The jugular venous pressure is the indirectly observed pressure over the venous system via
visualization of the internal jugular vein. It can be useful in the differentiation of
different forms of heart and lung disease. Classically three upward deflections and two
downward deflections have been described. The upward deflections are the "a", "c" and
"v" = atrial venous filling. The downward deflections of the wave are the
"x" and the "y" descent.
Method Visualization
The patient is positioned under 45°, and the filling level of the jugular vein determined.
Visualize the internal jugular vein when looking for the pulsation. In healthy people, the
filling level of the jugular vein should be less than 3 centimetres vertical height above
the sternal angle. A pen-light can aid in discerning the jugular filling level by providing
tangential light. The JVP is easiest to observe if one looks
along the surface of the sternocleidomastoid muscle, as it is easier to appreciate the
movement relative to the neck when looking from the side. Like judging the movement of
an automobile from a distance, it is easier to see the movement of an automobile when
it is crossing one's path at 90 degrees, as opposed to coming toward one.
Pulses in the JVP are rather hard to observe, but trained cardiologists do try to discern
these as signs of the state of the right atrium. Differentiation from the carotid pulse
The JVP and carotid pulse can be differentiated several ways:
multiphasic - the JVP "beats" twice in the cardiac cycle. In other words, there are two
waves in the JVP for each contraction-relaxation cycle by the heart. The first beat represents
that atrial contraction and second beat represents venous filling of the right atrium against
a closed tricuspid valve and not the commonly mistaken 'ventricular contraction'. These
wave forms may be altered by certain medical conditions; therefore, this is not always
an accurate way to differentiate the JVP from the carotid pulse. The carotid artery only
has one beat in the cardiac cycle. non-palpable - the JVP cannot be palpated.
If one feels a pulse in the neck, it is generally the common carotid artery.
occludable - the JVP can be stopped by occluding the internal jugular vein by lightly pressing
against the neck. It will fill from above. varies with head-up-tilt - the JVP varies
with the angle of neck. If a person is standing, his JVP appears to be lower on the neck. The
carotid pulse's location does not vary with HUT.
varies with respiration - the JVP usually decreases with deep inspiration. Physiologically,
this is a consequence of the Frank–Starling mechanism as inspiration decreases the thoracic
pressure and increases blood movement into the heart, which a healthy heart moves into
the pulmonary circulation. JVP waveform
The jugular venous pulsation has a biphasic waveform.
The " a " wave corresponds to right Atrial contraction and ends synchronously with the
carotid artery pulse. The peak of the 'a' wave demarcates the end of atrial systole.
The " c " wave corresponds to right ventricular Contraction causing the triCuspid valve to
bulge towards the right atrium. The " x " descent follows the 'a' wave and
corresponds to atrial relaXation and rapid atrial filling due to low pressure.
The " x' " descent follows the 'c' wave and occurs as a result of the right ventricle
pulling the tricuspid valve downward during ventricular systole.. The x' descent can be
used as a measure of right ventricle contractility. The " v " wave corresponds to Venous filling
when the tricuspid valve is closed and venous pressure increases from venous return - this
occurs during and following the carotid pulse. The " y " descent corresponds to the rapid
emptYing of the atrium into the ventricle following the opening of the tricuspid valve.
Quantification A classical method for quantifying the JVP
was described by Borst & Molhuysen in 1952. It has since been modified in various ways.
A venous arch may be used to measure the JVP more accurately.
Moodley's Sign This sign is used to determine which waveform you are viewing. Feel the radial
pulse while simultaneously watching the JVP. The waveform that is seen immediately after
the arterial pulsation is felt is the 'v wave' of the JVP.
Abdominojugular test
The term hepatojugular reflux was previously used as it was thought that compression of
the liver resulted in "reflux" of blood out the hepatic sinusoids into the great veins
thereby elevating right atrial pressure and visualized as jugular venous distention. The
exact physiologic mechanism of jugular venous distention with a positive test is much more
complex and the commonly accepted term is now "Abdominojugular test."
In a prospective randomized study involving 86 patients who underwent right and left cardiac
catheterization, the abdominojugular test was shown to correlate best with the pulmonary
arterial wedge pressure. Furthermore, patients with a positive response had lower left ventricular
ejection fractions and stroke volumes, higher left ventricular filling pressure, higher
mean pulmonary arterial, and higher right atrial pressures.
The abdominojugular test, when done in a standardized fashion, correlates best with the pulmonary
arterial wedge pressure, and therefore, is probably a reflection of an increased central
blood volume. In the absence of isolated right ventricular failure, seen in some patients
with right ventricular infarction, a positive abdominojugular test suggests a pulmonary
artery wedge pressure of 15 mm Hg or greater. Interpretation
Certain wave form abnormalities, include Cannon a-waves, or increased amplitude 'a' waves,
are associated with AV dissociation, when the atrium is contracting against a closed
tricuspid valve, or even in ventricular tachycardia. Another abnormality, "c-v waves", can be a
sign of tricuspid regurgitation. The absence of 'a' waves may be seen in atrial fibrillation.
An elevated JVP is the classic sign of venous hypertension. JVP elevation can be visualized
as jugular venous distention, whereby the JVP is visualized at a level of the neck that
is higher than normal. The paradoxical increase of the JVP with inspiration is referred to
as the Kussmaul sign, and indicates impaired filling of the right ventricle. The differential
diagnosis of Kussmaul's sign includes constrictive pericarditis, restrictive cardiomyopathy,
pericardial effusion, and severe right-sided heart failure.
Raised JVP, normal waveform Bradycardia
Fluid overload Heart Failure
Raised JVP, absent pulsation Superior vena cava syndrome
Large 'a' wave tricuspid stenosis
Right heart failure Pulmonary hypertension
Cannon 'a' wave Atrial flutter
Premature atrial rhythm third degree heart block
Ventricular ectopics Ventricular tachycardia
Absent 'a' wave atrial fibrillation
Large 'v' wave Tricuspid regurgitation
Slow 'y' descent Tricuspid stenosis
Cardiac Tamponade
Prominent & Deep 'y' descent Constrictive pericarditis
Parodoxical JVP Pericardial effusion
Constrictive pericarditis Pericardial tamponade
An important use of the jugular venous pressure is to assess the central venous pressure in
the absence of invasive measurements. A 1996 systematic review concluded that a high jugular
venous pressure makes a high central venous pressure more likely, but does not significantly
help confirm a low central venous pressure. The study also found that agreement between
doctors on the jugular venous pressure can be poor.
References
External links Clinical Examination page on JVP
JVP Normal jugular vein waves - Merck Manual
JVD bedside workup