It's safe to say medical-device maker St. Jude Medical (STJ) has had a big year. This stock's jumped more than 50% year to date as part of health care's rise in 2013. However, as shares have risen, St. Jude's sales and earnings haven't taken the same path higher.

How dicey is this company's financial situation? St. Jude's pacemaker and implantable cardioverter defibrillator sales, which make up a majority of the firm's revenue, have sunk over the first six months of the year. Meanwhile, the company's closest competitors are showing signs of a comeback while St. Jude's biggest growth segment lags behind these rivals.

Can St. Jude keep up its run, or is this stock bound to fall back to Earth? In the following video, Motley Fool contributor Dan Carroll tells you what's ahead for St. Jude -- and what investors need to watch if this company's going to turn around its struggling businesses.