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Cardiac-care stocks have been on a tear the past year, with investors in BioTelemetry, Inc. (BEAT), AngioDynamics Inc. (ANGO 2.29%), and Spectranetics Corp. (NASDAQ: SPNC) enjoying electrifying gains. Just consider these stocks' stunning performance: BioTelemetry is up 60.5%, AngioDynamics jumped 38%, and Spectranetics more than doubled, up 114.4%. That puts them vastly ahead of not just the S&P 500, but also the medical-device sector as a whole, with the iShares U.S. Medical Devices ETF (NYSEMKT: IHI) up 23%.

So why such strong upside, and why should it continue? The past is no guarantee of future performance, but in this case it could be. That's because each of these companies is front and center in one of the biggest trends in healthcare. Specifically, I mean a huge and radical push to simplify and reduce costs in the management of chronic diseases, which in the United States eats up 75% of healthcare spending, or about $2.25 trillion each year.  All three companies offer devices that provide earlier, less costly, and less invasive options for chronic diseases. In fact, these companies' devices can even help prevent a major health crisis such as a heart attack or reduce hospitalization time, saving significant costs for both patients and the healthcare system.

If that intrigues you, here are two other headwinds propelling these stocks. Over 79 million baby boomers are getting older and living longer, and that means they require more services such as treatments for ailing hearts, along with the other privileges of aging. In addition, cardiac care is becoming a key strategic area of interest for mergers and acquisitions. One massive $25 billion deal had juggernaut Abbott Labs scooping up cardiac-care specialist St. Jude Medical, but this trend is far from over.  Big medical-device companies are facing pricing pushback from hospitals and increased competition, and they need external innovation opportunities to maintain their growth. Given today's low interest rates and how that makes capital cheap and available, there's plenty of fuel for a continued blaze of M&A deals.

BioTelemetry keeps turning sci-fi into reality  

BioTelemetry is the leading company in wireless cardiac monitoring, which involves a wearable device used to rapidly diagnose dangerous cardiac events that seemed like sci-fi not long ago but that over a million patients are now using. The company's revenue has been growing in the high double digits year over year and notched an 18% gain last quarter on revenue of $52.7 million.

Many now consider BioTelemetry's mobile cardiac telemetry devices to be the gold standard in sensitivity and accuracy. In fact, the company recently received FDA approval for its next-generation MCOT Patch, which should reach the market this year. In addition, a recent decision from Anthem to provide coverage on its mobile cardiac telemetry devices added the health insurer's 40 million members to the list of those who might someday use the company's wearable monitors.   

Adding another avenue for future growth, digital health company Bloom Technologies recently licensed BioTelemetry's technology to develop a prenatal health sensor. That's a huge untapped market, so BioTelemetry has no shortage of big opportunities going ahead.

AngioDynamics' 55% leap in earnings

If you're looking for a stock with an unbelievable earnings ramp-up, AngioDynamics is it. Its quarterly earnings surged by 55% from the year-ago quarter. The company showed adjusted earnings of $0.17 per share, compared with $0.11 last quarter. I'd be more excited about that leap, except when you look a bit deeper, much of the ramp-up was driven by Angio's ability to leverage increased volume because of a recall of a competitor's devices.

Still, AngioDynamics has a history of coming up with extremely innovative devices. The most notable is the NanoKnife, which uses an electrical current to destroy cancerous tumors, often in locations where they're considered inoperable. Since in the past it would be virtually impossible for surgeons to remove these tumors, the NanoKnife is seeing strong pull-through patient demand. In fact, many hospitals and cancer centers are advertising it as an option for cancer patients who aren't candidates for conventional surgery.

The company is expanding the NanoKnife's label with multiple clinical trials. It also has launched other uniquely competitive devices that are seeing surging sales, such as the BioFlo catheter, whose clot-destroying material is built into its polymer base. Add it together, and AngioDyamics' growth should stay strong over the long haul.

Spectranetics' game-changing drug-eluting balloon

The final cardiac-care stock is only for the bravest investors. While Spectranectics beat on revenue of $67.5 million last quarter, up 10% year over year, this stock has yet to reach profitability. However, for those still undaunted, there could be impressive growth going forward. Spectranetics sells a range of minimally invasive devices, but what could move it to the next level is the coming launch of a new technology that should drive a strong new phase of growth. Dubbed the Stellarex, the device is a low-dose drug-coated balloon that significantly outperformed standard angioplasty in a recent trial.

Stellarex facilitates efficient drug delivery to the treatment site, and it's already being sold in the EU. Spectranetics expects commercialization next year in the U.S. and said the device should add $150 million in annual sales by 2020. Since the drug-coated-balloon market is expected to reach $700 million to $1 billion over the next seven years, that seems highly possible, particularly with this device's strong clinical data.

Of the three, Spectanetics is by far the riskiest, and BioTelemetry my favorite, but investors should realize none of these stocks are well-established blue chips. Still, when you put it all together, the future for these innovative device makers looks terrific, and growth-focused investors could find these stocks more than worth the risk.