Carella M J, Mantz S L, Rovner D R, Willis P W, Gossain V V, Bouknight R R, Ferenchick G S
Department of Medicine, Michigan State University, E. Lansing, USA.
Int J Obes Relat Metab Disord. 1996 Oct;20(10):938-42.
To determine the prevalence of QT interval prolongation in patients referred to an outpatient clinic for treatment of obesity; and to describe the change in the QT interval during rapid weight loss with a very-low-calorie diet.
Retrospective and prospective review of charts and electrocardiograms.
Five hundred twenty-two obese patients (411 female, 112 males) with a mean age 44 (18-78 y) and a mean initial weight of 116 kg (63-285 kg) completing 26 weeks of treatment between September, 1989 through to December, 1993.
We reviewed the EKGs of all patients and serially monitored the QTc if greater than 0.44 s or if more than 23 kg was lost during treatment. The QTc interval was calculated with Bazzett's formula using both a manual method and an automated software program. In some patients, body composition was measured by hydrodensitometry.
The QTc interval before treatment was 0.42 +/- 0.026 s by manual measurement and 0.41 +/- 0.021 s by automated measurement. Forty-one to 53% of patients showed a QTc interval of greater than 0.42 s and 10-24% demonstrated moderate prolongation (> 0.44 s). In those patients for whom repeat EKG were performed, QTc showed shortening with weight loss by both methods (mean +/- s.e. of 0.42 +/- 0.003 to 0.41 +/- 0.003 s, P < 0.01 manually and 0.41 +/- 0.003 to 0.40 +/- 0.003 s, p < 0.005 by automated program). Analyses were repeated excluding 179 patients with a cardiovascular-related diagnosis or intraventricular block and the results were similar. By regression analysis, gender and fat mass (FM) percentage above normal predicted the QTc.
QT Interval prolongation is common in obesity. For each 50% increase in FM% above normal, there is a 5 ms increase in the QTc above a 'normal' upper limit of 0.40 and 0.38 s in women and men, respectively. Moreover, the QT interval shortens with weight loss. This change may represent an additional benefit of weight loss along with the improvement in other cardiovascular risk factors.
确定在因肥胖症前往门诊治疗的患者中QT间期延长的患病率；并描述采用极低热量饮食快速减重期间QT间期的变化。
对病历和心电图进行回顾性和前瞻性分析。
522例肥胖患者（411例女性，112例男性），平均年龄44岁（18 - 78岁），初始平均体重116千克（63 - 285千克），于1989年9月至1993年12月期间完成了26周的治疗。
我们查阅了所有患者的心电图，若QTc大于0.44秒或治疗期间体重减轻超过23千克，则对QTc进行连续监测。QTc间期采用Bazzett公式通过手动方法和自动化软件程序计算得出。部分患者通过水下密度测定法测量身体成分。
手动测量治疗前QTc间期为0.42±0.026秒，自动测量为0.41±0.021秒。41%至53%的患者QTc间期大于0.42秒，10%至24%的患者表现为中度延长（>0.44秒）。在进行重复心电图检查的患者中，两种方法均显示QTc随体重减轻而缩短（手动测量时，平均±标准误从0.42±0.003秒降至0.41±0.003秒，P<0.01；自动测量时，从0.41±0.003秒降至0.40±0.003秒，P<0.005）。排除179例患有心血管相关诊断或室内传导阻滞的患者后重复分析，结果相似。通过回归分析，性别以及高于正常水平的脂肪量（FM）百分比可预测QTc。
QT间期延长在肥胖症中常见。女性和男性高于正常水平的FM%每增加50%，QTc分别比“正常”上限0.40秒和0.38秒增加5毫秒。此外，QT间期随体重减轻而缩短。这种变化可能代表了减重除改善其他心血管危险因素之外的额外益处。
