Hypertrophic Cardiomyopathy in Iran: General Characteristics, Clinical Presentations, Imaging Features, and Major Adverse Cardiovascular Events of 322 Patients.

Introduction: Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, has significant clinical presentation and outcome diversity. Early diagnosis and proper management are essential to improve the patient's quality of life and prevent sudden cardiac death. Collecting patient information in each country is the first step in finding the gaps in the proper diagnosis and management of these patients. We aimed to determine the general characteristics of HCM in the largest referral tertiary heart center in Iran. Methods: In this cross-sectional study, between 2016 and 2020, clinical, imaging, and therapeutic data of patients diagnosed with HCM at Rajaie Cardiovascular Medical Research Center were reviewed and followed up to 48 months for Major adverse cardiovascular events (MACE), defined as composite endpoint of death, stroke (nonfatal), hospitalization due to decompensated heart failure (HF) and malignant ventricular arrhythmia defined as sustained ventricular tachycardia or ventricular fibrillation. Results: A total of 322 patients, with a mean age of 49.7 ± 1 years, including 129 women (40%), were studied. Women were significantly older than men (53.1 ± 9.1 vs. 47.2 ± 8.9, P < 0.0001). The most prevalent symptom was dyspnea on exertion, affecting 158 patients (49%). Nonobstructive HCM was present in 180 patients (55.9%), and atrial fibrillation was observed in 82 patients (25.46%). Major Adverse Cardiovascular Events were more frequent in patients with obstructive forms of the disease. Beta-receptor-blocking agents were the most used medication (85%). In addition, 29 patients (9% overall and 20.4% of those with obstructive forms) were treated with disopyramide, and 19 patients (5.9%) underwent surgical myectomy. Late gadolinium enhancement (LGE) was detected in 56 out of 122 patients (45.9%) who underwent cardiac magnetic resonance imaging. MACE incidence was notably higher in patients with positive LGE. Overall, MACE occurred in 110 patients (34.16%). Malignant ventricular arrhythmias were reported in 64 patients (19.87%), HF in 36 patients (11.18%), and HCM-related death in 4 patients (1.24%). Conclusion: This study showed the general characteristics, clinical outcomes, and therapeutic approach of HCM patients in Iran. We found more MACE in obstructive versus nonobstructive forms and LGE ≥ 10%. Disopyramide and implantable cardioverter-defibrillator implantation are well-adapted therapeutic options, followed by surgical myectomy. However, genetic testing and alcohol septal ablation are uncommon procedures.