Heart rate variability (HRV) refers to the number of time variations between the main and secondary cardiac cycles, the heart rhythm is not absolutely regular, the small difference between the two heart beats, can be used to reflect the physiological response of the body after being stimulated by exogenous stimulation, is an index to evaluate the mutual checks and balances between the sympathetic and vagus nerves, which has important value for the evaluation of the body's functional state, the diagnosis of various diseases, prognosis and efficacy evaluation. HRV responds to the activity of the autonomic nerves in vivo and is an indicator of the quantitative determination of the vagus nerve and sympathetic nervous system. The reduction of HRV is closely related to severe arrhythmias and sudden cardiac death.
HRV analysis methods: Linear and nonlinear analysis methods.
First, a linear indicator of heart rate variability
HRV determination is available in both the domain method and the frequency domain method.
1.1 Time Domain Analysis:
SDNN (standard diviation of NN ntervals): standard deviation of all normal sinus R-R interval at 24 hours, normal value SDNN>100ms;
SDANN (standard deviation of the averages of normal NN intervals in all 5-minute segments of the entirerecording): the standard deviation of the mean sinus R-R interval every 5-minute period over a 24-hour period;
RMSSD (root mean square of successive differences): Root mean square of all normal sinus R-R interval differences in 24 hours;
p50: Percentage of neighboring RR intervals greater than 50ms within 24h;
1.2 Frequency domain analysis:
VLF is very low frequency, reflecting auxiliary information of the sympathetic nervous system;
LF low frequency power, reflecting the activity of the sympathetic nervous system; reference value: 0.04-0.15Hz;
HF high frequency power, reflecting the activity of the parasympathetic nervous system (vagus nerve); reference value: 0.15-0.4 Hz
total power total energy, reflecting the overall activity of the autonomic nervous system;
LF/HF ratio LF/HF ratio, which reflects the overall balance between sympathetic and parasympathetic; reference values: 1-2.25; less than 0.5: parasympathetic hyperactivity; 0.5-1: parasympathetic activity; 2.25-3: sympathetic activity; greater than 3: sympathetic hyperactivity.
The physiological significance of the HRV linear index is basically clear, provided that the regulation of heart rate by the autonomic nerve of the heart is regarded as a linear process, while in fact, the regulation of heart rate is a nonlinear process.
Second, the heart rate variability nonlinear analysis method:
Ponkale interface;
Determination of entropy: reflects the degree of chaos of the system;
Fractal dimensions;
ECG scatter plot: Visually expresses the nonlinear kinetic characteristics of HRV, with qualitative and quantitative effects. In the Lorenz scatter chart, the heart rhythm of the same nature of the heart rhythm is gathered into a "attractor", and when the origin and location of the heart rhythm change, the new "attractor" is changed, so that the pattern of the Lorenz scatter chart is changed, which provides corresponding evidence for the diagnosis of arrhythmia. Heart rate variability time series have chaotic properties, and Lorenz scatter plots can
To view the full original text, please click on the link below or scan the QR code below:
https://jsp.365heart.com/detail/5D9D9C1A-E43D-4D17-86CF-E56F16E25718?resourceType=t_manager_resource_article
Scan the QR code below to enter the 365 Medical Network website to learn more:
Scan the QR code below to enter the 365 Medical Network public account to learn more:
Scan the QR code below to enter the 365 Medical Network subscription account to learn more: