iRhythm Technologies Inc. (NASDAQ: IRTC) saw its stock surge 5.90% in pre-market trading on Friday, following the release of its impressive first-quarter 2025 financial results and an optimistic outlook for the full year.

The medical technology company, known for its wearable cardiac monitoring devices and AI-powered analysis services, reported Q1 revenue of $158.7 million, representing a 20.3% year-over-year growth and surpassing Wall Street estimates of $153.6 million. This strong performance was driven by upstream expansion in the patient care pathway and strength in the company's Zio AT business. Despite reporting a quarterly adjusted loss of $0.95 per share, which was slightly below analysts' expectations, investors appeared to focus on the company's robust top-line growth and improved market penetration.

Adding to the positive sentiment, iRhythm raised its full-year revenue guidance to $695 million at the midpoint, up from the previous $680 million, representing a 2.2% increase and exceeding analysts' estimates by 2%. The company's CEO, Quentin Blackford, highlighted the continued commercial momentum and significant market penetration in both U.S. and international markets. Notable achievements include surpassing 10 million cumulative patient reports and expanding into primary care channels, with nearly one-third of long-term continuous monitoring volumes now originating from primary care physicians. These factors, combined with the company's progress in international markets and ongoing innovation in its product lineup, appear to have fueled investor optimism and contributed to the pre-market stock surge.