iRhythm TechnologiesiRhythm Technologies (NASDAQ: IRTC) today reported mixed Q4 results but predicted strong sales growth in 2021.

The San Francisco–based company — maker of the Zio ambulatory cardiac monitoring patch — reported a loss of –$9.7 million, or –33¢ per share, on sales of $78.8 million for the three months ended Dec. 31, 2020, nearly halving its losses on 33% sales growth compared with Q4 2019.

The earnings were 2 pennies behind The Street, where the analyst consensus was a loss of –31¢ per share on sales of $76.57 million.

“Once again, fourth-quarter results were driven by further penetration of Zio XT in both existing and new accounts, continued ramp of Zio AT and continued utilization of our Home Enrollment service in telemedicine settings,” said iRhythm CEO Mike Coyle.

Due to continuing uncertainties in reimbursement, the company isn’t able to provide revenue or margin guidance, but Coyle in this evening’s news release mentioned continued strong volume growth in 2021.

With less than 20% penetration in our core market, we expect to see continued strong growth from Zio XT in new and existing accounts and proportionately greater growth from Zio AT and from the U.K. Demand for our Zio service remains strong and our physician customers are expanding their utilization of the service, driving Zio as the new standard of care in ambulatory cardiac monitoring,” Coyle said.