title: Influence of left ventricular relaxation on the pressure half time of aortic regurgitation.
abstract: BACKGROUND
  The severity of aortic regurgitation can be estimated using pressure half time (PHT) of the aortic regurgitation flow velocity, but the correlation between regurgitant fraction and PHT is weak.
  
  
  OBJECTIVE
  To test the hypothesis that the association between PHT and regurgitant fraction is substantially influenced by left ventricular relaxation.
  
  
  METHODS
  In 63 patients with aortic regurgitation, subdivided into a group without (n = 22) and a group with (n = 41) left ventricular hypertrophy, regurgitant fraction was calculated using the difference between right and left ventricular cardiac outputs. Left ventricular relaxation was assessed using the early to late diastolic Doppler tissue velocity ratio of the mitral annulus (E/ADTI), the E/A ratio of mitral inflow (E/AM), and the E deceleration time (E-DT). Left ventricular hypertrophy was assessed using the M mode derived left ventricular mass index.
  
  
  RESULTS
  The overall correlation between regurgitant fraction and PHT was weak (r = 0.36, p < 0.005). In patients without left ventricular hypertrophy, there was a significant correlation between regurgitant fraction and PHT (r = 0.62, p < 0.005), but not in patients with left ventricular hypertrophy. In patients with a left ventricular relaxation abnormality (defined as E/ADTI< 1, E/AM< age corrected lower limit, E-DT >/= 220 ms), no associations between regurgitant fraction and PHT were found, whereas in patients without left ventricular relaxation abnormalities, the regurgitant fraction to PHT relations were significant (normal E/AM: r = 0.57, p = 0.02; E-DT< 220 ms: r = 0.50, p < 0.001; E/ADTI < 1: r = 0.57, p = 0.02).
  
  
  CONCLUSIONS
  Only normal left ventricular relaxation allows a significant decay of PHT with increasing aortic regurgitation severity. In abnormal relaxation, which is usually present in left ventricular hypertrophy, wide variation in prolonged backward left ventricular filling may cause dissociation between the regurgitant fraction and PHT. Thus the PHT method should only be used in the absence of left ventricular relaxation abnormalities.
authors.affiliation: Cardiology, University Hospital, Inselspital, Freiburgstrasse, 3010 Bern, Switzerland.
authors.forename: S F
authors.initials: SF
authors.lastname: de Marchi
authors.forename: S
authors.initials: S
authors.lastname: Windecker
authors.forename: B C
authors.initials: BC
authors.lastname: Aeschbacher
authors.forename: C
authors.initials: C
authors.lastname: Seiler
mesh_terms: D000328:Adult; D001022:Aortic Valve Insufficiency / Q000150:complications / Q000503:physiopathology*; D002302:Cardiac Output; D006332:Cardiomegaly / Q000150:complications / Q000503:physiopathology*; D016009:Chi-Square Distribution; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*