Determination of the frequency bands for heart rate variability: Studies on the intact and isolated rabbit hearts

There are many different methods for diagnosis of cardiac disorders. One of them is spectral analysis of heart rate variability (HRV). Its frequency bands are standardized only for human hearts. The present study is focused on definition of frequency bands in isolated hearts of New Zealand rabbits and on analysis of changes of these bands caused by myocardial ischemia. The results of the study show that HRV of isolated hearts differs from that of intact hearts and the changes depend on the experiment phase (control, ischemia, and reperfusion). In particular, the limit between LF (low frequency) and HF (high frequency) bands is not constant in ischemic periods and reaches the same value in each reperfusion period. Thus, it is necessary to take into consideration anatomical and physiological differences between intact and isolated hearts when analysis of HRV is used for studying the heart function.