Heart Analysis Method and Apparatus

A method and device for monitoring heart behavior. In particular, a visual aid for clinician in which regions of the heart having aberrant characteristics can be displayed. A number of electrodes are positioned near/on an endocardium; electrical signals from the electrodes are monitored and recorded. A variability of a time varying parameter is calculated from each electrode location and displayed on a cardiac image. A user can select the parameter and measurement properties of the parameter, wherein the variability of the parameter is displayed and aberrant behavior can be detected.