In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The Atria (an adjacent/upper heart chamber that is smaller than a ventricle) primes the Pump. Interventricular means between two or more ventricles (for example the interventricular septum), while intraventricular means within one ventricle (for example an intraventricular block).
In a four-chambered heart, such as that in humans, there are two ventricles: the right ventricle pumps blood into the pulmonary circulation to/for the lungs, and the left ventricle pumps blood into the systemic circulation through the aorta (systemic circulation). (See Double circulatory system for details.)
Ventricles have thicker walls than atria and must allow and withstand higher incoming and outgoing blood pressures. The physiologic load on the ventricles requiring pumping of blood throughout the body and lungs is much greater than the pressure generated by the atria to fill the ventricles. Further, the left ventricle has thicker walls than the right because it needs to pump blood to most of the body while the right ventricle fills only the lungs.
The mass of the left ventricle, as estimated by magnetic resonance imaging, averages 143 g ± 38.4 g, with a range of 87 - 224 g.[1]
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During systole, the ventricles contract, pumping blood through the body. During diastole, the ventricles relax and fill with blood again.
In cardiology, the performance of the ventricles are measured with several volumetric parameters, including end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV)and ejection fraction (Ef).
| Measure | Typical value | Normal range |
|---|---|---|
| end-diastolic volume (EDV) | 120 ml[2] | 65 - 240 ml[2] |
| end-systolic volume (ESV) | 50 ml[2] | 16 - 143 ml[2] |
| stroke volume (SV) | 70 ml | 55 - 100 ml |
| ejection fraction (Ef) | 58% | 55 to 70%[3] |
| heart rate (HR) | 75 bpm | 60 to 100 bpm[4] |
| cardiac output (CO) | 5.25 L/minute | 4.0 - 8.0 L/min[5] |
The heart and its performance are also commonly measured in terms of dimensions, which in this case means one-dimensional distances, usually measured in millimeters. This is not as informative as volumes, but may be much easier to estimate with e.g. M-Mode echocardiography[6] or with sonomicrometry (mostly used for animal model research). Optimally, it is specified with which plane the distance is measured in, e.g. the dimension of the longitudinal plane.[7]
| Dimension | Abbreviation | Definition | Normally |
|---|---|---|---|
| End-diastolic dimension | EDD | The diameter across a ventricle at the end of diastole, if not else specified then usually referring to the transverse[8] (left-to-right) internal (luminal) distance, excluding thickness of walls, although it can also be measured as the external distance. | |
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LVEDD or sometimes LVDD | The end-diastolic dimension of the left ventricle. | 48 mm,[9] Range 36 – 56 mm[10] |
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RVEDD or sometimes RVDD | The end-diastolic dimension of the right ventricle. | Range 10 – 26 mm[10] |
| End-systolic dimension | ESD | ESD is similar to the end-diastolic dimension, but is measured at the end of systole (after the ventricles have pumped out blood) rather than at the end of diastole. | |
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LVESD or sometimes LVSD | The end-systolic dimension of the left ventricle. | Range 20 – 40 mm[10] |
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RVESD or sometimes RVSD | The end-systolic dimension of the right ventricle. | Range 10 – 26 mm[10] |
| Interventricular septal end diastolic dimension | IVSd | The thickness of the interventricular septum. | 8.3 mm,[9] Range 7 – 11 mm[10] |
| Left ventricular end diastolic posterior wall dimension | LVPWd | The thickness of the posterior left ventricular wall. | 8.3 mm,[9] Range 7 – 11 mm[10] |
| Left atrial dimension | LA | Range 24 – 40 mm[10] |
Fractional shortening (FS) is the fraction of any diastolic dimension that is lost in systole. When referring to endocardial luminal distances, it is EDD minus ESD divided by EDD (times 100 when measured in percentage).[11] Normal values may differ somewhat dependent on which anatomical plane is used to measure the distances, but a range from 30 to 42% is considered normal with 26 to 30% representing a mild decrease in function.[12] Midwall fractional shortening may also be used to measure diastolic/systolic changes for inter-ventricular septal dimensions[13] and posterior wall dimensions. However, both endocardial and midwall fractional shortening are dependent on myocardial wall thickness, and thereby dependent on long-axis function.[14] By comparison, a measure of short-axis function termed epicardial volume change (EVC) is independent of myocardial wall thickness and represents isolated short-axis function.[14]
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