Heart-device maker St. Jude Medical Inc. (STJ) issued preliminary third-quarter results Tuesday that landed below both company and Wall Street expectations while saying it felt pressure from a financial squeeze on hospitals.

The company's comments and weak sales in the $11 billion market for implantable heart-rhythm devices suggest a potential industry-wide issue. Shares of St. Jude and rivals Medtronic Inc. (MDT) and Boston Scientific Corp. (BSX) all fell in pre-market trading.

St. Jude traded down 14% to $32.70, while Medtronic was down 2% to $35.70. Boston Scientific slipped 3% to $9.80.

St. Jude also disclosed additional job cuts that, combined with reductions announced in August, will trigger a third-quarter charge. The company, which has roughly 15,000 employees worldwide, has terminated about 250 workers in its manufacturing divisions in addition to the prior elimination of about 200 U.S. sales, service and support jobs, a spokeswoman confirmed.

The St. Paul, Minn., company said it now expects adjusted third-quarter earnings of 57 cents to 58 cents per share, which is below guidance in July for 61 cents to 63 cents. This forecast excludes a charge of $50 million to $55 million, or 9 cents to 10 cents per share, associated with the job cuts.

Analysts surveyed by Thomson Reuters had projected earnings of 62 cents per share in the third quarter.

St. Jude expects to report sales of $1.16 billion for the quarter, which is below Wall Street's forecast for $1.19 billion.

The company said a slowdown in hospital stocking of certain medical devices was one factor that hurt sales.

"We believe that macro economic factors coupled with the continued pressures surrounding healthcare reform resulted in changes in purchasing behavior among some of our hospital customers," said Daniel J. Starks, St. Jude's chairman and chief executive, in a release.

The company will have an update during its earnings call in mid-October, Starks said.

The preliminary sales tally for the heart-rhythm business, which includes pacemakers and defibrillators, was $690 million. That is up 2% from a year ago, or 5% excluding the impact of foreign currency, but below the $700 million to $730 million range St. Jude had forecast in July.

In the company's business for devices that treat the common rhythm disorder atrial fibrillation, preliminary sales were $155 million. The company's cardiovascular business posted preliminary sales of $230 million. In both cases sales were at or near the low end of St. Jude's projections.

A lone bright spot was the neuromodulation business, where preliminary sales of $84 million exceeded the company's expectations.

-By Jon Kamp, Dow Jones Newswires; 617-654-6728; jon.kamp@dowjones.com

(Joan E. Solsman contributed to this article.)