Defibrillator System Research Articles

Coronary Venous Dissection from Left Ventricular Lead Placement During Cardiac Resynchronization Therapy With Defibrillator Implantation and Associated in-Hospital Adverse Events (from the NCDR ICD Registry)

Coronary venous dissection is a known complication of left ventricular lead placement during implantation of a cardiac resynchronization with defibrillator (CRT-D) system. A large-scale evaluation of the prevalence of coronary venous dissection and associated in-hospital clinical outcomes has not been performed. We sought to identify predictors of coronary venous dissection and evaluate subsequent in-hospital adverse events in those with the complication. We studied 140,991 first-time CRT-D recipients in the implantable cardioverter-defibrillator (ICD) Registry implanted between 2006 and 2011. Using hierarchical multivariable logistic regression adjusting for patient, implanting physician, and hospital characteristics, we examined predictors of coronary venous dissection and its association with other major complications, length of hospital stay, and in-hospital mortality. Coronary venous dissection occurred in 392 patients (0.28%). After multivariable adjustment, female gender and left bundle branch block were associated with greater odds of coronary venous dissection. Conversely, atrial fibrillation, previous coronary artery bypass graft, and higher implanter procedure volume were associated with lower odds of coronary venous dissection (all p values <0.05). After multivariable adjustment, CRT-D recipients with coronary venous dissection had greater odds of major complications (odds ratio [OR] 10.47, 95% confidence interval [CI] 6.75 to 16.24, p <0.0001), postprocedural hospital stays >3 days (OR 1.71, 95% CI 1.29 to 2.29, p <0.0001), but not in-hospital death (OR 0.78, 95% CI 0.12 to 5.25, p = 0.8012). In conclusion, in a large population of first-time CRT-D recipients, specific patient and implanter characteristics predicted coronary venous dissection risk. Coronary venous dissection was associated with major in-hospital complications and prolonged hospitalization, but not death.

Impact of ICD lead on the system durability, predictors of long-term survival following ICD system extraction.

Implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) systems are considered as having higher risk of complication and shorter durability but reasons of this multifactorial phenomenon remain unclear. We aimed to analyze this problem in population of patients with ICD leads referred for lead extraction (TLE). We have compared TLE indications, procedural results, and defined the long-term outcomes of TLE in patients with ICD/CRT-D devices (n=482, ICD (+)) with lead extractions in patients with standard pacemakers (n=1,402, ICD (-)). Demographic, clinical characteristics, and procedural outcomes were ascertained from single, primary operator registry. Long-term survival data were provided by the National Health Fund. The ICD (+) subgroup had a significantly higher incidence rate of either infective or noninfective indications for TLE. The clinical success rate of extraction was 99.2% in ICD (+) versus 97.4% in ICD (-) (P=0.05) at a complication rate of 1.04%versus 2.14% (NS), respectively. In the median follow-up of 3.39 years, 142 patients from the ICD (+) subgroup and 303 from the ICD (-) subgroup died. The highest mortality rate of 41.1% was observed in the ICD (+) subgroup with infective indications. Infection, renal failure, diabetes, and age were the multivariate factors associated with increased mortality in the ICD (+) subgroup. ICD leads remain more vulnerable, with respect to mechanical failure and their propensity to infection, in comparison to pacing leads. Their TLE is very effective at least complication rate, when performed by a highly skilled and experienced operator. However, long-term mortality after their TLE is high and is affected mostly by infections or patient-related factors.

Improving trend in ventricular fibrillation/pulseless ventricular tachycardia out-of-hospital cardiac arrest in Rochester, Minnesota: A 26-year observational study from 1991 to 2016

BackgroundMortality from out-of-hospital cardiac arrest (OHCA) is characterized by substantial regional variation. The Institute of Medicine (IOM) recently recommended enhancing the capabilities of EMS systems to improve outcome. In this study, we analyzed the trend in outcome from ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) OHCA in Rochester, MN. Survival from these forms of arrest is commonly employed as a benchmark of Emergency Medical Services (EMS) system performance. MethodsUsing a population-based Utstein-style registry in Rochester, MN where a first responder early defibrillation system is utilized, we evaluated outcome from all EMS-treated VF/pVT arrests and the subgroup of bystander-witnessed VF/pVT from 1991 to 2016. Outcome measurement was neurologically intact survival to discharge, defined as Cerebral Performance Category (CPC) 1 or 2. We divided the 26-year study into three periods: 1991–1997, 1998–2008, and 2009–2016, based on initiation of the first responder system of police officers in 1991 and fire-rescue personnel in 1998, and the latter period for comparison with our previous report in 2009. ResultsWe observed 355 all VF/pVT arrests and 292 bystander-witnessed VF/pVT arrests between 1991 and 2016. In 2009–2016, neurologically intact survival to discharge from overall VF/pVT and bystander-witnessed VF/pVT increased to 53.7% and 65.2%, respectively, compared with 39.5% and 43.4% in 1991–1997. Using multivariable analysis, survival significantly increased in 2009–2016 among all VF/pVT arrests (adjusted OR, 3.10; 95% CI, 1.54–6.40) and bystander-witnessed VF/pVT (adjusted OR, 4.28; 95% CI, 2.01–9.50), compared with those in 1991–1997. ConclusionsWe observed a significant improving secular trend in neurologically intact survival from VF/pVT cardiac arrests with a relatively high recent survival rate in this EMS System.

Access to magnetic resonance imaging of patients with magnetic resonance-conditional pacemaker and implantable cardioverter-defibrillator systems: results from the Really ProMRI study.

The Really ProMRI study evaluates magnetic resonance imaging (MRI) access for patients with cardiac implantable electronic devices (CIEDs) as well as the performance of magnetic resonance (MR)-conditional leads when undergoing MRI. Patients either with an MR-conditional pacemaker or implantable defibrillator (ICD) system or with at least a component (device or one or more leads) from an MR-conditional system, were asked to fill in a questionnaire when they were referred to a MR scan. The rate of prescription, denial, or execution of MR examinations was evaluated in a 1-year follow-up visit. In total, 555 patients [median age (interquartile range) 72.2 (62.2-78.6); 72% male] were enrolled, 49% (270) with a pacemaker, 51% (285) with an ICD system. Five-hundred and ten patients completed the follow-up period. A total of 37 MRI referrals were reported in 35 patients, with a consequent event rate of 7.0/100 patient-years (CI, 4.9-9.7). Fourteen were denied, while 23 [66%; (CI, 48-81%)] were performed. The number of patients with MR referrals was not statistically different between pacemaker and ICD groups (21 vs. 14; P = 0.178). The rate of scans performed was higher in the pacemaker subjects (19/23 vs. 4/14, P = 0.003), while it was similar between patients with or without a complete MR-conditional system (19/30 vs. 4/7, P = 0.606). In this study, we reported a 7.0/100 patient-year's event rate of MR prescriptions in CIED patients. Many examinations were denied, despite MR-conditional systems, especially in ICD patients. Regulatory and cultural changes are needed to allow wider access to MR imaging in CIED patients with MR-conditional systems.

Clinical Performance of Magnetic Resonance Imaging Conditional and Nonconditional Cardiac Implantable Electronic Devices.

This study compared risks associated with magnetic resonance imaging (MRI) in patients with non-MRI conditional and MRI conditional pacing and defibrillator systems with particular attention to clinically actionable outcomes. While recipients of new MRI conditional pacemaker and defibrillator systems may undergo MRI scanning with very low risk, safety and regulatory concerns persist regarding such scanning in recipients of non-MRI conditional systems. Patients with any cardiac device who were referred for MRI were prospectively enrolled at a single center and underwent scanning at 1.5 Tesla. Pre- and postscan lead characteristic changes, system integrity, and symptoms were analyzed. A comparison was made between non-MRI conditional and MRI conditional devices. 105 patients were evaluated allowing for comparison of 97 scans with non-MRI conditional devices and 16 scans with MRI conditional devices. The cohort included those with pacemaker dependency, defibrillator, and cardiac resynchronization devices. Small, nonsignificant changes were observed in lead characteristics following scanning, and there was no significant difference when comparing non-MRI and MRI conditional devices. Lead parameter changes did not require lead revision or programming changes. No device reset, failures, or premature scan termination was observed. 1.5 T MRI scanning in patients with MRI conditional and non-MRI conditional cardiac devices was performed with similar, low clinical risk.

A Novel Defibrillation Tool: Percutaneously Delivered, Partially Insulated Epicardial Defibrillation.

Epicardial defibrillation systems currently require surgical access. We aimed to develop a percutaneous defibrillation system with partially-insulated epicardial coils to focus electrical energy on the myocardium and prevent or minimize extra-cardiac stimulation. We tested 2 prototypes created for percutaneous introduction into the pericardial space via a steerable sheath. This included a partially-insulated defibrillation coil and a defibrillation mesh with a urethane balloon acting as an insulator to the face of the mesh not in contact with the epicardium. The average energy associated with a chance of successful defibrillation 75% of the time (ED75) was calculated for each experiment. Of 16 animal experiments, 3 pig experiments had malfunctioning mesh prototypes such that results were unreliable; these were excluded. Therefore, 13 animal experiments were analyzed - 6 canines (29.8±4.0kg); 7 pigs (41.1±4.4kg). The overall ED75 was 12.8±6.7J (10.9±9.1J for canines; 14.4±3.9J in pigs [P=0.37]). The lowest ED75 obtained in canines was 2.5J while in pigs it was 9.5J. The lowest energy resulting in successful defibrillation was 2J in canines and 5J in pigs. There was no evidence of coronary vessel injury or trauma to extra-pericardial structures. Percutaneous, epicardial defibrillation using a partially insulated coil is feasible and appears to be associated with low defibrillation thresholds. Focusing insulation may limit extra-cardiac stimulation and potentially lower energy requirements for efficient defibrillation.

Subcutaneous Implantable Cardioverter Defibrillators Implantation Without Defibrillation Threshold Testing: A Single Center Experience

BackgroundSubcutaneous implantable cardioverter defibrillator (S-ICD) system has been proven to be an effective therapy for prevention of sudden cardiac death (SCD) in selected patients. Although the Shockless IMPLant Evaluation (SIMPLE) trial has shown that defibrillation threshold (DFT) testing is not necessary for transvenous ICD (TV-ICD) systems, it is still recommended for S-ICD systems. We aimed to study the efficacy and safety of S-ICD implantation without DFT in our Heart Center with the comparison of S-ICD patients’ outcome to those with a single chamber TV-ICD without DFT in the same period.MethodsA retrospective analysis of patients underwent S-ICD without DFT from December 2014 to May 2016 with the comparison to single chamber TV-ICD patients implanted during the same period.ResultsThirty consecutive patients (23 males (76.7%); mean age 41 ± 13 years; mean left ventricular ejection fraction 30±12%) received a S-ICD for primary (25 patients, 83.3%) or secondary prevention (five patients, 16.7%) of SCD. During a mean follow-up of 710.6 ± 190 days, three patients received 38 appropriate ICD shocks (90.5%), and two patients received four inappropriate shocks (9.5%). There were two mortalities (6.7%): one cardiac and one non-cardiac. When compared to 30 consecutive who received a single chamber TV-ICD during the same period, there was no significant difference in mortality.ConclusionsImplantation of S-ICD using intermuscular approach without DFT seems to be safe and effective. Data from large S-ICD registries with long-term follow-up, and preferably randomized controlled studies, are needed to confirm this finding.

Intermuscular technique for implantation of the subcutaneous implantable cardioverter defibrillator: long-term performance and complications.

The subcutaneous cardioverter defibrillator was designed to overcome electrode complications of transvenous defibrillation systems. While largely achieved, pocket complications have increased. Subcutaneous implantation of the pulse generator leaves it prone to erosion, extrusion, discomfort, and poor cosmesis. We use a demonstration electrode and pulse generator with fluoroscopy, prior to prepping and draping, to maximize the left ventricular mass between them. We adapted a submuscular abdominal ICD technique to implant the S-ICD intermuscularly between the anterior surface of serratus anterior and the posterior surface of latissimus dorsi. Surgery in our patients beyond the subcutaneous tissue was bloodless, as muscle layers were carefully separated but not incised, which also protected the long thoracic nerve. Two layers of muscle protect the pulse generator. We have implanted 82 consecutive patients with this technique, taking ∼65 min. All patients were converted with 65 J standard polarity shock during induced arrhythmia conversion testing, with six (7.3%) patients requiring a repositioning of the pulse generator prior to successful conversion. Seven spontaneous episodes of ventricular fibrillation were detected in three (3.6%) patients, all successfully converted back to sinus rhythm. Long-term patient outcomes have been good with low complication rates over the mean ± standard deviation 3.6 ± 1.2 years. Our intermuscular technique and implant methodology is successful for placement of the subcutaneous defibrillator pulse generator. Our technique leads to an excellent cosmetic result and high levels of patient satisfaction. Rates of first shock conversion during defibrillation testing, inappropriate shocks, and complications during follow-up compare favourably with previous published case series. There were no left arm movement limitations post-operatively.

A Magnetic Resonance Imaging-Conditional External Cardiac Defibrillator for Resuscitation Within the Magnetic Resonance Imaging Scanner Bore.

Subjects undergoing cardiac arrest within a magnetic resonance imaging (MRI) scanner are currently removed from the bore and then from the MRI suite, before the delivery of cardiopulmonary resuscitation and defibrillation, potentially increasing the risk of mortality. This precludes many higher-risk (acute ischemic and acute stroke) patients from undergoing MRI and MRI-guided intervention. An MRI-conditional cardiac defibrillator should enable scanning with defibrillation pads attached and the generator ON, enabling application of defibrillation within the seconds of MRI after a cardiac event. An MRI-conditional external defibrillator may improve patient acceptance for MRI procedures. A commercial external defibrillator was rendered 1.5 Tesla MRI-conditional by the addition of novel radiofrequency filters between the generator and commercial disposable surface pads. The radiofrequency filters reduced emission into the MRI scanner and prevented cable/surface pad heating during imaging, while preserving all the defibrillator monitoring and delivery functions. Human volunteers were imaged using high specific absorption rate sequences to validate MRI image quality and lack of heating. Swine were electrically fibrillated (n=4) and thereafter defibrillated both outside and inside the MRI bore. MRI image quality was reduced by 0.8 or 1.6 dB, with the generator in monitoring mode and operating on battery or AC power, respectively. Commercial surface pads did not create artifacts deeper than 6 mm below the skin surface. Radiofrequency heating was within US Food and Drug Administration guidelines. Defibrillation was completely successful inside and outside the MRI bore. A prototype MRI-conditional defibrillation system successfully defibrillated in the MRI without degrading the image quality or increasing the time needed for defibrillation. It can increase patient acceptance for MRI procedures.

Worldwide Randomized Antibiotic EnveloPe Infection PrevenTion Trial (WRAP-IT)

Cardiac implantable electronic device (CIED) infection is a major complication that is associated with significant morbidity and mortality. The aim of this study is to determine whether Medtronic TYRX absorbable envelope reduces the risk of CIED infection through 12 months of follow-up post procedure. WRAP-IT is a randomized, prospective, multi center, international, single-blinded study. Up to 7,764 subjects who are undergoing CIED generator replacement, upgrade, or revision, or a de novo CRT-D implant, will be enrolled and randomized (1:1) to receive the TYRX envelope or not. The primary endpoint is major CIED infection throughout 12 months of follow up after the procedure. Data will be analyzed with an intention to treat approach. WRAP-IT will also assess the performance of Medtronic's lead monitoring algorithms in subjects whose CIED includes a transvenous right ventricular defibrillation system. WRAP-IT is a large randomized clinical trial that will assess the efficacy of TYRX absorbable envelope in reducing CIED infection, define its cost effectiveness, and will also provide a unique opportunity to better understand the pathophysiology and risk factors for CIED infection.

Intraoperative Defibrillation Testing Should Not Be Generally Abandoned for All ICD Procedures-A Multicenter Study on 4,572 Consecutive Patients.

Background The ongoing technical advances in development of new implantable cardioverter defibrillator (ICD) systems led some investigators to question the routine use of intraoperative defibrillation testing (DT). Therefore, we evaluated retrospectively in a multicenter study effectiveness, safety, and usefulness of intraoperative DT on unbiased large patient population. Methods Data from 4,572 consecutive patients undergoing any ICD intervention were retrospectively analyzed. Besides efficacy of DT, risk factors for DT failure were identified in a multiple logistic regression analysis. Results Overall 5,483 shock data from 4,532 patients were available. Not tested for medical reasons were 13.5%. DT-associated complications were not noted. Primary DT effectiveness was 95.8%, whereas 4.2% were ineffective. Optimization (51.6% increase of DT energy, 10.1% subcutaneous lead array (SQ array), 2% generator exchange, 4.8% lead reposition, 9.3% lead exchange, and 22.2% change of shock parameters) led to successful DT in 152 patients (96.2%). Subanalyses and logistic regression identified implantation of generator in any other position than left subpectoral, age, body mass index and left ventricular ejection fraction as independent predictors for primary DT failure. Conclusion The number of patients, including those undergoing generator exchange, system upgrade, or system revision, with inappropriate intraoperative testshock is relatively high. The results of recent prospective clinical trials can be extrapolated only on first ICD implantations with high-energy generators. For patients undergoing subcutaneous ICD implantation, right-sided implantation, patients with channelopathies and hypertrophic cardiomyopathy, as well as for procedures on already implanted ICD systems, the intraoperative DT might still be recommended.

Leadless Cardiac Devices-Pacemakers and Implantable Cardioverter-Defibrillators.

Since the initial introduction of pacemakers and defibrillators, the rapid growth in microcircuit and battery technology has increased the longevity demands and exposed the vulnerabilities of transvenous leads. Over a half of century later, leadless pacemaker and defibrillation systems are just reaching the clinical arena. Despite the remarkable advantages of leadless pacing systems, the data are still quite limited and broad implementation of these technologies need to occur in a cautious and deliberate fashion as the peri-procedural risks remains high. Two of the three systems, Nanostim(TM) (St. Jude Medical) and Micra Transcatheter Pacing System (Medtronic Inc.), have shown the greatest applicability, although they are currently only limited to single chamber pacing and procedural risks are modest. The WiCS(TM)-LV system (EBR Systems, Inc.) is anatomically limited and benefits a small subset of patients. Leadless implantable cardioverter-defibrillator (ICD) therapy, the subcutaneous ICD (S-ICD, Cameron Health/Boston Scientific), has demonstrated encouraging short-term safety and efficacy data supporting its use. Since its introduction, modifications to the implant procedure, pre-screening of patients, and programming of the devices have reduced procedural-related complications and inappropriate shocks. The S-ICD is a promising technology, but it is premature to conclude that it will supplant conventional ICDs. At this current time, the S-ICD may benefit select patients, such as those with recurrent bacteremia, vascular access limitations, and who may be prone to transvenous lead failure.

16-69: Upgrading CRT systems from previous pacemakers and ICD's, assessing the clinical outcomes

Purpose: Cardiac resynchronization therapy (CRT) is indicated in patients with heart failure and bundle branch block. It is less clear whether this includes patients with pre-existing right ventricular pacemaker/defibrillator systems, particularly with respect to having a clinical benefit. The indication for CRT therapy has been constantly widened following publication of randomized prospective clinical trials. However, among other important unanswered questions regarding CRT, it has not been assessed whether patients with previously implanted right ventricular pacemakers or cardioverter defibrillator (ICD) systems derive similar benefit from resynchronization therapy compared with patients undergoing de novo CRT implantation. Method: CRT implantation occurred in 147 patients (64 ± 11 years) between February 2010 – October 2015. From this cohort, we extracted data from 43 patients undergoing a CRT upgrade. The two groups were then compared, (de novo vs upgrade) and clinical outcomes were measured in terms of response, lead repositions and mortality. Inclusion criteria was class III-IV New York Heart Association heart failure symptoms and on optimal medical therapy. Furthermore, an LVEF ≤35% or a QRS width >120 ms was required and in patients with a previously implanted pacemaker or ICD with ventricular pacing, a paced QRS width was ≥160 ms present. Patients were followed up at 1 month in clinic and then at 4 monthly intervals either in clinic or via home monitoring after device implantation. In addition whenever clinical circumstances called for, unscheduled visits were made. At each visit, functional heart failure status (symptoms), and at the 6 months visit either the left ventricular ejection fraction or LV impairment were determined. Concomitant medication was adjusted according to the clinical status of the patient. Patients were considered responders to CRT if they survived to the 6 months follow-up and showed significant improvement in one out of three of the following criteria: improved clinical status (i.e. symptoms), and / or echocardiographic improvement. This was based on either an improved LVEF of >5% or an improved LV function i.e. from severe to moderate. Summary: Mean left ventricular ejection fraction was 27%. Over a mean follow-up of 3.7 ±1.5 years, the response rate was significantly higher in the upgraded CRT vs de novo CRT (76%vs 62% (p = 0.03). There was a significant difference between pacemaker upgrades and ICD upgrades. Pacemaker upgrades had the highest percentage of response (76% vs 44% p = 0.05) . Heart failure hospitalisation within 30 days showed no significant differences between the two groups (p = 0.15) Mortality rates showed borderline statistical significance (p = 0.051), 10.5% in the patients de novo CRT and 4 (7.2%) mortality in upgraded CRT. Lead repositions were non-significant and occurred in 10.2% of upgrade CRT and 12.6% de novo implants. (p = 1.0) Conclusion: Clinical response to CRT were comparable for patients undergoing de-novo vs. upgrade procedures. Accordingly, patient selection for upgrading should be the same as for new CRT implantation.

A Comparison of the Quality of Life of Patients With an Entirely Subcutaneous Implantable Defibrillator System Versus a Transvenous System (from the EFFORTLESS S-ICD Quality of Life Substudy)

The first clinical results from the Evaluation of Factors Impacting Clinical Outcome and Cost Effectiveness of the subcutaneous implantable cardioverter defibrillator (EFFORTLESS S-ICD) Registry on the entirely S-ICD system are promising, but the impact of the S-ICD system on patients' quality of life (QoL) is not known. We evaluated the QoL of patients with an S-ICD against an unrelated cohort with a transvenous (TV)-ICD system during 6months of follow-up. Consecutively implanted patients with an S-ICD system were matched with patients with a TV-ICD system on a priori selected variables including baseline QoL. QoL was measured with the Short-Form Health Survey at baseline, 3, and 6months after implant and compared using multivariable modeling with repeated measures. Patients with an S-ICD (n= 167) versus a TV-ICD system (n= 167) did not differ significantly on physical (p= 0.8157) and mental QoL scores (p= 0.9080) across baseline, 3, and 6months after implantation in adjusted analyses. The evolution in physical (p= 0.0503) and mental scores (p= 0.3772) during follow-up was similar for both cohorts, as indicated by the nonsignificant interaction effect for ICD system by time. Both patients with an S-ICD system and a TV-ICD system experienced significant improvements in physical and mental QoL between time of implant and 3months (both p's <0.0001) and between time of implant and 6months (both p's <0.0001) but not between 3 and 6months (both p's >0.05). In conclusion, these first results show that the QoL of patients with an S-ICD versus TV-ICD system is similar and that patients with either system experience improvements in QoL on the short term.

Wearable Cardioverter-Defibrillator Therapy for the Prevention of Sudden Cardiac Death: A Science Advisory From the American Heart Association.

Sudden cardiac death (SCD) accounts for >300 000 deaths in the United States annually.1 Although the majority of these deaths occur in low-risk populations2 in which aggressive interventions are not practical, some higher-risk populations have been established in whom intervention with an implantable cardioverter-defibrillator (ICD) has been shown in randomized trials to reduce mortality.3–7 Additionally, there is a population of patients who may benefit from automatic emergency cardioversion-defibrillation but are not deemed appropriate candidates for ICD implantation at the time of presentation. This group is defined by 2 populations. The first subgroup comprises those who are at perceived risk but for whom there may be optimism for clinical improvement (eg, patients soon after revascularization or those with a recent diagnosis of myocardial infarction [MI] or cardiomyopathy). Alternatively stated, the optimal management of these patients at risk (or perceived risk) during the waiting period before an ICD is indicated remains unknown. The second subgroup includes those who have a clear indication for ICD but also have a contraindication to immediate ICD placement (eg, active infection or unknown prognosis). The wearable cardioverter-defibrillator (WCD) is a device designed for patients at risk of SCD who are not immediate candidates for ICD therapy. By providing automatic therapy, the WCD does not depend on a second person to defibrillate, as required with a manual or automated external defibrillator (AED). Unlike the ICD (including both transvenous and subcutaneous devices), the WCD requires no surgical operation, can be provided for a short period of time, is temporary, and is easily removed. These characteristics of the WCD, along with safety and efficacy data presented to the US Food and Drug Administration (FDA), resulted in approval in the United States in 2002.8 Because of the increasing use of the WCD and uncertainty of indications …

Epidémiologie et prise en charge de l’insuffisance cardiaque dans un centre marocain

Il s'agit d'une étude observationnelle prospective colligée dans le service des soins intensifs et rythmologie de l'Hôpital militaire d'instruction Mohammed V de Rabat, entre décembre 2008 et décembre 2014, portant sur 424 patients hospitalisés pour insuffisance cardiaque. L’âge moyen était de 60,91±12,77 Les principaux facteurs de risque cardiovasculaires rencontrés étaient: l'hypertension artérielle (46%), le tabagisme (45%), et le diabète (43%). Cliniquement, 63% des patients ont été admis pour insuffisance cardiaque gauche. Le ventricule gauche était dilaté dans 58% des cas, avec une fraction d’éjection moyenne estimée à 36,33±13,5%. L’étiologie dominante était la cardiopathie ischémique (254 cas). En plus d'un traitement médical optimal, 14.4% de nos patients ont fait l'objet d'une resynchronisation cardiaque avec ou sans système de défibrillation. L’évolution intra-hospitalière sous traitement médical était marquée par 26 décès.la durée moyenne d'hospitalisation était de 12,1±6,6 jours.

Efficacy and Myocardial Injury With Subcutaneous Implantable Cardioverter Defibrillators - Computer Simulation of Defibrillation Shock Conduction.

Subcutaneous implantable cardiac defibrillator (S-ICD) systems have a lower invasiveness than traditional ICD systems, and expand the indications of ICD implantations. The S-ICD standard defibrillation shock output energy, however, is approximately 4 times that of the traditional ICD system. This raises concern about the efficacy of the defibrillation and myocardial injury. In this study, we investigated the defibrillation efficacy and myocardial injury with S-ICD systems based on computer simulations. First, computer simulations were performed based on the S-ICD system configurations proposed in a previous study. Furthermore, simulations were performed by placing the lead at the left or right parasternal margin and the pulse generator in the superior and inferior positions (0-10 cm) of the recommended site. The simulated defibrillation threshold (DFT) for the 4 S-ICD system configurations were 30.1, 41.6, 40.6, and 32.8 J, which were generally similar to the corresponding clinical results of 33.5, 40.4, 40.1, and 34.3 J. The simulated DFT were generally similar to their clinical counterparts. In the simulation, the S-ICD system had a higher DFT but relatively less severe myocardial injury compared with the traditional ICD system. Further, the lead at the right parasternal margin may correspond to a lower DFT and cause less myocardial injury.

Outcomes of single- or dual-chamber implantable cardioverter defibrillator systems in Japanese patients

BackgroundThere are no criteria for selecting single- or dual-chamber implantable cardioverter defibrillators (ICDs) in patients without a pacing indication. Recent reports showed no benefit of the dual-chamber system despite its preference in the United States. As data on ICD selection and respective outcomes in Japanese patients are scarce, we investigated trends regarding single- and dual-chamber ICD usage in Japan. MethodsData from a total of 205 ICD recipients with structural heart disease (median age, 63 years) in two Japanese university hospitals were reviewed. Patients with bradycardia with a pacing indication and permanent atrial fibrillation at implantation were excluded. ResultsSingle- and dual-chamber ICDs were implanted in 36 (18%) and 169 (82%) patients, respectively. Non-ischemic cardiomyopathy dominated both groups. Seventeen dual-chamber patients developed atrial pacing-dependency over 4.5 years, and it developed immediately after implantation in 14. Although preoperative testing showed no sign of bradycardia in these patients, their pacing rate was set higher than it was in patients who were pacing-independent (61 vs. 46 paces per min, p<0.01). Two single-chamber patients (5%) underwent atrial lead insertion.While inappropriate shock equally occurred in both groups (7 vs. 21 patients, single- vs. dual-chamber, P=0.285), device-related infection occurred only in dual-chamber patients (0 vs. 9 patients, P=0.155). No differences in death or heart failure hospitalization were observed between groups. ConclusionsDual-chamber ICDs were four-fold more common in Japanese patients without a pacing indication. No benefit over single-chamber ICD was observed. Newly developed atrial pacing-dependency seemed to be limited and could have been overestimated due to higher pacing rate settings in dual-chamber patients.

Subcutaneous defibrillator implantation in pediatric patients.

Objective:Although sudden cardiac death is rare in children, an intracardiac defibrillator system is indicated in children with various types of cardiomyopathy, primary electrical diseases, and after surgical repair of congenital heart defects. The use of transvenous defibrillator lead systems is limited in pediatric patients because of a small body size and/or limited vascular access. Subcutaneous array leads combined with an abdominally placed generator can enable implantation.Method:This is a retrospective study of 13 patients who underwent subcutaneous defibrillator implantation between September 2010 and March 2015. The subcutaneous system was preferred because patients were not amenable to transvenous lead placement.Results:The median patient age was 4.1 years, and the median patient weight was 12.1 kg. Diagnoses of patients were long-QT syndrome in 6, aborted cardiac arrest with left ventricular non-compaction in 3, hypertrophic cardiomyopathy with sustained ventricular tachycardia in 3, and arrythmogenic right ventricular cardiomyopathy in 1. Revision of the subcutaneous lead was required in 5 patients 2–26 months after the implantation. Appropriate shocks were observed in three patients. Inappropriate shock and lead fractures were observed in one patient during the follow-up period. The failure of therapy was observed in one patient. There were no perioperative complications and no early or late deaths.Conclusion:Subcutaneous defibrillator systems are safe and effective in pediatric patients when the transvenous method is risky and contraindicated. Because the high growth rate in this population leads to lead failures, a close follow-up of this population is essential. (Anatol J Cardiol 2016; 16: 630-4)

Abstract 9920: Outcomes Associated With Lead Abandonment versus Lead Extraction Strategies for Revision of Sterile Leads: An NCDR® Analysis

Introduction: While implantable cardioverter defibrillator (ICD) systems are lifesaving, leads often require replacement over time. When ICD leads require replacement, the existing lead can either be left in (abandoned) or be extracted, yet there are insufficient comparative data between these 2 strategies. Methods: We examined in-hospital events among propensity matched subjects undergoing lead replacement where the existing lead was either abandoned or extracted from National Cardiovascular Data Registry (NCDR) ICD Registry (2010 - 2011). Six month complication and 90-day and 1-year mortality rates were examined in a subset of Medicare subjects. We excluded those procedures involving infection and those performed by a cardiothoracic surgeon (extraction predetermined). Results: After 1:1 matching, we had 41744 subjects with in hospital outcomes, of which 2362 were Medicare aged and had 6-month complications and survival information. About 1/4 were women; average age was 66 yrs overall and 75 yrs in the Medicare cohort. In hospital events included 2.22% (n=463) and 3.63% (n=758) procedure related complications, and death in 0.21% (n=44) and 0.45% (n=94) in abandonment and extraction patients, respectively (p&lt;0.001 for both). In the Medicare cohort, at 6 months, there was no difference with respect to bleeding (4.92% vs 5.40%), tamponade (0.38% vs 0.66%), infection (2.27 % vs 3.03%), upper extremity thrombosis (0.76% vs 0.95%), pulmonary embolism (0.28% vs 0.57%), or urgent surgery (1.70% vs 0.85%) (p&gt;0.05 for all). At 90 days and 1 year, there was no difference in survival (p=0.55) (See Figure). Conclusion: Among propensity-matched patients undergoing ICD lead replacement, there were more in-hospital complications and deaths among extraction versus abandonment subjects. Among a Medicare subset, there were no differences in longer term outcomes. Thus, abandonment may be a reasonable alternative to extraction for sterile lead revision in some cases.