{{Short description|Heart condition}} {{Distinguish|Hypervolemia}} [[File:Response of cardiac stroke volume to ventricular filling under normal conditions.jpg|thumb|400px|Representation of the cardiac response in stroke volume to left ventricular filling under normal conditions. There is an optimum end-diastolic volume at which maximum stroke volume and cardiac output is achieved. Beyond this, there is '''volume overload''', and stroke volume is diminished.]]
'''Volume overload''' refers to the state of one of the chambers of the heart in which too large a volume of blood exists within it for it to function efficiently. Ventricular volume overload is approximately equivalent to an excessively high preload. It is a cause of cardiac failure.<ref name="isbn0-7817-7311-3">{{cite book |author=Costanzo, Linda S. |title=Physiology |publisher=Lippincott Williams & Wilkins |location=Hagerstwon, MD |year=2007 |pages=[https://archive.org/details/physiology00cost_0/page/81 81] |isbn=978-0-7817-7311-9 |oclc= |doi= |url-access=registration |url=https://archive.org/details/physiology00cost_0/page/81 }}</ref>
==Pathophysiology==
In accordance with the Frank–Starling law of the heart, the myocardium contracts more powerfully as the end-diastolic volume increases. Stretching of the myofibrils in cardiac muscle causes them to contract more powerfully due to a greater number of cross-bridges being formed between the myofibrils within cardiac myocytes.<ref name="Cardiovascular Physiology Concepts">Klabunde, Richard E. "Cardiovascular Physiology Concepts". Lippincott Williams & Wilkins, 2011, p. 74.</ref> This is true up to a point, however beyond this there is a loss of contractile ability due to loss of connection between myofibrils; see figure.{{cn|date=March 2021}}
Various pathologies, listed below, can lead to volume overload. Different mechanisms are involved depending on the cause, however the common theme is that of a high cardiac output with a low or normal afterload. The output may be high due to the inefficiency in valve disease, or it may be high due to shunting of blood in left-to-right shunts and arteriovenous malformations.{{cn|date=March 2021}}
Left ventricular volume overload may produce inverted u waves on the electrocardiogram.<ref name=Conrath_2005>{{cite journal |vauthors=Conrath C, Opthof T |title=The patient U wave |journal=Cardiovasc Res |volume=67 |issue=2 |pages=184–6 |year=2005 |pmid=15979057 | doi = 10.1016/j.cardiores.2005.05.027|doi-access=free }}</ref>
==Causes==
Causes may be considered according to which chamber is affected.{{cn|date=March 2021}}
'''Left ventricular volume overload''' * Valvular heart disease<ref name="Echoincontext">[http://www.echoincontext.com/int2/skillI2_04.asp Left Ventricular Volume Overload] {{Webarchive|url=https://web.archive.org/web/20130305110646/http://www.echoincontext.com/int2/skillI2_04.asp |date=2013-03-05 }}, Discussion of echocardiography findings.</ref> ** Aortic regurgitation ** Mitral regurgitation, also causing left atrial volume overload<ref name=Gehl>{{cite journal |vauthors=Gehl LG, Mintz GS, Kotler MN, Segal BL |title=Left atrial volume overload in mitral regurgitation: a two dimensional echocardiographic study |journal=Am J Cardiol |volume=49 |issue=1 |pages=33–8 |year=1982 |pmid=7053608 |doi=10.1016/0002-9149(82)90274-0}}</ref> * Congenital heart defects ** Patent ductus arteriosus ** Ventricular septal defect, also causing left atrial volume overload<ref name="Gardiner">Gardiner M, Eisen S, Murphy C. Training in paediatrics: the essential curriculum. Oxford University Press, Oxford 2009.</ref> * Arteriovenous malformation and fistula ** Giant hepatic haemangioma ** High-output haemodialysis fistula '''Right ventricular volume overload''' * Valvular heart disease ** Tricuspid regurgitation ** Pulmonary regurgitation * Congenital heart defects ** Atrial septal defect, also causing right atrial volume overload<ref name="Gardiner" />
==See also== * Cardiac failure * Frank–Starling law of the heart * Preload (cardiology) * Pressure overload ==References==
{{Reflist}} {{Cardiovascular physiology}}
Category:Cardiovascular physiology