A medical system includes communication circuitry configured to receive episode data for an episode sensed by a medical device of a patient, wherein the episode data comprises a cardiac electrogram sensed by the medical device during a period of time; and processing circuitry configured to generate an image based on the episode data, wherein the image is associated with an interval within the period of time; apply, by the processing circuitry, one or more machine learning models to the image, the one or more machine learning models configured to determine whether the image corresponds to an arrythmia type; and output an indication of whether the image corresponds to the arrythmia type.