Experience on application of transveneous implantable MINI Ⅱ cardioverterdefibrillator for ventricular tachycardia due to right ventricular dysplasia:a report of a case

Objectics: Implantable cardioverter-defibrillator (ICI)is an important mean for treating ventricular tachycardia (VT ) in patients with structural heart diseases .This report deals with our primary experiences in cliical application of transveneous implantable cardioverter defibrillator.Metgids: A 13- year-old male patient with right ventricular dysplasia (ARVD) ). who lhad a failed result from antiarrhythmic drug therapy was implanted with ICD transveneously. Results: During follow. up. the antitachycardia pacing (ATP) did not terminate the first 2 episodes of VT. The episodes of VT were reverted into sinus rhythm by 4 J shock. The patient had a strong uncomfortable sensation :After resettin ATP program . VTs of patient were automaticallly terminated by ICD with ATP therapy many times. Conclusion: ICD implantation is an effective approach for treating VT and reasonable resetting of ATP is needed.

Antitachycardia pacing programming in implantable cardioverter defibrillator:A systematic review

Implantable cardioverter defibrillator(ICD) programminginvolves several parameters. In recent years antitachycardia pacing(ATP) has gained an increasing importance in the treatment of ventricular arrhythmias, whether slow or fast. It reduces the number of unnecessary and inappropriate shocks and improves both patient's quality of life and device longevity. There is no clear indication regarding the type of ATP to be used, except for the treatment of fast ventricular tachycardias(188 bpm-250 bpm) where it has been shown a greater efficacy and safety of burst compared to ramp; 8 impulses in each sequence of ATP appears to be the best programming option in this setting. Beyond ATP use, excellent clinical results were obtained with programming standardization following these principles: extended detection time in ventricular fibrillation(VF) zone; supraventricular discrimination criteria up to 200 bpm; first shock in VF zone at the maximum energy in order to reduce the risk of multiple shocks. The MADIT-RIT trial and some observational registries have also recently demonstrated that programming with a widespread use of ATP, higher cut-off rates or delayed intervention reduces the number of inappropriate and unnecessary therapies and improves the survival of patients during mid-term follow-up.

Critical analysis of ineffective post implantation implantable cardioverter-defibrillator-testing

AIM To test of the implantable-cardioverter-defibrillator is done at the time of implantation. We investigate if any testing should be performed.METHODS All consecutive patients between January 2006 and December 2008 undergoing implantable cardioverterdefibrillator(ICD) implantation/replacement(a total of 634 patients) were included in the retrospective study.RESULTS Sixteen patients(2.5%) were not tested(9 with LA/LVthrombus, 7 due to operator's decision). Analyzed were 618 patients [76% men, 66.4 + 11 years, 24% secondary prevention(SP), 46% with left ventricular ejection fraction(LVEF) < 20%, 56% had coronary artery disease(CAD)] undergoing defibrillation safety testing(SMT) with an energy of 21 + 2.3 J. In 22/618 patients(3.6%) induced ventricular fibrillation(VF) could not be terminated with maximum energy of the ICD. Six of those(27%) had successful SMT after system modification or shock lead repositioning, 14 patients(64%) received a subcutaneous electrode array. Younger age(P = 0.0003), non-CAD(P = 0.007) and VF as index event for SP(P = 0.05) were associated with a higher incidence of ineffective SMT. LVEF < 20% and incomplete revascularisation in patients with CAD had no impact on SMT.CONCLUSION Defibrillation testing is well-tolerated. An ineffective SMT occurred in 4% and two third of those needed implantation of a subcutaneous electrode array to passa SMT > 10 J.

Subcutaneous implantable defibrillator: State-of-the art 2013

The subcutaneous implantable cardioverter-defibrillator(S-ICD)has recently been approved for commercial use in Europe,New Zealand and the United States.It is comprised of a pulse generator,placed subcutaneously in a left lateral position,and a parasternal subcutaneous lead-electrode with two sensing electrodes separated by a shocking coil.Being an entirely subcutaneous system it avoids important periprocedural and long-term complications associated with transvenous implantable cardioverter-defibrillator(TV-ICD)systems as well as the need for fluoroscopy during implant surgery.Suitable candidates include pediatric patients with congenital heart disease that limits intracavitary lead placements,those with obstructed venous access,chronic indwelling catheters or high infection risk,as well as young patients with electrical heart disease(e.g.,Brugada Syndrome,long QT syndrome,and hypertrophic cardiomyopathy).Nevertheless,given the absence of intracavitary leads,the S-ICD is unable to offer pacing(apart from shortterm post-shock pacing).It is therefore not suitable in patients with an indication for antibradycardia pacing or cardiac resynchronization therapy,or with a history of repetitive monomorphic ventricular tachycardia that would benefit from antitachycardia pacing.Current data from initial clinical studies and post-commercialization"real-life"case series,including over 700 patients,have so far been promising and shown that the S-ICD successfully converts induced and spontaneous ventricular tachycardia/ventricular fibrillation episodes with associated complication and inappropriate shock rates similar to that of TV-ICDs.Furthermore,by using far-field electrograms better tachyarrhythmia discrimination when compared to TV-ICDs has been reported.Future results from ongoing clinical studies will determine the S-ICD system’s long-term performance,and better define suitable patient profiles.

Transvenous defibrillator implantation in a patient with persistent left superior vena cava

Persistent left superior vena cava(LSVC) can be incidentally detected during pacemaker implantation through left pectoral side.There is technical difficulty of optimal site pacing and lead stability for right ventricle lead in such situation.We hereby report a case of successful single-chamber implantable cardioverter defibrillator(ICD) implantation in a 50 years-old male with LSVC.The practical issues related with right ventricle lead implantation and pacing/defibrillation parameters for ICD device are discussed.

Optimal programming management of ventricular tachycardia storm in ICD patients

Ventricular tachycardia storm （VTS） is defined as a life-threatening syndrome of three or more separate episodes of ventricular tachycardia （VT） leading to implantable cardioverter defibrillator （ICD） therapy within 24 hours. Patients with VTS have poor outcomes and require immediate medical attention. ICD shocks have been shown to be associated with increased mortality in several studies. Optimal programming in minimization of ICD shocks may decrease mortality. Large controlled trials showed that long detection time and high heart rate detection threshold reduced ICD shock burden without an increase in syncope or death. As a fundamental therapy of ICD, anti- tachycardia pacing （ATP） can terminate most slow VT with a low risk of acceleration. For fast VT, burst pacing is more effective and less likely to result in acceleration than ramp pacing. One algorithm of optimal programming management during a VTS is presented in the review.

Role of catheter ablation of ventricular tachycardia associated with structural heart disease

In patients with structural heart disease, ventricular tachycardia (VT) worsens the clinical condition and may severely affect the shortand long-term prognosis. Several therapeutic options can be considered for the management of this arrhythmia. Among others, catheter ablation, a closed-chest therapy, can prevent arrhythmia recurrences by abolishing the arrhythmogenic substrate. Over the last two decades, different techniques have been developed for an effective approach to both tolerated and untolerated VTs. The clinical outcome of patients undergoing ablation has been evaluated in multiple studies. This editorial gives an overview of the role, methodology, clinical outcome and innovative approaches in catheter ablation of VT.

Permanent Pacemaker Implantation in a Patient with Ventricular Fibrillation due to Spontaneous Coronary Artery Dissection: A Case Report

We present here the case of a 43-year-old female without any known past medical history who was brought into the emergency department (ED) by the emergency medical services (EMS) after receiving cardiopulmonary resuscitation (CPR) on the field. Per EMS, on arrival patient was found to be on ventricular fibrillation and was shocked 3 times. Patient had no past medical history. In the ED, EKG showed sinus rhythm and troponin was 23 which is slightly high compared to upper limit. Patient was taken to the cath lab immediately which showed small to medium caliber septal 1 branch severe mid segment disease with distal tapering suggestive of spontaneous coronary artery dissection. No stent was placed. Electrophysiology was consulted and an Implantable Cardioverter Defibrillator was placed. Spontaneous coronary artery dissection (SCAD) is a phenomenon where an epicardial coronary artery dissection occurs that is not related to atherosclerosis, trauma or iatrogenia. Patients with SCAD presenting with ventricular arrhythmias are not very common. In a Canadian registry analyzing 1056 patients with SCAD, only 84 of them presented with ventricular fibrillation (VF) or ventricular tachycardia (VT) and only 8 underwent ICD placement. They followed up the patients for 5 years and 8 patients suffered VT/VF. 5 of those 8 patients had VT/VF on initial SCAD presentation, and only 1 of them had undergone ICD insertion. There are no specific guidelines regarding ICD placement on patients with coronary artery dissection, but the AHA/ACC/HRS guidelines can help us make decisions. Our case underscores the importance of more prospective or retrospective studies to identify those patients with SCAD who would benefit from ICD placement for secondary prevention. The current guidelines for ventricular arrhythmias are an excellent tool for the electrophysiologist regarding the management of these arrhythmias in other specific scenarios but guidance on SCAD is still lacking.

Effects of medically generated electromagnetic interference from medical devices on cardiac implantable electronic devices: A review

As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.

Ventricular Tachycardia Unveiling an Obstructive Cardiomyopathy Complicated with an Apical Aneurysm

Background: We report the case of a 58-year-old hypertensive patient under treatment who presented with a ventricular tachycardia unveiling an obstructive cardiomyopathy complicated with an apical aneurysm. Aim: Highlight the rarity of the case and the difficulty of management. Case Presentation: This patient was transferred from Regional Hospital of Ziguinchor in southern Senegal for a brutal dizzy spell without loss of consciousness. The electrocardiogram showed a wide monomorphic QRS complex regular tachycardia with a rate of 215 beats/min. An external electrical cardio version at 300 joules was applied which led to the recovery of a sinus rhythm on the electrocardiogram. The Doppler echocardiography showed an asymetricalmedio-ventricular hypertrophy with a maximum left intraventricular gradient at 10 mm Hg at rest. The coronarography via the radial artery was normal. The evolution was labeled with a recurrence of the ventricular tachycardia. The patient was then put on amiodarone 200 mg, beta-blocker (bisoprolol 10 mg) and anti-vitamin K (acenocoumarol 4 mg). Facing rhythmic instability, an implantable automatic defibrillator was fitted. No complication has been reported after one year of evolution. Conclusion: HCM with medio ventricular obstruction and apical aneurysm complicated with ventricular arrhythmias is a rare entity. Its management is difficult and controversial.

Incidence and causes of inappropriate detection and therapy by implantable defibrillators of cardioversion in patients with ventricular tachyarrhythmia

Background Implantable cardioverter defibrillator （ICD） is the only effective therapy in patients with life threatening ventricular arrhythmias. Inappropriate detection and therapy by ICDs are the most common causes of side effects that affect the quality of life in ICD recipients. This study evaluated the incidence and causes of inappropriate detection and therapy by ICDs in patients in our hospital. Methods From January 2000 to December 2005, fifty patients who received ICD implantation for ventricular arrhythmias for prevention of sudden cardiac death were evaluated in this study. Each ICD was programmed using clinical arrhythmic and cardiac data of the patient before discharge. Patients were followed up by standard schedule after implantation and all data retrieved from each device were collected and saved for further analysis. Results No arrhythmic event was detected in 12/50 （24%） patients during the period of follow-up. Among the remaining patients, 11 （22%） experienced inappropriate detections and therapies during follow-up in this study. ICD detected 383 ventricular tachyarrhythmia （VT） and 108 ventricular fibrillation （VF） episodes and delivered 678 therapies. In VT group, ICD delivered 413 antitachycardiac pacings （ATPs） and 118 shocks, among which 78 ATPs and 9 shocks were initiated by 55/383 （14.3%） inappropriate detections. In VF group ICD delivered 147 shocks, among which 56 shocks were initiated by 28/108 （26.9%） inappropriate detections. Overall, more than 50% of these episodes were caused by atrial fibrillation （AF） with rapid ventricular response, followed by electromagnetic or myopotential interference. In addition, most inappropriate therapies occurred within one year after ICD implantation. Conclusions About one fifth of patients experienced ICD inappropriate detection and therapy after implantation. The main cause was AF with rapid ventricular response, followed by electromagnetic or myopotential interference.

Arrhythmogenic ventricular cardiomyopathy:A paradigm shift from right to biventricular disease

Arrhythmogenic ventricular cardiomyopathy(AVC) isgenerally referred to as arrhythmogenic right ventricu-lar(RV) cardiomyopathy/dysplasia and constitutesan inherited cardiomyopathy.Affected patients maysuccumb to sudden cardiac death(SCD),ventriculartachyarrhythmias(VTA) and heart failure.Geneticstudies have identified causative mutations in genesencoding proteins of the intercalated disk that lead toreduced myocardial electro-mechanical stability.Theterm arrhythmogenic RV cardiomyopathy is somewhatmisleading as biventricular involvement or isolated leftventricular(LV) involvement may be present and thus abroader term such as AVC should be preferred.The di-agnosis is established on a point score basis accordingto the revised 2010 task force criteria utilizing imagingmodalities,demonstrating fibrous replacement throughbiopsy,electrocardiographic abnormalities,ventricu-lar arrhythmias and a positive family history includingidentification of genetic mutations.Although severarisk factors for SCD such as previous cardiac arrest,syncope,documented VTA,severe RV/LV dysfunctionand young age at manifestation have been identified,risk stratification still needs improvement,especially inasymptomatic family members.Particularly,the roleof genetic testing and environmental factors has to befurther elucidated.Therapeutic interventions include re-striction from physical exercise,beta-blockers,sotalol,amiodarone,implantable cardioverter-defibrillators andcatheter ablation.Life-long follow-up is warranted insymptomatic patients,but also asymptomatic carriersof pathogenic mutations.

Heart rate-adjusted PR as a prognostic marker of long-term ventricular arrhythmias and cardiac death in ICD/CRT-D recipients

Objective To evaluate the PR to RR interval ratio (PR/RR,heart rate-adjusted PR) as a prognostic marker for long-term ventricular arrhythmias and cardiac death in patients with implantable cardioverter defibrillator (ICDs) and cardiac resynchronization therapy with defibrillators (CRT-D).Methods We retrospectively analyzed data from 428 patients who had an ICD/CRT-D equipped with home monitoring.Baseline PR and RR interval data prior to ICD/CRT-D implantation were collected from standard 12-lead electrocardiograph,and the PR/RR was calculated.The primary endpoint was appropriate ICD/CRT-D treatment of ventricular arrhythmias (VAs),and the secondary endpoint was cardiac death.Results During a mean follow-up period of 38.8 ± 10.6 months,197 patients (46%) experienced VAs,and 47 patients (11%) experienced cardiac death.The overall PR interval was 160 ± 40 ms,and the RR interval was 866 ± 124 ms.Based on the receiver operating characteristic curve,a cut-off value of 18.5% for the PR/RR was identified to predict VAs.A PR/RR ≥ 18.5% was associated with an increased risk of VAs [hazard ratio (HR)= 2.243,95% confidence interval (CI)= 1.665–3.022,P < 0.001) and cardiac death (HR = 2.358,95%CI = 1.240–4.483,P = 0.009) in an unadjusted analysis.After adjustment in a multivariate Cox model,the relationship remained significant among PR/RR ≥ 18.5%,VAs (HR = 2.230,95%CI = 1.555–2.825,P < 0.001) and cardiac death (HR = 2.105,95%CI = 1.101–4.025,P = 0.024.Conclusions A PR/RR ≥ 18.5% at baseline can serve as a predictor of future VAs and cardiac death in ICD/CRT-D recipients.

I-123 metaiodobenzylguanidine imaging for predicting ventricular arrhythmia in heart failure patients

Compared to antiarrhythmic drugs, implantable cardioverter defibrillator （ICD） leads to a more significant im- provement in preventing ventricular arrhythmia in heart failure patients. However, an important question has been raised that how to select appropriate patients for ICD therapy. 1-123 metaiodobenzylguanidine （MIBG） planar and SPECT imaging have shown great potentials to predict ventricular arrhythmia in heart failure patients by as- sessing the abnormalities of the sympathetic nervous system. Clinical trials demonstrated that several parameters measured from 1-123 MIBG planar and SPECT imaging, such as heart-to-mediastinum ratio, washout rate, defect score, and innervation/perfusion mismatch, predicted ventricular arrhythmias in heart failure patients. This paper introduces the current practice of ICD therapy and reviews the technical background of 1-123 MIBG planar and SPECT imaging and their clinical data in predicting ventricular arrhythmia.

The importance of avoiding unnecessary right ventricular pacing in clinical practice

Symptomatic bradycardia is effectively treated with the implantation of a cardiac pacemaker. Although a highly successful therapy, during recent years there has been a focus on the negative effects associated with longterm pacing of the apex of the right ventricle(RV). It has been shown in both experimental and clinical studies that RV pacing leads to ventricular dyssynchrony, similar to that of left bundle branch block, with subsequent detrimental effects on cardiac structure and function, and in some cases adverse clinical outcomes such as atrial fibrillation, heart failure and death. There is substantial evidence that patients with reduced left ventricular function(LVEF) are at particular high risk of suffering the detrimental clinical effects of long-term RV pacing. The evidence is, however, incomplete, coming largely from subanalyses of pacemaker and implantable cardiac defibrillator studies. In this group of patients with reduced LVEF and an expected high amount of RV pacing, biventricular pacing(cardiac resynchronization therapy) devices can prevent the negative effects of RV pacing and reduce ventricular dyssynchrony. Therefore, cardiac resynchronization therapy has emerged as an attractive option with promising results and more clinical studies are underway. Furthermore, specific pacemaker algorithms, which minimize RV pacing, can also reduce the negative effects of RV stimulation on cardiac function and may prevent clinical deterioration.

Concept of defibrillation vector in the management of high defibrillation threshold

We present a case where defibrillation threshold was dangerously elevated to the point that the patient had no safety margin,and his implantable cardioverter-defibrillator generator was discovered to have migrated.Generator migration reduces the distance between the can and the coil,effectively creating a smaller bipolar current and sparing the left ventricle from the current needed for defibrillation.This case underscores the importance of securing the generator in place,as this patient would have been spared multiple shocks and an invasive medical procedure had his generator been better secured.

室性心动过速非药物治疗的研究进展

室性心动过速(VT)是心脏病患者不良预后的重要原因之一,且药物疗效有限。近年来,随着植入式心律转复除颤器和导管消融技术等非药物治疗手段的发展,临床中VT患者的预后有了明显改善。目前,非药物治疗成为了临床治疗VT的主要手段,本文结合目前国内外相关研究和指南共识,围绕这一治疗手段的发展趋势做一综述。

接受植入型心律转复除颤器二级预防的缺血性心肌病患者复发性室性快速心律失常的临床预测因素

目的:分析接受植入型心律转复除颤器(implantable cardioverter defibrillator,ICD)二级预防的缺血性心肌病(ischemic cardiomyopathy,ICM)患者复发性室性快速心律失常(ventricular tachyarrhythmia,VTA)的临床预测因素。方法:回顾性纳入我院2013年1月至2018年12月期间,接受ICD二级预防的88例ICM幸存患者。收集患者基线资料,观察患者随访5年内复发性室性心动过速(ventricular tachycardia,VT)/心室颤动(ventricular fibrillation,VF)的发生情况。结果:单因素Cox回归分析结果显示,患者随访5年时发生复发性VT/VF的影响因素包括血管紧张素转换酶抑制剂/血管紧张素受体阻滞药的使用情况(HR=0.334,95%CI:0.159~0.705,P=0.004)以及左心室舒张末期容积(left ventricular end-diastolic volume,LVEDV)(HR=1.006,95%CI:1.002~1.011,P=0.006)。多因素Cox回归分析结果显示ACEI/ARB的使用情况以及LVEDV是影响患者随访5年时发生复发性VT/VF的独立临床因素(P<0.05)。LVEDV预测患者随访5年时发生复发性VT/VF的受试者工作特征曲线下面积为0.771(95%CI:0.672~0.869),在最佳截断值为163.5 mL。Kaplan-Meier生存曲线分析,LVEDV≤163.5 mL的患者随访1年(100.0%vs.76.7%,Log Rankχ^(2)=11.723,P=0.001)、3年(93.3%vs.58.1%,Log Rankχ^(2)=15.398,P<0.001)、5年(88.9%vs.46.5%,Log Rankχ^(2)=19.188,P<0.001)的无复发性VT/VF生存率明显更高。此外,57例患者在至少半年的医疗治疗后接受了随访超声心动图检查,LVEDV>163.5 mL的患者1年内复发性VTA发生率较高[LVEDV>163.5 mL vs.≤163.5 mL;37.9%(11/29)vs.7.1%(2/28);χ^(2)=7.670,P=0.006]。结论:LVEDV扩大可作为ICM患者随访5年内发生复发性VT/VF的独立预测因素。

1例Brugada综合征病人行全皮下埋藏式心脏转复除颤器植入术的护理

1例Brugada综合征病人在全身麻醉下行全皮下埋藏式心脏转复除颤器(S-ICD)植入术,围术期给予病人精准化护理,术前重点加强电风暴的应急准备和心理护理,预防因Brugada综合征发生室性心动过速/心室颤动导致的心脏性猝死(SCD),为病人赢得手术时机,同时帮助病人以平稳的心态接受手术;术中医护配合确保病人安全;术后给予生命体征观察、活动指导及切口护理等。经有效的治疗和护理成功植入S-ICD,无医疗及护理并发症的发生。