Overstock.com (OSTK) announced Tuesday that chief executive and chairman Patrick Byrne is taking a leave of absence for medical reasons.

The company’s president, Jonathan Johnson, will serve as acting CEO, while Byrne will remain chairman.

In a statement released Tuesday morning, the discount retailer said Byrne has undergone various procedures related to cardiac issues that may stem from his earlier bouts with cancer. His leave of absence is associated with these cardiac issues, the company added.

“We've worked hard this past year and delivered good results; our team is executing exceptionally well, putting points on the board,” Byrne said. “We have set our company plan for 2013 and I have great confidence in my colleagues to execute it.”

Acting CEO Johnson has worked for Overstock.com for over 10 years, serving as president since July 2008.

Shares of Overstock.com were down five cents, or 0.39%, to $12.79 Tuesday morning.

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