St. Jude Denies Report Heart Devices Are Vulnerable to Cyber Attacks

St. Jude Medical Inc. on Friday denied allegations made by a research firm that its pacemakers and other heart devices were vulnerable to hacking and other cybersecurity threats.

"St. Jude Medical stands behind the security and safety of our devices as confirmed by independent third parties and supported through our regulatory submissions," the company said Friday.

The medical-device maker's comments follow a report by Muddy Waters Capital LLC, which is known for shorting stocks, or betting that a company's share price will fall. Muddy Waters has said it has a short position in St. Jude.

In its report, Muddy Waters said it had seen demonstrations of cyber attacks against St. Jude devices, citing the work of cybersecurity startup MedSec. A call seeking a response from a Muddy Waters representative on St. Jude's comments wasn't immediately returned.

After the release of the Muddy Waters report on Thursday, St. Jude's stock slipped 5% and fell an additional 2.6% Friday before the medical-device maker issued its response.

Following the St. Jude statement, the company's stock ended the day at $78.01, up 19 cents from its close Thursday.

"We conclude that the report is false and misleading," St. Jude officials said.