We have previously shown that persons with low HRV showed potentiated startle responses to neutral stimuli. In the present study we replicated our prior findings and extended them to examine the effects of HRV on the startle magnitude to pictures that were presented outside of conscious awareness. A total of 85 male and female students were stratified via median split on their resting HRV. They...

electrocardiogram (ECG) is the most preferably used noninvasive test for diagnosis of cardiac rhythm. Irregular rhythm of heart beats is measured in terms of heart rate variability (HRV). Analysis of HRV plays an important role in automated diagnosis of cardiac status. This paper deals with development of an embedded system suitable for real time HRV analysis. A low cost embedded system for mon...

We examined the relationship between tonic--a correlate of self-regulatory functioning--and phasic cardiac vagal activity (indexed by heart rate variability; HRV) during a selective attentional task with varying levels of load. Participants detected a target letter among letter strings superimposed on either fearful or neutral face distractors. Letter strings consisted of six target letters und...

The study investigated whether supine-measured HRV indicators, and/or HRV indicators measured during orthostatic stress are related to conventional measures of exercise and performance ability such as VO(2max). Only two significant correlations (p<0.05) out of 30 tests were found between supine-determined HRV indicators and conventional measures. In contrast, fifteen of the 30 relationships cal...

This paper examines the past, present, and future use of the concept of historical range and variability (HRV) in landmanagement. The history, central concepts, benefits, and limitations of HRV are presented along with a discussion on the value of HRV in a changing world with rapid climate warming, exotic species invasions, and increased land development. This paper is meant as a reference on t...

As the predominant aetiological agent of the common cold, human rhinovirus (HRV) is the leading cause of human infectious disease. Early studies showed that a monovalent formalin-inactivated HRV vaccine can be protective, and virus-neutralizing antibodies (nAb) correlated with protection. However, co-circulation of many HRV types discouraged further vaccine efforts. Here, we test the hypothesis...

We studied heart rate variability (HRV) using spectral analysis techniques in 58 adult patients recovering from general anaesthesia. The aim was to discover how HRV was affected by a variety of common preoperative, intraoperative and postoperative factors. ECG, respiration, level of consciousness, nausea, pain and arterial pressure were recorded during the first hour of recovery from general an...

The neurovisceral integration model (Thayer and Lane, 2000) proposes that vagally mediated heart rate variability (HRV)--an index of cardiac vagal tone--is associated with autonomic flexibility and emotional self-regulation. Two experiments examined the relationship between vagally mediated HRV and visual perception of affectively significant stimuli at different spatial frequencies. In Experim...

A computer program for advanced heart rate variability (HRV) analysis is presented. The program calculates all the commonly used time- and frequency-domain measures of HRV as well as the nonlinear Poincaré plot. In frequency-domain analysis parametric and nonparametric spectrum estimates are calculated. The program generates an informative printable report sheet which can be exported to various...

The heart rate signal contains useful information about the condition of the human heart which cannot be extracted without the use of an information processing system. Various techniques for the analysis of the heart rate variability (HRV) have been proposed, derived from diverse scientific fields. In this paper we examine theoretically and experimentally the most commonly used algorithms as we...