The U.S. government expressed satisfaction with changes at a St. Jude Medical Inc. factory it cited earlier for testing and record-keeping problems, the company said Wednesday, resolving an issue that threatened approval of the company's products.

The Food and Drug Administration in January 2013 sent a warning letter about processes at St. Jude's plant in Sylmar, Calif., where it makes its Durata-labeled defibrillator leads. A lead is a wire that connects a defibrillator to a heart.

FDA inspectors in September 2012 raised several concerns about the plant, including the number of tests that were performed on the leads. The company a month later told investors that it expected to receive the warning letter. It subsequently publicized steps it was taking to address the FDA's concerns, including bolstering training for workers.

When it issued the warning, the FDA raised no safety concerns about the Durata lead or other St. Jude products.

In announcing the FDA's clearance of the matter, St. Jude said little about the changes it made at the Sylmar site over the last 18 months. The Little Canada-based company continued operating the Sylmar factory throughout the FDA's inspection and review process.

"We are encouraged by the resolution of the FDA's warning letter and will continue to work to ensure the highest standards are met across all our manufacturing facilities," Dan Starks, chief executive of St. Jude, said in a statement.

FDA warnings can prevent a company from getting products approved by the regulator until deficiencies are corrected.

Early this year, however, it appeared the matter had little effect as the FDA approved several new heart-related products St. Jude developed, including a new defibrillator lead and a new line of pacemakers.

A company spokeswoman said the firm couldn't comment on the effect the FDA's inspection and oversight of the Sylmar plant had on the broader business.

St. Jude shares closed up 0.4 percent to $70 Wednesday.

When the warning letter was issued, St. Jude told investors it was "giving the highest priority to fully remediating these concerns." The company stressed throughout the process that the FDA's concerns were on factory processes and did not identify issues related to the performance of the leads or other heart products.