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Electrocardiogram
Published in Kayvan Najarian, Robert Splinter, Biomedical Signal and Image Processing, 2016
Kayvan Najarian, Robert Splinter
An important disease that is often detected in the frequency domain is sinus tachycardia. A sinus rhythm of higher than 100 beats per minute is called sinus tachycardia. Similar conditions often occur as a physiological response to physical exercise or physical stress, but, in diseased cases, the condition results from congestive heart failure. More specifically, if the sinus rhythm is irregular such that the longest PP or RR intervals exceed the shortest interval by 0.16 s, the situation is diagnosed as sinus arrhythmia. This condition is very common in all age groups but more common in teenagers and preteens who may have never considered having a heart disease. One potential origin for the sinus arrhythmia may be the vagus nerve, which regulates respiration as well as heart rhythm. The nerve is active during respiration and through its effect on the sinus node, causes an increase in heart rate during inspiration and a decrease during expiration.
Mental Workload, Stress, and Individual Differences: Cognitive and Neuroergonomic Perspectives
Published in Christopher D. Wickens, Justin G. Hollands, Simon. Banbury, Raja. Parasuraman, Engineering Psychology and Human Performance, 2015
Christopher D. Wickens, Justin G. Hollands, Simon. Banbury, Raja. Parasuraman
Autonomic measures constitute the third class of neuroergonomic measure. Of these, heart-rate variability has been the object of sustained study. Several investigators have examined different measures associated with the variability or regularity of heart rate as a measure of mental load. Variability is generally found to decrease as the load increases, particularly that variability which cycles with a period of around 10 seconds (0.1 Hz) (Mulder & Mulder, 1981). When this variability is associated specifically with the cycles resulting from respiration, the measure is termed sinus arrhythmia (Backs et al., 2003; Derrick, 1988; Mulder et al., 2003; Sirevaag et al., 1993; Vicente et al., 1987).
Historical Development of HRV Analysis
Published in Herbert F. Jelinek, David J. Cornforth, Ahsan H. Khandoker, ECG Time Series Variability Analysis, 2017
In 1936, Anrep, Pascual, and Rössler proposed that the HR sinus arrhythmia is caused by the regulation of cardiac vagal outflow involving the same neuronal processes that generate the respiratory rhythm and reside within the brainstem (Garcia et al. 2013). This was more or less the introduction of interaction analyses in the investigation of couplings within the ANS.
Bodies in mind: using peripheral psychophysiology to probe emotional and social processes
Published in Journal of the Royal Society of New Zealand, 2021
Gina M. Grimshaw, Michael C. Philipp
Cardiac activity can be measured with electrodes (typically two on the chest, and a ground on the abdomen) that produce the electrocardiogram (ECG), a moment-to-moment recording that is the sum of all electrical activity associated with the beating heart (for a comprehensive overview of cardiac psychophysiology, see Berntson et al. 2016). Each beat propels blood to the rest of the body. Optimally, heart rate is finely tuned to the body’s needs: too slow and the body may run short of resources, but too fast and we waste metabolic effort. Heart rate is controlled by both sympathetic and parasympathetic branches of the autonomic system; sympathetic activation generally increases heart rate, and parasympathetic activation generally decreases it. These systems act over different time scales, with the sympathetic system producing slow changes that occur over several seconds, while the parasympathetic system mediates rapid changes that can occur beat-to-beat. These rapid changes are made via the vagus nerve through the parasympathetic brake: application of the brake slows heart rate, while releasing it speeds heart rate. The interplay between these modulatory systems gives rise to heart rate variability (HRV), continual fluctuations in heart rate that meet changing demands (Laborde et al. 2017). High HRV reflects a well-calibrated system and is associated with both cardiac health and emotional well-being (Thayer et al. 2009; Kemp et al. 2010; Smith et al. 2017). In the lab, HRV can be measured in response to a challenge, but it can also be measured as a stable trait at rest. Even when still, heart rate fluctuates with respiration (increasing during inspiration, decreasing during exhalation), producing respiratory sinus arrhythmia (RSA). For this reason, resting HRV and RSA are often used as individual difference measures to predict psychological outcomes (Porges 2007; Thayer and Lane 2009).