Objectives: The objectives were to evaluate QT interval (QTc) and QT-interval dispersion (QTd) in severely obese individuals and to determine the effects of biliopancreatic diversion (BPD) and weight loss after BPD on ventricular repolarization parameters.
Background: People with severe obesity (SO) have a 50% to 100% increased risk of death associated with a 1.6-fold increased risk of sudden death. BPD surgery induces rapid and considerable weight loss through severe lipid malabsorption, thus achieving long-term weight control.
Research methods and procedures: A total of 85 subjects with SO (age, 42 +/- 12 years; 66 females; mean body weight, 120 +/- 29 kg; BMI, 45 +/- 11 kg/m(2)) of 330 who had a bariatric surgical consultation between January 2001 and July 2002 were enrolled. Inclusion criteria were sinus rhythm, unremarkable 12 leads surface electrocardiogram, no atrioventricular blocks and/or bundle branch blocks, normal serum electrolyte profile, and no medical therapies exerting known effects on QTc. Exclusion criteria were previous diagnosis of coronary artery disease, known cardiovascular disease, atrial fibrillation or any other known cardiac arrhythmias, cancer, or renal dysfunction.
Results: A total of 86% of patients had QTc >440 ms and/or QTd >60 ms. Subjects with SO showed a mean maximum QTc of 446 +/- 28 ms and a mean QTd of 52 +/- 20 ms. A close correlation was found between QTc and QTd (p < 0.0001; R(2) = 0.33). One month after BPD, mean QTc was 420 ms and remained stable at follow-up; QTd was 32 ms at 1 and 6 months and became 35 ms at 1 year.
Conclusions: Ventricular repolarization abnormalities are significantly increased in subjects with SO. Reduction of QT abnormalities after BPD is independent of weight loss and is caused by the 100% reduction of glucose plasma shortly after surgery. This effect may be related to surgical interruption of the entero-insular axis.