Jan Opletal was killed as part of the Nazi occupation in 1939. He didn't have any sort of direct influence on the events in 1989, but the memory of his death burned brightly as a part of Czech history.
The demonstration on November 17th was originally planned as an event to commemorate the death of Jan Opletal. It was even officially sanctioned by the government.
The problem however was that the demonstration grew in size until numbers were as high as 50,000 and people began marching to Wenceslas Square as a form of protest. The police boxed them in there and beat the remaining 1,500 to 10,000 people.
The memory of Jan Opletal encouraged people to act following November 17th. They were reminded of his death by the tyrannical Nazi power and began to compare the Nazis to the communists. An event that occured fifty years prior came back to inspire the revolution against a new tyrannical power.