Research On Prognostic Factors And Median Nerve Regulation Of Ventricular Arrhythmia In Ischemic Heart Disease

Part Ⅰ Chronic median nerve modulation reduces ventricular arrhythmia and improves ventricular function in a post-myocardial infarction rabbit modelBackground:Median nerve stimulation(MNS)is a novel neuromodulation approach for treatment of ventricular arrhythmia,but little is known about its chronic effects.The aim of this study was to investigate the effects of chronic MNS on ventricular arrhythmia and ventricular dysfunction post-myocardial infarction(MI).Methods:Two weeks after MI,twelve rabbits were randomly divided into control and MNS groups,and chronic MNS was performed in MNS group for two weeks.Ventricular function and arrhythmias;sympathetic innervation and activity;and interleukin-1β(IL-1β)and norepinephrine(NE)levels were analyzed.Results:Both the total number of premature ventricular complex and episodes of ventricular tachycardia were lower in MNS group than in control group(20560±10314 beats vs.70079 ± 37184 beats,P=0.021,and 115±63 beats vs.307 ± 164 beats,P=0.034,respectively).Compared with control group,MNS for two weeks decreased the cardiac sympathetic nerve density and level of circulating NE in MNS group(1798.42±644.07 μm2/mm2 vs.1003.79 ± 453.00 μm2/mm2,P=0.041,and 20.86±4.54 pg/ml vs.11.07±1.43 pg/ml,P=0.002,respectively).MNS also improved the left ventricular ejection fraction(59.07 ± 1.91%vs.49.77 ± 3.47%,P=0.003)and inhibited the level of IL-1β in serum(69:19 ± 4.71 pg/ml vs.85.93 ± 12.80 pg/ml,P=0.013).Conclusion:Chronic MNS appears to protect against ventricular arrhythmia and improves ventricular function post-MI,which may be mediated by suppressing cardiac sympathetic activity and anti-inflammatory effects.Part Ⅱ Predictors of long-term outcome in patients with implantable cardioverter defibrillator:comparison of ischemic and non-ischemic heart diseaseBackground:Patients with high risk of sudden cardiac death could benefit from implantation of implantable cardioverter-defibrillator(ICD).We aimed to evaluate the predictors of outcome in ICD recipients with ischemic and non-ischemic heart diseases.Methods:This study retrospectively analyzed the clinical information and ICD device monitoring data of 572 ICD recipients.Among them,295 patients had ischemic heart disease(IHD)and 277 patients had non-ischemic heart disease(N-IHD).The endpoints were all-cause and cardiovascular mortality.Results:During a median follow up of 50 months(52-71),117 of the 572 patients(20.5%)experienced electrical storm(ES),with high incidence in IHD group than in N-IHD group(25.8%vs.14.8%,P=0.001),and 193 patients(33.7%)were treated by ICD shock.A total of 136 patients died of all cause,and the mortality in IHD group was higher than that in N-IHD group(31.9%vs.15.2%,P<0.001).In multivariate analysis,the presence of ES(adjusted hazard ratio(aHR)2.49,95%CI 1.56-3.97,P<0.001;aHR 2.39,95%CI 1.17-4.91,P=0.017),ICD shock(aHR 3.16,95%CI 1.94-5.15,P<0.001;aHR 6.57,95%CI 2.79-15.44,95%CI<0.001),and LVEDD(aHR 1.04,95%CI 1.01-1.06,P=0.002;aHR 1.07,95%CI 1.03-1.11,P=0.001)were associated with high risk of all-cause mortality in both IHD group and N-IHD group.However,age and LVEF as independent predictors had been observed only in IHD group(aHR 1.04,95%CI 1.02-1.06,P<0.001;1.03,95%CI 1.01-1.06).Conclusions:In ICD recipients,independent predictors of outcome were complex and differences existed between IHD and N-IHD groups.LVEDD may act as a new factor to evaluate the mortality risk.Part Ⅲ Predictors of mortality in patients with implantable cardioverter defibrillator and ischemic heart disease:Interactionbetween electrical storm and left ventricular dilationBackground:The aim of this study was to investigate whether there was a relationship between electrical storm(ES)and left ventricular dilation as long-term mortality predictors in patients with ischemic heart disease and implantable cardioverter defibrillator(ICD).Methods:We retrospectively studied the clinical and remote monitoring data of 295 ICD recipients with ischemic heart disease.Multivariate Logistic regression was used to analyze the clinical predictors of ES and the interaction between ES and other clinical variables in the impacts on outcome of patients.Multivariate Cox regression was used to estimate the adjusted hazard ratio(aHR)for all-cause mortality and cardiovascular mortality in patients with left ventricular end-diastolic dimension(LVEDD)≥60mm and LVEDD<60mm relative to ES.The patients were divided into 4 groups:group I,LVEDD≥60mm and ES;group Ⅱ,LVEDD≥60mm and without ES;group Ⅲ,LVEDD<60mm and ES;group IV,LVEDD<60mm and without ES.Results:Multivariate logistic regression results showed that only left ventricular dilation(LVEDD>60mm)was the predictor of ES,with a relative ratio of 2.86,95%confidence interval(CI)of 1.54-5.32,and P value of 0.001,although left ventricular ejection fraction less than 40%was also associated with ES occurrence in univariate model.The left ventricular dilation in the presence of ES substantially increased the risk of all-cause mortality and cardiovascular mortality compared with patients without ES and LVEDD<60mm(aHR 7.23,95%CI 3.16-16.54,P<0.001;aHR 16.00,95%CI 3.54-72.30,P<0.001).In patients with LVEDD≥60mm,ES could increased the all-cause and cardiovascular mortality when compared with those without ES(aHR 2.14,95%CI 1.30-3.52,P=0.003;aHR 2.88,95%CO 1.41-5.87,P=0.004);however,the impact of left ventricular dilation on the mortalities in patients with ES was not significantly different with normal left ventricular dimension(aHR 2.94,95%CI0.84-1.02,P=0.090;aHR 2.98,95%CI 0.84-10.53,P=0.092).Additionally,positive interactions existed between ES and ICD shocks in increasing the mortality of patients with LVEDD(interaction P value<0.001).Conclusion:The interaction of ES and left ventricular dilation in ICD recipients with ischemic heart disease significantly amplifies the deleterious effects of each other as distinct disease entities.