What is the V (Ventricular) wave in the cardiac cycle?

The V Wave in the Cardiac Cycle

The V wave is a pressure wave in the left atrium (and visible in the jugular venous pulse for right atrial assessment) that occurs during ventricular systole when the atrium fills passively while the atrioventricular valve is closed. 1

Physiologic Mechanism

The V wave represents the rise in atrial pressure that occurs as blood accumulates in the atrium during ventricular contraction, when the mitral valve (left side) or tricuspid valve (right side) is closed. 1 This is fundamentally a passive filling phenomenon—the atrium acts as a reservoir while the ventricle is contracting and ejecting blood. 1

Key Timing Features

• The V wave occurs during ventricular systole, specifically during the period when the AV valve is closed and blood is returning to the atrium from the pulmonary veins (left side) or systemic veins (right side). 1
• The peak of the V wave coincides with the end of ventricular systole, just before the AV valve opens. 1
• The V wave is followed by the Y descent, which represents the rapid fall in atrial pressure when the AV valve opens and blood rushes from the atrium into the ventricle during early diastolic filling. 1, 2

Clinical Relevance in Hemodynamic Assessment

Left Atrial V Wave

The left atrial V wave is clinically significant when assessing left ventricular diastolic function and filling pressures. 1 An elevated or prominent V wave in the left atrium suggests:

• Increased left atrial pressure (mean LAP), which correlates with elevated left ventricular filling pressures. 1
• Potential mitral regurgitation, where the V wave becomes abnormally large due to regurgitant flow into the atrium during ventricular systole. 1
• Reduced left atrial compliance, where the atrium cannot accommodate normal venous return without excessive pressure rise. 1

Right Atrial V Wave (Jugular Venous Pulse)

The right atrial V wave can be observed clinically through the jugular venous pulse (JVP) examination in the neck. 2, 3 The JVP waveform includes both the V wave and the A wave (atrial contraction). 1, 2

Normal JVP descent pattern is single x' or x' > y, where x' represents the descent after the c wave (ventricular contraction) and y represents the descent after the V wave. 2 Abnormal patterns include:

• x' = y, x' < y, or single y descent alone, which indicate pathological right heart hemodynamics. 2
• A prominent V wave with steep Y descent suggests tricuspid regurgitation or increased right atrial pressure. 2

Distinguishing V Wave from A Wave

It is essential to differentiate the V wave from the A wave, as they represent different physiologic events:

• A wave: Occurs during atrial contraction (late diastole), representing active atrial systole pushing blood into the ventricle. 1 The A wave precedes the late diastolic rise in ventricular pressure. 1
• V wave: Occurs during ventricular systole, representing passive atrial filling while the AV valve is closed. 1

The A wave pressure in the left atrium precedes the late diastolic rise (LV A wave) in left ventricular pressure, making timing critical for proper identification. 1

Echocardiographic and Hemodynamic Correlation

When performing echocardiographic assessment of diastolic function, understanding the V wave is important because:

• Doppler parameters that correlate with mean left atrial pressure (which includes the V wave contribution) include mitral E velocity, E/A ratio, E/e' ratio, and pulmonary vein systolic-to-diastolic velocity ratio. 1
• The V wave contributes to mean pulmonary capillary wedge pressure (PCWP), which is an indirect estimate of left ventricular diastolic pressures. 1

Common Clinical Pitfalls

• Confusing the V wave with the A wave during hemodynamic assessment can lead to misinterpretation of filling pressures and valve function. 1 Always correlate timing with the cardiac cycle using simultaneous ECG or ventricular pressure tracings. 1
• Overlooking the Y descent (the fall after the V wave) can miss important information about AV valve function and ventricular compliance. 2 The Y descent represents early diastolic filling and should be assessed alongside the V wave. 2
• In jugular venous examination, failing to observe inspiratory collapse can miss the opportunity to assess right atrial pressure non-invasively. 4 Normal jugular veins should show at least 50% collapse during deep inspiration, indicating normal right atrial pressure. 4