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Left ventricular hypertrophy (LVH) is the abnormal thickening of the myocardium (muscle) of the left ventricle of the heart.
While LVH itself is not a disease, it is usually a marker for disease involving the heart. Disease processes that can cause LVH include any disease that increases the afterload that the heart has to contract against, and some primary diseases of the muscle of the heart.
Causes of increased afterload that can cause LVH include aortic stenosis, aortic insufficiency, and hypertension. Primary disease of the muscle of the heart that cause LVH are known as hypertrophic cardiomyopathies.
Diagnosis
The principle method to diagnose LVH is echocardiography, during which the thickness of the muscle of the heart can be measured. The electrocardiogram (ECG) often shows signs of increased voltage from the heart in individuals with LVH, so this is often used as a screening test to determine who should undergo further testing with an echocardiogram.
Echocardiography
Two dimensional echocardiography can produce images of the left ventricle. The thickness of the left ventricle as visualized on echocardiography correlates with it's actual mass. Normal thickness of the left ventricular myocardium is from 0.6 to 1.1 cm (as measured at the very end of diastole. If the myocardium is more than 1.1 cm thick, the diagnosis of LVH can be made.
ECG criteria for LVH
There are multiple criteria used to diagnose LVH via electrocardiography. None of them are perfect. However, by using multiple different criteria the sensitivity and specificity are increased.
The Cornell criteria1 for the ECG diagnosis of LVH involves measurement of the sum of the R wave in lead aVL and the S wave in lead V3. The Cornell criteria for LVH are:
- In males, S in V3 + R in aVL > 28 mm
- In females, S in V3 + R aVL > 20 mm
References
1. Casale PN, Devereux RB, Alonso DR, Campo E, Kligfield P. Improved sex-specific criteria of left ventricular hypertrophy for clinical and computer interpretation of electrocardiograms: validation with autopsy findings. Circulation. 1987 Mar;75(3):565-72. (Medline abstract (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2949887))
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