Volume overload

<h2 id="pathophysiology">Pathophysiology</h2>
<p>In accordance with the <a href="/facts/Frank%E2%80%93Starling_law_of_the_heart/06VUxJUF">Frank–Starling law of the heart</a>, the <a href="/facts/Myocardium/oMqU4Sdu">myocardium</a> contracts more powerfully as the <a href="/facts/End-diastolic_volume/u9NQLB3a">end-diastolic volume</a> increases. Stretching of the <a href="/facts/Myofibrils/uGRRhxms">myofibrils</a> in cardiac muscle causes them to contract more powerfully due to a greater number of cross-bridges being formed between the <a href="/facts/Myofibrils/uGRRhxms">myofibrils</a> within <a href="/facts/Cardiac_myocytes/fE40oTQz">cardiac myocytes</a>.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> 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.
</p><p>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 <a href="/facts/Afterload/h5CGnv4r">afterload</a>. The output may be high due to the inefficiency in <a href="/facts/Valvular_heart_disease/jbURjwR9">valve disease</a>, or it may be high due to <a href="/facts/Shunt_(medical)/bp3tmFGn">shunting</a> of blood in left-to-right shunts and <a href="/facts/Arteriovenous_malformations/4yIVzsBR">arteriovenous malformations</a>.
</p><p>Left ventricular volume overload may produce inverted <a href="/facts/U_wave/5HlxgUSM">u waves</a> on the <a href="/facts/Electrocardiogram/YpVswJ0W">electrocardiogram</a>.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
</p>
<h2 id="causes">Causes</h2>
<p>Causes may be considered according to which chamber is affected.
</p><p>Left ventricular volume overload
</p>
<ul><li><a href="/facts/Valvular_heart_disease/jbURjwR9">Valvular heart disease</a><a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
<ul><li><a href="/facts/Aortic_regurgitation/UXB4JWg7">Aortic regurgitation</a></li>
<li><a href="/facts/Mitral_regurgitation/VEojWbau">Mitral regurgitation</a>, also causing <a href="/facts/Left_atrium/eYNg8Vw2">left atrial</a> volume overload<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a></li></ul></li>
<li><a href="/facts/Congenital_heart_defects/QsuPPC2Y">Congenital heart defects</a>
<ul><li><a href="/facts/Patent_ductus_arteriosus/cPmKMY6D">Patent ductus arteriosus</a></li>
<li><a href="/facts/Ventricular_septal_defect/WE2KHC6z">Ventricular septal defect</a>, also causing left atrial volume overload<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a></li></ul></li>
<li>Arteriovenous <a href="/facts/Arteriovenous_malformation/4yIVzsBR">malformation</a> and <a href="/facts/Arteriovenous_fistula/XbQmvF5m">fistula</a>
<ul><li><a href="/facts/Giant_hepatic_haemangioma/rJRR08Lg">Giant hepatic haemangioma</a></li>
<li>High-output <a href="/facts/Haemodialysis/oB7fIKP7">haemodialysis</a> fistula</li></ul></li></ul>
<p>Right ventricular volume overload
</p>
<ul><li><a href="/facts/Valvular_heart_disease/jbURjwR9">Valvular heart disease</a>
<ul><li><a href="/facts/Tricuspid_regurgitation/9hnjn3r5">Tricuspid regurgitation</a></li>
<li><a href="/facts/Pulmonary_regurgitation/uSaF5hqg">Pulmonary regurgitation</a></li></ul></li>
<li><a href="/facts/Congenital_heart_defects/QsuPPC2Y">Congenital heart defects</a>
<ul><li><a href="/facts/Atrial_septal_defect/56nsJeG5">Atrial septal defect</a>, also causing right atrial volume overload<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a></li></ul></li></ul>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Cardiac_failure/7fckX3Jm">Cardiac failure</a></li>
<li><a href="/facts/Frank%E2%80%93Starling_law_of_the_heart/06VUxJUF">Frank–Starling law of the heart</a></li>
<li><a href="/facts/Preload_(cardiology)/VTkgQ4tG">Preload (cardiology)</a></li>
<li><a href="/facts/Pressure_overload/7VQ9Fe1Y">Pressure overload</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Costanzo, Linda S. (2007). Physiology. Hagerstwon, MD: Lippincott Williams & Wilkins. pp. 81. ISBN 978-0-7817-7311-9. <a href="978-0-7817-7311-9" target="_blank">978-0-7817-7311-9</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Klabunde, Richard E. "Cardiovascular Physiology Concepts". Lippincott Williams & Wilkins, 2011, p. 74. <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Conrath C, Opthof T (2005). "The patient U wave". Cardiovasc Res. 67 (2): 184–6. doi:10.1016/j.cardiores.2005.05.027. PMID 15979057. <a href="https://doi.org/10.1016%2Fj.cardiores.2005.05.027" target="_blank">https://doi.org/10.1016%2Fj.cardiores.2005.05.027</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Left Ventricular Volume Overload, Discussion of echocardiography findings. <a href="http://www.echoincontext.com/int2/skillI2_04.asp" target="_blank">http://www.echoincontext.com/int2/skillI2_04.asp</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Gehl LG, Mintz GS, Kotler MN, Segal BL (1982). "Left atrial volume overload in mitral regurgitation: a two dimensional echocardiographic study". Am J Cardiol. 49 (1): 33–8. doi:10.1016/0002-9149(82)90274-0. PMID 7053608. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Gardiner M, Eisen S, Murphy C. Training in paediatrics: the essential curriculum. Oxford University Press, Oxford 2009. <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Gardiner M, Eisen S, Murphy C. Training in paediatrics: the essential curriculum. Oxford University Press, Oxford 2009. <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
</ol>

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Volume overload