Management Of ICD Shock After CRT-D Therapy In Patients With Chronic Heart Failure

Objective: To evaluate the incidence of ICD shocks after cardiac CRT-D in patients with chronic heart failure,to investigate the causes of appropriate and inappropriate shocks,to identify the predictors of ICD shock,and to explore the step-wise managements and effects of CRT-D shocks in single-center.Methods: The patients implanted CRT-D with indications were continuously enrolled from January 2009 to April 2015.Baseline characteristics,parameters of CRT-D before and after the procedure,were collected.All patients were divided into two groups:ischemic cardiomyopathy and non-ischemic cardiomyopathy.If CRTD delivered ? 1 ICD shocks during follow-up,the patient belonged to CRT-D shocks group.Appropriate shock was defined as an episode of shock that was delivered for a rhythm classified as lifethreatening ventricular arrhythmias.Inappropriate shocks included three categories: shocks delivered for hemodynamically stable or nonsustained or senstive to ATP ventricular tachycardia.shock delivered for atrial fibrillation,atrial flutter,sinus tachycardia,or regular supraventricular.shocks delivered for nonarrhymias events including detected noise,mypotentials,electromecnical interference,and T-wave over sensing.All Patients were regularly followed up at 1 month,3 months after implantation and every 6 months follow-up.Clinical evaluate and CRT interrogation were performed regularly,including reviewing of echocardiography and elcetrocardiogram,adjusting medication simultaneously,gradually titrating of the dosages of drugs for heart failure,and changing of the dosages and kinds of the drugs for the underlying diseases.Syncope,pre-syncope,the treatments of heart failure and co-morbidity were mainly inquired.Patient education and self-management were done simultaneously.CRT interrogation revealed the record of episodes,CRT-D therapy,and parameters.If theCRT-D discharged during the follow-up,the patient was admitted to hospital at any time.The step-wise therapy of arrhythmias identified and treated by an ICD,including the following four aspects:(1)Medical therapy.Manage the arrhythmias,heart failure and underlying diseases.(2)CRT interrogate: Evaluate the episodes of ICD discharge,and adjust the parameters,including prolonging the detection rates,numbers of intervals to detect or time(NID),supraventricular tachycardia discrimination(SVT discrimination),and empirical ATP.(3)Revascularization:Evaluate the episode of the myocardial ischemia in ischemic cardiomyopathy patients,Revascularization therapy includes PCI or CABG.(4)catheter ablation:If ventricular tachycarda is recurrent,catheter ablation may be considered.Analyze the arrythmias episodes and CRT-D shock in two groups.Compare Baseline characteristics in CRT-D shocks group and non CRT-D shocks group.Explore predictors of ICD shocks in two groups.Results:Totally 42 patients were enrolled,12 patients were in ischemic cardiomyopathy groups,8 patients implanted ICD for primary prevention indication,4 patients implanted ICD for secondary prevention.30 patients were in nonischemic cardiomyopathy groups,19 patients implanted ICD for primary prevention,11 patients implanted ICD for secondary prevention.During the median follow-up period of30.6+20.1 months,8 patients died,1 patient was operated heart transplant.During the follow-up period,21 patients(50%)received CRT-D shocks,15 patients received appropriate shocks and 6 patients received inappropriate shocks.1.Ventricular arrhythmias episodes and ICD identification as well as shocks in ischemic cardiomyopathy and nonischemic cardiomyopathy groupsIn ischemic cardiomyopathy group,ventricular arrhythmias(VT)were recorded in7 patients(58%),4 of these patients implanted ICD for secondary prevention,3 of these patients implanted ICD for primary prevention.Totally 90 VT episodes happened,2 of these episodes not identified by an ICD,88 of these episodes were identified and treated by an ICD.1 of these episodes were not terminated by ICD therapy,87 of these episodes were terminated by ICD therapy.61 of these episodes(70%)were terminated by ATP,27 of these episodes were terminated by ICD shocks.All shocks were appropriate and happened in 5 patients(42%).In nonischemic cardiomyopathy group,11 patients(37%)were recorded ventricular arrhythmias,8 of these patients implanted ICD for secondary prevention,3of these patients implanted ICD for primary prevention.Totally 99 VT episodes happened,4 of these episodes not identified by an ICD,95 of these episodes were identified and treated by an ICD.52 of these episodes(55%)were terminated by ATP,43 of these episodes were terminated by ICD shocks.All these shocks were appropriate and happened in 10 patients(33%).No obviously difference during follow-up period(38.1+24.0 months vs.27.5+17.8months,P > 0.05,P=0.897),No obviously difference in ventricular arrhythmias rate(P=0.200)and in appropriate shocks rate(P=0.897).In ischemic cardiomyopathy group,patients had a significantly higher ratio of ATP effective(P=0.033).2.Nonventricular arrhythmia episodes identified and treated by an ICD in ischemic cardiomyopathy and nonischemic cardiomyopathy groupsIn ischemic cardiomyopathy group,nonventricular arrhythmia identified and treated by an ICD were recorded in 3 patients.Totally 18 nonventricular arrythmias episodes happened,9 of these episodes were treated by ATP,9 of these episodes treated by ICD shocks.All these shocks were in inappropriate,7 episodes(78%)for AF,2 episodes(22%)for SVT.All these shocks happened in 3 patients(25%).In nonischemic cardiomyopathy group,nonventricular arrhythmia identified and treated by an ICD were recorded in 5 patients.Totally 23 nonventricular arrythmias episodes happened,14 of these episodes were treated by ATP,9 of these episodes were treated by ICD shocks.All these shocks were in inappropriate,8 episodes(89%)for AF,1 episodes(11%)for ST.All these shocks happened in 3 patients(10%).No obviously difference in inappropriate shocks rate(P=0.443)3.CRT-D shocks and the mortality21 patients received CRT-D shocks,9 of these patients(43%)died.21 patients didn't received CRT-D shocks,0 of these(0%)patients died.No obviously difference during follow-up period(35.4+22.0 months vs.25.7+17.1 months,P<0.05,P=0.001),In CRT-D shocks group,patients had a significantly higher ratio of mortality(P=0.001).In ischemic cardiomyopathy groups,8 patients received CRT-D shocks,2 of these patients(25%)died.In nonischemic cardiomyopathy groups,13 patients received CRT-D shocks,7 of these patients(54%)died.No obviously difference duringfollow-up period(38.1+24.0 months vs.27.5+17.8 months,P > 0.05,P=0.125),No obviously difference in mortality(P=0.367).In CRT-D appropriate shocks group,8 of these patients(53%)died.In CRT-D inappropriate shocks group,1 of these patients(17%)died.No obviously difference during follow-up period(30.9+20.6months vs.46.7+23.1months,P>0.05,P=0.182),No obviously difference in mortality(P=0.367).4.The Predictors of CRT-D shocksNo obviously difference in CRT-D shocks group and non CRT-D shocks group during follow-up period(35.4+22.0months vs.25.7+17.1months,P>0.05,P=0.12).In ischemic cardiomyopathy group,patients had a significantly higher ratio of atrial fibrillation(62%vs.19%,P < 0.05,P=0.005),ventricular arrhythmias(57%vs.14%,P <0.050,P= 0.004)and longer course of heart failure(7.5+7.1years vs.4.0 +3.8years,P <0.050,P=0.048)before implantation.Multivariate analysis indicated atrial afibrilation(OR6.156,95%CL1.233-30.738,,P < 0.05,P=0.027),ventricular arrythmias(OR7.019,95%CL1.164-42.319,P<0.05,P=0.034)was an independent predictor of ICD shocks.No obviously difference in atrial fibrillation(P=0.428)and ventricular arrhythmias(P=0.331)in CRT-D appropriate shocks and inappropriate shocks groups.5.Managements and effects of CRT-D appropriate shocks in ischemic cardiomyopathy and nonischemic cardiomyopathy patients groupsAppropriate shocks were deliveried in 5 patients in ischemic cardiomyopathy group,3 of these patients(60%)didn't received ICD shock after adjusting medication therapy.1 of these patients(20%)didn't received ICD shock after revascularization therapy(PCI).Appropriate shocks were deliveried in 10 patients in ischemic cardiomyopathy group,7 of these patients(70%)didn't received ICD shock after adjusting medication therapy.1 of these patients(10%)didn't received ICD shock,1 of these patients(10%)received CRT-D shock times falling afteradjusting parameters.1 of these patients(10%)didn't received CRT-D shock after catheter ablation.6.Managements and effects of CRT-D inappropriate shocks in ischemic cardiomyopathy and nonischemic cardiomyopathy patients groupsInappropriate shocks were deliveried in 3 patients in ischemic cardiomyopathy group in ischemic cardiomyopathy group,3 of these patients(100%)didn't receivedICD shock after adjusting medication therapy and parameters,and 1 of these patients received PCI.3 patients received inappropriate shocks in nonischemic cardiomyopathy group,3of these patients didn't received CRT-D shock after adjusting medication therapy.Conclusions:1.CRT-D therapy is necessary for ischemic cardiomyopathy patients and nonischemic cardiomyopathy patients,no matter patients implanted ICD for secondary prevention or primary prevention,.2.Management is necessary for CRT-D shocks,which can result in increasing mortality,no matter CRT-D appropriate shocks or inappropriate.3.Atrial fibrillation,ventricular arrhythmias was an independent predictor of CRT-D shocks,which should be intervened as soon as possible in these patients.4.Management of CRT-D inappropriate shocks should focus on adjusting parameters and medical therapy simultaneously.5.Step-wise therapy was very important after CRT-D shocks: adjusting parameters,medical therapy,revascularization therapy,catheter ablation.