Search results
Results from the WOW.Com Content Network
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 ...
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 ...
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 ...
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 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.
Examples of used parameters are blood pressure, heart rate, heart rate variability, photoplethysmography and skin conductance. Essentially, physiologic parameters are measured in order to assess sympathetic tone as a surrogate measure of stress. Intraoperative neurophysiological monitoring can also be used.
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.
Effect on heart rate variability [ edit ] The baroreflex may be responsible for a part of the low-frequency component of heart rate variability , the so-called Mayer waves , at 0.1 Hz.