Cardiac embolism after implantable cardiac defibrillator shock in non-anticoagulated atrial fibrillation:The role of left atrial appendage occlusion

Cardioembolic events are one of the most feared complications in patients with non-valvular atrial fibrillation(NVAF) and a formal contraindication to oral anticoagulation(OAC).The present case report describes a case of massive peripheral embolism after an implantable cardiac defibrillator(ICD) shock in a patient with NVAF and a formal contraindication to OAC due to previous intracranial hemorrhage.In order to reduce the risk of future cardioembolic events,the patient underwent percutaneous left atrial appendage(LAA) occlusion.A 25 mm AmplatzerTM Amulet was implanted and the patient was discharged the following day without complications.The potential risk of thrombus dislodgement after an electrical shock in patients with NVAF and no anticoagulation constitutes a particular scenario that might be associated with an additional cardioembolicrisk.Although LAA occlusion is a relatively new technique,its usage is rapidly expanding worldwide and constitutes a very valid alternative for patients with NVAF and a formal contraindication to OAC.

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.

Induced atrial fibrillation during defibrillation test on implantation of subcutaneous implantable cardioverter defibrillator

The subcutaneous implantable cardioverter defibrillator(S-ICD)has become an alternative to the transvenous ICD in indicated patients.However,inappropriate shock or failed ventricular tachycardia/fibrillation conversion is the most alarming complication of S-ICD.Therefore,defibrillation test(DFT)is recommended for the S-ICD implantation.

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.

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.

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.

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.

Ventricular fibrillation and sudden cardiac arrest in apical hypertrophic cardiomyopathy:Two case reports

BACKGROUND Apical hypertrophic cardiomyopathy(HCM)is considered to have a benign prognosis in terms of cardiovascular mortality.This serial case report aimed to raise awareness of ventricular fibrillation(VF)and sudden cardiac death(SCD)in apical HCM.CASE SUMMARY Here we describe two rare cases of apical HCM that presented with documented VF and sudden cardiac collapse.These patients were previously not recommended for primary prevention using implantable cardioverter-defibrillator(ICD)therapy based on current guidelines.However,both received ICD therapy for the secondary prevention of SCD.CONCLUSION These cases illustrate serious complications including VF and aborted sudden cardiac arrest in apical HCM patients who are initially not candidates for primary prevention using ICD implantation based on current guidelines.

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.

Is cardiac MRI an effective test for arrhythmogenic right ventricular cardiomyopathy diagnosis?

AIM:To evaluate the referrals with suspected arrhythmogenic right ventricular cardiomyopathy(ARVC)and compare cardiac MR(cMR)findings against clinical diagnosis.METHODS:A retrospective analysis of 114(age range16 to 83,males 55%and females 45%)patients referred for cMR with a suspected diagnosis of ARVC between May 2006 and February 2010 was performed after obtaining institutional approval for service evaluation.Reasons for referral including clinical symptoms and family history of sudden death,electrocardiogram and echo abnormalities,cMR findings,final clinical diagnosis and information about clinical management were obtained.The results of cMR were classified as major,minor,non-specific or negative depending on both functional and tissue characterisation and the cMR results were compared against the final clinical diagnosis.RESULTS:The most common reasons for referral included arrhythmias(30%)and a family history of sudden death(20%).Of the total cohort of 114 patients:4 patients(4%)had major cMR findings for ARVC,13patients(11%)had minor cMR findings,2 patients had non-specific cMR findings relating to the right ventricle and 95 patients had a negative cMR.Of the 4 patients who had major cMR findings,3(75%)had a positive clinical diagnosis.In contrast,of the 13 patients who had minor cMR findings,only 2(15%)had a positive clinical diagnosis.Out of the 95 negative patients,clinical details were available for 81 patients and none of them had ARVC.Excluding the 14 patients with no clinical data and final diagnosis,the sensitivity of the test was 100%,specificity 87%,positive predictive value29%and the negative predictive value 100%.CONCLUSION:CMR is a useful tool for ARVC evaluation because of the high negative predictive value as the outcome has a significant impact on the clinical decision-making.

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.

Coronary Artery Bypass Surgery for Patients Presenting with Ventricular Arrhythmias: Propensity Matched Early and Late Outcome

Objectives: Patients with ischemic ventricular arrhythmia (IVA) in the form of fibrillation or tachycardia represent a surgical challenge. Evidence in the literature suggests that ventricular arrhythmia threatens survival even after cardiac surgery. We aim to review the results of our patients presenting with IVA with regard to short and long term outcome following cardiac surgery. Methods: This was a retrospective study of data entered prospectively into our cardiac surgical database between January 1999 and September 2015. A total of 9609 patients underwent Cardiac Surgery which included 54 patients after surviving IVA. The short- and long-term outcomes were compared to a propensity matched group. Actuarial survival was calculated using Kaplan Meier analysis. Results: The 54 study group patients were propensity matched on a 1:2 basis with a control group of non-IVA (n = 108). The baseline preoperative characteristics and risk factors were similar between the 2 groups and all cases underwent CABG only. Univariate analysis showed pacing postoperatively (33.3 vs 66.7%;p = 0.001) and postoperative ventricular arrhythmia (10 vs 22.2%;p = 0.039) to be significantly higher in the IVA group. Cox-multivariate analysis showed postoperative ventricular arrhythmia in either group (Hazard ratio = 1.5) to be the only significant factor to impact mortality (p 0.001). Long term survival was not significantly different between the two groups (10.4;CI: 9.08 - 11.75 vs 9.3;CI: 7.61 - 11.01 yrs, p = 0.3). Conclusion: Cardiac surgery on patients presenting with IVA can be performed safely yielding short and long term results equivalent to non-IVA cases. These patients should not be denied surgery with consideration of good long term outcome.

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.

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.

Energy Level and Success of Internal Defibrillation for Shockable Rhythm during Cardiopulmonary Bypass in Cardiac Surgery:A Retrospective Study

Internal defibrillation is commonly indicated for shockable rhythm following cross-clamp removal in cardiac surgery.Low energy decreases the success rate of defibrillation but high energy can cause myocardial damage.This study aimed to determine the success rate of internal defibrillation for shockable arrhythmias after cardiac surgery.Retrospective data of 1,424 patients who developed shockable rhythms(ventricular fibrillation or ventricular tachycardia),and required internal defibrillation after aortic cross-clamp removal during cardiac surgery,without deep hypothermic circulatory arrest technique,from August 2015 to July 2017,were reviewed.The overall success rate of internal defibrillation in the first attempt of defibrillation was 61.5%.The success rate of the energy levels at 30,10,and 7 Jules were 66.7,64.9,and 61.5%,respectively.The success rate was higher in patients who had a better ejection fraction than those who failed after defibrillation.This was significantly associated with higher pH,higher bicarbonate,lower serum calcium,and lower total cardioplegic volume during cardiopulmonary bypass(CPB).Redo-valve surgery,valvular surgery,and combined coronary artery bypass graft with valvular surgery had a non-significantly lower success rate(p-value=0.989).Incidence of failure for defibrillate patients in redo-valvular surgery,combined coronary artery bypass graft with valve surgery,adult congenital heart defect,and valvular surgery;requiring four or five shocks was non-significantly increased.Recurrent rate of ventricular fibrillation/ventricular tachycardia was 13.5%.The success rate of internal defibrillation was not related to the dose of energy used after being weaned off CPB.