The U.S. Food and Drug Administration has granted fast-track designation for ivabradine, a heart drug licensed for sale by Amgen Inc. in Thousand Oaks. Ivabradine is an oral drug that inhibits electric signals in the heart, thus reducing the long-term pulse rate. It was developed by Servier Laboratories, a French pharmaceutical company, but Amgen has a license to market it in the United States. The drug is sold under a variety of commercial names in Europe and Asia. The FDA’s fast-track status is designed to expedite development and review of a drug to treat a serious condition and fill an unmet medical need. It means ivabradine could get priority review for approval. Amgen plans to file for FDA approval in the second quarter of 2014. “Amgen looks forward to working closely with the FDA to potentially bring this treatment option to patients with chronic heart failure in the U.S.,” the company said in a statement. About 26 million people have chronic heart failure worldwide, including 5.1 million in the United States. Shares of Amgen closed down Thursday 8 cents or less than 1 percent to $155.46 in trading on the Nasdaq. Markets were closed for Good Friday.