<prompt> a wave in JVP indicates:Atrial systoleVentricular systoleAtrial relaxationTricuspid regurgitation  <response>: A wave: Arc positive waves due to distention producedby right atrial contraction Large a waves: Indicate atrium is contracting against increased resistance tricuspid stenosis, pulmonary stenosis, pulmonary hypertension.Cannon S wavesRegularly: During junctional rhythm. Irregularly: complete Heart Block. Absent a waves: Atrial Fibrillation 