Major rapid weight loss induces changes in cardiac repolarization

Area of Science:

• Cardiology
• Metabolic Health
• Physiology

Background:

• Obesity increases mortality risk, but weight loss interventions may not always reduce cardiovascular events.
• Very low-calorie diets have been linked to cardiac arrhythmias and sudden death.
• T-wave morphology analysis offers a potentially more sensitive method for assessing cardiac repolarization than the standard QT interval.

Purpose of the Study:

• To investigate the impact of significant and rapid weight loss on T-wave morphology.
• To compare the sensitivity of T-wave morphology analysis (MCS) versus QT interval in detecting repolarization changes during weight loss.

Main Methods:

• Twenty-six participants underwent electrocardiograms (ECGs) and plasma measurements (glucose, HbA1c, potassium) before and after an 8-week weight loss intervention.
• Cardiac repolarization was assessed using T-wave Morphology Combination Score (MCS) and ECG intervals (RR, PR, QT, QTcF, QRS duration).
• Participants achieved an average bodyweight reduction of 13.4%.

Main Results:

• Significant increases in MCS, QRS, and RR intervals were observed post-intervention (p<0.01).
• Fasting plasma glucose and HbA1c levels significantly decreased (p<0.001 and p<10(-5), respectively), while plasma potassium remained unchanged.
• MCS showed a negative correlation with HbA1c (p<0.001) and fasting plasma glucose (p<0.01), unlike QTcF.

Conclusions:

• Major rapid weight loss induces alterations in cardiac repolarization.
• Morphology Combination Score (MCS) provides a more discriminative assessment of repolarization changes during rapid weight loss compared to the QT interval.
• The correlation between MCS and reduced HbA1c suggests that sustained lower blood glucose levels may influence cardiac repolarization.