Left ventricular hypertrophy (LVH) is thickening of the heart muscle of the left ventricle of the

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

, that is, left-sided ventricular hypertrophy and resulting increased left ventricular mass.

Causes

While ventricular hypertrophy occurs naturally as a reaction to

aerobic exercise Aerobic exercise, also known as cardio, is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. "Aerobic" is defined as "relating to, involving, or requiring oxygen", and refers to the use of ...

and

strength training Strength training, also known as weight training or resistance training, is exercise designed to improve physical strength. It is often associated with the lifting of Weightlifting, weights. It can also incorporate techniques such as bodyweigh ...

, it is most frequently referred to as a pathological reaction to

cardiovascular disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...

, or

high blood pressure Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...

. It is one aspect of

ventricular remodeling In cardiology, ventricular remodeling (or cardiac remodeling) refers to changes in the size, shape, structure, and function of the heart. This can happen as a result of exercise (physiological remodeling) or after injury to the heart muscle (patho ...

. 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 Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a conse ...

and

hypertension Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...

. 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. LV mass increases with

ageing Ageing (or aging in American English) is the process of becoming older until death. The term refers mainly to humans, many other animals, and fungi; whereas for example, bacteria, perennial plants and some simple animals are potentially biol ...

. Associated genes include OGN, osteoglycin.

Diagnosis

The commonly used method to diagnose LVH is

echocardiography Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an ec ...

, with 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.

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. Left ventricular mass can be further estimated based on geometric assumptions of ventricular shape using the measured wall thickness and internal diameter. Average thickness of the left ventricle, with numbers given as 95%

prediction interval In statistical inference, specifically predictive inference, a prediction interval is an estimate of an interval (statistics), interval in which a future observation will fall, with a certain probability, given what has already been observed. Pr ...

for the short axis images at the mid-cavity level are: * Women: 4 – 8 mm * Men: 5 – 9 mm

CT & MRI

CT and

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

-based measurement can be used to measure the left ventricle in three dimensions and calculate left ventricular mass directly. MRI based measurement is considered the “

gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...

” for left ventricular mass, though is usually not readily available for common practice. In older individuals, age related remodeling of the left ventricle's geometry can lead to a discordancy between CT and echocardiographic based measurements of left ventricular mass.

ECG criteria

Left ventricular hypertrophy with secondary repolarization

Histopathology of myocardial hypertrophy

Gross pathology of left ventricular hypertrophy

There are several sets of criteria used to diagnose LVH via electrocardiography. None of them are 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 (whichever is larger) ≥ 35 mm (≥ 7 large squares) * 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 (men) * S in V₃ + R in aVL > 20 mm (women) The Romhilt-Estes point score system ("diagnostic" >5 points; "probable" 4 points): 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 Diagnostic accuracy of electrocardiography in left ventricular hypertrophy can be enhanced with

artificial intelligence Artificial intelligence (AI) is the capability of computer, computational systems to perform tasks typically associated with human intelligence, such as learning, reasoning, problem-solving, perception, and decision-making. It is a field of re ...

analysis.

Treatment

Treatment is typically focused on resolving the cause of the LVH with the enlargement not permanent in all cases. In some cases the growth can regress with the reduction of blood pressure. LVH may be a factor in determining treatment or diagnosis for other conditions, for example, LVH is used in the staging and risk stratification of Non-ischemic cardiomyopathies such as Fabry's Disease. Patients with LVH may have to participate in more complicated and precise diagnostic procedures, such as echocardiography or cardiac MRI.

References

External links

{{DEFAULTSORT:Left Ventricular Hypertrophy Cardiomegaly