Hypertrophic cardiomyopathy: functional aspects by tagged magnetic resonance imaging

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Imaging

Background:

• Hypertrophic cardiomyopathy (HCM) is a genetic heart disease characterized by abnormal thickening of the heart muscle.
• Regional differences in myocardial function and structure are key features of HCM.
• Understanding these regional variations is crucial for diagnosing and managing HCM.

Purpose of the Study:

• To investigate the relationship between regional myocardial thickness and systolic function in patients with HCM.
• To explore how local wall stress influences regional function in HCM.
• To assess whether enhanced function in normal-thickness regions occurs in HCM patients.

Main Methods:

• Utilized three-dimensional (3D) tagged magnetic resonance imaging (MRI) to analyze regional function.
• Employed the volume-element approach to quantify myocardial thickening and circumferential shortening.
• Related regional function indices to local myocardial thickness and wall stress.

Main Results:

• An inverse relationship was observed between myocardial thickening and local wall thickness.
• Circumferential shortening also showed an inverse correlation with local wall thickness.
• Thicker myocardial segments exhibited lower regional wall stress.
• Normal-thickness regions in HCM patients displayed enhanced function compared to healthy subjects.

Conclusions:

• Thicker myocardial segments in HCM patients have reduced systolic function at lower stress levels.
• This finding supports the hypothesis of reduced contractile activity in thickened segments.
• Genetic mutations affecting contractile proteins likely contribute to impaired function in these HCM segments.