The jugular venous pressure or sometimes referred to as jugular venous pulse (jvp) is the indirectly observed pressure via visualization of the internal jugular vein.
Normal Jugular Venous Pulse
The normal JVP consists of three positive pulse waves a, c and v and two negative pulse waves x and y.
The ‘A’ Wave
The ‘a’ wave is produced by retrograde transmission of the pressure pulse produced by right atrial contraction. In normal subjects the ‘a’ wave is often the largest positive wave visible, coinciding with the fourth heart sound.
1. ‘a’ wave is absent in atrial fibrillation
2. ‘a’ wave is diminished in
- Prolonged PR interval
3. Large or giant ‘a’ waves are present in
- Tricuspid stenosis
- Tricuspid atresia
- Right atrial myxoma
- Pulmonary stenosis
- Pulmonary hypertension
4. Cannon ‘a’ waves occur in
- Complete heart block when the right atrium and right ventricle contract simultaneously with a closed tricuspid valve.
- Ventricular tachycardia
- Ectopic beats
The ‘C’ Wave
the ‘c’ wave is produced by two events:
- Impact of the carotid artery adjacent to the jugular vein.
- Retrograde transmission of a positive wave in the right atrium produced by the right ventricular systole and the bulging of the tricuspid valve into the right atrium.
It normally begins at the end of the first heart sound and reaches its peak shortly after the first heart sound. The ‘c’ wave is not often seen clinically.
The ‘X’ Wave
‘x’ descent is produced by:
- The downward displacement of the tricuspid valve during ventricular systole and the resultant fall in right atrial pressure.
- Continued atrial relaxation.
Abnormalities of ‘x’ wave
- The ‘x’ descent is obliterated or may be replaced by a positive wave (‘s’ wave) in tricuspid regurgitation. This ‘s’ wave may fuse with ‘c’ and ‘v’ waves to produce a giant ‘v’ wave.
- The ‘x’ wave may sometimes be prominent in constrictive pericarditis.
The ‘V’ Wave
The ‘v’ wave occurs because of right atrial filling with the tricuspid valve closed during ventricular systole.
Abnormalities of ‘v’ wave
Giant ‘v’ waves, as discussed earlier, appear in tricuspid regurgitation:
The ‘Y’ Wave
The ‘y’ descent is produced by the opening of the tricuspid valve and subsequent rapid inflow of blood from the right atrium to the right ventricle leading to a sudden fall of pressure in the right atrium which is reflected in the jugular veins. It corresponds with the third heart sound.
The ascending limb of the ‘y’ wave is due to continuous diastolic inflow of blood into the great veins, right atrium, and ventricle which are all in free communication during diastole.
1. Rapid ‘y’ descent occurs in
- Constrictive pericarditis (Friedreich’s sign).
- Severe heart failure.
- Tricuspid regurgitation.
2. A short ‘y’ descent occurs in tricuspid stenosis
Jugular Venous Pressure
Normal value is 3-4 cm of water.
The patient is given a backrest to keep him/her at 45 degrees. In this position, normally, the jugular vein is just seen above the clavicle. The upper level of the vein is noted and a ruler is kept at that level, parallel to the ground.
Another ruler is put perpendicular to the first ruler up to the angle of Louis. The distance from the angle of Louis to the first ruler gives the jugular pressure. In the supine position the jugular pressure may falsely appear elevated whilst in the upright position, it is falsely lowered.
The jugular veins are in direct continuity with the superior vena cava and the right atrium.
Elevated venous pressure occurs in:
- Right ventricular failure
- Cardiac tamponade
- Tricuspid stenosis
- Superior vena cava obstruction
- Hyperkinetic circulatory state
- Increased blood volume
- Pulmonary diseases like asthma, emphysema
Normally inspiration lowers the jugular venous pressure giving an inspiratory collapse because intrathoracic pressure falls and there is increased blood flow into the thorax. In contrast, when the intrapericardial pressure is raised as in constrictive pericarditis, there is a paradoxical increase in jugular venous pressure on inspiration. This is called Kussmaul’s sign.
Normally, when pressure is applied over the abdomen for 30 seconds, initially there is a rise in jugular venous pressure (due to increased venous return), followed by a fall (due to the capacity of normal myocardium to accommodate the extra venous return).
However, in early cardiac failure, even before jugular pressure is elevated, there is a sustained elevated pressure in the jugular veins (for more than a minute) on pressure over the abdomen because the failing heart cannot compensate for the extra venous return. This is positive hepatojugular reflux.
Decreased venous pressure is seen in