WAVELET ANALYSIS OF HEART RATE VARIABILITY. New Method of Studying the Heart's Function
Posted by bmhegde on 1
Conventional electrocardiogram is the sum total of the millions of cardiac cell depolarization potentials. They are being recorded; using twelve surface leads (ECG), based on the Einthovan's triangle principle. The whole process represents just about a few seconds recording of the above mentioned potentials at any given time. Many times the procedure is done over a period of a day or two; the latter is called Holter monitoring. The graph is then interpreted using linear mathematical rules. This complicated wave structure is artificially split into parts, like the PR interval and ST segment etc. Researchers have been looking for better methods to have more positive predictability. The present study is an attempt in that direction. "Doctors have been predicting the unpredictable" all these years was the observation of a physicist in a recent study.1
No organ of the human body works in isolation, although in reductionist science, organ based specialties have developed to the detriment of patient care! The various organs of the human body work in tandem having been "mode-locked" to one another. Mode locking makes it possible for the most dominant rhythm to control all other rhythms in the human body. The most dominant rhythm is the rhythm of breathing. Heart rhythm is, therefore, mode-locked to breathing. This could be made out in children even by the nurse, called sinus arrhythmia, wherein the pulse goes fast during inspiration and slows down during expiration. However, this becomes less marked as age advances. If one could analyze the heart rhythm more carefully using non-linear methods, one sees this happening even right up to the time of death. The intensity varies depending on the health of the whole system. Heart rate variability (HRV) is one such measure that gives a good indication of the health of the cardiovascular system.
We have gone a step further in this study. Instead of analyzing the whole wave pattern, we have studied the wavelet analysis. The latter is much more accurate measure of the ECG pattern. Coupled with mode locking, represented by HRV, wavelet analysis could assess the heart's function much more accurately. This enables better prediction of the future events possible, although predicting the future with one hundred per cent accuracy in a dynamic organism needs the total initial knowledge of the organism.