Things seemed to be going so well for medical device maker Medtronic (NYSE: MDT). It recently got FDA approval for its drug coated stent, a product that holds clogged arteries open. At over $56, its stock had moved near a 52-week high.

The few days of celebration ended abruptly. The company warned that a wire in its newest defibrillator models has malfunctioned in hundreds of patients. It may have even caused several deaths. According to The New York Times, a defibrillator is a "device that shocks faltering hearts back into normal rhythm." The company is asking that 235,000 patients see their doctors to check for the defect. The Times also writes that replacing the wire on a heart device like a defibrillator is considered by experts to be far more dangerous than replacing the device itself.

The announcement points to one of the problems that big medical device companies face as their products become more complex. Boston Scientific (NYSE: BSX) has recently lost significant revenue as studies have shown that its drug coated stents may cause blood clots in the heart. That and other problems have taken the company's stock from over $27 less than two years ago to $15 in recent trading.

It is too early to say what may have caused the defect in the Medtronic device, but if there is a hint that the defect was discovered some time ago or that the product's flaw was due to faulty manufacturing, some smart attorney will be filing a class action suit before the year's end.

Douglas A. McIntyre is a partner at 24/7 Wall St.

Put back the crash carts. Boston Scientific (NYSE:BSX) is up and walking. A sharp, short-term decline in use of drug coated stents, brought on by studies that show they may cause heart problems, has not significantly hurts sales overall. The FDA, after a survey of its own, has not restricted use of the devices.

According to analysts at several Wall Street firms, drug coated stents will keep a 75% to 80% share of the market. At Boston Scientific, sales of the stents represent 25% of sales. If the market in the product stabilizes, it could be the event that helps repair the company's image which has been damaged by worries about stent sales and problems with products from its Guidant unit.

Boston Scientific's stock has been pounded like a red-headed mule as concerns about stents and problems with Guidant have mounted. The stock traded for $36 two years ago and now changes hands at a little over $16. While the S&P is up close to 20% over the 24 months, BSX stock is off by slightly over 50%.

With stents back in fashion, it is now or, perhaps, never for a BSX recovery.

Douglas A. McIntyre is a partner at 24/7 Wall St.