The increasing adoption of digital healthcare technologies is reshaping patient care, enabling intelligent environments that support both healthcare professionals and patients. However, challenges such as data heterogeneity, interoperability, security, and regulatory compliance hinder seamless integration into existing healthcare systems. This paper proposes a modular and scalable architecture for remote patient monitoring, designed to standardize data exchange, ensure secure communication, and enhance adaptability. The system leverages HL7 FHIR to facilitate interoperability across diverse healthcare platforms while incorporating privacy-preserving mechanisms, including encryption, authentication, and compliance with GDPR and HIPAA regulations. To validate its effectiveness, the proposed architecture is applied to cardiac surgery monitoring, integrating diverse devices and enabling personalized reporting to support patient care decisions.