Impact of changes in myocardial velocity assessed by tissue Doppler imaging during exercise on dynamic mitral regurgitation in patients with nonischemic cardiomyopathy.
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.
Kang
Soo-Jin
SJ
Division of Cardiology, Ajou University Hospital, Suwon, South Korea.
Lim
Hong-Seok
HS
Hwang
Jungwon
J
Choi
Jung-Hyun
JH
Seo
Kyoung-Woo
KW
Choi
Byung-Joo
BJ
Choi
So-Yeon
SY
Hwang
Gyo-Seung
GS
Yoon
Myeong-Ho
MH
Shin
Joon-Han
JH
Tahk
Seung-Jea
SJ
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