Health Institutions use the EHR (Electronic Health Record) for many years to register the patients’ information electronically. On the other hand, this data is still in many different systems of the health institutions, which the patient interacted over life. During a medical appointment, one does not have a current view of the patient's health history. One of the goals of the PHR (Personal Health Record) concept is to obtain a unified view of the records scattered in various health organizations. Many experts now believe that blockchain technology allows storing a patient's pertinent medical information where needed, allowing both the patient and health care professionals to have access to up-to-date information. However, among the challenges to achieve the goal of an interoperable PHR model is the choice of a blockchain platform that supports the storage of this data in a secure, transparent, and decentralized manner. This article proposes an architecture model for health records based on blockchain. The main outcome is storing part of an electronic medical record in the proposed solution. It aims to process and store medical data, which comes from different health institutions safely inside the blockchain network. Then the EHR data is available to authorized stakeholders in a unique viewpoint through a decentralized blockchain application. After experimenting with two different blockchain frameworks, we decided to implement the prototype in a permissioned blockchain. We created and deployed a business network composed of two different organizations, which stored and shared EHR data among the network participants. Performance tests while retrieving EHR data from the blockchain showed an average response time in milliseconds of 201.08 with 500 users and 15,402.9 with 1000 users. Our proposed solution was able to address the main challenge faced by patients that have EHR data scattered in many distinct locations. The prototype supplies a unique view of this data where the participating organizations accessed the EHR data. However, a more robust hardware setup is necessary to test the blockchain solution in future works. Additionally, our intent is to focus on internal aspects of HIS, especially on how to convert the current EHR data from any health data standard to HL7 FHIR, as this would allow many different health institutions, which are using different data standards to take part in the network.