iRhythm Technologies (NSDQ:IRTC) posted first-quarter results today that beat the consensus forecast on Wall Street and increased its outlook for the rest of the year, sending the stock up nearly 30% in after-hours trading.

The San Francisco-based developer of remote external electrocardiogram monitors reported a net loss of $50.6 million, or -$1.71 per share, on sales of $92.4 million for the three months ended March 31, 2022. That was a 24.3% increase in sales and a smaller loss than the -$27.8 million (or -$0.95 per share) reported in Q1 2021.

“Our strong first-quarter results are indicative of the momentum we carried into 2022 with an acceleration in daily registrations leading to record quarterly volumes,” President and CEO Quentin Blackford said in a news release. “New account openings were up 15% quarter-over-quarter, and we realized significant growth in our core U.S. market. Evidence supporting the clinical superiority of the Zio service continued to build at the annual ACC and HRS meetings through multiple presentations that demonstrated the effectiveness of long-term continuous ECG monitoring in a variety of use cases.”

Adjusted to exclude one-time items, earnings per share were -$0.80, $0.28 ahead of the Street, where analysts were looking for adjusted EPS of $-1.08 on sales of $86.76 million.

The company updated its full-year guidance to reflect the strong first quarter and the positive impact of updated pricing from National Government Services, a Medicare Administrative Contractor serving suburban Chicago, where iRhythm has an independent diagnostic testing facility.

iRhythm’s new outlook calls for adjusted EBITDA of -$15 million to -$25 million this year, improved from prior guidance of -$30 million to -$40 million. The company also increased its top-line outlook to a range of $410 million to $420 million for the full year, compared with $400 million to $410 million previously.

Investors reacted by sending IRTC shares up 28% to $151.52 in after-hours trading.

iRhythm also recently announced the hiring of Dr. Mintu Turakhia for the new role of chief medical officer and chief scientific officer, as well as the planned retirement of Chief Clinical Officer Judy Lenane.

Turakhia — a cardiac electrophysiologist, professor of medicine at the Stanford University School of Medicine, and director and co-founder of the Stanford Center for Digital Health — performed the first-ever study of silent atrial fibrillation with the original Zio patch, iRhythm said.

Lenane joined iRhythm in 2008; her successor has not been announced.

“We would like to thank Judy for her significant contributions to iRhythm during her tenure,” Blackford said in a news release last week. “Her clinical, medical and strategic expertise has been crucial to getting our company to where we are today, and her unwavering patient focus will have an enduring influence on our company.”