Left axis deviation
The hexaxial reference system is a diagram that is used to determine the heart's electrical axis in the frontal plane.
Left axis deviation (LAD) is a condition whereby the mean electrical axis of ventricular contraction of the heart lies in a frontal plane direction between −30° and −90°. This is reflected by a QRS complex positive in lead I and negative in leads aVF and II.[1]
Cause
Common causes of LAD include left ventricular hypertrophy (LVH), left anterior fascicular block (or hemiblock) and inferior myocardial infarction.[2][3] Less commonly LAD may be a normal variant, particularly in obese or stocky individuals, or it may be associated with Wolff–Parkinson–White syndrome or an ostium primum atrial septal defect.
LVH is generally recognised as a cause of LAD,[2][3][4] although some sources claim that LVH does not cause LAD.[1][5]
See also
References
- 1 2 http://www.ecglibrary.com/axis.html
- 1 2 Lilly, Leonard (2006). Pathophysiology of Heart Disease. Lippincott Williams and Wilkins. ISBN 978-0-7817-6321-9.
- 1 2 Kasper D, Braunwald E, Fauci A, Hauser S, Longo D, Jameson J (2005). Harrison's Principles of Internal Medicine (16th ed.). McGraw-Hill. p. 1314. ISBN 0-07-147760-8.
- ↑ http://lifeinthefastlane.com/ecg-library/basics/left-axis-deviation/
- ↑ http://www.fpnotebook.com/cv/exam/LftAxsDvtn.htm
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