Wave	Description	Abnormalities
a wave	The first peak caused by atrial contraction	Absent in atrial fibrillation
c wave	The second peak caused by tricuspid valve closure, contraction of the right ventricle, and bulging of the tricuspid valve into the right atrium	cv wave : severe tricuspid valve regurgitation
x descent	A drop in JVP caused by atrial relaxation	Absent in:
		Tricuspid valve regurgitation
		Right heart failure
v wave	The third peak caused by venous refilling of the right atrium against the closed tricuspid valve	Prominent in:
		Tricuspid valve regurgitation
		Right heart failure
y descent	A drop in JVP caused by decreased right atrial pressure as blood flows into the right ventricle after opening of the tricuspid valve	Prominent in: [7]
		Tricuspid valve regurgitation
		Constrictive pericarditis
		Absent in:
		Cardiac tamponade
		Tricuspid valve stenosis

Pathology

Common abnormalities of the JVP waveform include:

• Constrictive pericarditis: elevated JVP (due to increased external atrial pressure) with a prominent x (exaggerated atrial relaxation) and y (early rapid ventricular filling) descent
• Cardiac tamponade: elevated JVP (due to increased external atrial pressure), a prominent x descent (exaggerated atrial relaxation), and a blunt or absent y descent (minimal ventricular filling)
• Tricuspid regurgitation: prominent v wave as the blood from the right ventricle regurgitates into the right atrium during ventricular systole (atrial diastole), increasing interatrial pressure and volume
• Tricuspid stenosis: giant a wave due to high right atrial systolic pressure
• Atrial septal defect: v wave ≥ a wave due to the left-to-right shunting of blood
• Third-degree atrioventricular (AV) block: cannon a waves due to the loss of AV synchronization and contraction of the atria against a closed tricuspid valve
• Atrial fibrillation: absent a waves due to ineffective contraction of the atria