Response of cardiac stroke volume to ventricular filling under normal conditions

Volume overload refers to the state of one of the

chambers of the heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon diox ...

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 Preload may refer to: Science and technology * Preload (cardiology), maximum stretch of the heart at the end of diastole * preload (software), code-prefetching software for Linux * Preload (engineering), the internal application of stress to cert ...

. It is a cause of

cardiac failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...

Pathophysiology

In accordance with the Frank–Starling law of the heart, the

myocardium Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that ...

contracts more powerfully as the

end-diastolic volume In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in the right or left ventricle at end of filling in diastole which is ammount of blood present in ventricle at the end of diastole systole. Because greater EDVs cause ...

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 Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate Muscle tissue, muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striat ...

.Klabunde, Richard E. "Cardiovascular Physiology Concepts". Lippincott Williams & Wilkins, 2011, p. 74. 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. 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 Afterload is the pressure that the heart must work against to eject blood during systole (ventricular contraction). Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on ...

. 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 Arteriovenous malformation is an abnormal connection between arteries and veins, bypassing the capillary system. This vascular anomaly is widely known because of its occurrence in the central nervous system (usually cerebral AVM), but can app ...

. Left ventricular volume overload may produce inverted

u wave The 'U' wave is a wave on an electrocardiogram (ECG). It comes after the T wave of ventricular repolarization and may not always be observed as a result of its small size. 'U' waves are thought to represent repolarization of the Purkinje fibers. ...

s on the electrocardiogram.

Causes

Causes may be considered according to which chamber is affected. Left ventricular volume overload *

Valvular heart disease Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart (the aortic and mitral valves on the left side of heart and the pulmonic and tricuspid valves on the right side of heart). These ...

Left Ventricular Volume Overload
Discussion of echocardiography findings. **

Aortic regurgitation 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 conseq ...

** Mitral regurgitation, also causing left atrial volume overload *

Congenital heart defects A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...

Patent ductus arteriosus ''Patent ductus arteriosus'' (PDA) is a medical condition in which the ''ductus arteriosus'' fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has ...

Ventricular septal defect A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one ...

, also causing left atrial volume overloadGardiner M, Eisen S, Murphy C. Training in paediatrics: the essential curriculum. Oxford University Press, Oxford 2009. * Arteriovenous

malformation A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

and

fistula A fistula (plural: fistulas or fistulae ; from Latin ''fistula'', "tube, pipe") in anatomy is an abnormal connection between two hollow spaces (technically, two epithelialized surfaces), such as blood vessels, intestines, or other hollow or ...

Giant hepatic haemangioma A cavernous liver hemangioma or hepatic hemangioma is a benign tumor of the liver composed of hepatic endothelial cells. It is the most common benign liver tumour, and is usually asymptomatic and diagnosed incidentally on radiological imaging. Li ...

** High-output

haemodialysis Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatini ...

fistula Right ventricular volume overload *

Tricuspid regurgitation Tricuspid regurgitation (TR), also called tricuspid insufficiency, is a type of valvular heart disease in which the tricuspid valve of the heart, located between the right atrium and right ventricle, does not close completely when the right ventr ...

Pulmonary regurgitation Pulmonary (or pulmonic) insufficiency (or incompetence, or regurgitation) is a condition in which the pulmonary valve is incompetent and allows backflow from the pulmonary artery to the right ventricle of the heart during diastole. While a small ...

Atrial septal defect Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...

, also causing right atrial volume overload

References

{{Cardiovascular physiology Cardiovascular physiology

Pathophysiology

Causes

See also

References