Clinical Study On The Onset Of Ventricular Arrhythmia

Part One Relation between Overload and Heart Rate and Circadian Distribution of Idiopathic Outflow Tract Premature Ventricular ContractionsBackground and objective Outflow tract premature ventricular contractions(OT-PVCs)are a very common arrhythmia.The analysis of circadian pattern and affecting factors could provide information to evaluate occurrence and optimal treatment.The present study is to investigate the association of OT-PVCs overload with heart rate(HR)and the circadian pattern.The analysis could provide information to evaluate occurrence of OT-PVCs.Methods One hundred and thirty five OT-PVCs patients were enrolled.Patients were divided into Groupl(<5000/24h),Group2(5000-10000/24h),Group3(10000-20000/24h),Group4(20000-30000/24h)and Group5(>30000/24h)based on the sum of the PVCs evaluated by the 24h Holter.The relationship between PVCs overload and mean HR was analyzed in each group.The distribution of PVCs was assessed by grouping the events into four time periods:6AM to 12PM,12PM to 6PM,6PM to 12AM,and 12AM to 6AM.Results In 135 subjects,there were 25 Groupl,24 Group2,30 Group3,28 Group4,and 28 Group5.PVCs were positively associated with mean HR(r=0.379,P<0.05),especially in Group3(r=0.561,P<0.05).The occurrence of PVCs had a trend of circadian variation.Only in group 3 and group 4,the occurrence of PVCs showed an apparent circadian variation with a nadir about at midnight.(P<0.05)Conclusion In certain overload of OT-PVCs(10000-30000/24h),an apparent circadian variation and evident correlations between PVCs and mean HR were found.Part TwoThe short-term effect of air pollution for ventricular arrhythmias recorded by home monitoring of implantable cardioverter defibrillatorsBackground and objective The HM system in ICD patients can help to monitor VAs and evaluate the association between air pollution and VAs.The present study is to investigate the acute effects of exposure to air pollution on ventricular arrhythmias(VTs)in China during different period of the day and month.Methods We reviewed patients with implantable cardioverter defibrillator(ICD)equipped with HM from February 2009 to May 2013 in China.325 patients were enrolled in the study.After 3 years follow-up period,530 VAs were recorded by HM of ICD.HM records of VAs matched with hourly measurements of air pollutant concentrations was used to investigate the association between VAs that occurred during different period of the day and month,and exposure to air pollution.The associations between hourly air pollution and VAs occurrence were analyzed during the time of 6:00-11:00,12:00-17:00,18:00-23:00,and 0:00-5:00.The relation between air pollutants and P-P variability was also explored.Results During the follow-up period,530 VAs events were observed.A significant risk of VAs was associated with an increase in PM2.5 at lag 2-6 hours(lag 2h,OR 1.013,95%CI 1.006-1.02,p<0.001;lag 6h,OR 1.01,95%CI 1.003-1.017,p=0.004).The association between air pollutants and VAs events shows a seasonal and circadian pattern.The elevated risk was associated with PM2.5 during 18:00-23:00 in autumn(OR 1.113,95%CI 1.04-1.191,p=0.002).Air pollutants(S02,03 and CO)were positively related with P-P variability(P<0.05),with a certain degree of interaction among the pollutants(P<0.001).Conclusions Exposures to air pollutants were significantly associated with VAs in ICD patients during certain period of the day and month based on geography.And it is partly related with the autonomic nervous system control.Part Three Analysis of Contact Force of Premature Ventricular Contractions Originating From the Right Ventricular Outflow Tract during AblationBackground and objective This study aimed to assess contact force(CF)of premature ventricular contractions originating from the right ventricular outflow tract(RVOT-PVCs)during ablation application and analyze CF data in common RVOT ablation sites.Methods CF-sensing catheter ablation was performed in 46 patients.All points were divided into groups according to the target site of RVOT:septum(SM)and free wall(FW).The best CF value was calculated in total points and each group.The distribution of CF in SM and FW subgroups was also evaluated.Results After three-month follow-up study,43 RVOT patients(20 SM,23 FW)without recurrence were enrolled in our study.In total,134 successful ablation points were analyzed.The mean CF of all points was 12.0 ± 7.5 g.There was statistically significant difference in CF of SM and FM subgroups(13.0±9.4g vs.11.0±4.4g,P<0.05).The FW group had 74%points with the moderate CF of 5-15g,while the SM group had 39%points with moderate CF(P<0.05).There was statistically significant difference in the relative standard deviation(RSD)of SM and FM subgroups(71.5%vs.40.9%,P<0.05).Electrogram amplitudes and impedance values correlated with CF,but there were large variations and overlaps.Conclusions The optimal CF of RVOT in the phase of energy application is 12 + 7.5 g,with significant difference in common ablation regions of RVOT.The modest and stable CF is needed in the free wall of RVOT for effective ablation.