Relationship Between The Burden Of Premature Ventricular Contractiong And The Heart Rate Variability

Background:PVCs is one commonly clinical type of cardiac arrhythmia. High-burden PVCs tend to cause the structural and functional disorder of ventricles and even to bring about cardiac failure. In recent year, with the development of research into autonomic nervous function such as the heart rate variability, it is found that there is a close relationship between dysfunction of autonomic nerve and PVCs. As medication effects of PVCs are not satisfying, high-burden PVCs are usually treated by radiofrequency ablation. Thus, treatment success has increased and recurrence rate declined.Objective:This paper aims to research the relationship between idiopathic PVCs of different burden and the heart rate variability. It also discusses the occurrence mechanism idiopathic PVCs and explores the value of the heart rate variability in predicting cardiac risk of PVCs of different burden. Methods:(1)Retrospective analysis is applied to 117 patients who have had 24h-holter in our hospital. According to the different amount of PVCs burden, 117 patients will be classified in four groups, namely low-burden group (1% to 10%), medium burden group (10% to 20%) and high burden group (more than 20%).We choose at random the patients as normal controls who have had 24-hour electrocardiogram examinations and whose PVCs’burden are less than 1%. Then we compare the following indicators of heart rate variability:time domain methods indicator, frequency domain methods indicator, heart rate turbulence and deceleration capacity of rate. Spearman correlation analysis is adopted to evaluate the relevancy between the PVCs amount and the indicators of heart rate variability. (2) indications of 17 PVCs patients before they have had radiofrequency ablationare and those after they had radiofrequency ablationare are compared.Results:(1) There is no obvious difference among PVCs of different burden in time domain analysis. However, frequency domain analysis indicates that there is apparent difference between high-burden group, medium-burden group and their corresponding control group in LF and HF index (P<0.05). Obvious differences are found among high-burden group, corresponding control group and low-load group in LF/HF. (2) Heart rate turbulence changes according to the different burden of PVCs. When low-risk, medium-risk and high-risk groups are respectively compared to their control groups, it is found that TS decreases and TO increases(P>0.05). (3) As the amount of PVCs burden increases, deceleration capacity of rate decreases. Compared to the control groups, DC of high-burden and medium-burden obviously falls. DC in high-burden group falls in contrast to low-burden group (P<0.05). (4) There is a weak negative correlation between PVCs and D、TO、LF、BF、LF/HF、 PNN50.(5) There is no obvious change between time domain indicator and frequency domain indicator before radiofrequency ablation and those two indicators after radiofrequency ablation. TO and TS obviously decrease after the operation.Conclusions:(1)LF、HF、LF/HF of PVCs patients with different burden fall as their burden grows. Compared to control groups, TO increases as TS decreases.The phenomenon to indicate heart rate turbulencebecome worse. With the growth of PVCsburden, deceleration capacity of rate obviously falls. The autonomic dysfunction has more aggravated when the happening of PVCs increases. (2) The occurrence of PVCs is like to have a connection with the decrease of vagus nerve excitability. (3) It is shown that there is no evident change in heart rate variability and the dysfunction of autonomic nerve is hard to recover after radiofrequency ablation has treated PVCs.