CMR-Derived Strain and Torsion Reveal Subclinical Dysfunction in Hypertrophic Cardiomyopathy: A Prospective...

Area of Science:

• Cardiology
• Medical Imaging
• Biophysics

Background:

• Hypertrophic cardiomyopathy (HCM) often presents with preserved ejection fraction, masking subclinical myocardial dysfunction.
• Conventional imaging techniques may fail to detect early signs of impaired cardiac mechanics in HCM.
• Cardiac magnetic resonance (CMR) with feature tracking (FT) offers advanced capabilities for assessing myocardial deformation.

Purpose of the Study:

• To evaluate the utility of CMR-derived strain and torsion parameters in detecting early myocardial dysfunction in HCM patients.
• To compare the diagnostic performance of FT-CMR metrics with established markers of myocardial fibrosis.
• To investigate the prognostic value of global left ventricular (LV) torsion in HCM.

Main Methods:

• A prospective case-control study involving 150 HCM patients and 100 healthy controls.
• Standardized CMR protocols were used to quantify global longitudinal strain (GLS), circumferential strain (GCS), radial strain (GRS), and LV torsion via FT-CMR.
• Myocardial fibrosis was assessed using late gadolinium enhancement (LGE), native T1 mapping, and extracellular volume (ECV).

Main Results:

• HCM patients exhibited significantly impaired GLS, GCS, GRS, and LV torsion compared to controls (p < 0.001).
• These functional abnormalities were present even in LGE-negative HCM patients, indicating early remodeling.
• Global LV torsion demonstrated superior diagnostic performance (AUC = 0.995) for LGE detection compared to GLS, T1 mapping, and ECV.

Conclusions:

• CMR-derived strain and torsion parameters effectively detect subclinical myocardial dysfunction in HCM.
• Global LV torsion is a sensitive and robust non-invasive marker with significant diagnostic and prognostic potential in HCM.
• These findings highlight the value of advanced CMR techniques in understanding HCM pathophysiology and patient outcomes.