gVARVI: A graphical software tool for the acquisition of the heart rate in response to external stimuli

At present, tools capable of acquiring heart rate data can be found both in commercial and research fields. However, these tools do not allow users to manage experiments comprising sequences of activities or to store the information needed to perform heart rate variability analysis across different activities. One exception is VARVI, a simple software tool developed previously in our research group that does not have a graphical user interface and it works only with visual stimuli. In this paper, we present gVARVI, a software tool aimed at obtaining heart rate data signals while the user is either receiving a sequence of external stimuli or performing a sequence of actions (an activity).

gVARVI is an open source application developed in Python programming language. It can acquire heart rate data by means of a wireless chest strap using either Bluetooth or ANT+ protocols. Users can define activities of different types (video, sounds, pictures or keyboard controlled actions) which will associate contextual information to the heart rate data. gVARVI allows users to preview this data or to store it to be used for heart rate variability studies. Our tool was validated by 15 researchers, who worked with the application and filled in a usability questionnaire.

The outcome of the usability test was satisfactory, giving a mean score of 4.75 in a 1-5 scale (1 - strongly disagree, 5 - strongly agree). Participants also contributed with valuable comments, which we used to include new features in the last version of our tool.

gVARVI is an open source tool that offers new possibilities to both physicians and clinicians to perform heart rate variability studies. It allows users to acquire heart rate data including information on the activity performed by subjects while recording. In this paper, we describe all the functionalities included in gVARVI, and a complete example of use is provided.