Cardiac function curve
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Cardiology Network |
 Discuss Cardiac function curve further in the WikiDoc Cardiology Network |
| Adult Congenital |
|---|
| Biomarkers |
| Cardiac Rehabilitation |
| Congestive Heart Failure |
| CT Angiography |
| Echocardiography |
| Electrophysiology |
| Cardiology General |
| Genetics |
| Health Economics |
| Hypertension |
| Interventional Cardiology |
| MRI |
| Nuclear Cardiology |
| Peripheral Arterial Disease |
| Prevention |
| Public Policy |
| Pulmonary Embolism |
| Stable Angina |
| Valvular Heart Disease |
| Vascular Medicine |
| WikiDoc Cardiology News |
 Read more about Cardiac function curve in the WikiDoc Cardiology News |
| All News Articles |
|---|
| Acute Coronary Syndromes |
| Biomarkers |
| Cardiovascular Imaging |
| CT Surgery |
| Diabetes |
| Electrophysiology |
| General Cardiology |
| Guidelines |
| Health Policy |
| Heart Failure |
| Hypertension |
| Interventional |
| Peripheral Arterial Disease |
| Prevention |
| Valvular Heart Disease |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-525-6884
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
A cardiac function curve is a graph showing the relationship between right atrial pressure (x-axis) and cardiac output (y-axis).
Shape of curve
It shows a steep relationship at relatively low filling pressures and a plateau, where further stretch is not possible and so increases in pressure have little effect on output. The pressures where there is a steep relationship lie within the normal range of right atrial pressure (RAP) found in the healthy human during life. This range is about -1 to +2 mmHg. The higher pressures normally occur only in disease, in conditions such as heart failure, where the heart is unable to pump forward all the blood returning to it and so the pressure builds up in the right atrium and the great veins. Swollen neck veins are often an indicator of this type of heart failure.
At low right atrial pressures this graph serves as a graphic demonstration of the Frank-Starling mechanism, that is as more blood is returned to the heart, more blood is pumped from it without extrinsic signals.
Changes in the cardiac function curve
In vivo however, extrinsic factors such as an increase in activity of the sympathetic nerves, and a decrease in vagal tone cause the heart to beat more frequently and more forcefully. This alters the cardiac function curve, shifting it upwards. This allows the heart to cope with the required cardiac output at a relatively low right atrial pressure. We get what is known as a family of cardiac function curves, as the heart rate increases before the plateau is reached, and without the RAP having to rise dramatically to stretch the heart more and get the Starling effect.
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
