It has been reported through a series of memoirs that the founder of the Islamic Republic used to recite ‘Ahad supplication’ which is a pledge with the last infallible Imam; May God Almighty hasten his appearance.
Imam Khomeini used to hold Mafatih—the collection of supplications -during his hospitalization time and recite the mentioned supplication with patience and calm before getting ready for any surgery or heading towards operating room.
It is worth mentioning that Imam had great devotion towards reciting supplications narrated by the holy prophet and his infallible successors through all thick and thin times.
(A memoirs by Hojjat al-Islam Ashtiani)