JVP refers to Jugular Venous Pressure and Jugular Venous Pulsations.
Checking JVP involves assessing the pressure in the jugular system and the waveform in the jugular system.
Anatomy and Physiology
The internal jugular vein drains into the superior vena cava, which drains into the right atrium.
No valve between the right atrium and the venous system allows pressure in the right atrium to transmit backward into the venous system.
Normal pressure in the right atrium is about 8 cm of water.
Jugular venous pressure is measured as the vertical height of the blood column in the jugular system above the sterno-manubrial angle, usually around 3 cm.
Importance of JVP
Acts as a biological manometer, reflecting right atrial pressure and pulse patterns.
Internal jugular vein's pulsations mirror the pressure changes in the right atrium.
Normal JVP Waveform
A Wave: Caused by atrial contraction, leading to back pressure into the venous system.
C Wave: Due to onset of ventricular contraction and tricuspid valve closure.
X Descent: Atrial relaxation continues, causing the pressure to fall.
V Wave: Venous return accumulates in right atrium and jugular system.
Y Descent: Onset of ventricular diastole leads to blood moving from the atrium to the ventricle.
JVP and the Cardiac Cycle
A Wave: Matches atrial systole.
C Wave: Represents the onset of ventricular systole.
X Descent and V Wave: Occur during atrial diastole.
Y Descent: Occurs with ventricular diastole.
Clinical Assessment
To check JVP, the patient should be positioned at a 45-degree angle.
Differentiate between venous and arterial pulsations (venous pulsations are not palpable and move up/down).
JVP is considered elevated if more than 4 cm above the sterno-manubrial joint.
Abnormal JVP Patterns
Elevated JVP without Pulsations: Indicates superior vena cava obstruction.
Large A Waves: Seen in pulmonary stenosis, hypertension, or tricuspid stenosis.
Cannon A Waves: Result from atrial contraction against a closed tricuspid valve (e.g., in complete heart block or nodal rhythm).
Fused C-V Wave: Seen in tricuspid regurgitation.
Special Features
Kussmaul's Sign: Paradoxical rise in JVP during inspiration, seen in constrictive pericarditis.
Friedreich's Sign: Steep Y descent due to rapid ventricular filling, associated with constrictive pericarditis.
Hepatojugular Reflux
Applying pressure to the right upper abdominal quadrant increases JVP.
Significant and sustained elevation indicates right ventricular stiffness or failure.