Shivananda Patil, 54, was recently announced as the JDS's candidate from Sindagi constituency.
Janata Dal (Secular) candidate for Sindagi Assembly Constituency, Sivananda Patil died late on Friday night after a cardiac attack, former Karnataka Chief Minister H D Kumaraswamy said on Saturday.
Shivananda Patil, 54, was recently announced as the party's candidate from Sindagi constituency for the next assembly elections.
Mr Patil was immediately rushed to the hospital where he died on Friday night.
HD Kumaraswamy condoled the sudden death of Mr Patil.
"The untimely death of Mr Sivananda Patil, the party candidate for Sindagi Assembly Constituency @JanataDal_S has deeply shocked me. I am personally deeply saddened by the passing away of Mr Sivananda Patil. I pray that his soul rests in eternal peace and that the family is given the strength to bear the grief," the Minister tweeted in Kannada.
"Mr Patil, who retired after selfless service in the army, had an irrepressible desire for social service. He had excellent organizational skills, and dynamism and became very dear to me within a short time of his acquaintance," Mr Kumaraswamy said.
The JD(U) also expressed its grief over Mr Patil's death. "Deeply saddened to report that Mr Sivananda Patil, JDS candidate for Sindagi Assembly Constituency passed away untimely due to heart attack. On this occasion, we pray that his family gets the strength to bear this grief. Let us pray for the departed soul to rest in peace."
Sivananda Patil is survived by his wife, son and daughter.