[Exercise echocardiography in the evaluation of obstructive types of hypertrophic cardiomyopathy].
OBJECTIVE
To assess the condition of left ventricular outflow tract obstruction (LVOTO) under resting conditions and physiological exercise in hypertrophic cardiomyopathy (HCM) patients.


METHODS
A total of 60 patients with HCM and left ventricular outflow tract gradient (LVOTG) <50 mm Hg (1 mm Hg = 0.133 kPa) at rest were enrolled consecutively, and LVOTG at rest and exercise were measured by echocardiography. Of 51 patients with gradients <30 mm Hg at rest, 26 were latent LVOTO with exercise peak value LVOTG ≥ 30 mm Hg, 25 were non LVOTO with exercise peak value LVOTG < 30 mm Hg, and 9 were resting obstruction with LVOTG 30-49 mm Hg. The morphological characteristics of different types of obstruction were analyzed.


RESULTS
Patients with latent LVOTO were more likely to have SAM (73.1% vs 8.0%) , narrow of LVOT (46.2% vs 4.0%) , higher resting gradients [(16.9 ± 7.2) mm Hg vs (7.1 ± 4.3) mm Hg] and mitral regurgitation grade at rest than patients with non-obstructive (all P values <0.05). The distribution of septal hypertrophy were different in the two groups (P < 0.05). Multivariate logistic regression analysis showed independent predictors of latent LVOTO were SAM (OR 6.431, 95%CI 2.323-291.112, P = 0.002) at rest and distribution of septal hypertrophy(OR 0.011, 95% CI 0.001-0.179, P = 0.008).


CONCLUSIONS
Approximately half of patients with non-obstructive HCM at rest have latent LVOTO. SAM and distribution of septal hypertrophy may be useful to identify patients with latent obstruction.
Chinese Academy of Medical Science of Medical Sciences and Peking Union Medical College, Fuwai Hospital, 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
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged