title: Increased right ventricular afterload induces postsystolic thickening of the ventricular septum in nonischemic hearts.
abstract: BACKGROUND
  We aimed to assess whether myocardial postsystolic thickening (PST) can be induced by an acute increase in right ventricular (RV) afterload and, thus, demonstrate that PST may have a nonischemic cause.
  
  
  METHODS
  In 8 anesthetized open-chest pigs, radial strains of the interventricular septum (IVS) and left ventricular inferolateral wall were obtained by Doppler tissue echocardiography before and during constriction of the pulmonary artery.
  
  
  RESULTS
  After each constriction, RV peak systolic pressure increased from 30 +/- 5 to 57 +/- 8 mm Hg (P < .001). Peak systolic radial strain of the IVS decreased from 20.8% +/- 5.3% to 9.5% +/- 4.1% (P = .003), and PST of the IVS increased from 0.3% +/- 0.5% to 6.1% +/- 4.8% (P = .01). The onset of PST started 41 +/- 20 milliseconds after peak negative dP/dt of RV pressure. The inferolateral wall did not show PST.
  
  
  CONCLUSIONS
  An acute increase in RV pressure causes a significant reduction in peak systolic strain of the IVS associated with the nonischemic appearance of PST.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
authors.forename: Stig
authors.initials: S
authors.lastname: Urheim
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Abraham
authors.forename: Josef
authors.initials: J
authors.lastname: Korinek
authors.forename: JianWen
authors.initials: J
authors.lastname: Wang
authors.forename: Marek
authors.initials: M
authors.lastname: Belohlavek
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D015150:Echocardiography, Doppler; D005260:Female; D006346:Heart Septum / Q000000981:diagnostic imaging / Q000502:physiology*; D006439:Hemodynamics; D023421:Models, Animal; D009200:Myocardial Contraction / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D013552:Swine; D013599:Systole; D016276:Ventricular Function; D016278:Ventricular Function, Right / Q000502:physiology*