Beyond Symptom Relief: Transforming HOCM Management with Far Reaching Benefits on Septal Reduction, LVOT Pressure Control and HCM Risk Mitigation

Background: Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder characterized by thickening of the heart muscle, particularly of the interventricular septum, which can obstruct blood flow from the left ventricle. This condition manifests through symptoms such as chest pain, shortness of breath, and, in severe cases, sudden cardiac death. HOCM holds considerable significance globally due to its association with sudden cardiac events, especially in young individuals and athletes, underscoring the importance of early diagnosis and effective management. Traditional treatment options have included beta-blockers, surgical myectomy, or septal ablation to reduce outflow obstruction. Recently, Camzyos® (mavacamten), a novel therapeutic agent, has emerged as a targeted non-invasive treatment for HOCM. By modulating myosin activity in heart muscle cells, Camzyos® reduces excessive contractility, alleviating symptoms and significantly improving quality of life. This advancement represents a major step forward in personalized and non-invasive treatment for HOCM, offering new possibilities for managing this complex condition effectively.

Methods: This study included 25 patients with hypertrophic cardiomyopathy and additional obstruction in the left ventricular outflow tract [HOCM]. All patients were acquired in the department of cardiology of the university hospital TUM Klinikum of the Technical University Munich. Patients were seen in standardized regular intervals after qualifying for treatment with mavacamten and checked for intraventricular septum thickness, LVOT pressure and HCM Risk Score with echocardiography and anamnesis at each appointment. The course of these parameters was analyzed during the ongoing treatment.

Results: For all 25 patients we initially observed an average thickness of the intraventricular septum of 18mm, an HCM Risk Score of 2.9% and an average maximal pressure of 64mmHg in the left ventricular outflow tract.  Patients received an average dose of mavacamten of 5mg. At the point of our analysis treatment had been ongoing for an average of ten months [spanning from 18 – 3 months]. We could observe a reduction not only in HOCM related symptoms. More than that, HCM Risk Score dropped from an average of 2,95% to 1,97% and intraventricular septum thickness decreased from an average of 18mm to 16,5mm. Most prominently, however, we saw a significant decrease of the max. pressure in left ventricular outflow tract from an average of 64mmHg to a mere 28,5mmHg. In several cases implantation of an implantable cardioverter defibrillator could be avoided due to the regressiveness of the HCM Risk Score to below 5%.

Conclusion: With this analysis we identified several benefits of mavacamten additive to symptomatic relief. Namely, we observed a significant reduction of intraventricular septum thickness, pressure in the left ventricular outflow tract and the risk for sudden cardiac death in 5 years depicted by the HCM Risk Score in the majority of the patients. Moreover, invasive treatment and ICD implantation could be avoided in several cases due to this treatment.