QRS axis: Difference between revisions

11 bytes added ,  19 December 2008
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[[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:einthhartas.png|thumb|Heartaxis from the original publication of Einthoven. Reprinted from The Lancet, March 30 1912, Einthoven W.,
[[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]]
''The Different Forms of The Human Electrocardiogram and Their Signification'', 853-861, 1912, with permission from
Elsevier]]
The electrical heartaxis is an average of all depolarizations in the heart. The depolarization wave begins in the right atrium and proceeds to  the left and right ventricle. Because the left ventricle wall is thicker than the right wall, the arrow indicating the direction of the depolarization wave is directed to the left.
The electrical heartaxis is an average of all depolarizations in the heart. The depolarization wave begins in the right atrium and proceeds to  the left and right ventricle. Because the left ventricle wall is thicker than the right wall, the arrow indicating the direction of the depolarization wave is directed to the left.