Left ventricular hypertrophy is the thickening of the myocardium of the left ventricle of
the heart.
Causes While ventricular hypertrophy occurs naturally
as a reaction to aerobic exercise and strength training, it is most frequently referred to
as a pathological reaction to cardiovascular disease, or high blood pressure.
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, which can lead into heart failure.
Long-standing mitral insufficiency also leads to LVH as a compensatory mechanism.
Diagnosis The principal method to diagnose LVH is echocardiography,
with which the thickness of the muscle of the heart can be measured. The electrocardiogram
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.
Echocardiography Two dimensional echocardiography can produce
images of the left ventricle. The thickness of the left ventricle as visualized on echocardiography
correlates with its 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 several sets of criteria used to
diagnose LVH via electrocardiography. None of them is perfect, though by using multiple
criteria sets, the sensitivity and specificity are increased.
The Sokolow-Lyon index: S in V1 + R in V5 or V6 ≥ 35 mm
R in aVL ≥ 11 mm The Cornell voltage criteria for the ECG diagnosis
of LVH involve measurement of the sum of the R wave in lead aVL and the S wave in lead
V3. The Cornell criteria for LVH are: S in V3 + R in aVL > 28 mm
S in V3 + R in aVL > 20 mm The Romhilt-Estes point score system:
Other voltage-based criteria for LVH include: Lead I: R wave > 14 mm
Lead aVR: S wave > 15 mm Lead aVL: R wave > 12 mm
Lead aVF: R wave > 21 mm Lead V5: R wave > 26 mm
Lead V6: R wave > 20 mm Treatment
The enlargement is not permanent in all cases, and in some cases the growth can regress with
the reduction of blood pressure and controlling excitements/emotions strictly.
LVH may be a factor in determining treatment or diagnosis for other conditions. For example,
LVH causes a patient to have an irregular ECG. Patients with LVH may have to participate
in more complicated and precise diagnostic procedures, such as imaging, in situations
in which a physician could otherwise give advice based on an ECG.
Associated genes OGN, osteoglycin
See also Cardiomegaly
Ventricular hypertrophy Primary hyperparathyroidism
References