Saga of the fourth heart sound.
D003327:Coronary Disease / Q000175:diagnosis; D004562:Electrocardiography; D006326:Heart Auscultation / Q000266:history*; D006331:Heart Diseases / Q000175:diagnosis*; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D007702:Kinetocardiography; D008944:Mitral Valve Insufficiency / Q000175:diagnosis; D010701:Phonocardiography