Despite rising revenue and a burgeoning pipeline of medical devices, Medtronic PLC revealed Tuesday that it expects to see little, if any, real growth in worldwide earnings next year.

Company executives and independent analysts placed the blame on unfavorable currency fluctuations, noting that underlying sales of such devices as pacemakers, implantable heart monitors and minimally invasive replacement aortic valves are strong and improving for the Minnesota-run company.

In late January, Medtronic moved its legal headquarters from Fridley to Ireland and acquired the Dublin-based hospital supplier Covidien PLC for $49.9 billion. The deal greatly expanded the company, but brought some challenges as well, like the $1.2 billion in one-time costs that helped to wipe out net profits for the company's fourth quarter, which ended April 15.

The impact of a strong dollar on overseas sales is a longer-term ­challenge. Multinational manufacturers like Medtronic say that sales of goods in Europe and Japan, whose currencies have fallen sharply against the dollar, look smaller on paper when they're recorded in dollars. Medtronic took an even larger than expected currency hit in its most recent quarter because Covidien's earnings were not protected by hedging contracts before the deal, as Medtronic's were.

The result is that real earnings were flattened at a time when the company's overall revenue is projected to grow 4 to 6 percent.

On Tuesday, Medtronic executives said in the fiscal year that will end next April, the company expects negative currency impacts to wipe out as much as $1.5 billion in sales, amounting to between 40 and 50 cents per share. They forecast earnings for the year to be between $4.30 and $4.40 a share. That compares with actual earnings of $4.28 for the year that just ended.

Ishrak

"If you account for [the currency impact], they are actually growing earnings," said Mike Matson, an analyst with Needham & Co. Without the impact, he estimated Medtronic would be projecting earnings growth of more than 10 percent.

For the fourth quarter, sales were up in most divisions.

Sales of the Reveal Linq heart monitor accounted for about $500 million in sales during its first year on the market, well ahead of the company's ramping-up timelines for the device, Chief Financial Officer Gary Ellis said. The device is on pace for $1 billion in global sales within five years, though competitor devices may eventually enter the market.

The Linq collects information about heart patients who sometimes go on to need other Medtronic therapies, including pacemakers. "Linq is resulting in not only increased diagnostic sales, but also pacemaker pull-through, as Linq is resulting in more cardiac diagnosis in syncope patients" with unexplained fainting, Chief Executive Omar Ishrak told investors in a conference call.

Sales of aortic heart valves — usually implanted via a small incision in the leg — grew 50 percent in the quarter, though exact sales were not revealed. The bioprosthetic valve, called CoreValve, is a second-to-market heart device that is quickly gaining market share on its only competitor in the U.S., Edwards Lifesciences' Sapien valve.

Quarterly sales in Medtronic's spine-products division fell by 2 percent to $743 million, despite a small uptick in sales of the InFuse spinal-fusion system. Ishrak acknowledged that Medtronic's spine sales weren't growing as fast as the overall product market, but he said the company recently reorganized its "distribution channels" to drive growth.

"We'll see how this thing plays out in the next few quarters, and we are watching closely," Ishrak said in an interview. "Clearly it's one that we need to be clear about what our strategies are, our new strategies, and we need to see how they are working out and make adjustments as we see fit."

Overall sales were $7.3 billion for the just-ended quarter, a 7 percent increase over the same period last year after adjusting for the negative currency impact of $483 million.

Yet a laundry list of roughly $1.6 billion in one-time expenses caused Medtronic to post a net quarterly loss of $1 million. That included more than $1.2 billion in acquisition expenses, which Ishrak said would be the largest such bundle of expenses in a single quarter related to the Covidien deal.

"The integration is going well, both from a cultural perspective, as well as a financial perspective," Ishrak said. "We're just accelerating our growth strategies. We're excited about the quarter we just finished, but we look ahead with optimism."

Joe Carlson • 612-673-4779

Twitter: @_JoeCarlson