"The early bird catches the worm" is an old saying that still rings true.

Indeed, reference to the "early bird" could be seen on Friday, when Medtronic (NYSE:MDT) received regulatory approval 3 months ahead of schedule for its heart valve replacement technology, CoreValve, which involves the use of minimally invasive surgery and is therefore suitable for patients who are unable to cope with the demands of traditional surgery.

Although shares posted only mild gains in the hours following the update, the stock could be one to watch in the future as investors digest the encouraging news. Medtronic could "catch the worm" in terms of it experiencing improved sentiment and a firmer share price in future.

The approval begins what could be a lengthy battle between Medtronic and Edwards Lifesciences (NYSE:EW), which has a similar device already on the market. The Sapien system has been approved in the USA since 2011, and is used with patients who are able to withstand more invasive surgery than that required to implement CoreValve, but who are at a greater risk of complications resulting from the surgery.

Interestingly, the global market for such valves -- called transcatheter aortic valve replacements, or TAVRs -- stands at more than $1 billion, with Edwards Lifesciences making up around two-thirds of those sales. Clearly, there is potential for Medtronic to win market share from Edwards Lifesciences, although both companies may ultimately be hampered to a degree by onerous Medicare procedures and the high costs of the TAVRs.

Indeed, Medicare stipulates that hospitals must first document that patients are not up to traditional, open surgery and therefore require TAVR. The cost of making that assessment, as well as the $30,000-plus expense of the TAVR procedure, means that many hospitals consider the surgery to be a loss-making activity, thereby reducing total demand.

Still, Medtronic believes that the total market for TAVRs could hit upward of $2 billion by 2020 if further regulatory approvals mean they could be used even on patients who can withstand traditional surgery. Investors, though, may wish to budget for a lower total sales volume, since traditional, open surgery remains the safer option for patients who can withstand the operation. This is due to the higher incidence of complications resulting from the use of TAVRs.

However, Medtronic investors should be upbeat about the news, since the current $1 billion market could be shaken up by the new product. Gains here would bolster Medtronic's top line, and it looks as though competitive pricing will enable CoreValve to win sales from Edwards Lifesciences. As a result, Edwards Lifesciences saw its shares fall by just under 5% in Friday trading.

Meanwhile, although not exactly "early", sector peer St. Jude Medical appears to be "getting the worm," as shares have been firmer since the company recently announced an upgrade to its fourth-quarter guidance following an impressive level of sales growth.

The news comes at an opportune moment for the company, after the first three quarters of 2013 had been challenging. While an upgrade on one quarter may not be enough to cause sentiment to pick up drastically in the short run, both it and Medtronic could be stocks to watch over the course of 2014.