The relationship between QTc changes and nutrition during weight loss after gastroplasty

Electrocardiograms, serum electrolytes, plasma concentrations of pre-albumin and retinol-binding globulin, and dietary intakes were analyzed in 22 women during weight loss after gastroplasty surgery for morbid obesity. QT interval corrected for heart rate (QTc) was prolonged (greater than 0.44 sec) in 32% (95% confidence limits 14-55%) on one or more occasions. No clinical or electrocardiographic complications were seen. Occurrence of QTc prolongation was significantly (p less than 0.05) associated with protein intake below recommendation and with low plasma pre-albumin concentrations. QTc prolongation was not associated with mineral intake and occurred in spite of normal serum levels of calcium (uncorrected and albumin-corrected), magnesium, potassium and sodium. Because QTc prolongation may precede fatal arrhythmias, adequate protein intake is mandatory during weight reduction.