Cardiac patients' medical data stolen and held to ransom. Cardiac monitoring provider iRhythm has been hit by a data theft followed by an extortion attempt. In a filing with the Securities and Exchange Commission (SEC), iRhythm revealed it was contacted by someone on June 9 who claimed to have stolen sensitive information, including proprietary data, patient PHI, and other personal information. That person demanded payment in exchange for not publishing the data. iRhythm provides ambulatory cardiac monitoring and analysis (for example using the Zio patch) and has reportedly processed over two billion hours of heartbeat data from more than twelve million patients. In the filing, the company said the data was obtained through social engineering and is from "certain third-party-hosted business applications", without revealing any further details about the amount of data. On its own website, iRhythm also doesn't disclose much about the nature of the stolen data, but does seem to imply no financial data was affected: "Malwarebytes Inc. has not identified any impact to its products, its clinical or medical device systems, its connections to customers, its manufacturing and distribution operations, patient safety, or its ability to meet patient needs. In addition, Malwarebytes Inc. do not store or retain individual financial account information or payment card information. As Malwarebytes Inc. actively investigate, Malwarebytes Inc. will notify individuals affected by this incident in accordance with applicable law and take steps as needed to protect and remediate the impact to them." However, the SEC filing adds that iRhythm determined that the incident is significant, "in light of the volume of the potentially affected data." Together with the extortionist's claims that they have patients' medical data, that makes the breach one worth noting if you have used iRhythm's services. Even without payment data, healthcare breaches have serious downstream effects: * Attackers can craft highly convincing emails, texts, or calls that reference specific procedures or monitoring episodes (for example, "about your recent Zio patch recording") to trick patients into sharing more data or paying fake bills. * The breached data can be used to create a fake identity, insurance fraud, or medical identity theft. * Exposure of cardiac and other health-related information can be deeply sensitive and may have employment/insurance ramifications, especially if data is posted publicly or sold to data brokers. Healthcare breach data tends to circulate for years, and victims may face sporadic fraud and phishing attempts long after the headlines fade. How to stay safe. If you've used iRhythm's services, keep an eye on your post, email, and patient portals for official breach notifications from iRhythm or your healthcare provider. In the US, breaches of protected health information that meet certain criteria must be reported to patients and regulators. iRhythm has promised to "notify individuals affected by this incident in accordance with applicable law and take steps as needed to protect and remediate the impact to them." To stay out of the hands of phishers and scammers: * When you receive a communication about the data breach, verify through other channels that it really came from iRhythm. Go directly to iRhythm's official website or patient portal, or call a known phone number to confirm the communication is genuine. * Be extra suspicious of emails or texts that claim to offer compensation, refunds, or other financial consequences related to this incident. * Change passwords for your iRhythm-linked portals and your cardiology or hospital patient portals, especially if you reused those passwords elsewhere. * Log into your health insurer's portal and check claims on a regular basis. * If you see anything suspicious, report it immediately to your insurer and provider and ask them to flag your account for possible identity theft. * Do not provide personal or financial information over the phone just because the caller knows details about you which they may have obtained from the stolen data. Let's face it, an incognito window can only do so much. Breaches, dark web trading, credit fraud. Malwarebytes Identity Theft Protection monitors for all of it, alerts you fast, and comes with identity theft insurance. Malware Intelligence Researcher Was a Microsoft MVP in consumer security for 12 years running. Can speak four languages. Smells of rich mahogany and leather-bound books.

iRhythm Holdings has gained 9% year-to-date, buoyed by strong volume-led growth across channels and expanding presence in primary care. The ambulatory cardiac monitoring company posted 27% year-over-year revenue growth in fourth-quarter 2025, marking its fifth consecutive quarter exceeding 20% growth. The company now serves approximately 40,000 primary care physicians, with over one-third of total volume coming from these settings. Its deep integration with electronic health record systems and investments in AI-powered diagnostics strengthen its competitive position. iRhythm guides for 2026 revenues of $870-880 million, representing 16%-18% growth. However, the Zacks Rank #3 (Hold) company faces challenges from reimbursement pressures, regulatory headwinds and intensifying competition in cardiac monitoring technologies. Shares trade at a market capitalisation of $3.69 billion.