By Jonathan Wilson A heart condition has brought an abrupt and premature conclusion to the career for a player responsible for so many moments of joy and triumph. View the original article to see embedded media. Briefly, it seemed like Barcelona might offer Sergio Agüero the perfect finale to his career (with maybe a year back at Independiente in his native Argentina to finish). His relationship with Pep Guardiola had never been entirely straightforward, and as opportunities for him dried up at Manchester City, a reunion with his old friend Lionel Messi seemed ideal. But financial pressures at…