Brad Nau

LAWRENCEVILLE, N.J. (CBS) - A retired accountant in Lawrenceville, New Jersey, is crediting his smart watch for saving his life.Frank Haggerty had no idea he had a heart problem, but he’s glad he had the heart rate app activated on his Apple Watch.“I wanted to be cool, I always thought these were really sharp looking. They’re hip, they’re in style,” Haggerty said. They’re trendy all right, but for Haggerty, his Apple Watch became a lifesaver. “My wife and I were sleeping and the alarm went off…