In hypertensive patients the presence of non-sustained ventricular tachycardia has prognostic value.
Background-Oxidation of LDL plays a role in endothelial dysfunction. Paraoxonase, an enzyme present on HDL, protects LDL against oxidation. Paraoxonase activity is genetically determined in part, and 3 genotypes have been described with variable enzymatic activity. We hypothesized that the paraoxonase polymorphism might influence endothelial function. Methods and Results-Twenty-seven patients with clinical manifestations of coronary artery disease underwent provocative testing by intracoronary administration of serotonin. None of the coronary arteries studied had significant (Ͼ50%) stenosis. Ten patients had the QQ genotype and 17 had the QR genotype. At proximal segments, the mean percentage reduction in lumen diameter in response to serotonin was greater in QQ patients than in QR patients (10
Background: During insulin resistance, sympathetic nerve activity is increased. However insulin resistance is a common feature of obesity and essential hypertension, it is unclear if chronic hyperinsulinemia per se contributes to sympathetic overactivation. The purpose of our study was to explore the relationship between hyperinsulinemia and heart rate variability (HRV), a noninvasive tool to assess autonomic function, in obese and hypertensive subjects.Methods: 24-hour Holter ECC for HRV time and frequency domain analysis was performed in 77 patients: mean age 53 2 10 years; 52 men and 25 women; free of diabetes; without beta-blockers. The patient were divided into four groups according to three parameters, body mass index (BMI > 27 kg/m2 in the men and > 25 kg/m2 in the women defined obesity), arterial pressure, and insulinemia (fasting insulinemia > 25 mUI/L defined hyperinsulinemia). Twenty-seven patients were obese, hypertensive, with hyperinsulinemia; 28 patients obese, hypertensive, without hyperinsulinemia; 12 patients nonobese, hypertensive, without hyperinsulinemia; 10 patients obese, normotensive, without hyperinsulinemia. Results:In comparison with the three other groups , patients with hyperinsulinemia showed a significant decrease (P < 0.05) of SDNN and the power of total spectrum (0.01-1 Hz) band, which are indexes of global HRV, and a significant decrease (P < 0.005) of SD and the normalized power of the low frequency (0.04-0.1 5 Hz) band, both indexes reflecting sympathetic modulation of HRV. In contrast, no significant difference was observed among the four groups for indexes of HRV reflecting parasympathetic tone. These relations were independent of mean R-R. Fasting insulinemia was significantly (P < 0.0001) related with HRV in time domain (SDNN: r = -0.43; SD: r =-0.49) and spectral domain (total spectrum: r = -0.49; low frequency: r = -0.52).Conclusion: Chronic hyperinsulinemia appears to be an important determinant of HRV, particularly for the indexes reflecting sympathetic influence, independent of obesity and hypertension.A .N.E. 1999;4(3):316-324 hyperinsulinemia; heart rate variability; sympathetic overactivationDisturbed sympathetic nervous function may be of importance in the obese hypertensive subjects. Hyperinsulinemia could be the prime mover for sympathetic nervous activation in central obesity. In fact, it is now firmly established that acute, short-term insulin infusion1.2 and carbohydrate in-
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.