Central venous pressure and the jugular pulse !
- Measurement
- Exam priority: medium
Central venous pressure is the pressure of blood entering the right heart; the internal jugular vein shows it in the neck.
Updated 2026-11-01
Also called: CVP, Jugular venous pressure
See it in 3D: Internal jugular vein · Superior vena cava · Right atrium · Tricuspid anterior leaflet
What it is
Central venous pressure (CVP) is almost the same as right atrial pressure and reflects the balance between venous return and the right heart's ability to pump it on. The internal jugular vein, with no valves between it and the atrium, acts as a manometer: its height estimates CVP and its a, c and v waves copy the events of the right atrium.
Key facts
- Kussmaul sign: the jugular rises on inspiration (instead of falling) in constrictive pericarditis and severe RV failure.
- Hepatojugular reflux: pressing on the abdomen raises the jugular for a sustained period when the right heart cannot take more volume.
- In tamponade the y descent disappears because the tense pericardium prevents rapid filling.
- Tricuspid regurgitation merges c and v into one large systolic wave (cv wave).
Cardiac cycle (Wiggers diagram)
HR 75/minCycle 800 msSystole ≈ 300 msSV 70 mLEF 58%
1. Atrial systole (≈ 0–170 ms)
The atrium contracts (after the P wave) and tops up the ventricle: the 'atrial kick', about 10–20% of filling at rest, and more important with tachycardia or a stiff ventricle. The atrial pressure shows the a wave.
- Valves: mitral open, aortic closed
- Sound: none normally; an S4 here means a stiff ventricle
- ECG: P wave and PR segment
- Aorta
- Left ventricle (LV)
- Left atrium (LA)
- LV volume
- ECG
- S1 and S2
- Ventricular systole
- Ventricular diastole
- Valve events (MC, AO, AC, MO)
Reference values
| Parameter | Value | Note |
|---|---|---|
| Central venous pressure | ≈2–8 mmHg | ≈3–11 cmH₂O |
| Height of the jugular pulsation | ≤3–4 cm above the sternal angle | patient at 45° |
| Right atrial pressure | ≈0–5 mmHg |
Approximate values for a healthy adult at rest; each laboratory sets its own ranges.
Reading the jugular pulse
| Finding | Physiological cause |
|---|---|
| Large a wave | The atrium pushes against resistance: tricuspid stenosis, RV hypertrophy, pulmonary hypertension |
| Cannon a waves | Atrium and ventricle contract together with the tricuspid shut (complete AV block) |
| Absent a wave | No organized atrial contraction (atrial fibrillation) |
| Large systolic cv wave | Tricuspid regurgitation: blood flows back into the atrium in systole |
| Absent y descent with prominent x | Cardiac tamponade: diastolic filling is restricted |
| High jugular and hepatojugular reflux | Right or biventricular failure with raised volume |
Clinical notes
- Low CVP with tachycardia and hypotension points to hypovolemia; high CVP with hypotension points to pump failure, tamponade or massive pulmonary embolism.
- In nursing, the transducer is leveled at the phlebostatic axis (4th intercostal space, mid-axillary line) before reading CVP.
- Beck's triad of tamponade includes jugular distension, hypotension and muffled heart sounds.
Test yourself
Think of the answer, then tap the question to see it.
Why do cannon a waves appear in complete AV block?
Atria and ventricles beat independently; sometimes the atrium contracts against a closed tricuspid valve and blood surges back up the jugular.
Which jugular wave disappears in atrial fibrillation and why?
The a wave, because there is no organized atrial contraction to produce it.
Why does a high CVP not by itself mean the patient has "too much volume"?
CVP reflects the balance of venous return and right heart function; it rises with RV failure, tamponade, embolism or positive-pressure ventilation even when volume is normal or low.
What explains the Kussmaul sign in constrictive pericarditis?
Inspiration increases venous return, but the rigid pericardium stops the right heart from expanding: venous pressure rises instead of falling.
See it in 3D
The structures of Durgical's 3D anatomy where it happens.
Related topics
- Venous return and the Guyton curves
- The cardiac cycle
- Heart failure physiology
- Shock physiology
- Vascular compliance and capacitance
Related conditions
- Heart failure
- Cardiac tamponade
- Atrioventricular (heart) block
- Atrial fibrillation
- Pulmonary embolism
- Hypovolaemic shock
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: 19.3 Cardiac Cycle (OpenStax (Rice University), 2022); 20.2 Blood Flow, Blood Pressure, and Resistance (OpenStax (Rice University), 2022); Heart Failure (Congestive Heart Failure) (StatPearls (NCBI Bookshelf), 2025); Cardiac Tamponade (StatPearls (NCBI Bookshelf), 2026); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 15). 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.