Effect of the Postural Challenge on the Dependence of the Cardiovascular Control Complexity on Age

Abstract

Short-term complexity of heart period (HP) and systolic arterial pressure (SAP) was computed to detect age and gender influences over cardiovascular control in resting supine condition (REST) and during standing (STAND). Healthy subjects (n = 110, men = 55) were equally divided into five groups (21-30; 31-40; 41-50; 51-60; and 61-70 years of age). HP and SAP series were recorded for 15 min at REST and during STAND. A normalized complexity index (NCI) based on conditional entropy was assessed. At REST we found that both NCIHP and NCISAP decreased with age in the overall population, but only women were OPEN ACCESSEntropy 2014, 16 6687 responsible for this trend. During STAND we observed that both NCIHP and NCISAP were unrelated to age in the overall population, even when divided by gender. When the variation of NCI in response to STAND (ΔNCI = NCI at REST-NCI during STAND) was computed individually, we found that ΔNCIHP progressively decreased with age in the overall population, and women were again responsible for this trend. Conversely, ΔNCISAP was unrelated to age and gender. This study stresses that the complexity of cardiovascular control and its ability to respond to stressors are more importantly lost with age in women than in men.

Entropy Measures in the Assessment of Heart Rate Variability in Patients with Cardiodepressive Vasovagal Syncope

“…Therefore, the proportion of men and women in our study mirrors the unequal proportion of both sexes in our population of vasovagal patients, which is in agreement with data from previous studies analyzing the epidemiology of reflex syncope in relatively young populations [43,44]. However, the complexity of the heart rate strongly depends on age and gender [45], which is confirmed by very recent studies using conditional entropy [46], as well as symbolic dynamics methods [47]. Because of the small number of patients in each group, we are not able to perform additional analyses focused on age and gender, but further studies are needed to check whether differences in entropy-based parameters between the NEG and VVS_2 groups are gender dependent.…”

Maximal expiratory pressure and Valsalva manoeuvre do not produce similar cardiovascular responses in healthy men

“…However, according to a recent study carried out by our group (Catai et al . ), changes to autonomic cardiac regulation become evident in men after the age range of 41–50 years and explain the age range (middle aged) adopted for this study.…”

“…; Catai et al . ) that affect their function. Based on these changes, several studies have shown that MEP (Black & Hyatt, ; Chaunchaiyakul et al .…”

“…The cardiovascular responses to the VM are mediated by the autonomic nervous system and vary according to sympathetic and parasympathetic activation and/or inhibition, which makes this manoeuvre a useful tool to evaluate the function of this system (Freeman, 2006;Low et al 2013). This dynamic pattern of cardiovascular autonomic activity is determined by different stimuli, such as breathing, muscle contraction, stimulation of arterial baroreceptors (Huang et al 2007;Wada et al 2014), postural changes (Singer et al 2001;Minatel et al 2012) and ageing (Laitinen et al 2004;Huang et al 2007;Milic et al 2009;Takahashi et al 2012;Catai et al 2014).…”

Entropy in Investigation of Vasovagal Syndrome in Passive Head Up Tilt Test

“…The unequal proportion in gender reflects the occurrence of syncope in the general population [47,48]. We are also aware that the hemodynamic parameters and their complexity are age-dependent [49,50]. Accounting for gender and age in the analysis would require a breakdown of the study population into small subgroups, not allowing them to reach statistical significance.…”