A singer, songwriter and guitarist, David Ponder knows the importance of a strong, steady beat. But this was ridiculous. “My heart now, it’s so strong,” said Ponder, 60, a Poway resident who in August 2016 underwent a successful heart transplant at Sharp Memorial Hospital. “The first night home, it was beating so hard it woke me up.” This Christmas, David Ponder is dazzled by the gifts he’s received from strangers: a life-sustaining organ and a life-enhancing relationship. He’s alive because a car wreck killed a man he’d never met, Coronado’s Juan Carlos Lopez, 26. When surgeons removed Lopez’s heart and transplanted it in Ponder’s chest, two families were stitched together in sorrow and joy. Months after the surgery, Ponder visited Lopez’s mother. The bond was instant.