While measuring jugular venous pressure, 'a' wave is indicative of:
Atrial filling
Atrial relaxation
Atrial contraction
Ventricular relaxation
The pressure pulsations that occur in the right atrium are transmitted in retrograde fashion to the large veins near the hea. Atrial contraction produces the first pressure peak called the a wave. The c wave is the transmitted manifestation of the rise in atrial pressure produced by the bulging of the tricuspid valve into the atria during isovolumetric ventricular contraction. The v wave mirrors the rise in atrial pressure before the tricuspid valve opens during diastole. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 30. The Hea as a Pump. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.