Kia has released exterior images of its new domestic-market K5 fastback sedan, which should reach the U.S. as the next-generation Optima next year.  Styling direction takes a bold new turn, with a wide grille that flows into the headlights, which feature a "heartbeat" -themed daytime running light that resembles a heart rate monitor's zigzag line.  The crisply contoured body narrows slightly midway between the wheels, and a chrome accent strip arches above the frameless windows and around the rear glass, presenting a muscular and dramatic profile.  The heartbeat theme is echoed in the design of the tail lamps, while a subtle spoiler caps off the sporty theme.  The K5 will be released in Korea this December, with global markets to follow next year.