Retrofitting the Heart: Explaining the Enigmatic Septal Thickening in Hypertrophic Cardiomyopathy

Area of Science:

• Cardiology
• Genetics
• Biomedical Engineering

Background:

• Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disease, characterized by left ventricular hypertrophy.
• Diastolic dysfunction, preceding hypertrophy, is linked to hypercontractility and myofibril asynchrony.
• Septal thickening is a primary feature of HCM, but its cause is not fully understood.

Purpose of the Study:

• To propose a novel hypothesis explaining the predisposition of the interventricular septum to hypertrophy in HCM.
• To elucidate the role of baseline muscle fiber geometry and biomechanical stress in septal remodeling.

Main Methods:

• Conceptual analysis of cardiac mechanics and cytoskeletal remodeling.
• Application of biomechanical principles, including Laplace Law.
• Drawing parallels with structural engineering principles for protective adaptation.

Main Results:

• Alterations in congenital muscle fiber geometry predispose the septum to isometric contraction.
• Hypercontractility and outflow tract obstruction exacerbate biomechanical stress on the septum.
• The septum remodels by synthesizing viscoelastic elements, leading to hypertrophy as a protective mechanism.

Conclusions:

• The study provides a coherent explanation for septal hypertrophy in HCM, linking it to biomechanical adaptation.
• This remodeling attenuates myofibril shortening and reduces cavity tension, protecting the heart.
• Understanding these mechanisms can inform future therapeutic strategies for HCM.