PO26 Clinical Profiles and Outcomes of Genotype-Positive Hypertrophic Cardiomyopathy in an Ultraperipheral Region: A Decade of Experience

Abstract Hypertrophic cardiomyopathy (HCM) is a common inherited cardiomyopathy that can manifest with a wide range of presentations, from asymptomatic individuals to patients who develop heart failure, arrhythmias or sudden cardiac death (SCD). We retrospectively reviewed all HCM patients who underwent genetic testing in our center between January 2015 and August 2025 and were found to carry a pathogenic or likely pathogenic variant. Clinical data as well as findings from electrocardiogram (ECG), Holter monitoring and imaging were analysed. Among genotype-positive patients (n=54), 64% were male and the median age at genetic diagnosis was 58 years (IQR 24). Hypertensive patients were older at the genetic diagnosis (median 63 years, IQR 24) compared to those without hypertension. The cohort had a high burden of comorbidities, namely hypertension (67%), dyslipidaemia (59%) and current smoking habits (33%). Fatigue was the most frequently reported symptom (53%). Regarding ECG patterns, we observed a predominance of nonspecific repolarization abnormalities (42%) followed by T-wave inversion (25%) and LVH by Sokolow-Lyon criteria (13%). An apparently normal ECG was present in 13% of the cohort. No statistically significant correlation was found between the maximum LVH thickness and these ECG patterns. All patients with apical HCM (n=3) had giant negative T waves in V4-V6. Imaging assessment revealed a predominance of asymmetric septal hypertrophy involvement, classified as severe hypertrophy (mean wall thickness 19,7 ± 4,4 mm). During follow up (median 4.6 years, IQR 79), approximately one-third of the patients had aggravated heart failure symptoms (NYHA III-IV). There were no cardiovascular deaths. Atrial fibrillation was the most common sustained arrhythmia affecting nearly half of the study group and approximately 30% developed ventricular tachycardia. About 1 in 5 patients had an implantable cardioverter-defibrillator (ICD) for primary prevention of SCD, and two patients had ICD for secondary prevention. Obstructive HCM was present in 19% (n=10) of our cohort. Three of these individuals required invasive septal reduction via surgical myectomy, while one patient ultimately underwent cardiac transplantation. Another three patients are currently being treated with the cardiac myosin inhibitor mavacamten, with a mean resting outflow gradient of 72.3 ± 10.2 mmHg before therapy initiation, improving to 39 ± 8.5 mmHg after one month. In conclusion, our decade-long experience highlights that patients with genetically confirmed HCM present with a broad spectrum of clinical features. Despite the presence of severe hypertrophy and a frequent need for beta-blocker therapy, most patients remained clinically stable, with only a small subgroup requiring invasive interventions. These outcomes emphasise the importance of early genetic identification, comprehensive comorbidity management and personalized follow up to minimize the risks of heart failure progression and SCD.