Exercise echocardiography in the evaluation of obstructive types of hypertrophic cardiomyopathy / 中华内科杂志

ABSTRACT

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 ventri cular 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 nonobstructive HCM at rest have latent LVOTO.SAM and distribution of septal hypertrophy may be useful to identify patients with latent obstruction.