title: The relationship of increased left atrial volume and pressure to abnormal P waves on the electrocardiogram.
mesh_terms: D000790:Angiocardiography; D006328:Cardiac Catheterization; D006332:Cardiomegaly / Q000175:diagnosis*; D004562:Electrocardiography; D006334:Heart Function Tests; D006349:Heart Valve Diseases / Q000175:diagnosis*; D006801:Humans