Melody Gardot’s backstory is plenty tragic. She was seriously injured in a car-meets-bicycle collision at age 19, and endured 18 months of grueling rehab that left her disabled and in constant pain. But Worrisome Heart needs no melodramatic props. Devoid of self-pity, the 11 understated original songs here inhabit the intersection of folk, blues and jazz, and Gardot’s horn-like vocal timbre and sense of swing lift them far beyond the ordinary. She’s a luminous singer. Consider the amazing scat interplay between Gardot and violinist Diane Monroe on “Wicked Ride,” or the title track, in which Fiona Apple sits in on Miles Davis’ “Blue in Green” at 3 a.m. in a dimly lit bar.