ECG: The Einthoven leads & the mean electrical axis — Transcript

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1. 0:01Hi there, my name is Vaso and today I'm
2. 0:06going to show you how I record my ECG
3. 0:09with the Antoven leads called one, two
4. 0:13and three. We do this with our
5. 0:15differential amplifier which is this one
6. 0:18here.
7. 0:20Now remember that every biomplifier has
8. 0:24got three
9. 0:26inputs positive, negative and ground and
10. 0:31these need to be connected to my limbs
11. 0:34for the Antoven
12. 0:36ECG. The convention is to use the left
13. 0:40arm, the right arm and the left foot for
14. 0:43the electrode placements. And this gives
15. 0:46us three combinations or three different
16. 0:49signals called Eintoven one, two and
17. 0:52three leads. And they can be symbolized
18. 0:55by the famous Eintoven
19. 0:58triangle. The tip of the arrow indicates
20. 1:01the positive and the opposite end the
21. 1:03negative input and ground is always
22. 1:07connected to the right foot.
23. 1:10So now let us measure the Eintoven one
24. 1:14two and three leads one by
25. 1:17one. Eintoven one we take the positive
26. 1:21input which is the first cable here the
27. 1:24yellow cable and connect this one to the
28. 1:27left
29. 1:28arm there.
30. 1:31Then we take the negative
31. 1:33input last cable here and connect this
32. 1:37one to the right
33. 1:39arm. And we take ground blue cable and
34. 1:45connect this one to the right
35. 1:47foot
36. 1:51there. So this was einhovven one. Now
37. 1:55let's go to anthovven two.
38. 1:58We take the positive
39. 2:00input yellow cable and connect this one
40. 2:03to the left
41. 2:06foot
42. 2:08there. The negative
43. 2:10input which is my red cable. I connect
44. 2:14this one to the right arm and
45. 2:17ground blue cable here stays connected
46. 2:20to the right
47. 2:24foot. Eintoven
48. 2:273 positive
49. 2:31input connect it to the left
50. 2:34foot. Then we take the negative
51. 2:37input last cable here and connect this
52. 2:40one to the left
53. 2:42arm
54. 2:44there. And ground stays connected to the
55. 2:48right foot.
56. 2:52So now we have got three different
57. 2:56traces. A normal ECG machine would
58. 3:00record these three traces
59. 3:02simultaneously using three different
60. 3:05amplifiers. And with the help of these
61. 3:08three traces, it is now possible to
62. 3:12measure the angle of the electrical
63. 3:14field of the heart using the anten
64. 3:17triangle. And to do this we take the R
65. 3:21peaks of 1 2 and three and back project
66. 3:25their amplitude with the help of the
67. 3:27Antoven triangle to obtain the angle. In
68. 3:31my case the angle is 65°.