A new group of patients that qualifies for Medicare reimbursement for implantable heart defibrillators may have to wait a few days longer until payment is available, the federal government said on Thursday.

The U.S. Centers for Medicare and Medicaid Services in late September broadened federal reimbursement for the $25,000 devices that regulate heartbeats for thousands more people, a move benefiting makers Medtronic Inc., Guidant Corp. and St. Jude Medical Inc.

The delay in Medicare’s ruling for broader reimbursement will be because the study that spurred the agency’s decision might not be published in a peer-reviewed journal before Dec. 28.

“There is definitely a backlog of cases not being treated that are waiting for reimbursement,” said David Zimbalist, an equity analyst at Natexis Bleichroeder.

The Medicare decision, which inflated the patient pool by one-third so that nearly 500,000 Medicare patients are eligible, is expected to boost the $5 billion-a-year market by as much as 20 percent, analysts said.

In the trial, the devices lowered the risk of sudden cardiac death by 23 percent in patients with heart failure - a chronic condition that weakens the heart and impairs pumping ability.

A spokesman for Medtronic said until the agency makes it official, a doctor cannot be reimbursed for the device for someone in the new group of patients unless they are given a special test.

“It points to the critical nature of the decision,” Medtronic spokesman Bob Hanvik said.