Exhibit 99.1 iRhythm Holdings Announces First Quarter 2026 Financial Results Operating expenses for the first quarter of 2026 were $157.5 million, compared to $141.8 million for the same period in 2025. Adjusted operating expenses for the first quarter of 2026 were $153.5 million, compared to $140.4 million during the same period in 2025. The increase in adjusted operating expenses, period over period, was driven by an increase in volume-related costs to serve, litigation-related expenses and investments to ...