Liquid protein diets and torsade de pointes

Area of Science:

• Cardiology
• Endocrinology
• Metabolic Disorders

Background:

• Liquid protein diets are popular for rapid weight loss.
• Potential adverse effects on cardiac function are not fully understood.

Observation:

• Three women experienced recurrent syncope (fainting) after significant weight loss (36-41 kg) on liquid protein diets.
• Hypokalemia (serum potassium 2.9-3.9 mEq/L) and hypothyroidism were noted in some patients.

Findings:

• Electrocardiograms (ECGs) revealed prominent U waves, QUc prolongation, and ST-T wave abnormalities.
• Syncopal episodes were attributed to ventricular tachycardia and fibrillation, unresponsive to conventional antiarrhythmics.

Implications:

• Liquid protein diets can induce reversible QUc prolongation, leading to life-threatening arrhythmias.
• Treatment may involve agents that shorten the QTc interval.
• Clinical caution is warranted when prescribing liquid protein diets for obesity management.