Dataset of Sirius Red-Stained Atrial Histology Microphotographs from Rats Under Sedentary, Moderate, or Intensive Exercise Conditions

This dataset contains 50 microphotographs of rat atrial histological sections stained with Sirius Red, used to assess collagen deposition. These were analyzed as part of a study investigating the development of atrial fibrosis under three experimental conditions: **SED** (sedentary), **MOD** (moderate activity), and **INT** (strenuous exercise). Each image corresponds to a left or right atrial section.