&;V&; wave in jugular venous pulse is due to

&;V&; wave in jugular venous pressure corresponds to right atrial filling during ventricular systole when the tricuspid valve is closed. The JVP has a biphasic waveform. * The "a" wave: First positive presystolic wave. * Right Atrial contraction. * Precedes the upstroke of carotid pulse, syn follows P wave of ECG. J. * * Peak of the &;a&; wave demarcates (\c the end of atrial systole. * Dominant wave in JVP during inspiration. * Larger than "v" wave. s, * The "x" descent: (Systolic collapse) * Follows the &;a&; wave * Corresponds to atrial relaXation and rapid atrial filling pressure. * Most prominent motion of normal JVP. * Begins during systole and ends just before S2. * Larger than "y" descent. * The " x&; " (x prime) descent * Follows the &;c&; wave * Occurs as a result of the right ventricle pulling the tricuspid valve downward during ventricular systole. * As stroke volume is ejected, the ventricle takes up less space in pericardium, allowing relaXed atrium to enlarge. * Can be used as a measure of right ventricle contractility. * The "c" wave * and positive venous wave. * Right ventricular (isovolumic) Contraction 4 tricuspid valve to bulge towards the right atrium. The "v" wave * 3rd positive wave. * Begins in late systole and ends in early diastole. * Corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return. * Occurs during and following the carotid pulse and peaks after S2. * The "y" descent: * Downslope of v wave. * Decline in RA pressure -rapid emptYing of the RA into the RV following the opening of the tricuspid valve in early diastole. Reference : Harrison 20th edition, pg 1421