The problem with buying companies heavily involved in one market is that if the market experiences a heart attack, the company suffers greatly. That's what happened to Boston Scientific (NYSE:BSX) when the stent market collapsed on safety worries, but the company is getting some relief from a new market.

Last week, Boston Scientific announced that it had received European marketing approval for its LIVIAN cardiac resynchronization therapy defibrillator (CRT-D). The implantable device monitors heartbeats in patients and delivers a small electrical impulse to reset the heart should it get out of rhythm.

The device is still under review by the FDA, but with 6.5 million people in Europe suffering from heart failure, the European approval should give Boston Scientific a revenue boost even if the U.S. approval is delayed.

This is Boston Scientific's first approval of a branded cardiac rhythm management device to treat heart failure. With Medtronic's (NYSE:MDT) slip-up in the related implantable cardioverter-defibrillator (ICD) market, I'd expect Boston Scientific to continue moving down the path to mend broken hearts with defibrillators rather than mesh tubes.

This increased diversification should be a welcome relief for shareholders. In the most recent quarter, sales of stents were down 22% year over year in a segment that accounted for 22% of Boston Scientific's revenue. And even if the stent market turns around, which I think is likely, Boston Scientific is going to see steep competition next year.

With both Medtronic and Abbott Laboratories (NYSE:ABT) likely getting FDA approval for their stents shortly, and Johnson & Johnson (NYSE:JNJ) desperate enough to advertise directly to consumers, the stent market looks more packed than a matinee show featuring The Wiggles. Diversifying away from the crowded stent business seems like a prudent move to me.

More Foolishness to keep your blood flowing:

Help us in our goal to give every young person around the globe a financial education! Learn more about the new direction of Foolanthropy, now in its second decade, here.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Johnson & Johnson is a selection of the Income Investor newsletter. The Fool has a disclosure policy.