title: Magnetic resonance imaging (MRI) assessment of ventricular remodeling after myocardial infarction in rabbits.
abstract: To understand the structure-function relationship in the postinfarcted myocardium in rabbits, we induced cardiac ischemia by ligating the left circumflex coronary artery. Sham controls underwent thoracotomy only. At 7 and 30 d after ligation, cardiac MRI was conducted by using  pulse-oxymetry-gated cine acquisition to provide complete phases of the heartbeat. The rabbits were anesthetized under 1.5% isoflurane ventilation, and ultrafast techniques made breath-hold 3D coverage in different cardiac axes feasible. Viability imaging was performed after intravenous  injection of 0.15 mmol/kg gadolinium to assess the extent of infarction. Data (n ≥ 6) are presented as mean ± SEM and analyzed by ANOVA and ANCOVA. In postligation rabbits, end-systolic (mean ± SEM, 2.3 ± 0.3 mL) and end-diastolic (4.2 ± 0.4 mL) volumes  were increased compared with preligation values (end-systolic, 1.1 ± 0.1 mL; end-diastolic, 2.98 ± 0.2 mL). Ejection fraction was influenced adversely by the presence of scar tissue at both 7 and 30 d after ligation and apparently nonlinear with the heart rate. Cardiac force  was increased in the basal region in both end-systole and end-diastole in postligation hearts but progressively decreased toward the apex. Late gadolinium enhancement delineated 15.2 ± 5.8% myocardial infarction at 7 d after ligation and 14.5 ± 5.8% at 30 d, with limited wall  motion and wall thinness. Compensatory wall thickening was present in the basal region when compared with that in preligation hearts. MRI offers detailed spatial resolution and tissue characterization after myocardial infarction.
authors.affiliation: Division of Cardiothoracic Surgery, Department of Surgery, University of Utah, Salt Lake City, Utah, USA. norm.hu@hsc.utah.edu
authors.forename: Norman
authors.initials: N
authors.lastname: Hu
authors.forename: Kyle H
authors.initials: KH
authors.lastname: Sabey
authors.forename: Heather R
authors.initials: HR
authors.lastname: Curtis
authors.forename: Nguyen
authors.initials: N
authors.lastname: Hoang
authors.forename: Spencer B
authors.initials: SB
authors.lastname: Dowdle
authors.forename: Aida A
authors.initials: AA
authors.lastname: Garzarelli
authors.forename: Henry R
authors.initials: HR
authors.lastname: Buswell
authors.forename: Edward
authors.initials: E
authors.lastname: Dibella
authors.forename: James W
authors.initials: JW
authors.lastname: Yockman
authors.forename: David A
authors.initials: DA
authors.lastname: Bull
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D006339:Heart Rate; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D009942:Organometallic Compounds; D010092:Oximetry; D011237:Predictive Value of Tests; D011817:Rabbits; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine