Nagy D, DeMeersman R, Gallagher D, Pietrobelli A, Zion A S, Daly D, Heymsfield S B
Obesity Research Center, St. Luke's-Roosevelt Hospital, New York, NY 10025, USA.
Obes Res. 1997 Nov;5(6):531-7. doi: 10.1002/j.1550-8528.1997.tb00573.x.
Weight reduction, either by dietary or surgical means, is associated with prolongation of the heart rate corrected QT interval (QTc = QT/R-R0.5) and, on occasion, sudden death. Screening subjects with obesity before weight loss for prolonged QTc intervals is an accepted practice, although at present, there are no guidelines for whether subjects should be fasting before electrocardiogram (EKG) evaluation. The aim of this study was to test the hypothesis that EKG QTc interval duration is independent of meal ingestion. The hypothesis was tested in 11 healthy subjects who ingested a 500-kcal formula meal. A small decrease in absolute QT interval and a steady decline in R-R interval were observed for up to 60 minutes after formula ingestion. The QTc interval increased above baseline at 15 minutes (p < 0.007) after meal, a change that persisted for the 1-hour postmeal observation period. Spectral analysis of EKG R-R intervals (low-/high-frequency amplitude ratio) indicated a change in cardiac autonomic flow after meal ingestion. The QTc interval did not lengthen and R-R low-/high-frequency amplitude ratio remained unchanged in eight subjects evaluated in a similar manner but in whom isovolumic amounts of water replaced the meal. These observations suggest that (1) cardiac repolarization changes with fasting and feeding, (2) the QTc interval is influenced by meal intake, and (3) the autonomic nervous system may play a role in meal-related QTc changes. These findings have implications for the evaluation of patients with obesity before starting and during weight loss treatment.
通过饮食或手术方式减轻体重与心率校正QT间期（QTc = QT/R-R0.5）延长有关，有时还与猝死有关。在减肥前对肥胖受试者进行QTc间期延长的筛查是一种公认的做法，尽管目前对于在进行心电图（EKG）评估前受试者是否应禁食尚无指导原则。本研究的目的是检验EKG QTc间期持续时间与进餐摄入无关这一假设。该假设在11名摄入500千卡配方餐的健康受试者中进行了测试。摄入配方餐后长达60分钟观察到绝对QT间期略有下降，R-R间期持续下降。餐后15分钟时QTc间期高于基线水平（p < 0.007），这一变化在餐后1小时观察期内持续存在。对EKG的R-R间期进行频谱分析（低频/高频振幅比）表明，进餐摄入后心脏自主神经活动发生了变化。在以类似方式评估的另外8名受试者中，用等容量的水替代餐食，QTc间期未延长，R-R低频/高频振幅比也未改变。这些观察结果表明：（1）心脏复极随禁食和进食而变化；（2）QTc间期受进餐摄入影响；（3）自主神经系统可能在与进餐相关的QTc变化中起作用。这些发现对于在开始减肥治疗前及治疗期间对肥胖患者的评估具有重要意义。
