title: Determinants of the development of mitral regurgitation in pacing-induced heart failure.
abstract: The pacing-induced heart failure model provides an opportunity to assess the structural and functional determinants of mitral regurgitation (MR) in dilated cardiomyopathy. This study aimed to evaluate MR to better understand the multitude of factors contributing to its development. Heart failure was induced by rapid ventricular pacing (230 beats/min) in 40 mongrel dogs. Left ventricular (LV) size and MR were evaluated echocardiographically. LV contractility was analyzed using a conductance catheter. MR increased to mild in 12 animals (regurgitant orifice area, 0.06+/-0.05 cm(2)), moderate in 15 (0.14+/-0.07 cm(2)), and severe in 13 (0.34+/-0.16 cm(2)). The grade of MR had an inverse relationships with E(max) (the slope of the end-systolic pressure-volume relationship, p<0.01) and dE/dt (the slope of the maximum rate of change of pressure-end-diastolic volume [V(ED)] relationship, p<0.01) and positive relationships with V(ED) and end-diastolic cross-sectional areas and lengths (p<0.05) by univariate analysis. The dE/dt had an independently significant (p<0.01) relationship by multivariable logistic regression. Many factors influence the development of MR and because of its similarity to the clinical situation, this model can be used to investigate MR and heart failure, as well as new surgical therapies.
authors.affiliation: Department of Biomedical Engineering, Lerner Research Institute, The Cleveland Clinic Foundation, OH 44195, USA.
authors.forename: Masami
authors.initials: M
authors.lastname: Takagaki
authors.forename: Patrick M
authors.initials: PM
authors.lastname: McCarthy
authors.forename: Marlene
authors.initials: M
authors.lastname: Goormastic
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Ochiai
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Doi
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kopcak
authors.forename: Tomotsugu
authors.initials: T
authors.lastname: Tabata
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Cardon
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Fukamachi
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002303:Cardiac Output, Low / Q000150:complications* / Q000209:etiology*; D002304:Cardiac Pacing, Artificial; D003971:Diastole; D004285:Dogs; D004452:Echocardiography; D006439:Hemodynamics; D008944:Mitral Valve Insufficiency / Q000209:etiology* / Q000503:physiopathology; D009200:Myocardial Contraction; D010496:Pericardium / Q000000981:diagnostic imaging; D012044:Regression Analysis; D012720:Severity of Illness Index; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left