Basic concept of HRV heart rate variability

1 HRV is just the time difference between successive cardiac cycles. By listing the differences between each cardiac cycle, we can see that many seemingly disordered parameters reflect the continuous instantaneous fluctuation of heart rate. The fluctuation of heart rate is not accidental, but a response to different physiological conditions or some pathological conditions, which is regulated by neurohumors in the body.

2.2 HF component. HRV reflects the heart rate fluctuation caused by the modulation of cardiac vagus nerve fiber conduction, which is also called "respiratory arrhythmia" (RSA) in the literature. Respiratory activity regulates heart rate through central mechanism and mechanical influence. The peak height of HRV heart failure is significantly related to the modulation degree of vagus nerve efferent activity on heart rate.

Spectrum analysis shows that heart rate variability generally includes high frequency (HF) and low frequency (LF), and some scholars further divide LF into ultra-low frequency and low frequency. Among them, the high-frequency component is synchronous with respiratory movement, so it is also called respiratory component, which appears every 3 seconds. Scholars believe that high-frequency components reflect parasympathetic nerve function, while the ratio of low-frequency components to high-frequency components (LF/HF) reflects sympathetic nerve activity.