LV twisting and untwisting in HCM: ejection begets filling. Diastolic functional aspects of HCM

Area of Science:

• Cardiology
• Biomedical Engineering
• Structural Biology

Background:

• Diastolic dysfunction is a key feature of hypertrophic cardiomyopathy (HCM).
• Current understanding of HCM's impact on diastolic function relies on traditional left ventricular (LV) approaches.
• Polymorphic phenotypes of HCM present complex challenges in understanding LV filling dynamics.

Purpose of the Study:

• To survey conventional and emerging concepts on how hypertrophic cardiomyopathy (HCM) causes diastolic dysfunction.
• To propose a shift towards advanced models for understanding LV diastolic function in HCM.
• To clarify intricate patterns of early diastolic rebound and suction in HCM phenotypes.

Main Methods:

• Review of conventional and emerging scientific literature on diastolic dysfunction in HCM.
• Conceptualization of large-scale (twist-untwist) and small-scale (titin unfolding-refolding) wall rebound models.
• Integration of myofiber sheet dynamics and ultrastructural constituent interactions.

Main Results:

• A paradigm shift is suggested from traditional LV diastolic function assessment to dynamic wall rebound models.
• Incorporation of myofiber sheet distortion and ultrastructural rearrangements offers a new perspective.
• These advanced models may elucidate complex diastolic filling patterns in HCM.

Conclusions:

• Emerging paradigms in diastolic dynamics, focusing on myofiber sheet and ultraconstituent distortion, are crucial for understanding HCM.
• The relationship between structural distortions and LV mechanics is key to explaining diastolic dysfunction in HCM.
• This new perspective may clarify early diastolic rebound and suction mechanisms essential for LV filling in diverse HCM phenotypes.