From AvHerald:
http://avherald.com/h?article=44aef202By Simon Hradecky, created Wednesday, Feb 15th 2012 15:36Z, last updated Wednesday, Feb 15th 2012 15:36Z
A CSA Czech Airlines Avion de Transport Regional ATR-42-500, registration OK-KFN performing flight OK-777 from Warsaw (Poland) to Prague (Czech), was on approach to Prague when the first officer declared emergency reporting the captain had become incapacitated. The first officer continued for a safe landing in Prague, responding emergency services however were not able to save the captain's life.
The airline confirmed one of the flight crew members became incapacitated during the flight stressing that the second pilot would be fully capable to land the aircraft safely. Doctors were unable to save the captain's life.