iRhythm (IRTC) Q4 2025: ZOAT Growth Tops 50%, Margin Expansion Signals Durable Scale

2026-02-19 | By EarningsIQ Research

iRhythm closed 2025 with ZOAT, its mobile cardiac telemetry (MCT) solution, growing at more than twice the company average, while adjusted EBITDA margin surged past its 15% target ahead of schedule. Margin expansion and diversified channel momentum position iRhythm for durable, volume-led growth as it eyes a $1 billion revenue milestone in 2027. Guidance remains disciplined, with upside potential from innovative channel ramp and international expansion not fully baked into outlook.

Summary

• Channel Diversification Drives Volume: Primary care and innovative partnerships now contribute a third of volume, broadening iRhythm’s reach beyond cardiology.
• Margin Inflection Achieved Early: Operating leverage and cost discipline produced record adjusted EBITDA margin, validating scalable economics.
• Upside Optionality in Guidance: Management’s 2026 outlook excludes potential tailwinds from regulatory changes and emerging channels.

Performance Analysis

iRhythm delivered a breakout Q4, with revenue up 27% YoY and full-year growth exceeding 26%—marking its fifth consecutive quarter above 20%. ZOAT, the company’s MCT product, was the standout, achieving unit growth north of 50% for the year and more than twice the company average, while core long-term continuous monitoring (LTCM) maintained a 72% market share in a segment growing high teens. Volume growth was broad-based, with new accounts (less than 12 months old) generating 68% of YoY volume gains, and primary care channels now representing over a third of total volume.

Margins advanced sharply, with Q4 gross margin up 90 basis points YoY to 70.9%, and adjusted EBITDA margin reaching 16.4%—well above the 15% target previously set for the $1B run rate. Free cash flow turned positive for the first time in company history, totaling $34.5M for the year and ending with a robust $583.8M in liquidity. Pricing was a modest tailwind, aided by improved collections and payer contracting, but guidance for 2026 assumes flat pricing, reflecting a conservative stance despite Medicare rate dynamics.

• ZOAT Outpaces Growth: MCT segment grew over 50%, twice the company rate, signaling strong competitive traction.
• New Channels Scale: Innovative channel and primary care now comprise a third of volume, reducing reliance on traditional cardiology.
• Margin Expansion Surpasses Plan: Adjusted EBITDA margin hit 16.4%, with further leverage expected as remediation costs moderate.

International markets remain nascent but are growing ahead of company average, with UK and Japan showing promising early traction. Management’s disciplined guidance approach leaves room for outperformance if innovative channel partners and EHR-integrated accounts continue to ramp as seen in Q4.

Executive Commentary

Strategic Positioning

1. Primary Care and Channel Diversification

More than one-third of iRhythm’s volume now originates from primary care settings, supported by EHR-integrated workflows and partnerships. This upstream shift not only expands total addressable market but also aligns with value-based care and population health trends, allowing cardiology to focus on higher acuity cases.

2. Platform Stickiness via EHR Integration

Over half of iRhythm’s volume flows through EHR-integrated accounts, with 75 of its top 100 customers fully integrated. These integrations create account durability and prescribing consistency, embedding iRhythm deeper into provider workflows and increasing switching costs.

3. Predictive AI and Data Assets

iRhythm’s predictive AI pilots, powered by nearly 3 billion hours of curated ECG data, are showing over 85% accuracy in identifying at-risk patients. Early results from partnerships like Lucem Health suggest the company could shift from episodic detection to proactive risk stratification, reinforcing its long-term competitive moat.

4. MCT Product Roadmap and Market Share Opportunity

ZOAT’s momentum and the upcoming next-gen MCT device (targeting 21-day wear, mobile gateway, and enhanced algorithms) underpin management’s confidence in expanding from its current 15% MCT share. Every 10-point share gain represents $80-100M incremental annual revenue, with the new device expected in 1H 2027.

5. International and Adjacent Market Expansion

iRhythm is now commercial in the UK, select EU markets, and Japan, with collective market share still under 1%. Disciplined execution and evidence generation are the focus, with UK NHS pilots and Japanese reimbursement applications underway. Adjacent opportunities in sleep diagnostics are also being piloted, leveraging workflow and patient overlap.

Key Considerations

iRhythm’s Q4 reflected operating leverage, channel diversification, and platform innovation, but the guidance for 2026 is intentionally conservative, leaving room for upside if recent momentum continues.

Key Considerations:

• Innovative Channel Ramp: Innovative partnerships are only low single digits of revenue but are growing and could accelerate if new contracts scale faster than expected.
• Regulatory Tailwinds: CMS scrutiny of chart-derived diagnoses may drive providers toward confirmatory solutions like Zio, creating incremental demand.
• International Scaling: Early UK and Japan traction could become more material in 2027 and beyond as reimbursement and evidence build.
• AI Differentiation: Proprietary data and workflow integration provide a defensible position against AI commoditization and disruptors.
• Operating Expense Leverage: G&A and remediation costs are now fixed or declining, allowing incremental growth to flow through margins.

Risks

Regulatory and reimbursement dynamics remain fluid, especially around CMS policies and Medicare Advantage audit scrutiny. While management sees potential tailwinds, guidance does not assume material benefit from these changes. AI commoditization and the risk of provider self-analysis could pressure pricing or billing, though iRhythm’s data assets and workflow integration are current mitigants. International expansion is still early and subject to local market risk and reimbursement hurdles.

Forward Outlook

For Q1 2026, iRhythm guided to:

• Revenue of $193M to $195M, reflecting typical seasonality
• Adjusted EBITDA margin of 3% to 4%

For full-year 2026, management guided:

• Revenue of $870M to $880M (16% to 18% YoY growth)
• Adjusted EBITDA margin of 11.5% to 12.5%
• Gross margin to improve 80–100 basis points over 2025

Management stressed that guidance assumes flat pricing, conservative innovative channel ramp, and international growth only slightly ahead of company average. Potential upside exists if regulatory tailwinds or new partner scale materialize faster than forecast.

• Upside from audit-driven demand for confirmatory diagnostics is not included in the outlook.
• International and sleep channel contributions are expected to become more meaningful post-2026.

Takeaways

iRhythm’s Q4 2025 results confirm the company’s durable growth engine, early margin inflection, and strategic positioning at the intersection of clinical need and workflow integration.

• Margin Leverage Validated: Operating discipline and automation are driving sustainable margin expansion, with remediation costs set to decline.
• Channel and Platform Expansion: EHR and primary care channel growth are reshaping the business model and expanding TAM beyond legacy cardiology.
• Optionality for Upside: Guidance remains conservative, with significant upside from regulatory, channel, and international catalysts over the next 12–24 months.

Conclusion

iRhythm exits 2025 with strong volume momentum, early profitability, and a platform positioned for continued channel and international expansion. Conservative 2026 guidance leaves room for upside as new channels and regulatory tailwinds develop, while operational leverage and data-driven innovation provide a durable foundation for long-term value creation.

Industry Read-Through

iRhythm’s results highlight the accelerating shift of diagnostics from specialty to primary care, with workflow integration and data-driven risk stratification emerging as key differentiators in digital health. Audit scrutiny and regulatory tightening around documentation are likely to favor solutions offering objective, confirmatory diagnoses, with implications for other device and digital health companies reliant on symptom-driven or short-duration monitoring. Margin inflection and positive free cash flow in a high-growth medtech platform set a new benchmark for peers facing rising cost and regulatory headwinds.

IRTC Healthcare Medical Devices Digital Health Cardiac Monitoring AI Workflow Integration Primary Care