Key result
In patients with nonischemic cardiomyopathy, impaired contractile reserve assessed by TDI independently correlated with exercise-induced changes in effective regurgitant orifice area (r=-0.707, P<0.001).
Why the study?
Does impaired myocardial contractile reserve assessed by TDI correlate with exercise-induced changes in dynamic mitral regurgitation in patients with nonischemic cardiomyopathy?
Observational (n=35)
Does impaired myocardial contractile reserve assessed by TDI correlate with exercise-induced changes in dynamic mitral regurgitation in patients with nonischemic cardiomyopathy?
Impaired myocardial contractile reserve assessed by tissue Doppler imaging is an independent determinant of exercise-induced worsening of dynamic mitral regurgitation in nonischemic cardiomyopathy.
May link impaired TDI reserve to dynamic MR worsening in NICM; hypothesis-generating and requires prospective validation before practice change.
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). CONCLUSION: 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.
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Kang et al. (2008) conducted an observational in Nonischemic cardiomyopathy (n=35). Myocardial contractile reserve (DeltaV(avg)) assessed by TDI was evaluated on Exercise-induced changes in effective regurgitant orifice area (DeltaERO) and JLA% (DeltaJLA%) (r = -0.707 for DeltaERO; r = -0.663 for DeltaJLA%, p=< 0.001). In patients with nonischemic cardiomyopathy, impaired contractile reserve assessed by TDI independently correlated with exercise-induced changes in effective regurgitant orifice area (r=-0.707, P<0.001).
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