<prompt> a wave in JVP IndicatesRight atrial contractionClosure of tricuspid valveOnset of ventricular systoleMaximal atrial filling  <response>: a Right atrial contractionRef: Harrison, 18th ed.,pg. 1823, fig. 227-1Graph of height of JVP with timeThe upward deflections are thea atrial contractionc ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systolev venous fillingThe downward deflections of the wave are thex the atrium relaxes, and the tricuspid valve moves downwardthe y descent filling of ventricle after tricuspid opening. 