Onset of Depressed Heart Work is Correlated with the Increased Heart Rate and Shorten QT-Interval in High-Carbohydrate Fed Overweight Rats

Mechanical activity of the heart is adversely affected with metabolic syndrome (MetS) characterized with increased body-mass and marked insulin-resistance. Herein, we examined effects of high-carbohydrate intake on cardiac functional abnormalities via evaluating in situ heart-work, heart-rate and electrocardiograms (ECG) in rats. MetS is induced in Wistar male rats by adding 32% sucrose for 22-24 weeks and confirmed with insulin-resistance, increased body-weight, blood glucose and insulin, systolic and diastolic blood pressures besides significant left ventricular integrity-lost and increased connective-tissue around myofibrils. Analysis of in situ ECG-recordings showed markedly shorten QT-interval and depressed QRP with increased heart-rate. We also observed augmented oxidative stress and decreased antioxidant defense characterized with decreases in serum total thiol-level and attenuated paraoxonase and arylesterase activities. Our data clearly indicate that increased heart-rate and shortened QT-interval concomitant with higher left ventricular developed pressure responses to β-adrenoreceptor stimulation as a result of less cAMP-release could be regarded as natural compensation mechanisms in overweight MetS rats. Since MetS leads further to persistent insulin-resistance and obesity, one should get into consideration these important facts associated with onset of the depressed heart-work, the increased heart-rate and shorten QT-interval in high-carbohydrate intake, which will possible lead to more deleterious effects on mammalian heart.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author