Which of the following condition is associated with giant 'a' wave in a JVP?

'a' wave in a JVP reflects right atrial presystolic contraction and occurs just after P wave on ecg and precedes first hea sound. Giant a waves occur in tricuspid stenosis and right ventricular hyperophy. Giant a waves are produced when right atrium contracts with increased force due to the increase in resistance to the flow of blood from right atrium to right ventricle. Reference: Harrison's Principles of Internal Medicine 18th edition chapter 227.