title: Effects of ventricular insertion sites on rotational motion of left ventricular segments studied by cardiac MR.
abstract: OBJECTIVE
  Obtaining new details for rotational motion of left ventricular (LV) segments using velocity encoding cardiac MR and correlating the regional motion patterns to LV insertion sites.
  
  
  METHODS
  Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Peak rotational velocities and circumferential velocity curves were obtained for 16 ventricular segments.
  
  
  RESULTS
  Reduced peak clockwise velocities of anteroseptal segments (i.e. Segments 2 and 8) and peak counterclockwise velocities of inferoseptal segments (i.e. Segments 3 and 9) were the most prominent findings. The observations can be attributed to the LV insertion sites into the right ventricle, limiting the clockwise rotation of anteroseptal LV segments and the counterclockwise rotation of inferoseptal segments as viewed from the apex. Relatively lower clockwise velocities of Segment 5 and counterclockwise velocities of Segment 6 were also noted, suggesting a cardiac fixation point between these two segments, which is in close proximity to the lateral LV wall.
  
  
  CONCLUSIONS
  Apart from showing different rotational patterns of LV base, mid ventricle and apex, the study showed significant differences in the rotational velocities of individual LV segments. Correlating regional wall motion with known orientation of myocardial aggregates has also provided new insights into the mechanisms of LV rotational motions during a cardiac cycle.
  
  
  CONCLUSIONS
  LV insertion into the right ventricle limits the clockwise rotation of anteroseptal LV segments and the counterclockwise rotation of inferoseptal segments adjacent to the ventricular insertion sites. The pattern should be differentiated from wall motion abnormalities in cardiac pathology.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
authors.forename: I
authors.initials: I
authors.lastname: Codreanu
authors.forename: M D
authors.initials: MD
authors.lastname: Robson
authors.forename: O J
authors.initials: OJ
authors.lastname: Rider
authors.forename: T J
authors.initials: TJ
authors.lastname: Pegg
authors.forename: C A
authors.initials: CA
authors.lastname: Dasanu
authors.forename: B A
authors.initials: BA
authors.lastname: Jung
authors.forename: K
authors.initials: K
authors.lastname: Clarke
authors.forename: C J
authors.initials: CJ
authors.lastname: Holloway
mesh_terms: D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012016:Reference Values; D012399:Rotation; D016277:Ventricular Function, Left / Q000502:physiology*; D055815:Young Adult