Incident Sequence
After departure from Denver, during climbout, the first officer observed the captain twitch and inquired about his well-being. The captain replied that he was fine but put on his oxygen mask at the suggestion of the first officer. Approximately twenty minutes later, while the aircraft was descending through 10,000 feet on approach to Boise, the captain's body stiffened. His left foot applied pressure to the left rudder pedal.
Intervention
A flight attendant and a passenger intervened by moving the captain from his seat to the floor. The first officer assumed control, declared an emergency, and continued to fly the approach. The landing was completed without any additional issues.
Aftermath
Upon arrival, an ambulance was waiting and transported the captain to a hospital for evaluation. Tests, including an EKG and blood chemistry analysis, showed results consistent with myocardial infarction.