A system for visualizing cardiac activity, comprising: a visualization module configured to: receive a plurality of electrophysiology data points, wherein each EP data point of the plurality of EP data points includes an electrogram signal; classify a first subset of the plurality of EP data points as substrate EP data points and a second subset of the plurality of EP data points as healthy EP data points; generate a cloud map of the first subset of the plurality of EP data points; and output a graphical representation (600, 700) of the cloud map of the first subset of the plurality of EP data points in combination with a graphical representation of an electrophysiology map of the second subset of the plurality of EP data points, wherein the visualization module is configured to generate the cloud map of the first subset of the plurality of EP data points by: applying a Gaussian splatting algorithm to the first subset of the plurality of EP data points to create a structured points dataset; and applying an iso-contouring algorithm to the structured points dataset, wherein classifying a first subset of the plurality of EP data points as substrate EP data points and a second subset of the plurality of EP data points as healthy EP data points comprises classifying a given EP data point of the plurality of EP data points as a substrate EP data point when a QRS duration metric for the given EP data point exceeds a preset threshold and as a healthy EP data point otherwise. a visualization module configured to: receive a plurality of electrophysiology data points, wherein each EP data point of the plurality of EP data points includes an electrogram signal; classify a first subset of the plurality of EP data points as substrate EP data points and a second subset of the plurality of EP data points as healthy EP data points; generate a cloud map of the first subset of the plurality of EP data points; and output a graphical representation (600, 700) of the cloud map of the first subset of the plurality of EP data points in combination with a graphical representation of an electrophysiology map of the second subset of the plurality of EP data points, receive a plurality of electrophysiology data points, wherein each EP data point of the plurality of EP data points includes an electrogram signal; classify a first subset of the plurality of EP data points as substrate EP data points and a second subset of the plurality of EP data points as healthy EP data points; generate a cloud map of the first subset of the plurality of EP data points; and output a graphical representation (600, 700) of the cloud map of the first subset of the plurality of EP data points in combination with a graphical representation of an electrophysiology map of the second subset of the plurality of EP data points, wherein the visualization module is configured to generate the cloud map of the first subset of the plurality of EP data points by: applying a Gaussian splatting algorithm to the first subset of the plurality of EP data points to create a structured points dataset; and applying an iso-contouring algorithm to the structured points dataset, wherein classifying a first subset of the plurality of EP data points as substrate EP data points and a second subset of the plurality of EP data points as healthy EP data points comprises classifying a given EP data point of the plurality of EP data points as a substrate EP data point when a QRS duration metric for the given EP data point exceeds a preset threshold and as a healthy EP data point otherwise. applying a Gaussian splatting algorithm to the first subset of the plurality of EP data points to create a structured points dataset; and applying an iso-contouring algorithm to the structured points dataset, wherein classifying a first subset of the plurality of EP data points as substrate EP data points and a second subset of the plurality of EP data points as healthy EP data points comprises classifying a given EP data point of the plurality of EP data points as a substrate EP data point when a QRS duration metric for the given EP data point exceeds a preset threshold and as a healthy EP data point otherwise.