Clinical prevalence of hypertrophic cardiomyopathy phenotype: an echocardiography-based multicenter cross-sectional study in China

Abstract Background Hypertrophic cardiomyopathy (HCM) is a genetic disorder that contributes to disabling symptoms, heart failure, and premature death across all age groups. Echocardiography serves as the primary diagnostic tool for HCM; however, its diagnosis is often delayed or missed due to various factors. Therefore, earlier and more accurate identification of HCM patients is crucial. Currently, there is a paucity of population-based screening studies for HCM, and large-scale epidemiological studies on HCM prevalence are lacking in China. Purpose To investigate the detection rate and echocardiographic characteristics of patients with HCM phenotypes (and their major subtypes) identified by echocardiography in year 2023 across echocardiography databases from nine large medical centers in China. Methods This is a multicenter, cross-sectional study. Data were collected from the echocardiography databases of participating centers, including all outpatients, emergency patients, and inpatients who underwent echocardiography from January 1st, 2023, to December 31st, 2023. All adult patients with HCM phenotypes identified by echocardiography were enrolled. For patients who underwent multiple echocardiographic examinations, the results from the first examination within the study period were used for analysis. According to current guideline recommendations, an end-diastolic wall thickness ≥15 mm anywhere in the left ventricle was identified as an HCM phenotype. Applying a left ventricular outflow tract obstruction ≥30 mmHg (when documented), we further identified obstructive HCM (oHCM). Results Among 655,383 echocardiographic examinations conducted in 2023 across nine medical centers in mainland China, 1,925 patients met the diagnostic criteria for HCM phenotype. Thus, the detection rate of HCM in this cohort was approximately 0.29% (Figure 1). Among patients with HCM phenotype, the mean age was 59.1 ± 15.0 years, and 71.5% were male. The maximum left ventricular wall thickness averaged 18.9 ± 3.9 mm in all HCM phenotype patients. Of these, 172/1,924 (8.9%) met the diagnostic criteria for obstructive HCM (oHCM). In patients with oHCM, 91/172 (52.9%) exhibited a left ventricular outflow tract peak pressure gradient of ≥50 mmHg on either rest or stimulation test. Patients with oHCM exhibited significantly greater maximum left ventricular wall thickness and a higher incidence of moderate to severe mitral regurgitation compared to non-oHCM patients (Table 1). Conclusion In this multicenter echocardiography cohort from China, the detection rate of HCM phenotypes in year 2023 was approximately 0.29%, which aligns with the prevalence reported in other large-scale epidemiological studies on hypertrophic cardiomyopathy. A relatively lower detection rate of obstructive HCM phenotype reinforces the necessity of stimulation test training.Figure 1 Table 1