title: Effect of preload on left atrial function: evaluated by tissue Doppler and strain imaging.
abstract: OBJECTIVE
  Both strain and strain rate (SR) measure the regional myocardial deformation and can assess phasic left atrial (LA) function. However, there is still a lack of evidence for their volume independency. In this study, strain and SR determined by tissue Doppler imaging were used to evaluate the effect of preload reduction in end-stage renal disease patients who were undergoing regular haemodialysis (HD).
  
  
  RESULTS
  Forty-one subjects who underwent transthoracic echocardiography just before and after HD were enrolled. LA strain was measured during late systole, and LA peak tissue velocity and SR were measured during systole and during early and late diastolic periods. The values of tissue velocity, strain, and SR were obtained in the basal septal, lateral, inferior, and anterior walls of the LA. The mean strain value was 23.89 ± 7.29% at baseline and decreased to 21.88 ± 5.85% after HD (P = 0.019). SR during systole (before HD 1.55 ± 0.40; after HD 1.38 ± 0.35, P = 0.001) and early diastole (before HD -1.41 ± 0.54; after HD -1.16 ± 0.45, P = 0.001) also changed. However, the acute preload change caused by HD did not affect the peak tissue velocity (before HD -6.34 ± 1.58 cm/s; after HD -6.46 ± 1.54 cm/s, P = 0.436) and the SR (before HD -1.36 ± 0.45/s; after HD -1.34 ± 0.29/s, P = 0.621) measured during late diastole.
  
  
  CONCLUSIONS
  Both tissue velocity and SR during late diastole, representing the contractile function of the LA, are relatively preload-independent parameters and are available for the evaluation of the LA function.
authors.affiliation: Division of Cardiology and Nephrology, College of Medicine,  Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701,  Republic of Korea.
authors.forename: Chan Seok
authors.initials: CS
authors.lastname: Park
authors.forename: Yong-Kyun
authors.initials: YK
authors.lastname: Kim
authors.forename: Ho Chul
authors.initials: HC
authors.lastname: Song
authors.forename: Euy Jin
authors.initials: EJ
authors.lastname: Choi
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Ihm
authors.forename: Hee-Yeol
authors.initials: HY
authors.lastname: Kim
authors.forename: Ho-Joong
authors.initials: HJ
authors.lastname: Youn
authors.forename: Ki Bae
authors.initials: KB
authors.lastname: Seung
mesh_terms: D001794:Blood Pressure; D016001:Confidence Intervals; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000473:pathology; D006339:Heart Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D013223:Statistics as Topic; D013599:Systole; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color