Velocity-encoded magnetic resonance imaging of normal subjects is performed to produce flow fields of blood in right atrium. The aim of this experiment is to demonstrate the state of change in swirling of blood within a cardiac chamber using a flow imaging modality, and to quantify it for clinical applications. Velocity maps that are displayed using streamline tracings illustrate the flow behavior at various cardiac phases. Rotation of blood can be observed in the atrium, and we have developed a statistical based system for characterizing the strength of the vortices. From our study, we are able to acquire an indication of the changes in vorticity magnitude during one cardiac cycle with the support of vorticity fields based on the cardiac flow. This has improved our understanding of blood motion within the heart chamber which may have implications in blood circulation efficiency.