title: Left ventricular remodeling after myocardial infarction: characterization of a swine model on beta-blocker therapy.
abstract: Current guidelines recommend beta blockers for patients after myocardial infarction (MI). Novel therapies for heart failure should be tested in combination with this medication before entering clinical trials. In this methodologic study, we sought to describe the time course of systolic and diastolic parameters of cardiac performance over a 6-wk period in closed-chest model of swine MI treated with a beta blocker. Myocardial infarction in pigs (n = 10) was induced by 90-min balloon occlusion of the left anterior descending coronary artery. Echocardiography and pressure-volume data were collected before and at 1 and 6 wk after MI; histopathology was assessed at 6 wk. Left-ventricular (LV) volume increased significantly over 6 wk, with significant decreases in ejection fraction, wall motion index, stroke work, rate of pressure development (dP/dt(max)), preload recruitable stroke work, and mechanical efficiency. Impairment of diastolic function was manifested by a significant increase in the exponential beta coefficient of the LV end-diastolic pressure-volume relation and reduction of LV pressure decay. At 6 wk, histopathologic analysis showed that the size of the infarct area was 16.3% +/- 4.4%, and the LV mass and myocyte cross-sectional area in both the infarct border and remote zones were increased compared with those of noninfarcted pigs (n = 5). These findings suggest a dynamic pattern of remodeling over time in a closed-chest ischemia-reperfusion swine model of acute MI on beta-blocker therapy and may guide future studies.
authors.affiliation: Division of Cardiology, Department of Medicine, University of California, San Francisco, California, USA.
authors.forename: Franca S
authors.initials: FS
authors.lastname: Angeli
authors.forename: Mia
authors.initials: M
authors.lastname: Shapiro
authors.forename: Nicolas
authors.initials: N
authors.lastname: Amabile
authors.forename: Gina
authors.initials: G
authors.lastname: Orcino
authors.forename: Charles S
authors.initials: CS
authors.lastname: Smith
authors.forename: Theresa
authors.initials: T
authors.lastname: Tacy
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Boyle
authors.forename: Kanu
authors.initials: K
authors.lastname: Chatterjee
authors.forename: Stanton A
authors.initials: SA
authors.lastname: Glantz
authors.forename: William
authors.initials: W
authors.lastname: Grossman
authors.forename: Yerem
authors.initials: Y
authors.lastname: Yeghiazarians
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000818:Animals; D001262:Atenolol / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004452:Echocardiography; D006352:Heart Ventricles / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000473:pathology* / Q000503:physiopathology; D013552:Swine; D020257:Ventricular Remodeling / Q000187:drug effects*
chemical_list: D000319:Adrenergic beta-Antagonists; D001262:Atenolol