Information from Graphical Analysis of Heart Rate Variability using Chaos Theory

Heart period continually varies from beat to beat as a result of autonomic effects on the sinoatrial node; these changes can be computed as heart rate variability (HRV). HRV has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration � the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Additionally, following a premature ventricular beat, reproducible variations take place in RR interval as a result of baroreflex mediated autonomic effects on the sinoatrial node, which can be gauged as heart rate turbulence (HRT). Apparently, impaired autonomic task as gauged through HRV and HRT are reliable in the prediction of adverse results within clinical surroundings. The ability of decreased HRV and HRT in the prediction of adverse results has been justified by their reliance on vagal mechanisms, which are capable of echoing an improved sympathetic and a decreased sinus node�s vagal modulation thereby promoting cardiac electrical instability.