[Comparison of dobutamine stress echocardiography and exercise echocardiography in evaluating left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy].
OBJECTIVE
To compare left ventricular outflow tract (LVOT) gradient induced by dobutamine stress echocardiography (DSE) and exercise echocardiography (EE) in patients with hypertrophic cardiomyopathy (HCM).


METHODS
DSE and EE were performed in 40 consecutive patients with HCM and LVOT gradient < 50 mm Hg (1 mm Hg = 0.133 kPa) at rest. Dobutamine was administered intravenously at incremental doses of 200, 400, 600, 800 and 1200 µg/min at 5 min intervals. LVOT gradients were measured at rest, at peak exercise and during each dose of DSE.


RESULTS
LVOT gradient at rest was lower than 30 mm Hg in 36 patients and between 30 and 49 mm Hg in 4 patients. Of the 36 patients with LVOT gradient < 30 mm Hg at rest, mechanical LVOT obstruction (latent LVOTO) was evidenced in 17 patients during EE and in 18 patients during DSE and good consistency (91.7%, kappa value 0.833) was found between the two maneuvers. The provoked gradient was similar between DSE at 800 µg/min and EE at peak exercise (P = 0.181). In the 4 patients with LVOT gradient between 30 and 49 mm Hg [(38.8 ± 2.6) mm Hg], LVOT gradient increased to (85.3 ± 26.4) mm Hg during EE and (105.0 ± 28.0) mm Hg during DES.


CONCLUSIONS
DES and EE are comparable and suitable provoke methods for identifying LVOT obstruction in patients with HCM.
Center of Coronary Heart Disease, Cardiovascular Institute and Fuwai Hospital, Medical Sciences and Peking Union Medical College, Chinese Academy of Medical Science, Beijing 100037, China.
Chun-li
CL
Shao
Fu-jian
FJ
Duan
Shu-bin
SB
Qiao
Shi-jie
SJ
You
Feng-huan
FH
Hu
Jian-song
JS
Yuan
Wei-xian
WX
Yang
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D025401:Echocardiography, Stress / Q000379:methods*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging*