title: Advantages of strain echocardiography in assessment of myocardial function in severe sepsis: an experimental study.
abstract: OBJECTIVE
  Cardiovascular failure is an important feature of severe sepsis and mortality in sepsis. The aim of our study was to explore myocardial dysfunction in severe sepsis.
  
  
  METHODS
  Prospective experimental study.
  
  
  METHODS
  Operating room at Intervention Centre, Oslo University Hospital.
  
  
  METHODS
  Eight Norwegian Landrace pigs.
  
  
  METHODS
  The pigs were anesthetized, a medial sternotomy performed and miniature sensors for wall-thickness measurements attached to the epicardium and invasive pressure monitoring established, and an infusion of Escherichia coli started. Hemodynamic response was monitored and myocardial strain assessed by echocardiography.
  
  
  RESULTS
  Left ventricular myocardial function was significantly reduced assessed by longitudinal myocardial strain (-17.2% ± 2.8% to -12.3% ± 3.2%, p = 0.04), despite a reduced afterload as expressed by the left ventricular end-systolic meridional wall stress (35 ± 13 to 18 ± 8 kdyn/cm, p = 0.04). Left ventricular ejection fraction remained unaltered (48% ± 7% to 49% ± 5%, p = 0.4) as did cardiac output (6.3 ± 1.3 to 5.9 ± 3 L/min, p = 0.7). The decline in left ventricular function was further supported by significant reductions in the index of regional work by pressure-wall thickness loop area (121 ± 45 to 73 ± 37 mm × mm Hg, p = 0.005). Left ventricular myocardial wall thickness increased in both end diastole (11.5 ± 2.7 to 13.7 ± 2.4 mm, p = 0.03) and end systole (16.1 ± 2.9 to 18.5 ± 1.8 mm, p = 0.03), implying edema of the left ventricular myocardial wall. Right ventricular myocardial function by strain was reduced (-24.2% ± 4.1% to -16.9% ± 5.7%, p = 0.02). High right ventricular pressures caused septal shift as demonstrated by the end-diastolic transseptal pressure gradient (4.1 ± 3.3 to -2.2 ± 5.8 mm Hg, p = 0.01).
  
  
  CONCLUSIONS
  The present study demonstrates myocardial dysfunction in severe sepsis. Strain echocardiography reveals myocardial dysfunction before significant changes in ejection fraction and cardiac output and could prove to be a useful tool in clinical evaluation of septic patients.
authors.affiliation: 1Intervention Centre, Oslo University Hospital, Oslo, Norway. 2Department of Anaesthesiology, Oslo University Hospital, Oslo, Norway. 3Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway. 4KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway. 5Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway. 6Department of Emergency Medicine, Nordland Hospital, Bodø, Norway. 7University of Nordland, Bodø, Norway. 8Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Siv M
authors.initials: SM
authors.lastname: Hestenes
authors.forename: Per S
authors.initials: PS
authors.lastname: Halvorsen
authors.forename: Helge
authors.initials: H
authors.lastname: Skulstad
authors.forename: Espen W
authors.initials: EW
authors.lastname: Remme
authors.forename: Andreas
authors.initials: A
authors.lastname: Espinoza
authors.forename: Stefan
authors.initials: S
authors.lastname: Hyler
authors.forename: Jan F
authors.initials: JF
authors.lastname: Bugge
authors.forename: Erik
authors.initials: E
authors.lastname: Fosse
authors.forename: Erik W
authors.initials: EW
authors.lastname: Nielsen
authors.forename: Thor
authors.initials: T
authors.lastname: Edvardsen
mesh_terms: D000818:Animals; D002302:Cardiac Output / Q000502:physiology*; D015150:Echocardiography, Doppler / Q000379:methods*; D004927:Escherichia coli Infections; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006439:Hemodynamics / Q000502:physiology; D009206:Myocardium / Q000473:pathology*; D011446:Prospective Studies; D018805:Sepsis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013318:Stroke Volume / Q000502:physiology*; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*