Structural and Functional Feature Comparison Between Dilated Phenotype and Restrictive Phenotype of Hypertrophic Cardiomyopathy Patients With Severe Heart Failure / 中国循环杂志

ABSTRACT

Objectives:To compare the structural and functional features between dilated phenotype and restrictive phenotype of hypertrophic cardiomyopathy patients with severe heart failure. Methods:We retrospectively enrolled the hypertrophic cardiomyopathy patients with severe heart failure (NYHA classⅢ/Ⅳ) who were admitted in our hospital during January 2010 to June 2017. The structural and functional characteristics between dilated phenotype and restrictive phenotype of hypertrophic cardiomyopathy patients with severe heart failure were compared. Results:One hundred and seventy-six hypertrophic cardiomyopathy patients with heart failure were enrolled, including 112 patients with dilated phenotype (dilated group) and 64 patients with restrictive phenotype (restrictive group). Echocardiographic examination showed that LVEDd was larger[(66.9±12.6) mm vs (44.6±10.1) mm,P＜0.001],the maximum left ventricular wall thickness (MLVWT) was thinner(13.1±3.1)mm vs (16.3±3.9)mm, P＜0.001], the proportion of patients with a thinner MLVWT was higher[26.8%(30/112) vs 6.3%(4/64),P=0.003], LVEF was lower ([29.7±10.1]% vs [53.0±18.2]%, P=0.006),the proportion of patients with a LVEF＜50% was higher(96.4%[108/112] vs 14.1%[9/64], P＜0.001),the proportion of patients with both left and right atrium enlarged was lower (42.9%[48/112] vs 100%[64/64], P＜0.001), and the proportion of patients with tricuspid insufficiency was also lower in the dilated group (55.4%[62/112] vs 71.9%[46/64], P=0.031) compared with the restrictive group. Cardiovascular magnetic resonance imaging examination evidenced that the proportion of patients with local ventricular septum hypertrophy was higher[78.7%(48/61) vs 9.4%(3/32), P＜0.001], the proportion of patients with extensive areas of transmural post-contrast delayed hyper-enhancement within septal and left ventricular free wall myocardium was higher(90.2%[55/61] vs 65.6%[21/32], P=0.013)in dilated group compared with the restrictive group. However, the proportion of patients with limited areas of transmural post-contrast delayed hyper-enhancement within interventricular septum or apex is less than that in the restricted group (9.8% [6/61] vs 34.4% [11/32], P=0.026). The maximum ventricular wall thickness was also less than that of the restrictive group ([15.8 ± 3.1] mm vs [19.8±3.4] mm, P=0.001). Conclusions:There are many differences in characteristics of cardiac structure and function between dilated phenotype and restrictive phenotype in hypertrophic cardiomyopathy patients with severe heart failure, such as the size of ventricular and atrium, the ventricular wall thickness, location and area of ventricular hypertrophy, LVEF, prevalence of mitral valve insufficiency and tricuspid insufficiency, myocardial fibrosis. The difference in location and area of ventricular hypertrophy and myocardial fibrosis may be the fundamental changes leading to these two phenotypes of hypertrophic cardiomyopathy.