Shareholders of ZOLLMedical (NASDAQ:ZOLL) received an early Christmas present today when the company reported fourth-quarter earnings. Profits more than doubled when compared with the year-ago quarter. Net income grew to $5.4 million, or $0.55 per share, up from $2.2 million, or $0.23 per share, for the year-ago quarter. Wall Street analysts had been expecting $0.37 per share.

News of ZOLL's earnings sent the shares up 25% in midday trading. The company designs and sells noninvasive resuscitation devices and related software solutions and manufactures defibrillators and other emergency medical care products.

For its full-year results, ZOLL registered lights-out numbers. Fiscal 2006 revenues increased 18% to $248.8 million versus $211.3 million. Diluted EPS rose to $1.15, compared with $0.20 in the prior year. Richard A. Packer, ZOLL's president and chief executive officer, said, "Our annual and fourth-quarter results exceeded our expectations. Fiscal 2006 was a big step forward for ZOLL. We continue to plan for enough top-line growth, coupled with tight expense control, to drive strong profit growth."

ZOLL's stock price has doubled year to date. In 2007, investors can expect to see continued growth in revenues. At the end of fiscal 2006, the company had a backlog of $13.4 million, which clearly demonstrates the demand for its products.

ZOLL's stock was trading at seven times its average volume by midday. While I would wait to see whether there is a pullback based on profit-taking for a few weeks before I would consider buying the stock, the company's future appears promising. Of particular interest is the AutoPulse device -- a battery-operated support pump that's used to provide chest compressions to victims of sudden cardiac arrest.

In addition to the explosive sales growth for ZOLL's existing products, Fools can expect this company to be an innovator. During the fourth quarter, the company received Food and Drug Administration marketing clearance for a new defibrillator designed specifically for hospitals. Its R-Series defibrillator, which is aimed at improving in-hospital resuscitation efforts, was unveiled at the recent American Heart Association meeting in Chicago. The company expects the product to hit the market next year.

While ZOLL's market cap of $500 million is a far cry from that of competitors St. Jude Medical (NYSE:STJ) at $12 billion and Medtronic (NYSE:MDT) at $56 billion, ZOLL is quickly emerging as a force to be reckoned with.

For a fun new way to do research on stocks, check out CAPS, the Fool's new investment community.

Fool contributor Billy Fisher does not own shares of any of the companies mentioned.