Selective Mid-Wall Cardiac Dysfunction in Obesity: The Role of Muscle-to-Fat Balance

Area of Science:

• Cardiology
• Obesity Medicine
• Body Composition Analysis

Background:

• Obesity is linked to cardiovascular complications.
• Understanding the mechanisms of cardiac dysfunction in young obese adults is crucial.
• Body composition, particularly the balance between muscle and fat, may influence cardiac health.

Purpose of the Study:

• To analyze the relationship between body composition, biochemical markers, and cardiac function in young adults.
• To identify specific mechanisms contributing to cardiac dysfunction in obesity.
• To evaluate the predictive value of the skeletal muscle mass-to-fat ratio for cardiac dysfunction.

Main Methods:

• Cross-sectional study of 60 young adults (healthy vs. overweight/obese).
• Body composition assessed via bioelectrical impedance analysis, calculating skeletal muscle mass %-to-fat % ratio (SMM-to-Fat ratio).
• Cardiac function evaluated using 3D speckle-tracking echocardiography, focusing on 3D global circumferential strain.

Main Results:

• Obese group had lower skeletal muscle mass % and SMM-to-Fat ratio, and higher body fat % (p < 0.001).
• Obese group exhibited impaired circumferential strain (p = 0.023), indicating selective mid-wall dysfunction.
• SMM-to-Fat ratio strongly predicted circumferential strain (r = -0.467, p = 0.008) and was an independent predictor, outperforming skeletal muscle mass % alone.

Conclusions:

• Young obese adults present with selective mid-wall cardiac dysfunction.
• The SMM-to-Fat ratio is a superior predictor of cardiac dysfunction compared to skeletal muscle mass % alone.
• Relative muscle-adiposity balance, not just absolute muscle mass, is key for cardiac health in obesity.