-
8/20/2019 LEB02_01
1/318 PHYWE Systeme GmbH & Co. KG · D-37070
GöttingenLaboratory Experiments, Biology
Heart and Circulatory System LEB 02
02.01 Human electrocardiography (ECG)
Principle and tasks:
To record an electrocardiogram (ECG)between the left leg and the
rightand left arm (lead II according toEinthoven). To relate the
ECG seg-ments to the course of heart con-traction (P wave, P-Q
segment, QRScomplex, T wave)
Circuit diagram
What you can learn about
Electrocardiogram accordingto Einthoven II
Heart rate
Quiet and strained heart
ECG segments
Atria
Ventricles
AV nodes
Cobra3, Basic Unit 12150.00 1
Power supply, 12 V 12151.99 1
RS232 data cable 14602.00 1Cobra3 Universal Recorder Software
14504.61 1
Bio-amplifier 65961.93 1
Electrode collecting cable 65981.03 1
ECG electrodes, 3 pieces 65981.01 1
Potassium chloride, 250 g 30098.25 1
Connection cord, 32 A, l = 25 cm, red 07360.01 1
Connection cord, 32 A, l = 25 cm, blue 07360.04 1
Spoon with spatula end, l = 150 mm, steel, wide 33398.00
1
Balance SAS51, 200 g/0.01 g, RS232 45990.93 1
Graduated cylinder, 100 ml 36629.00 1
PC, Windows® 95 or higher
Tempo/Kleenex Tissues
What you need:
Human electrocardiography (ECG)P4020111
Typical measuring results
-
8/20/2019 LEB02_01
2/3
Related topics
Electrocardiogram according to Einthoven II, heart rate,
quiet and strained heart, ECG segments, atria, ventricles,
AV nodes
Principle and task
To record an electrocardiogram (ECG) between the left leg
and the right and left arm (lead II according to Einthoven).
To relate the ECG segments to the course of heart con-
traction (P wave, P-Q segment, QRS complex, T wave)
Equipment
Cobra3, Basic Unit 12150.00 1
Power supply, 12 V 12151.99 1
RS232 data cable 14602.00 1
Cobra3 Universal Recorder Software 14504.61 1
Bio-amplifier 65961.93 1Electrode collecting cable 65981.03
1
ECG electrodes, 3 pieces 65981.01 1
Potassium chloride, 250 g 30098.25 1
Connection cord, 32 A, l = 25 cm, red 07360.01 1
Connection cord, 32 A, l = 25 cm, blue 07360.04 1
Spoon with spatula end,
l = 150 mm, steel, wide 33398.00 1
Balance SAS51, 200 g/0.01 g, RS232 45990.93 1
Graduated cylinder, 100 ml 36629.00 1
PC, WINDOWS®
Tempo/ Kleenex Tissues
Set-up
— According to Figs. 1 and 2.
Phywe Series of publication • Laboratory Experiments Biology • ©
PHYWE SYSTEME GMBH & Co. KG • D-37070 Göttingen 40201 25
LEB
02.01Human electrocardiography (ECG)
Fig. 1. Experimental set-up
Fig. 2. Circuit diagram
-
8/20/2019 LEB02_01
3/3
— Prepare a 1% KCl solution. Cut Kleenex/Tempo tis-
sues to size such that they are approximately as large
as ECG electrodes. Moisten the pieces of cut tissue
with KCl solution.
— Using tightening bands, attach one electrode each to
the inner sides of the right and left wrists as well as to
that of the left ankle. In the process, place a piece of
the cut tissue that has been moistened with KCl solu-
tion between the skin and the electrode in each case.
— Have the experimental subject sit in a relaxed posture
with his or her underarms resting on his or her knees.
— Connect the electrode collecting cable as follows: red
plug to the electrode on the right arm; yellow plug to
the electrode on the left arm; green plug to the elec-
trode on the left leg.
— Connect the electrode collecting cable to the input
port on the bioamplifier and the amplifier output porton the
bioamplifier to the Analog IN 2 port on the
Cobra3 Interface: the red jack of the bioamplifier with
the upper yellow jack (+) on the Cobra3 Interface; the
blue jack on the bioamplifier with the lower yellow
jack (-).
Procedure
— Switch on the bioamplifier; set the amplification to 100
times and the measuring mode to ”EKG”.
— Start recording the measured values using parame-
ters in accordance with those shown in Fig. 3:
CONTINUE, START MEASUREMENT.
— After conclusion of the measurement process (ca.
5 s), select an appropriate section of the measure-
ment signal.
— Measure the maximum amplitude of the ECG.
— Calculate the pulse rate using the ”Survey” icon.
— Impose a strain on the heart (e.g. 10 deep-knee
bends) and repeat the measurement as described
above.
— Several ECG plots can be simultaneously displayed
and compared on the screen.
Results and evaluation
— The amplitude of the QRS group is 1 to 2 mV (take the
100-times preamplification into consideration!).
Depending on the strain, the pulse rate lies between
50 and 130 beats/min (time separation between twocorresponding
peaks: 1.2 to 0.5 s).
— Relationship of the ECG segments to the course of
contraction:
P wave = Spreading of excitation across the
two atria
P-Q segment = Delay of excitation conduction at
the AV nodes
QRS complex = Excitation conduction across the
two ventricles
T wave = repolarization of the two ventricles
Phywe Series of publication • Laboratory Experiments Biology • ©
PHYWE SYSTEME GMBH & Co. KG • D-37070 Göttingen4020126
LEB
02.01 Human electrocardiography
Fig. 3. Measurement parameters
Fig. 4. Typical measuring results
