The use of health applications on mobile phones is gaining traction especially when the COVID-19 pandemic hit the world. Such applications enable patients to keep track of their health without the need of physically going to the hospitals to meet their doctors. In the context of mobile heart applications for heart disease patients, the need for a highly usable application is even more vital as the heart patients are considered most vulnerable if they infected by the COVID-19 virus. HeartM 3.0 is the application developed to enable the patients to carry out self-monitoring of their heart conditions. This study aims to discuss the affordances and usability evaluations of HeartM 3.0 from the perspective of the heart patients. HeartM 3.0 were evaluated based on its affordances which consist of medical, social and technological affordances, and usability elements which consist of learnability, effectiveness, memorability, error, and satisfaction. The questionnaire was adapted from the PSSUQ (Post Study System Usability Questionnaire). The study recruited thirty five heart patients in Charitas Hospital Palembang, Indonesia. From the participants’ assessments, the study found that the heart patients feel satisfied with what is provided by the HeartM 3.0 application and stated that HeartM 3.0 is comfortable to use, patients are willing to use it continuously, and in overall, they are satisfied with HeartM 3.0. This paper theoretically contributes to provide recommendations to application developers and mobile health designers on the importance of meeting the affordances and usability elements desired by the users, especially for mobile health applications for chronic illnesses.