Features of diastolic dysfunction in patients with different phenotypes of hypertrophic cardiomyopathy

Objective: to evaluate the presence and characteristics of left ventricular (LV) diastolic dysfunction (DDА) in various phenotypic variants of hypertrophic cardiomyopathy (HCM) based on Doppler echocardiography (EchoCG). Materials and methods: a total of 305 patients with HCM aged 18-88 years (mean age 60.6 ± 11 years) were examined, including 189 (62 %) men and 116 (38 %) women. The diagnosis was established based on two-dimensional EchoCG data upon detection of LV myocardial hypertrophy in the absence of any other pathological process responsible for the severity of such hypertrophy. The control group consisted of 50 practically healthy individuals comparable in gender and age. The severity, localization and extent of hypertrophy, transmitral blood flow parameters, size and volume of the left atrium were assessed. Depending on the predominant localization of hypertrophy, all patients were divided into 8 morphological groups according to the recommendations for HCM of the Ministry of Health of the Russian Federation 2020. An analysis and comparison of the parameters of diastolic function was carried out depending on the HCM phenotype. Results: 305 patients with HCM were divided into 8 typical groups: 128 patients in group 1 (hypertrophy of the basal part of the interventricular septum, IVS), 45 — in group 2 (hypertrophy of the entire IVS, “neutral septum”), 50 — in group 3 (IVS hypertrophy of “reverse curve”), 11 — in group 4 (combined hypertrophy of the IVS and other parts of the left or right ventricle), 7 — in group 5 (apical hypertrophy with or without involvement of other LV segments), 11 — in group 6 (midventricular IVS hypertrophy with LV free wall hypertrophy), 12 — in group 7 (LV free wall hypertrophy), and 41 — in group 8 (symmetrical or concentric LV hypertrophy). Among all patients, DDF was detected in 286 (93.8 %) of cases. The most frequently recorded DDF type I (impaired relaxation) was in 196 (64.3 %) patients, type II (pseudonormalization) — in 64 (21%) and type III (restrictive type) — in 26 (8.5 %). In the control group, DDF type I was recorded in 8 (16 %) patients, type II — in 6 (12 %) and type III in none of the cases. Despite the noted variations in the frequency of detection of one or another type of DDF in the phenotypic groups, statistical analysis did not reveal any significant differences. Conclusion: diastolic function disorders were detected in the overwhelming majority of patients with HCM: in 93.8 % of cases. The spectrum of DDF in this disease is wide and includes all types of diastolic abnormalities. In patients with HCM, impaired relaxation (DDF type I) is detected in 64.3 % of patients, pseudonormalization (II) — in 21 % and restrictive type (III) — in 8.5%. Analysis of the dependence of the frequency of registration of the noted types of DDF depending on any hypertrophy phenotype did not show significant differences.