title: Impact of changes in myocardial velocity assessed by tissue Doppler imaging during exercise on dynamic mitral regurgitation in patients with nonischemic cardiomyopathy.
abstract: BACKGROUND
  We evaluated the myocardial contractile reserve related to exercise-induced changes in functional mitral regurgitation (MR) by tissue Doppler imaging (TDI).
  
  
  METHODS
  Supine bicycle exercise was performed in 35 patients with nonischemic cardiomyopathy (age 51 +/- 12 years; EF < 40%) and resting, and peak exercise 2D echocardiographic parameters, and TDI data were obtained. V(avg) was defined as the average of peak systolic velocities of six basal LV segments by TDI. Myocardial contractile reserve, which was calculated by [peak exercise V(avg)- baseline V(avg)], was represented as DeltaV(avg). Dyssynchrony index was derived from the standard deviation of the time to the peak systolic velocity of 12 LV segments.
  
  
  RESULTS
  During exercise (9.7 +/- 2.4 minutes), the mean V(avg) increased from 4.0 +/- 0.8 cm/s to 5.5 +/- 1.0 cm/s. The effective regurgitant orifice area (ERO) and the ratio of MR jet area to the left atrial area (JLA%) were 1.9 +/- 2.9 mm(2) and 12 +/- 12%, respectively. During exercise, ERO and JLA% significantly increased to 6.2 +/- 6.4 mm(2) and 21 +/- 13% (P < 0.05), respectively, with individually variable changes. Tenting area was found to be an independent factor that showed a relationship with the baseline severity of MR (r = 0.561, P < 0.001). Dyssynchrony index and DeltaV(avg) were found to correlate with both maximal MR severity at peak exercise and changes in MR during exercise. By multivariate analysis, DeltaV(avg) was found to be an independent determinant of exercise-induced changes in ERO (DeltaERO; r =-0.707, P< 0.001) and changes in JLA% (DeltaJLA%; r =-0.663, P< 0.001).
  
  
  CONCLUSIONS
  In patients with nonischemic cardiomyopathy, impaired contractile reserve assessed by TDI velocity data may be an independent determinant affecting exercise-induced changes in dynamic MR.
authors: Division of Cardiology, Ajou University Hospital, Suwon, South Korea.
authors: Soo-Jin
authors: SJ
authors: Kang
authors: Hong-Seok
authors: HS
authors: Lim
authors: Jungwon
authors: J
authors: Hwang
authors: Jung-Hyun
authors: JH
authors: Choi
authors: Kyoung-Woo
authors: KW
authors: Seo
authors: Byung-Joo
authors: BJ
authors: Choi
authors: So-Yeon
authors: SY
authors: Choi
authors: Gyo-Seung
authors: GS
authors: Hwang
authors: Myeong-Ho
authors: MH
authors: Yoon
authors: Joon-Han
authors: JH
authors: Shin
authors: Seung-Jea
authors: SJ
authors: Tahk
mesh_terms: D009202:Cardiomyopathies / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D015150:Echocardiography, Doppler / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000502:physiology*; D011379:Prognosis; D011446:Prospective Studies; D012720:Severity of Illness Index