View source for Ventricular hypertrophy

{{DiseaseDisorder infobox |
  Name           = Ventricular hypertrophy |
  ICD10          = {{ICD10|I|51|7|i|30}} |
  ICD9           = {{ICD9|429.3}} |
  ICDO           = |
  Image          = Right Ventricular hypertrophy svg.png|
  Caption        = |
  OMIM           = |
  MedlinePlus    = |
  eMedicineSubj  = |
  eMedicineTopic = |
  DiseasesDB     = |
}}
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{{WikiDoc Cardiology Network Infobox}}
{{CMG}}



Although '''ventricular hypertrophy''' may occur in either the left or right or both [[Ventricle (heart)|ventricle]]s of the [[heart]], [[left ventricular hypertrophy]] (LVH) is more commonly encountered. 

== Physiology ==
The ventricles are the chambers in the heart responsible for pumping blood either to the lungs (right ventricle) or the rest of the body (left ventricle). Increased ventricular mass is an adaptation by the [[Ventricle (heart)|ventricle]](s) of the heart to increased stress, such as chronically increased volume load (preload) or increased pressure load (afterload). 

It is a physiological response that enables the heart to adapt to increased stress; however, the response can become [[pathological]] and ultimately lead to a deterioration in function. For example, hypertrophy is a normal [[physiological]] adaptation to [[exercise]] that enables the ventricle to enhance its pumping capacity.  [[Aerobic exercise|Aerobic]] training results in the heart being able to pump a larger volume of blood through an increase in the size of the ventricles.  [[Anaerobic exercise|Anaerobic]] training results in the thickening of the myocardial wall to push blood through arteries compressed by [[Muscle contraction|muscular contraction]]. This type of physiologic hypertrophy is reversible and non-pathological, increasing the heart's ability to circulate blood. Chronic hypertension causes pathological ventricular hypertrophy.  This response enables the heart to maintain a normal stroke volume despite the increase in afterload.  However, over time, pathological changes occur in the heart that lead to a functional degradation and heart failure.

If the precipitating stress is volume overload (as through aerobic exercise, which increases blood return to the heart through the action of the [[skeletal-muscle pump]]), the ventricle responds by adding new sarcomeres in-series with existing sarcomeres (i.e. the sarcomeres lengthen rather than thicken). This results in ventricular dilation while maintaining normal sarcomere lengths - the heart can expand to receive a greater volume of blood. The wall thickness normally increases in proportion to the increase in chamber radius. This type of hypertrophy is termed eccentric hypertrophy. 

In the case of chronic pressure overload (as through anaerobic exercise, which increases resistance to blood flow by compressing arteries), the chamber radius may not change; however, the wall thickness greatly increases as new sarcomeres are added in-parallel to existing sarcomeres. This is termed concentric hypertrophy. This type of ventricle is capable of generating greater forces and higher pressures, while the increased wall thickness maintains normal wall stress. This type of ventricle becomes "stiff" (i.e., compliance is reduced) which can impair filling and lead to [[diastolic]] dysfunction.

==See also==
* [[Cardiac fibrosis]]
* [[Cardiology]] 
* [[Cardiomegaly]]
* [[Cardiovascular disease]]
* [[Right ventricular hypertrophy]]

==External links==
*[http://library.med.utah.edu/kw/ecg/ecg_outline/Lesson8/ Tutorial at University of Utah]

{{Circulatory system pathology}}

[[Category:Cardiovascular diseases]]
[[Category:Cardiomyopathy]]
[[Category:Cardiology]]
[[Category:Exercise physiology]]

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