabrera leads order makes it easier to visualize waveform progression in the frontal plane. 19

8 electrodes


Electrocardiogram – FRANK lead system

3 leads

Vx = 0.610 A + 0.171 C – 0.781 I Vy = 0.655 F + 0.345 M – 1.000 H Vz = 0.133 A + 0.736 M – 0.264 I – 0.374 E – 0.231 C Frank lead system is not supported by ECG diagnostic (Glasgow, BTL).

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LEADS

ELECTRODES

I

I=L–R

II

II = F – R

III

III = F – L

aVR

aVR = R – (L + F) / 2

aVR = (III – 2*II) / 2

aVL

aVL = L – (R + F) / 2

aVL = (I – III) / 2

aVF

aVF = F – (L + R) / 2

aVF = (II + III) / 2

V1

V1 = C1 – (L + R + F) / 3

V2

V2 = C2 – (L + R + F) / 3

V3

V3 = C3 – (L + R + F) / 3

V4

V4 = C4 – (L + R + F) / 3

V5

V5 = C5 – (L + R + F) / 3

V6

V6 = C6 – (L + R + F) / 3

I = II – III

(L + R + F) / 3 = “NOISE” = – N 21


Electrocardiogram – BTL lead system


Electrocardiograph – BTL lead system

The output meets with requirements of IEC 60601-2-51:2003. 22

Extremity electrode R – wrong contact I, II, aVR, aVL, aVF leads disappear (III – distorted) Extremity electrode L – wrong contact I, III, aVR, aVL, aVF leads disappear (II – distorted) Extremity electrode F – wrong contact all extremity leads disappear  other leads can be distorted Extremity electrode N – wrong contact all leads disappear or are distorted Chest electrode Cx – wrong contact only chest lead Vx disappear  other leads are not affected


BTL lead system – practical results

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How to reduce noise – 1st possibility Connect extremity electrodes close to patient body:

It is used mainly for ergometry investigation to reduce extremity muscles artifacts. 24


Calculation of the heart’s electrical axis The heart's electrical axis is usually oriented in a right shoulder to left leg direction, although -30° to +90° is considered to be normal.

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BTL ECG Internal Design ČVUT, March 2011 Jan Daněk, BTL

CARDIOLOGY – ECG DESIGN

Electrocardiograph – BTL lead system

The output meets with requirements of IEC 60601-2-51:2003. 27


ECG – inputs connection

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ECG – defibrillator protection 1st stage – implemented in the ECG cable 2nd stage – on the Analog board in the ECG machine (1st components on the input) maximal energy of the pulse could be 500 J

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ECG – input impedance Resistor R300 define “ground” potential. Used amplifier is type J-FET with high impedance input. Final input impedance ≈ 330MΩ || 220pF

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ECG – input radio filter 1st stage – good ECG cable 2nd stage – low pass filter, band width 12 kHz (without any influence on the ECG signal)

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1st stage – differential amp. – gain 10, bandwidth 1.59 kHz 2nd stage – gain 22.4, band width 339 Hz, 2nd order (without any influence on the ECG signal)

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ECG – amplifier


ECG – amplifier 1st differential stage Used resistors have accuracy 0.1%. Used capacitor are linear with accuracy 5%. It guarantees perfect removing of the common signal.

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ECG – high pass filter High pass filter, according IEC 60601-2-51. 1st order, bandwidth 0.05Hz (3.2 sec) Used capacitors is linear foil type, accuracy 5%.

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ECG – high pass filter / restart circuit Activated when you press button RESTART. Fast discharging of high pass filter.

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Low pass filter, bandwidth 339Hz, 2nd order. It is last filter in front of A/D converter, reduce signal above 1000Hz (sample frequency is 2000Hz).

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ECG – amplifier 2nd stage / low pass filter

Final frequency response, include response of the ADC and basic digital filters meets requirements of IEC 60601-2-51.

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ECG amplifier – frequency response


ECG amplifier – phase response All used filters are designed with the respect to have linear phase response – to do not change time parameters of the ECG signal.

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Cardiology, ECG, ČVUT, March 2010

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ECG – neutral electrode Calculation of neutral signal – accuracy resistor 0.1%.

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ECG – neutral electrode Calculation of neutral signal – accuracy resistor 0.1%. Compensation of ECG cable.

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ECG – neutral electrode Calculation of neutral signal – accuracy resistor 0.1%. Compensation of ECG cable. Defibrillator protection.

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ECG cable – active shielding To reduce influence of ECG cable on the ECG signal. Signal of Neutral Electrode is connected to shielding.

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Detection of disconnected leads – how works 1st stage – measuring of DC offset of each lead 2nd stage – amplitude of 50Hz (60Hz) noise signal (it is possible to change the level of the detection)

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Pacemaker detection Bandwidth gate – 159 Hz >> derivative + integrative element – 47 µs >> negative part – integrative element 10 ms >> comparator

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A/D converter 15-bits, 1 kHz / lead, 8 inputs, sensitivity 3.9 µV

Power Filtration: 46


ECG block scheme Stepper motor Touch-Panel + LCD

073-51SHCPUxxx CPU BOARD Main Microprocessor Watch-Dog Supply Supervisor RAM & ROM Memory Drivers for LCD Drivers for LED Sound generator

Power supply for processor board 1,9V; 3,3V; 5V; 21V Power supply for CFL

USB in/out

073-51POWERxxx POWER SUPPLY BOARD

RS232 in/out

Main switch

Mains Filter F1

Mains Filter

P1

S1

F2

32V

POJ3 external fuse folder

Pulse power supply

Main transformer TR2

P2

S2 Battery charger 28V/1A

2n2/250V Mains inlet

F200

Battery 24V (2x12V)

Power & Communication line

Insulation 4kV, creepage distance 8mm. Insulation 1.5kV, creepage distance 4mm.

070-51ANALOGxxx MEASURE INPUT BOARD ADC Monitoring Circiuts Protection Circuits Interference Filter Supply Supervisor Microprocessor Program Memory Data Memory

Patient Intput

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BTL ECG Implemented filters ČVUT, March 2011 Jan Daněk, BTL

CARDIOLOGY – ECG FILTERS

ECG Filters – 0.07-80Hz adaptive

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The “adaptive” filter was developed according requirements of users they want to have ECG signal without distortion of QRST complex (amplitude + time parameters) they want to have smooth curve between QRST complexes (mainly with respect to time parameters) Similar problem solved by HP / Philips, GE, Schiller solution – adaptive filter which change parameters according ECG signal  QRST – almost without filtration  T-P-Q – strong filtration 50



The 0.07-80Hz adaptive filter is combination of these filters: muscle adaptive filter mains 50 / 60 Hz adaptive filter baseline spline filter (ADS cubic). Muscle adaptive filter: detects of the dynamic changes of the signal (QRS) according its chooses between 5 low pass filters typical bandwidth is 80 Hz

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ECG Filters – 0.07-80Hz adaptive Practical example:

original ECG signal

signal for the control function 52


ECG Filters – 0.07-80Hz adaptive Final filtration (momentary bandwidth): 90Hz 88Hz

12Hz

18Hz

13Hz

18Hz

20Hz 53

It is two sinus software oscillators which work as phaseloop circuits (1st & 3rd harmonic) it searches harmonic mains frequencies in the ECG signal in the range 45 to 65 Hz / 135 to 195 Hz when the signal is found it starts to subtract the found signal from the original for quick response is good to set correct starting condition – 50 Hz <> 60 Hz It has no affect on the ECG signal because it removes just one – mains frequency – no damage frequency spectrum. 54


ECG Filters – 50/60Hz adaptive


ECG Filters – baseline spline filters It works with 10 sec strips of ECG signal looks for “null” points in ECG signal in the middle between P and Q wave (the part with smallest change in the time) insets a curve in the “null” points subtract the curve from original ECG signal The filter use special type of “spline hermit function”. This type of filter used first GE.

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The name of spine filter (cubic – 3rd, square – 2nd, linear – 1st order of function) says which curve will be used for connection of the nearby “null” points.

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ECG Filters – baseline spline filters

It is a linear simulation of the basic 1st order high pass filter designed in hardware variant by RC elements linear characteristics (frequency, phase) but small filtration power 0.05Hz (3.20sec) & 0.10Hz (1.50sec) small influents on the signal 0.25Hz (0.60sec) influents on ST segments 0.50Hz (0.30sec) & 1.50Hz (0.10sec) use just for rhythm measurement (ergometry) damage QRS amplitude, ST segments... 57


ECG Filters – baseline filters ADS 0.05 – 1.5 Hz


ECG Filters – baseline filters ADS 0.05 – 1.5 Hz

no damage ECG signal

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ECG Filters – muscular filters The muscular filters removes high frequencies from the ECG signal 35Hz – acceptable affect on the QRS complex 25Hz – just for rhythm measurements

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ECG Filters – muscular filters

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BTL ECG Processing of ECG signal ČVUT, March 2011 Jan Daněk, BTL

CARDIOLOGY – ECG SIGNAL PROCESSING

ECG signal processing

Setting of the user’s filters has no effect on the measuring and diagnostic interpretation. 62

ECG SIGNAL PROCESSING – ECG FILTERS

ECG processing – User filtration

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ECG SIGNAL PROCESSING - MEASURING

ECG processing – Measuring of ECG signal based on 10 sec strip of ECG signal find all P-QRS-T complexes into strip & count them compute AVG HR (Heart Rate) to place found P-QRS-T complexes over them to have one average P-QRS-T complex without any noise to measure this complex – time & amplitude parameters the word interpretation is based on the calculated parameters

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CARDIOLOGY – TYPICAL ECG RECORD

Typical ECG record 3 pages A5, print format 6x2+1 + interpretation

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BTL

Co nového v roce 2010 / 2011 v BTL Radiofrekvence 3 MHz (neinvazivní liposukce) – see Exilis on the webpage balneoterapie Diatermie 27.12 MHz – 2011 IPL (Intensive Pulse Linght) – 2011 podpora stávajících produktů expanze do světa  otevřít 8 nových prodejních poboček  otevřít nákupní kancelář v Číně

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BTL

Competitors Cardiology: Schiller, www.schiller.ch Philips, www.medical.philips.com General Electric, www.gehealthcare.com Mortara, www.mortara.com Physiotherapy: Enraf-Nonius, www.enraf-nonius.com Gymna-Uniphy, www.gymna-uniphy.com Chattanooga, www.chattanoogagroup.com 67

BTL

Další výborné české firmy LINET, www.linet.com světový výrobce nemocničních postelí EGO, www.egozlin.cz mobilní nemocnice Beznoska, www.beznoska.com kloubní náhrady BMT, www.bmt.cz vybavení operačních sálů, sterilizace... Cheirón, www.cheiron.cz dýchací zařízení a odsávačky krve BTL, www.btlnet.com  ...a další viz www.medica.de 68

CARDIOLOGY – CONTACT INFORMATION

Contact information Medical Technologies CZ a.s. Jan Daněk Development Department Radimova 36 169 00 Praha 6 Czech Republic [email protected] tel. +420 602 163 525 fax +420 270 001 699 www.btlnet.com, www.btl.cz, www.medictech.com

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CONTACT INFORMATION

Chcete u nás pracovat? Aktuální pracovní nabídky zveřejněny na: www.jobs.cz http://www.jobs.cz/firma/548000-medical-technologies-cz-as

www.ikariera.cz http://www.btl.cz/o-spolecnosti/kariera/ a nebo mail: Jan Daněk, [email protected]

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CARDIOLOGY – LITERATURE

Used literature and sources http://www.wikipedia.com http://en.wikipedia.org/wiki/Ecg http://www.btlnet.com Jan Havlík, Czech Technical University at Prague. International Standard IEC 60601-2-51:2003. Malmivuo, J. – Plonsey, R: Bioelectromagnetism. Oxford University Press, New York, 1995. BTL marketing and production materials. GE marketing materials. PHILIPS / HP marketing materials.

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CARDIOLOGY ECG basic information. ČVUT, March 2011 Jan Daněk, BTL

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