Abstract 16637: Effect of Weight Loss on QTc And QTc Dispersion in Normotensive Severely Obese Patients With and Without Heart Failure
Objectives: To compare the corrected QT interval (QTc) and QTc dispersion in normotensive severely obese subjects with and without heart failure (HF) and to assess the effect of weight loss from bariatric surgery on QTc and QTc dispersion in such patients.
Methods: This was a prospective cohort study. Twenty-eight normotensive patients (mean age-40.6 years) with HF and 39 patients (mean age-38.7 years) without HF whose body mass index was ≥ 40kg/m2 were studied before and after substantial weight loss from bariatric surgery.QTc was measured on a standard 12 lead electrocardiogram using Bazett’s formula. QTc dispersion was calculated by subtracting the minimum from the maximum QTc on the 12 lead electrocardiogram. Electrocardiograms and transthoracic echocardiograms were performed prior to and at the nadir of post-operative weight loss.
Results: Mean QTc was significantly longer and QTc dispersion was significantly greater in subjects with HF than in those without HF (p<0.0001 for both). Substantial weight loss, produced significant reductions in mean QTc and QTc dispersion both subgroups (p<0.0001 for both). Multiple stepwise linear regression analysis identified pre-weight loss LV mass/height2.7 and presence or absence of HF as the strongest predictors of pre-weight loss QTc and QTc dispersion (p<0.001 for both). Weight loss-induced change (decrease) in LV mass/height2.7 was the strongest predictor of weight loss-induced changes (decreases) in QTc and QTc dispersion (p<0.0001 for both).
Conclusions: HF is an independent predictor of QTc and QTc dispersion in normotensive severely obese patients, possibly due to increased LV mass. Change (decrease) in LV mass resulting from weight loss independently predicts reduction in QTc and QTc dispersion in such patients.
- © 2013 by American Heart Association, Inc.