Abstract 3717: Corrected Qt Interval (qtc) Is Prolonged In Metabolic Syndrome Population
Background: Prolonged corrected QT interval (QTc) is a risk factor for cardiovascular disease, recent studies suggested that patients with metabolic syndrome had significantly higher values of QTc, but those studies were conducted in small sample, the result should be verified in large population.
Purpose: The study is to evaluate the relationship between QTc and metabolic syndrome in large population and to elucidate the possible pathophysiological mechanism.
Methods: The date was collected in a hypertensive survey in rural China, a total of 5467 individuals (men 3667, women 1800), aged from 20 to 80 years, were enrolled. Subjects with history of coronary heart disease, valvular heart disease, stroke, hepatic, renal, thyroid diseases and all kinds of arrhythmia (recorded by 12 lead ECGs) were excluded. Electrocardiogram was recorded and the value of QTc was calculated using Bazett’s equation. All individuals had ultrasonic echocardiograph examination and blood test. Using revised NCEP-ATPIII definition, 2271 individuals were diagnosed with metabolic syndrome, 3128 were non-metabolic syndrome.
Results: Both men and women individuals with metabolic syndrome had longer QTc than those with no metabolic syndrome (404.1±30.7ms vs 407.6±31.5 ms, p<0.05; 412.3±32.1 ms vs 417.5 ±32.4ms, p<0.001 respectively). The value of QTc increased with the number of abnormal metabolic parameters. After adjusted age and sex, QTc is negatively correlated to serum potassium concentration and positively correlated with posterior left ventricular wall and intraventricular septum in both men and womem.
Conclusion: Metabolic syndrome, even its single component is a risk factor for prolonged QTc. As metabolic syndrome individuals have lower serum potassium concentration and thicker posterior left ventricular wall and intraventricular septum than non-metabolic syndrome individuals, we propose that low serum potassium concentration and myocardial hypertrophy might play important roles in the development of prolonged QTc in metabolic syndrome.