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Heart rate variability visualized with R-R interval changes Electrocardiogram (ECG) recording of a canine heart that illustrates beat-to-beat variability in R–R interval (top) and heart rate (bottom). Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the ...
In the context of electrocardiography, the rate of the healthy heart is normally tightly controlled by the body's regulatory mechanisms (specifically, by the autonomic nervous system). Several research papers [ 4 ] [ 5 ] demonstrate the potential of ECG signal-based Poincaré plots in detecting heart-related diseases or abnormalities.
Sedation, respiratory depression and hypotension due to a reduction in systematic vascular resistance, and an increase in heart rate can occur. [23] [41] If intravenous midazolam is given too quickly, hypotension may occur. A "midazolam infusion syndrome" may result from high doses, is characterised by delayed arousal hours to days after ...
This natural variation is known as heart rate variability (HRV). However, certain cardiac conditions may cause the individual IBI values to become nearly constant, resulting in the HRV being nearly zero. This can happen, for example, during periods of exercise as the heart rate increases and the beats become regular.
The HR is often used to compute the heart rate variability (HRV) a measure of the variability of the time interval between heartbeats. HRV is often used in the clinical field [ 6 ] to diagnose and monitor pathological conditions and their treatment, but also in the affective computing research to study new methods to assess the emotional state ...
In most cases, vagal tone is not measured directly. Instead the processes affected by the vagus nerve – specifically heart rate and heart rate variability – are measured and used as a surrogate for vagal tone. Increased vagal tone (and thus vagal action) is generally associated with a lower heart rate and increased heart rate variability.
QT interval variability (QTV) refers to the physiological phenomenon of beat-to-beat fluctuations in QT interval of electrocardiograms. Increased QTV appears to be a marker of arrhythmic and cardiovascular death; it may also play a role for noninvasive assessment of sympathetic nervous system activity.
In statistical quality control, the individual/moving-range chart is a type of control chart used to monitor variables data from a business or industrial process for which it is impractical to use rational subgroups. [1] The chart is necessary in the following situations: [2]: 231