Police confirm a massive six-car crash on the Gowanus Expressway Wednesday night was caused by a driver experiencing a medical episode.

Authorities say one of the drivers, 51-year-old Dimitri Kontoleon, from Dyker Heights, has died. Police have not confirmed what medical episode Kontoleon experienced, but fire officials say the original call came in for cardiac arrest.

The crash happened just before 4 p.m. near Exit 23. Kontoleon was driving his Volkswagen when he lost control and struck a car which caused the chain reaction involving the other vehicles.

Officials say four patients between the ages of 26-60 are now recovering after being sent to the hospital.