JVP

Jugular Venous Pulse waves:

a - wave : due to Atrial contraction
x - descent : due to atrial relaXation
c - wave : Bulging (Closure ) of Tricuspid valve into right atrium
v - wave : Venacaval blood Volume increased when Tricuspid valve is closed
y - descent: Tricuspid valve opening and inflow of blood into right ventricle ( Yahooooo ! - Tricuspid valve open! )

Note that first 2 waves are described in relation to Atrium and the next 3 waves in relation to Tricuspid.