title: Mechanism of influence of PR interval on loudness of first heart sound.
authors.affiliation: Clinica Medica, University of Ferrara, Italy, and Department of Cardiology, Oak Forest Hospital, Chicago, USA.
authors.forename: F
authors.initials: F
authors.lastname: Portaluppi
authors.forename: N
authors.initials: N
authors.lastname: Brooks
authors.forename: G
authors.initials: G
authors.lastname: Leech
authors.forename: A
authors.initials: A
authors.lastname: Leatham