The ventricular pressure–volume loop !
- Measurement
- Exam priority: high
Plotting the ventricle's pressure against its volume in one beat draws a loop whose shape shows how well it fills and pumps.
Updated 2026-11-01
Also called: PV loop
See it in 3D: Left ventricle · Mitral anterior leaflet · Aortic right coronary cusp
What it is
The pressure–volume loop plots left ventricular pressure (y) against volume (x) through one beat. Its width is the stroke volume, its area is the stroke work, and its corners mark the four valve events. Shifts of the loop show changes in preload, afterload and contractility, and the patterns of valve disease and heart failure.
Left-ventricular pressure–volume loop
EDV 120 mLESV 50 mLSV 70 mLEF 58%ESP 105 mmHg
Normal
Normal loop: EDV about 120 mL, ESV about 50 mL, SV about 70 mL and EF about 60%. The loop's width is the stroke volume and its area is the stroke work.
Tap a corner of the loop (MC, AO, AC, MO) to see the valve event.
- Current loop
- Normal loop
- ESPVR (contractility, Ees)
- EDPVR (passive filling)
- Ea (arterial afterload)
- Stroke volume (SV)
Equations
- EDV
- end-diastolic volume
- ESV
- end-systolic volume
Normal ≈ 55–70%.
How the loop changes
| Situation | Loop change | Stroke volume |
|---|---|---|
| More preload (fluids) | Wider, shifted right | Up |
| More afterload (hypertension) | Taller, end-systolic volume up | Down |
| More contractility (inotropes, sympathetic) | Shifted left, steeper ESPVR | Up |
| Heart failure with reduced EF | Shifted right, flatter ESPVR | Down |
| Aortic stenosis | Very tall, LV pressure ≫ aortic | Down or normal |
| Mitral regurgitation | No isovolumetric contraction, large EDV | Total up, forward down |
Clinical notes
- Aortic regurgitation: huge end-diastolic volume and no isovolumetric relaxation, because blood flows back from the aorta as soon as ejection ends.
- Positive inotropes move the loop left; vasodilators lower afterload and let it eject more.
Test yourself
Think of the answer, then tap the question to see it.
On a PV loop, what do the width and the area represent?
The width is stroke volume (EDV − ESV); the area enclosed is the external stroke work done by the ventricle.
How does an acute rise in afterload change the loop?
The aortic valve opens at a higher pressure, the loop is taller, the ventricle ends ejection at a larger ESV, so stroke volume falls.
Why is there no true isovolumetric contraction phase in mitral regurgitation?
As soon as the ventricle starts to contract, blood leaks back into the left atrium, so volume falls before the aortic valve opens.
Which line on the PV diagram best reflects contractility, and how does a positive inotrope change it?
The end-systolic pressure–volume relationship; an inotrope makes it steeper, so the ventricle empties to a smaller ESV at the same pressure.
See it in 3D
The structures of Durgical's 3D anatomy where it happens.
Related topics
- The cardiac cycle
- The Frank–Starling mechanism
- Preload, afterload and contractility
- Heart failure physiology
- Murmurs and the hemodynamics of valve disease
Related conditions
Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Sources: 19.4 Cardiac Physiology (OpenStax (Rice University), 2022); Aortic Stenosis (StatPearls (NCBI Bookshelf), 2025); Mitral Regurgitation (StatPearls (NCBI Bookshelf), 2025); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 9). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016).
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Representative model, for educational purposes only.