Analysis Of Risk Factors Associated With Ventricular Arrhythmia Patients And Risk Prediction Of Sudden Cardiac Death

Objectives: This study explored the risk factors associated with left ventricular enlargement in patients with frequent premature ventricular contractions(PVCs)and their reversibility.And this study investigated the correlation between ventricular arrhythmias and autonomic function and provided a new approach to risk stratification in high-risk populations of sudden cardiac death.Methods: Patients with frequent PVCs(n=571)who presented to our center for radiofrequency catheter ablation were consecutively recruited.Patients with frequent PVCs were divided into two groups based on left ventricular end-diastolic diameter: left ventricular(LV)enlargement group(n=161)and LV normal group(n=410).Two groups were compared on their clinical parameters.Logistic regression analysis was used to predict the risk factors of LV enlargement in patients with frequent PVCs.At least 3-6 months after radiofrequency catheter ablation,echocardiography was performed to assess the reversibility of LV enlargement in patients with frequent PVCs.In addition,patients with underwent implantable cardioverter defibrillator(ICD)(n=156)were also recruited in this study.Patients with ICD implantation were divided into two subgroups according to ventricular tachyarrhythmia(VTA)events.Moreover,patients with frequent PVCs were divided into three subgroups based on the level of PVC burden.This study analyzed the difference in heart rate variability indices between different subgroups of patients with ICD and patients with frequent PVCs,respectively.Meanwhile,the changes in heart rate variability(HRV)indexes after radiofrequency catheter ablation in patients with frequent PVC were analyzed.Finally,the method of unadjusted Kaplan-Meier was used to estimate the difference in survival in the subgroups of patients with ICD implantation.The risk factors for all-cause mortality and VTA episodes of ICD implantation patients were evaluated using Cox proportional hazards regression models.Results: Multivariate analysis showed that female gender,increased N-terminal pro-brain natriuretic peptide(NT-pro BNP),decreased LVEF,increased 24-hour PVCs burden,increased standard deviation of normal to normal(SDNN),decreased the percentage of normal-to-normal intervals differing by more than 50ms(PNN50)were predictors for LV enlargement in patients with frequent PVCs.84.4%(54/64)of patients with LV enlargement at baseline had normalized their LV structure after ablation.The HRV indices of patients with frequent PVCs were significantly decreased after ablation(all p<0.05).Among patients implanted with a primary prevention ICD,most HRV indices of patients in the VTA group were significantly higher than those without the VTA group(all p<0.05).The survival rate of patients with implanted ICD with the characteristics of fragmented QRS decreased significantly.Increased heart rate on admission,decreased left ventricular ejection fraction,hyperlipidemia,and increased QRS duration were associated with an increased risk of allcause mortality.Multivariate Cox regression analysis showed that decreased age,increased heart rate on admission,increased left ventricular end-diastolic diameter,and hyperlipidemia were independent risk factors of VTA events in patients with ICD implantation.Conclusion: Female gender,increased level of NT-pro BNP,lower LVEF,higher PVC burden,increased sympathetic parameters SDNN,and reduced parasympathetic parameters PNN50 were the independent risk factors of LV enlargement in patients with frequent PVCs.LV enlargement induced by PVCs could be reversible after PVC elimination by ablation.In addition,studies have shown that ventricular arrhythmias are strongly associated with autonomic regulation.In addition,fragmented QRS was considered the risk factor for 6-year survival in ICD patients.Increased heart rate on admission and hyperlipidemia have predictive value for VTA events and all-cause mortality.It could optimize SCD risk stratification.