Cardiac Autonomic Alteration and Metabolic Syndrome: An Ambulatory ECG-based Study in A General Population

Yan Ma,Ping-Huei Tseng,Ming-Shiang Wu,Andrew Ahn,Yi-Lwun Ho,Ming-Fong Chen,Chung-Kang Peng

doi:10.1038/srep44363

Abstract

Metabolic syndrome (MetS) has been associated with chronic damage to the cardiovascular system. This study aimed to evaluate early stage cardiac autonomic dysfunction with electrocardiography (ECG)-based measures in MetS subjects. During 2012–2013, 175 subjects with MetS and 226 healthy controls underwent ECG recordings of at least 4 hours starting in the morning with ambulatory one-lead ECG monitors. MetS was diagnosed using the criteria defined in the Adult Treatment Panel III, with a modification of waist circumference for Asians. Conventional heart rate variability (HRV) analysis, and complexity index (CI1–20) calculated from 20 scales of entropy (multiscale entropy, MSE), were compared between subjects with MetS and controls. Compared with the healthy controls, subjects with MetS had significantly reduced HRV, including SDNN and pNN20 in time domain, VLF, LF and HF in frequency domain, as well as SD2 in Poincaré analysis. MetS subjects have significantly lower complexity index (CI1–20) than healthy subjects (1.69 ± 0.18 vs. 1.77 ± 0.12, p < 0.001). MetS severity was inversely associated with the CI1–20 (r = −0.27, p < 0.001). MetS is associated with significant alterations in heart rate dynamics, including HRV and complexity.

Highlights

Reciprocal reinforcement of insulin resistance[14,15,16] and sympathetic activity[17,18,19] plays an important role in the pathophysiology of cardiac dysfunction
We hypothesized that subjects with Metabolic syndrome (MetS) may have early cardiac autonomic dysfunction in terms of alterations of heart rate dynamics, which may further lead to significant cardiovascular comorbidities and complications
These findings indicate reduced heart rate variability and lower complexity in MetS group than healthy group

Summary

Introduction

Reciprocal reinforcement of insulin resistance[14,15,16] and sympathetic activity[17,18,19] plays an important role in the pathophysiology of cardiac dysfunction. Cardiac autonomic function can be evaluated non-invasively with ECG-based measurements. Entropy measurement is considered an important index for complexity. Multiscale entropy (MSE)[26,27,28] has been widely used to evaluate human health conditions on a system level, but has not yet been applied in subjects with MetS. We hypothesized that subjects with MetS may have early cardiac autonomic dysfunction in terms of alterations of heart rate dynamics, which may further lead to significant cardiovascular comorbidities and complications. We compared various ECG-derived measurements of cardiac autonomic functions between subjects with and without MetS. We tested the clinical utility of complexity index in the evaluation of the presence and the severity of MetS in the general population

Objectives

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Conclusion