Heart rate variability are needed to address the LF component (with a lower bound of 0.04 Hz). Although time domain methods, especially the SDNN and RMSSD methods, can be used to investigate recordings of long durations, a substantial part of the long-term variability is day–night differences. Thus, long-term recordings analyzed by time domain methods should contain at least 18 hours of analyzable ECG data that include the whole night. Although cardiac automaticity is intrinsic to various pacemaker tissues, heart rate and rhythm are largely under the control of the autonomic nervous system. The parasympathetic influence on heart rate is mediated via release of
Cardiac contractility modulation which delivers an electrical signal with the intention to result in cardiac contraction, the Cardiac contractility modulation treatment applies the NES, adjusted to and synchronized with the electrical action in the cardiac cycle. In Cardiac contractility modulation therapy, electrical stimulation is applied to the cardiac muscle during the absolute refractory period. In this phase of the cardiac cycle, electrical signals cannot trigger new cardiac muscle contractions, hence this type of stimulation is known as a non-excitatory stimulation. However, the electrical signals increase the influx of calcium ions into the cardiac muscle cells (cardiomyocytes). In contrast to other electrical stimulation treatments