title: Assessment of regional myocardial work in rats.
abstract: BACKGROUND
  Left ventricular (LV) motion and deformation is dependent on mechanical load and do therefore not reflect myocardial energy consumption directly. Regional myocardial work, however, constitutes a more complete assessment of myocardial function.
  
  
  RESULTS
  Strain was measured using high-resolution phase-contrast MRI in 9 adult male rats with myocardial infarction (MI) and in 5 sham-operated control animals. Timing of LV valvular events and LV dimensions were evaluated by cine MRI. A separate cohort of 14 animals (MI/sham=9/5) underwent measurement of LV pressure concurrent with identification of valvular events by Doppler-echocardiography for the purpose of generating a standard LV pressure curve, normalized to valvular events. The infarctions were localized to the anterolateral LV wall. Combining strain with timing of valvular events and a measurement of peak arterial pressure, regional myocardial work could be calculated by applying the standard LV pressure curves. Cardiac output and stroke work was preserved in the MI hearts, suggesting a compensatory redistribution of myocardial work from the infarcted region to the viable tissue. In the septum, regional work was indeed increased in MI rats compared with sham (median work per unit long-axis length in a mid-ventricular slice: 241.2 [224.1-271.2] versus 137.2 [127.0-143.8] mJ/m; P<0.001). Myocardial work in infarcted regions was zero. Additionally, eccentric work was increased in the MI hearts.
  
  
  CONCLUSIONS
  Phase-contrast MRI, in combination with measurement of peak arterial pressure and MRI-derived timing of valvular events, represent a noninvasive approach for estimation of regional myocardial work in rodents.
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway. ekespe@medisin.uio.no.
authors: Emil K S
authors: EK
authors: Espe
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Jan Magnus
authors: JM
authors: Aronsen
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Guro S
authors: GS
authors: Eriksen
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Lili
authors: L
authors: Zhang
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Otto A
authors: OA
authors: Smiseth
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Thor
authors: T
authors: Edvardsen
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Ivar
authors: I
authors: Sjaastad
authors: From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and Institute for Surgical Research (O.A.S., T.E., M.E.), Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Morten
authors: M
authors: Eriksen
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D004195:Disease Models, Animal; D015150:Echocardiography, Doppler; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D011237:Predictive Value of Tests; D017208:Rats, Wistar; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
keywords: magnetic resonance imaging; myocardial contraction