Heart rate variability: for real doctors. Translation from the Russian version of the book, published at Kharkiv, 2010, 131 p.
The basics and practice of the clinical use of the technology of heart rate variability are outlined for doctors of all specialties and students of medical faculties of universities.
The study of HRV is based on the measurement of time RR intervals or cardiointervals of an electrocardiogram (ECG) and the construction of a rhythmogram on their basis with its subsequent analysis by various mathematical methods.
For these purposes, each QRS complex determines in continuous ECG recording and all subsequent RR – intervals measure with the calculation of the so-called normal intervals (NN) between adjacent QRS complexes. All processes from detecting ECG R-waves to measuring the duration of cardiointervals (with an accuracy of at least 1 ms) performed by software.
On the rhythmogram, each vertical line corresponds to the duration of the corresponding RR – interval. The length of cardio-intervals varies from cycle to cycle (varies).
The nature of these per-cycle changes in the length of RR-intervals completely determines by the state of regulation and reflects it.
Note that the rhythmogram envelope is an oscillatory or wave function.
This understanding of changes in cardiac rhythm makes it possible to apply methods developed for oscillatory functions to their research.