A preliminary analysis on the influencing factors of myocardial thickness in patients with apical hypertrophic cardiomyopathy

Objective To analysize the apical thickening rate detected by echocardiography and to explore the influencing factors of apical thickness in patients with apical hypertrophic cardiomyopathy (AHCM). Method Patients with the diagnosis of AHCM which was defined by the maximum apical thickness (Apmax) at the end-diastole of ≥15 mm and the ratio of maximum apical thickness to posterior wall thickness at basal segment (ABR) of >1.5, in the first affiliated hospital of Fujian Medical University from May 2007 to November 2017 were enrolled and divided into two groups, group A who was diagnosed with AHCM at first visit and group B who was diagnosed with AHCM during follow-up. The difference of Apmax between the last and first follow-up (∆Apmax, mm) and its thickening velocity during follow-up (V-Apmax, mm/a) were calculated. The influencing factors of apical thickness was analyzed. Results A total of 32 patients were enrolled in the analysis, including 21 males and 11 females with a median age of 64 years (range 28~91 years), of which 18 cases in group A and 14 cases in group B. The mean follow-up duration was 59 months (range 24~118 months). There was a significant increase in Apmax at the last visit in comparison with the first visit for the whole [(20.5±4.1) mm vs. (17.2±5.0) mm, P<0.01]. Moreover, the ∆Apmax [7.7 (4.5, 10.7) mm vs. 1.4 (0.3, 2.0) mm, P<0.05] and V-Apmax[1.1 (0.6, 2.6) mm/year vs. 0.4 (0.0, 0.6) mm/year, P<0.05] in group B were significantly higher than those in group A. Correlation analysis showed that the V-Apmax was negatively correlated with age and apical thickness at initial diagnosis (r value of -0.392, -0.416, both P<0.05). Conclusions The progression of apical thickness in AHCM patients is likely to be related to the age of onset and the stage of disease. Apical thickening faster in young patients or those at early stage of the disease. Key words: Cardiomyopathy, hypertrophic; Myocardial thickness; Thickening rate; Echocardiography