The waiting room in Minneapolis General felt like a pressure chamber.

Alex Rivera sat frozen in a plastic chair, head in his hands, the fluorescent lights casting harsh shadows on his face. His shirt was wrinkled from the frantic drive, eyes red from tears he hadn’t let fall yet.

Clara had been in the cath lab for five hours.

It had happened in the dead of night, months after her first heart attack—the one that had come without warning on the pond, the one they’d ...