Article Text
PDF
Abstract
Background Apical hypertrophic cardiomyopathy (HCM) is a rare variant of HCM, often considered to have a benign prognosis. This study aimed to compare the clinical characteristics and genetic predisposition of apical HCM with non-apical HCM.
Methods We included 195 patients with HCM who underwent next-generation sequencing at two tertiary centres in South Korea (2017–2024). The primary outcome was a composite of lethal arrhythmic events (LAE), including death, ventricular arrhythmia, implantable cardioverter defibrillator (ICD) implantation and appropriate ICD shock. Secondary outcomes included major adverse cardiovascular events (MACE), such as new-onset atrial fibrillation, ischaemic stroke, heart failure hospitalisation, septal reduction therapy or heart transplant.
Results Of the 195 patients, 67 (34.4%) had apical HCM. Patients with apical HCM were older at diagnosis and had lower maximal left ventricular wall thickness compared with non-apical HCM. Disease-causing variants were less frequent in apical HCM (20.9% vs 46.9%, p<0.001). MYBPC3 and MYH7 variants were less common in apical HCM (50.0%) than in non-apical HCM (75.0%). MACE occurred less frequently in apical HCM (HR 0.38, 95% CI 0.19 to 0.75), but no difference was observed in LAE (HR 0.62, 95% CI 0.36 to 1.08). The presence of disease-causing variants was independently associated with LAE (adjusted HR 2.50, 95% CI 1.44 to 4.35).
Conclusions Although apical HCM is associated with less hypertrophy and lower genetic yield, it is not entirely benign. The presence of disease-causing variants is an important predictor of arrhythmic risk, underscoring the value of genetic testing in all HCM patients, regardless of phenotype.
- Hypertrophic cardiomyopathy
- Genetics
- Arrhythmias, Cardiac
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information. Data used in this study are presented in this article. The raw data underlying this article cannot be shared publicly due to privacy concerns and legal regulations of the Republic of Korea.
Statistics from Altmetric.com
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information. Data used in this study are presented in this article. The raw data underlying this article cannot be shared publicly due to privacy concerns and legal regulations of the Republic of Korea.
Footnotes
JHJ and HK are joint first authors.
Contributors J-IC and YC had full access to all data in this study and take responsibility for data integrity and analytical accuracy. The concept and design of the study were developed by JHJ, HK, YC and J-IC. Data analysis and interpretation were performed by JHJ, HK, SHH, YC and J-IC. The manuscript was drafted by JHJ, HJK, YC and J-IC. Data collection was performed by JHJ, HK, YC, YGK, HSL, YK, C-OS, SHH, JS, Y-HK and J-IC. J-IC is responsible for the overall content as a guarantor.
Funding This work was supported by a Korea University Grant (J-IC), a grant from the Korea University Anam Hospital, Seoul, Republic of Korea (J-IC), and in part by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT, Ministry of Science and ICT) (Number 2021R1A2C2011325 to J-IC). The funders had no role in data collection, analysis or interpretation; trial design; patient recruitment; or any other aspect pertinent to the study.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer-reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.