QRS axis: Difference between revisions

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==How do you determine the electrical heartaxis==
==How do you determine the electrical heartaxis==
[[Image:ECG_lead_angulation.png|thumb]]
[[Image:hartas2.jpg|thumb|The heartaxis indicates the average direction of the depolarization wave. A normal heartaxis, the picture shows an example, is between -30 and +90 degrees. In this example, the heartaxis is +45 degrees.]]
[[Image:hartas2.jpg|thumb|The heartaxis indicates the average direction of the depolarization wave. A normal heartaxis, the picture shows an example, is between -30 and +90 degrees. In this example, the heartaxis is +45 degrees.]]
[[Image:hart_axis.png|thumb]]
[[Image:einthhartas.png|thumb|200px|left|Heartaxis from the original publication of Einthoven. Reprinted from The Lancet, March 30 1912, Einthoven W., ''The Different Forms of The Human Electrocardiogram and Their Signification'', 853-861, 1912, with permission from Elsevier]]
[[Image:einthhartas.png|thumb|200px|left|Heartaxis from the original publication of Einthoven. Reprinted from The Lancet, March 30 1912, Einthoven W., ''The Different Forms of The Human Electrocardiogram and Their Signification'', 853-861, 1912, with permission from Elsevier]]
[[Image:hart_axis.png|thumb]]
[[Image:ECG_lead_angulation.png|thumb]]


When you average all electrical signals from the heart, you can indicate the direction of the average electrical depolarization with an arrow (vector). This is the heartaxis. Especially a change of the heartaxis or an extreme deviation can be an indication for pathology.
When you average all electrical signals from the heart, you can indicate the direction of the average electrical depolarization with an arrow (vector). This is the heartaxis. Especially a change of the heartaxis or an extreme deviation can be an indication for pathology.
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So positive deflections in I and II indicates a normal heartaxis.
So positive deflections in I and II indicates a normal heartaxis.


{{clr}}
====Interpretation====
====Interpretation====
The interpretation of the electrical heartaxis has a few rules of thumb:
The interpretation of the electrical heartaxis has a few rules of thumb: