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Components of heart rate variability have attracted considerable attention in psychology and medicine and have become important dependent measures in psychophysiology and behavioral medicine. Quantification and interpretation of heart rate variability, however, remain complex issues and are fraught with pitfalls. The present report (a) examines the(More)
BACKGROUND Identification of high-risk patients after acute myocardial infarction is essential for successful prophylactic therapy. The predictive accuracy of currently used risk predictors is modest even when several factors are combined. Thus, establishment of a new powerful method for risk prediction independent of the available stratifiers is of(More)
BACKGROUND Decreased vagal activity after myocardial infarction results in reduced heart-rate variability and increased risk of death. To distinguish between vagal and sympathetic factors that affect heart-rate variability, we used a signal-processing algorithm to separately characterise deceleration and acceleration of heart rate. We postulated that(More)
AIMS To determine the biological and behavioural factors linking work stress with coronary heart disease (CHD). METHODS AND RESULTS A total of 10 308 London-based male and female civil servants aged 35-55 at phase 1 (1985-88) of the Whitehall II study were studied. Exposures included work stress (assessed at phases 1 and 2), and outcomes included(More)
Sudden cardiac death (SCD) remains a daunting problem. It is a major public health issue for several reasons: from its prevalence (20% of total mortality in the industrialized world) to the devastating psycho-social impact on society and on the families of victims often still in their prime, and it represents a challenge for medicine, and especially for(More)
BACKGROUND To examine the relationship between reduced heart rate variability (HRV) and cognitive function in middle-aged adults in the general population. METHODS HRV, in both time and frequency domains, and cognitive functioning were measured twice in 5,375 male and female participants of the UK Whitehall II study (mean ages = 55 and 61 years,(More)
BACKGROUND The stratification of post-myocardial infarction (MI) patients at risk of sudden cardiac death remains important. The aim of the present study was to assess the prognostic value of novel T-wave morphology descriptors derived from resting 12-lead ECGs. METHODS AND RESULTS In 280 consecutive post-MI patients, a 12-lead ECG was recorded before(More)
BACKGROUND Laboratory and clinical studies suggest that the autonomic nervous system responds to chronic behavioral and psychosocial stressors with adverse metabolic consequences and that this may explain the relation between low social position and high coronary risk. We sought to test this hypothesis in a healthy occupational cohort. METHODS AND RESULTS(More)
Standard time and frequency parameters of heart rate variability (HRV) describe only linear and periodic behaviour, whereas more complex relationships cannot be recognised. A method that may be capable of assessing more complex properties is the non-linear measure of 'renormalised entropy.' A new concept of the method, RE(AR), has been developed, based on a(More)
The time lag of the QT interval adaptation to heart rate changes (QT/RR hysteresis) was studied in 40 healthy subjects (18 females; mean age, 30.4+/-8.1 yr) with 3 separate daytime (>13 h) 12-lead electrocardiograms (ECG) in each subject. In each recording, 330 individual 10-s ECG segments were measured, including 100 segments preceded by 2 min of heart(More)