Erik K Grasser1, Barbara Ernst2, Martin Thurnheer2, Bernd Schultes3. 1. Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland. 2. eSwiss Medical and Surgical Center, Interdisciplinary Obesity Center, St. Gallen, Switzerland. 3. eSwiss Medical and Surgical Center, Interdisciplinary Obesity Center, St. Gallen, Switzerland. bernd.schultes@eswiss.center.
Abstract
BACKGROUND: A shortening of electrocardiographic QT interval has been observed in obese subjects after weight loss, but previous results may have been biased by inappropriate heart rate (HR) correction. METHODS: Electrocardiography (ECG) recordings of 49 (35 females) severely obese patients before and 12 months after Roux-en-Y gastric bypass (RYGB) surgery were analysed. QT interval (QTc) was calculated by using four different equations, i.e. Bazett, Fridericia, Framingham and Hodges. RESULTS: Irrespectively of the used correction formula, QTc interval length was reduced after the surgery (QTcBazett -31 ± 18 ms; QTcFridericia -12 ± 15 ms; QTcFramingham -14 ± 15 ms; QTcHodges -9 ± 15 ms; all Ps < 0.001), but QTcBazett reduction was significantly greater than the reduction in QTc calculated upon the other three equations (all Ps < 0.001). Moreover, changes in QTcBazett (P < 0.001) but not in QTcFridericia, QTcFramingham and QTcHodges (all Ps > 0.05) were significantly correlated with concurrent changes in HR. Multivariate regression analyses revealed a significant independent association of serum insulin levels with QTcFridericia, QTcFramingham and QTcHodges values (all Ps < 0.05) preoperatively, whilst changes in QTc interval length after the surgery were not consistently associated to concurrent changes in metabolic traits. CONCLUSIONS: Our data show that the extent of weight loss-associated QTc interval shortening largely depends on the applied HR correction equation and appears to be overestimated when the most popular Bazett's equation is used.
BACKGROUND: A shortening of electrocardiographic QT interval has been observed in obese subjects after weight loss, but previous results may have been biased by inappropriate heart rate (HR) correction. METHODS: Electrocardiography (ECG) recordings of 49 (35 females) severely obesepatients before and 12 months after Roux-en-Y gastric bypass (RYGB) surgery were analysed. QT interval (QTc) was calculated by using four different equations, i.e. Bazett, Fridericia, Framingham and Hodges. RESULTS: Irrespectively of the used correction formula, QTc interval length was reduced after the surgery (QTcBazett -31 ± 18 ms; QTcFridericia -12 ± 15 ms; QTcFramingham -14 ± 15 ms; QTcHodges -9 ± 15 ms; all Ps < 0.001), but QTcBazett reduction was significantly greater than the reduction in QTc calculated upon the other three equations (all Ps < 0.001). Moreover, changes in QTcBazett (P < 0.001) but not in QTcFridericia, QTcFramingham and QTcHodges (all Ps > 0.05) were significantly correlated with concurrent changes in HR. Multivariate regression analyses revealed a significant independent association of serum insulin levels with QTcFridericia, QTcFramingham and QTcHodges values (all Ps < 0.05) preoperatively, whilst changes in QTc interval length after the surgery were not consistently associated to concurrent changes in metabolic traits. CONCLUSIONS: Our data show that the extent of weight loss-associated QTc interval shortening largely depends on the applied HR correction equation and appears to be overestimated when the most popular Bazett's equation is used.
Authors: A Gastaldelli; M Emdin; F Conforti; S Camastra; E Ferrannini Journal: Am J Physiol Regul Integr Comp Physiol Date: 2000-12 Impact factor: 3.619