Implantable Cardioverter Defibrillator Complications Research Articles

Slowly conducting anatomic isthmuses of tetralogy of Fallot: An opportunity for “prophylactic” ventricular tachycardia ablation

BackgroundPatients with repaired tetralogy of Fallot are at risk of ventricular tachycardia (VT) and sudden cardiac death. Most VTs arise from 5 slowly conducting anatomic isthmuses (SCAIs; conduction velocity ≤0.5 m/s) bound by the right ventriculotomy, ventricular septal defect patch, and tricuspid and pulmonic valves. Historically, risk stratification electrophysiologic studies involved programmed ventricular stimulation with VT induction guiding implantable cardioverter-defibrillator (ICD) implantation or VT ablation. ObjectiveThis study aimed to evaluate a “prophylactic” strategy of ablating SCAIs even in the absence of inducible VT to reduce ICD implantation and arrhythmic events and to compare this with the “historical” strategy. MethodsThis was a single-center, retrospective cohort study. The historical cohort underwent programmed ventricular stimulation to guide ICD implantation or VT ablation. The prophylactic cohort underwent right ventricular electroanatomic mapping and ablation of SCAIs. A composite end point of arrhythmic death, cardiac arrest, sustained VT, and ICD complication was compared between the cohorts. ResultsNinety-two patients with repaired tetralogy of Fallot had risk stratification electrophysiologic studies. Of 57 prophylactic patients, SCAIs were identified or ablated in 33 (58%), 16 (28%) had inducible VT before ablation, and 1 received ICD. Of 35 historical patients, 15 (43%) had inducible VT; 3 had cryoablation during pulmonic valve replacement and 11 received ICDs. No prophylactic patients met the composite end point during a median 21 months (interquartile range, 8–35 months) vs 10 (29%) historical patients during a median 125 months (interquartile range, 90–142 months; P = .017). There were no ablation-related complications. ConclusionProphylactic SCAI ablation is associated with fewer ICD implantations and a reduction in incident arrhythmic events without ablation-related complications.

Long term follow up of Implantable Cardioverter Defibrillators (ICD) in hypertrophic cardiomyopathy: is subcutaneous the way forward?

Abstract Introduction Young patients have greater risks of longer-term complications including inappropriate therapy (IT) from Implantable Cardioverter Defibrillators (ICD) than older ICD patients. In prevention of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM), these complications are critical in determining treatment thresholds. When comparing transvenous ICDs (TV), subcutaneous ICDs (SICD) may have different risks & benefits that define their relative utility. We investigated TV & SICD outcomes in a propensity matched cohort of HCM patients. Methods We used electronic health records in a retrospective study of HCM patients receiving an ICD between 2006-22 at tertiary centre. Indications for ICD implantation, including type of device, were determined by the treating cardiomyopathy team according to ESC guidance. All TV device types were included & eligibility for SICD included passing screening in at least 1 sensing vector. Outcome data included patients lost to follow-up until the last device check & patients who had both device types were included twice. Patients were censored after their first IT for an analysis of IT, & their first ‘ICD complication’ for that analysis. ICD complications are defined as all other complications that resulted in a re-intervention procedure (excl SICD battery advisory), or extra procedure at box change. The audit was registered with local institutional review board for ethical approval. Propensity scoring was used for stratification and covariate adjustment. Matching was conducted using the 12 baseline variables. Associations with IT, ICD complications and their composite were assessed using proportional hazard regression (Cox) models, with time to event starting at implant date. Univariable & multivariable regression analyses were used as appropriate. Hazard ratios (HRs) of 95% confidence intervals were estimated by fitting a model with the propensity score and dichotomous variable (TV vs SICD). A p value of <0.05 was considered statistically significant. Analyses were conducted using R- Version 2023.06.0+421. Results Mean age was 55±14.2 years with follow-up of 73±63 months; 70.7% were male. Of a total of 611 patients, with 469 in the TV group & 164 in the SICD. SICD patients had fewer complications, with no differences in IT across all and propensity matched analyses (CI 0.64), fig 1. Conclusion In HCM, when compared to TV, SICDs are associated with fewer ICD complications & not associated with more frequent IT. Intriguingly, there was a higher rate of IT with the first generation SICD, causing the wide IT errors at longer durations. Complications over long term follow up require more assessment, but the absence of TV lead intervention creates reduced risks for SICD complications. In HCM patients without pacing needs, SICDs may be preferred for HCM-SCD prevention. In addition, the lower risks associated with SICD could lead to lower treatment thresholds for people with elevated lifetime HCM-SCD risk.

Microbial specturm and antibiotic sensitivity of pocket swabs in ICD patients undergoing device replacement or lead revision surgery- findings from a ICD registry observational study

Abstract Introduction Infection is a serious complication of implantable cardioverter defibrillator (ICD) therapy, necessitating effective preventive measures during implantation or revision surgery. The intraoperative use of antibacterial envelopes containing rifampicin and minocycline has shown promising results in reducing infection, yet, it is expensive and not cost-effective. Gentamicin sponges might be an alternative to the antibacterial envelope, however its efficacy on targeting the specific microbial spectrum found in device infection must be further investigated. Aim of the study was to identify the bacterial species obtained from pocket swabs of ICD patients undergoing revision surgery, and assess their sensitivity to gentamicin, rifampicin and minocycline. Methods A total of 459 intraoperative pocket swabs were collected from consecutive ICD patients who underwent elective device replacement, system upgrade or lead revision between 2017 and 6/2023. The baseline characteristics were similar in both groups (Table 1). Results Out of the 459 swabs analysed: 416 (90.6%) were negative for microbial growth. The remaining 43 swabs (9.4%) were tested positive for microbial growth (Table 2). Coagulase-negative- staphylococci (CoNS) were the most commonly isolated bacteria, accounting for 56% of cases. Bacteria with available antibiograms exhibited a sensitivity of 92% to gentamicin, 96% to rifampicin and 96% to Minocycline (Table 2). Conclusion The antibiotic sensitivity of the bacteria obtained from the pocket swabs to gentamycin, rifampicin and minocycline was similar. Thus, gentamicin sponges might be an alternative to the antibacterial envelope in patients with ICD undergoing generator replacement or revision surgery.

Outcomes and complications of transvenous implantable cardioverter defibrillator systems in the pediatric population: a systematic review and meta-analysis

Abstract Background Implantable cardioverter defibrillators (ICDs) are an important therapy for prevention of sudden cardiac death (SCD). Data on transvenous (TV) ICD therapy rates, complications, and system survival in children ≤ 21 years is limited by absolute numbers and inclusion of adults with congenital heart disease. Purpose To determine ICD therapy rates and complications in pediatric patients ≤ 21 years of age. Methods A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Medline, Embase, PubMed Ahead-of-Print and in-process records, and Cochrane Database of Systematic Reviews were searched for full-text articles on pediatric ICD. Articles were assessed for inclusion by two authors via a consensus process; the exclusion criteria included: case reports, review articles, abstracts, editorials, articles not in English, articles solely on epicardial or subcutaneous leads, articles on unrelated topics, articles with <50% ICD leads, and articles with any patients >21 years old. Data were extracted by 1 author and verified by a 2nd author. Meta-analysis of aggregate data was performed, where possible. Random effects models were used for pooled inferences. All reported rates are annualized rates based on reported follow-up times in each study. Results Of 1325 articles, 23 met all inclusion and no exclusion criteria (Figure) representing 1700 patients implanted from 1987-2020. The average age of patients was 12.8 years (95% confidence interval [CI]: 11.9 – 13.7) with weight of 51.1 kg (95% CI: 42.2 – 60.0) (Table). Primary prevention was the indication in 56.4 % (95% CI: 45.0% – 67.7%). Only 14.8% (95% CI: 10.6% – 19.0%) of the patients had congenital heart disease while 22.6% (95% CI: 15.8% – 29.3%) had long QT syndrome. The annualized rate of appropriate shock was 7.0% (95% CI: 5.6% – 8.8%) and the rate of inappropriate shock was 4.8% (95% CI: 3.8% – 6.0%). Annualized rates of reported adverse events included lead failure: 2.3% (95% CI: 1.6% – 3.3%) and infection: 0.8% (95% CI: 0.4% – 1.6%), which could have led to system revision: 4.4% (95% CI: 2.1% – 9.4%). The all-cause mortality rate was 0.8% (95% CI: 0.6% – 1.2%) across 17 studies. In 9 studies with 719 patients, the heart transplant rate was 1.6% (95% CI: 0.6% – 3.9%). Conclusion In this first systematic review and meta-analysis of ICDs in pediatric patients, ICD therapy was effective for prevention of SCD with a 7.0% annualized rate of appropriate ICD shocks. This is comparable to the annualized rate of appropriate ICD shock for secondary prevention of SCD in adult randomized controlled trials. Most common adverse events in the pediatric population were lead failure and system revision. Further refinements in patient selection criteria for implantation and improvements in lead and device technology are needed for pediatric patients.FigureTable

Risk for appropriate ICD intervention and complications in patients implanted after an out-hospital cardiac arrest compared to patients implanted for primary and other secondary prevention indication

Abstract Background Few data are available about patients implanted with an implantable cardioverter defibrillators (ICDs) after an out-of-hospital cardiac arrest (OHCA). In particular, it is unclear if these patients have a higher risk of appropriate device therapy than patients implanted for primary and other secondary prevention. Purpose To assess if appropriate device interventions (ATP/shocks) are higher in patients implanted after OHCA compared to patients implanted for primary and secondary prevention other than OHCA. To verify also if mortality, implantation-related complications (pneumothorax, hemothorax, hematoma, cardiac tamponade), device-related complications (lead displacement and fracture, infections) and inappropriate shocks/ATP are higher in OHCA patients compared to other patients. Methods This is a retrospective multicenter international study. All the patients implanted with an ICD between January 2015 and December 2016 in the participating centers were included. Follow-up was considered concluded in case of death or at the last follow-up available until December 2023. Patients were divided according to ICD implantation indication (secondary prevention after OHCA, other secondary prevention, primary prevention). Results 1386 patients (79% males; median age 67, IQR 59-74) from 15 centers were included with a median follow-up of 83 months: 111 patients in OHCA group, 134 in other secondary prevention group and 1141 in primary prevention group. Considering the first appropriate intervention, a significant difference among the three groups was observed (Fig.1A) and, at post-hoc comparison, the OHCA group was at higher risk than primary prevention (HR 1.51, 95%CI 1.06-2.17, p=0.02), but was at similar risk than other secondary prevention (HR 0.79, 95%CI 0.51-1.23, p=0.3). This was confirmed also after correction for age, gender, history of atrial fibrillation, aetiology and multi-comorbidity (Fig.2A). However, considering the number of appropriate interventions during follow-up, the risk of OHCA group was lower than other secondary prevention (IRR 0.28, 95%CI 0.11-0.68, p<0.01) and similar to primary prevention (IRR 0.97, 95%CI 0.47-1.96, p=0.93), also after correction for the other predictors (Fig.2B). The three groups showed no differences in survival (Fig.1B), implantation-related complication, device-related complications (Fig.1C) and inappropriate shocks/ATP. Conclusion Patients implanted with an ICD after an OHCA have a risk similar to those implanted for other secondary prevention, when considering the first appropriate intervention, but a risk similar to those implanted for primary prevention when considering the number of appropriate interventions during follow-up. Our study confirms that OHCA patients represents a peculiar population with the same chance of survival and rate of complications compared to primary and other secondary prevention patients suggesting the need of more studies to improve their long-term treatment.Figure 1 (Panel A, B and C)Figure 2 (Panel A and B)

An international multicenter cohort study on implantable cardioverter-defibrillators for the treatment of symptomatic children with catecholaminergic polymorphic ventricular tachycardia

BackgroundCatecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there is limited data on the outcomes of ICD use in children. ObjectiveThe purpose of this study was to compare the risk of arrhythmic events in pediatric patients with CPVT with and without an ICD. MethodsWe compared the risk of SCD in patients with RYR2 (ryanodine receptor 2) variants and phenotype-positive symptomatic CPVT patients with and without an ICD who were younger than 19 years and had no history of sudden cardiac arrest at phenotype diagnosis. The primary outcome was SCD; secondary outcomes were composite end points of SCD, sudden cardiac arrest, or appropriate ICD shocks with or without arrhythmic syncope. ResultsThe study included 235 patients, 73 with an ICD (31.1%) and 162 without an ICD (68.9%). Over a median follow-up of 8.0 years (interquartile range 4.3–13.4 years), SCD occurred in 7 patients (3.0%), of whom 4 (57.1%) were noncompliant with medications and none had an ICD. Patients with ICD had a higher risk of both secondary composite outcomes (without syncope: hazard ratio 5.85; 95% confidence interval 3.40–10.09; P < .0001; with syncope: hazard ratio 2.55; 95% confidence interval 1.50–4.34; P = .0005). Thirty-one patients with ICD (42.5%) experienced appropriate shocks, 18 (24.7%) inappropriate shocks, and 21 (28.8%) device-related complications. ConclusionSCD events occurred only in patients without an ICD and mostly in those not on optimal medical therapy. Patients with an ICD had a high risk of appropriate and inappropriate shocks, which may be reduced with appropriate device programming. Severe ICD complications were common, and risks vs benefits of ICDs need to be considered.

Comparing adolescent- and adult-onset unexplained cardiac arrest: Results from the Dutch Idiopathic VF Registry

BackgroundCurrent cohorts of patients with idiopathic ventricular fibrillation (IVF) primarily include adult-onset patients. Underlying causes of sudden cardiac arrest vary with age; therefore, underlying causes and disease course may differ for adolescent-onset vs adult-onset patients. ObjectiveThe purpose of this study was to compare adolescent-onset with adult-onset patients having an initially unexplained cause of VF. MethodsThe study included 39 patients with an index event aged ≤19 years (adolescent-onset) and 417 adult-onset patients from the Dutch Idiopathic VF Registry. Data on event circumstances, clinical characteristics, change in diagnosis, and arrhythmia recurrences were collected and compared between the 2 groups. ResultsIn total, 42 patients received an underlying diagnosis during follow-up (median 7 [2–12] years), with similar yields (15% adolescent-onset vs 9% adult-onset; P = .16). Among the remaining unexplained patients, adolescent-onset patients (n = 33) had their index event at a median age of 17 [16–18] years, and 72% were male. The youngest patient was aged 13 years. In comparison with adults (n = 381), adolescent-onset patients more often had their index event during exercise (P <.01). Adolescent-onset patients experienced more appropriate implantable cardioverter-defibrillator (ICD) therapy during follow-up compared with adults (44% vs 26%; P = .03). Inappropriate ICD therapy (26% vs 17%; P = .19), ICD complications (19% vs 14%; P = .41), and deaths (3% vs 4%; P = 1) did not significantly differ between adolescent-onset and adult-onset patients. ConclusionIVF may occur during adolescence. Adolescent-onset patients more often present during exercise compared with adults. Furthermore, they are more vulnerable to ventricular arrhythmias as reflected by a higher incidence of appropriate ICD therapy.

Use of subcutaneous cardioverter-defibrillator. First cases reported from National Institute of Cardiology Ignacio Chávez-Mexico.

The transvenous implantable cardioverter defibrillator (ICD) is the treatment of choice for the prevention of sudden cardiac death (SCD). Its use could be restricted when device-related infections occurs or in the pediatric population. In the later, an ICD represents a challenge, due to the minimal dimensions of the venous system in children, the length of the electrodes, the size of the generator, as well as the anatomical complexity in cases with associated congenital heart disease. This article presents the first Mexican patients with a subcutaneous ICD (SC-ICD) implant as a therapy for the prevention of SCD. The first four cases were implanted at the Ignacio Chávez National Institute of Cardiology with a SC-ICD (Emblem, Boston Scientific, USA), three of them were pediatric patients, including the first implant of this type of device in a pediatric patient in Latin America. The 3-incision and 2-incision techniques were used under general anesthesia. A successful implantation was obtained with the 3-incision technique in the first 2 cases and the last 2 with the 2-incision technique. Proper functioning of the device was corroborated in the operating room with proof of appropriate therapy (65 J) for ventricular fibrillation induced with 50 Hz stimulation. No immediate complications were observed. One patient had appropriate shocks two months after the implant. During follow-up, one child developed skin erosion at the level of the curve of the electrode on the sternum, with no signs of infection. In the operating room, the damaged skin was resected, the barrel and the fixation silk were removed, surgical lavage was performed, and the skin was closed again, thus avoiding removal of the system. The SC-ICD is an alternative therapy to the transvenous ICD. It can be considered first choice in subjects who do not require ventricular pacing, including pediatric patients. Skin complications can occur but do not pose a threat as venous complications of conventional ICDs.

Two-incision versus three-incision implantation technique of subcutaneous implantable cardioverter defibrillator: Systematic review and meta-analysis of 2076 patients.

The implantable cardioverter-defibrillator (ICD) was designed to detect and treat ventricular arrhythmias, which account for nearly half of all cardiovascular fatalities. Transvenous ICD (TV-ICD) complications were reduced by introducing subcutaneous ICD (S-ICD). S-ICD can be implanted using a three (3IT)- or two (2IT)-incision technique. This systematic review and meta-analysis was conducted to compare the 3IT to the 2IT. We searched medical electronic databases of Cochrane Central, Embase, PubMed, Scopus, and Web of Science (WOS) from the study's inception until March 8, 2023. We compared 2IT and 3IT techniques of S-ICDs in terms of procedural, safety, and efficacy outcomes. We used Review Manager software for the statistical analysis. We calculated the risk ratio (RR) with its 95% confidence interval (CI) for dichotomous variables; and the mean difference with its 95% CI for continuous variables. We measured the heterogeneity using the chi-squared and I-squared tests. If the data were heterogeneous, the random-effect (RE) model was applied; otherwise, the fixed-effect model (FE) was used. We included three retrospective observational studies of 2076 patients, 1209 in the 2IT group and 867 in the 3IT. There was no statistically significant difference in erosion after S-ICD when 2IT compared with 3IT (RR=0.27, 95% CI: [0.07, 1.02]; P=.05) (I2=0%, P=.90). There was no difference in risk of infection, lead dislocation, or inappropriate shock with either incision technique (RR=0.78, 95% CI: [0.48, 1.29]; P=.34) (I2=0%, P=.71) and (RR=0.37, 95% CI: [0.02, 8.14]; P=.53) (I2=66%, P=.05) respectively. Our meta-analysis showed that the efficacy of both techniques is comparable; Appropriate shock (RR=0.94, 95% CI: [0.78, 1.12]; P=.48) (I2=0%, P=.81) and first shock efficacy (RR=0.89, 95% CI: [0.44, 1.82]; P=.76) (I2=0%, P=.87). 2IT and 3IT of S-ICD have comparable efficacy and complication rates; however, the 3IT exposes patients to an additional incision without any additional benefits. These findings may provide clinicians with a simpler method for subcutaneous ICD implantation and likely result in improved cosmetic outcomes. Before the 2IT technique can be considered the standard of care, randomized controlled trials (RCTs) must be conducted to assess its long-term safety and efficacy.

Complications of Implantable Cardioverter Defibrillator and Their Potential Risk Factors in Patients with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) has different complications such as cardiac arrhythmia and sudden cardiac death (SCD). Insertion of an implantable cardioverter defibrillator (ICD) is recommended for HCM patients who are at high risk of SCD and malignant arrhythmias, despite having their own potential complications. Hypothesis. We aimed to investigate the prevalence of different complications of ICD insertion and the impact of the potential influential baseline characteristics in a one-year follow-up period. This was a retrospective study with a total of 71 HCM patients with ICD insertion. We evaluated the prevalence of different complications of ICD implantation and the impact of baseline characteristics on the occurrence of ICD complications using multivariate regression analysis in three 4-month periods. In a one-year follow-up, 13 patients (18.3%) experienced at least one of the complications including pneumothorax, lead failure, ICD infection, inappropriate shocks, perforation, and upper limb deep vein thrombosis (DVT) with no mortality. Inappropriate shocks were reported as the most common (11.3%) complication during this period, with a gradual increase in the second (4.2%) and third (5.6%) follow-up sessions. Among all of the baseline characteristics that were investigated in this study, a positive history of hypertension was the only risk factor with significant impact on the occurrence of complications (P = 0.01). We demonstrated the occurrence of complications during a one-year follow-up as 18.3% in HCM patients with ICD insertion. A positive history of hypertension was the only baseline characteristic affecting the occurrence of complications, and inappropriate shocks were the most common complication.

Clinical course of hypertrophic cardiomyopathy patients implanted with a transvenous or subcutaneous defibrillator.

The implantable cardioverter-defibrillator (ICD) is a life-saving therapy in patients with hypertrophic cardiomyopathy (HCM) at risk of sudden cardiac death. Implantable cardioverter-defibrillator complications are of concern. The subcutaneous ICD (S-ICD) does not use transvenous leads and is expected to reduce complications. However, it does not provide bradycardia and anti-tachycardia pacing (ATP). The aim of this study was to compare appropriate and inappropriate ICD interventions, complications, disease-related adverse events and mortality between HCM patients implanted with a S- or transvenous (TV)-ICD. Consecutive HCM patients implanted with a S- (n = 216) or TV-ICD (n = 211) were enrolled. Propensity-adjusted cumulative Kaplan-Meier curves and multivariate Cox proportional hazard ratios were used to compare 5-year event-free survival and the risk of events. The S-ICD patients had lower 5-year risk of appropriate (HR: 0.32; 95%CI: 0.15-0.65; P = 0.002) and inappropriate (HR: 0.44; 95%CI: 0.20-0.95; P = 0.038) ICD interventions, driven by a high incidence of ATP therapy in the TV-ICD group. The S- and TV-ICD patients experienced similar 5-year rate of device-related complications, albeit the risk of major lead-related complications was lower in S-ICD patients (HR: 0.17; 95%CI: 0.038-0.79; P = 0.023). The TV- and S-ICD patients displayed similar risk of disease-related complications (HR: 0.64; 95%CI: 0.27-1.52; P = 0.309) and mortality (HR: 0.74; 95%CI: 0.29-1.87; P = 0.521). Hypertrophic cardiomyopathy patients implanted with a S-ICD had lower 5-year risk of appropriate and inappropriate ICD therapies as well as of major lead-related complications as compared to those implanted with a TV-ICD. Long-term comparative follow-up studies will clarify whether the lower incidence of major lead-related complications will translate into a morbidity or survival benefit.

Myocardial ATP depletion detected noninvasively predicts sudden cardiac death risk in patients with heart failure.

BACKGROUNDSudden cardiac death (SCD) remains a worldwide public health problem in need of better noninvasive predictive tools. Current guidelines for primary preventive SCD therapies, such as implantable cardioverter defibrillators (ICDs), are based on left ventricular ejection fraction (LVEF), but these guidelines are imprecise: fewer than 5% of ICDs deliver lifesaving therapy per year. Impaired cardiac metabolism and ATP depletion cause arrhythmias in experimental models, but to our knowledge a link between arrhythmias and cardiac energetic abnormalities in people has not been explored, nor has the potential for metabolically predicting clinical SCD risk.METHODSWe prospectively measured myocardial energy metabolism noninvasively with phosphorus magnetic resonance spectroscopy in patients with no history of significant arrhythmias prior to scheduled ICD implantation for primary prevention in the setting of reduced LVEF (≤35%).RESULTSBy 2 different analyses, low myocardial ATP significantly predicted the composite of subsequent appropriate ICD firings for life-threatening arrhythmias and cardiac death over approximately 10 years. Life-threatening arrhythmia risk was approximately 3-fold higher in patients with low ATP and independent of established risk factors, including LVEF. In patients with normal ATP, rates of appropriate ICD firings were several-fold lower than reported rates of ICD complications and inappropriate firings.CONCLUSIONTo the best of our knowledge, these are the first data linking in vivo myocardial ATP depletion and subsequent significant arrhythmic events in people, suggesting an energetic component to clinical life-threatening ventricular arrhythmogenesis. The findings support investigation of metabolic strategies that limit ATP loss to treat or prevent life-threatening cardiac arrhythmias and herald noninvasive metabolic imaging as a complementary SCD risk stratification tool.TRIAL REGISTRATIONClinicalTrials.gov NCT00181233.FUNDINGThis work was supported by the DW Reynolds Foundation, the NIH (grants HL61912, HL056882, HL103812, HL132181, HL140034), and Russell H. Morgan and Clarence Doodeman endowments at Johns Hopkins.

Ventricular Arrhythmias and Implantable Cardioverter-Defibrillator Use in Patients with Left-Ventricular Assist Device: Validation of the VT-LVAD Prediction Score

<h3>Purpose</h3> In the absence of proven survival benefit, <i>de novo</i> implantation of an implantable cardioverter defibrillator (ICD) in patients treated with a durable left ventricular assist device (LVAD) remains controversial. This study aims to assess the incidence of ventricular arrhythmias (VA) and ICD complications in patients stratified by VT-LVAD Score. <h3>Methods</h3> Patients implanted with a durable LVAD at our institution between 2010 and 2020 were reviewed (n=63). They were retrospectively classified into two groups according to the VT-LVAD prediction score: 27 patients were deemed at low/intermediate risk (<5) and 36 patients at high/very high arrhythmic risk (>5). Preoperative characteristics, outcomes, ICD-related complications and arrhythmic events were compared between the two groups. <h3>Results</h3> Mean follow-up was 43±35 months, and mean duration of support was 11±16 months. Patients in the low/intermediate risk group were generally healthier. They were younger (53 vs. 60 years old) and had less atrial fibrillation (18% vs. 64%) and VA (22% vs. 81%). In the low/intermediate risk group, 12 (44%) patients had an ICD prior to LVAD implantation, 8 (30%) patients had an ICD post LVAD implantation and 7 (26%) patients either died or underwent cardiac transplantation before consideration of an ICD. In the high/very high risk group, 28 (78%) patients had an ICD prior to LVAD implantation, 5 (14%) patients had an ICD post LVAD implantation and 3 (8%) patients either died before consideration of an ICD. Among patients with an ICD in the low/intermediate-risk group (n=20), 2 (10%) patients had an inappropriate shock secondary to supraventricular tachycardia (SVT). Two patients required appropriate antitachycardia pacing (ATP) without shock. In patients with an ICD in the high/very high risk group (n=33), 9 (27%) required appropriate ATP and 1 (3%) had an inappropriate shock secondary to SVT. There was no other ICD complication. <h3>Conclusion</h3> Our analysis showed that patients with LVAD do not seem to derive a mortality benefit from a primary prevention strategy for ICD implantation. Nevertheless, the rate of ICD-associated complications was low. The VT-LVAD score may be useful to discriminate amongst LVAD patients at high risk of arrhythmic events. However, a large, randomized trial is needed to validate this strategy.

Pooled Analysis of Complications with Transvenous ICD Compared to Subcutaneous ICD in Patients with Catecholaminergic Polymorphic Ventricular Arrhythmia.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is associated with arrhythmic events which may lead to sudden cardiac death (SCD). A leading therapy for CPVT besides medical treatment with beta-blockers is the use of an implantable cardioverter-defibrillator (ICD). For this paper we compared data from a pooled analysis to get further evidence about the complications of transvenous and subcutaneous ICDs. Methods: We gathered data from a search of PubMed, Web of Science, Cochrane Library and Cinahl. For our analysis, we chose 30 studies with a total number of 784 patients. We compared the data regarding complications caused by different ICD device types. Results: During a mean follow up of 38.9 months for the patients with ICD implantation (n = 337), data showed a complication rate of 101 (30%). A total of 330 (98%) of them received a transvenous-ICD (T-ICD) and 7 (2%) a subcutaneous-ICD (S-ICD). A total of 97 (29.4%) of the T-ICD patients and 4 (57.1%) of the S-ICD patients had at least one complication. Of the 234 complications that occurred in T-ICD patients 152 (65%) were inappropriate shocks due to supraventricular arrhythmias, T/R-wave oversensing or electrode defect, 26 (11.1%) lead fracture/failure, 1 (0.4%) electrode defect, 46 were (19.7%) events of electrical storms, 1 (0.4%) thromboembolic event, 2 (0.8%) cases of endocarditis and 6 (2.6%) infections of the ICD-pocket. Ten (100%) of the complications for the four patients with the S-ICD were an event of an inappropriate shock due to supraventricular arrhythmias, T/R-wave oversensing or electrode defect. Conclusion: Subcutaneous ICDs (S-ICD) show a certain advantage over T-ICDs regarding lead-related complications. Nevertheless, they still show problems with inappropriate shocks and other ICD related complications. Therefore, a case-by-case decision is advised, but the continuous improvement of S-ICD might make it an overall advantageous therapy option in the future.

Ten-year follow-up of implantable cardioverter-defibrillator device implantation in non-ischaemic cardiomyopathy – an insight from real world practice in a large district general hospital

Abstract Introduction The benefits of implantable cardioverter-defibrillators (ICDs) in ischaemic cardiomyopathy are well established. The DANISH study, a large randomized controlled trial of prophylactic ICD implantation, found no benefit in preventing all-cause mortality in patients with non-ischaemic cardiomyopathy (NICM). However, ESC guidelines recommend ICDs for patients with NICM and LVEF ≤35% who receive optimal medical therapy (IB recommendation). The 2014 NICE guidelines have similar endorsements but prior to that ICDs were not routinely recommended in NICM in the UK. Purpose We evaluated clinical outcomes of patients who had ICDs implanted prior to 2014 in a NICM population at a large district general hospital. Methods An ICD database of 454 patients at our district general hospital was retrospectively reviewed. We identified 70 patients who had ICD insertion for non-ischaemic cardiomyopathy between 2006 and 2014. Mean follow up time was 9 years 9 months (SD 23 months). 39 patients had an ICD inserted for primary prevention and 31 for secondary prevention. Data was collected from patients' electronic notes and analysed with relation to baseline demographics, mortality, complications and both appropriate and inappropriate therapy in these two subgroups. Results The baseline patient characteristics are presented in Table 1 and show similar characteristics between the primary and secondary prevention groups, except for a higher level of CRT-D implantation in the primary prevention group (p=0.006). Table 2 shows therapy that the device delivered and complication rates. Overall, 16% of patients with an ICD for non-ischaemic cardiomyopathy received a shock for VF. 41% of patients received appropriate therapy (Shocks or Anti-Tachycardia Pacing (ATP)) from their ICD with median time to first therapy of 30 months (IQR 12–66). Shocks for VF were similar in each group (15% vs. 16%, p=0.919). Six patients (8.6%) had inappropriate shocks and two inappropriate ATP (2.9%). 9 (13%) of patients had a complication either at implant or during follow-up; two had pericardial effusions following implant of which one required pericardiocentesis, three required lead replacement due to lead failure, two developed device infections, one was anticoagulated for a lead thrombus and one patient's device failed to treat VF. Conclusion 16% of non-ischaemic cardiomyopathy patients received a shock for VF and 41% received ICD therapy for VT or VF over a mean follow-up period of almost 10 years. This was seen in both primary and secondary prevention. Inappropriate shocks and life-threatening complications were uncommon. Funding Acknowledgement Type of funding sources: None. Table 1. Patient characteristicsTable 2. ICD therapy and complications

Long-term follow-up of patients with tetralogy of fallot and implantable cardioverter defibrillator–The DAI-T4F nationwide registry

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and sudden cardiac death represents an important mode of death in these patients. Data evaluating the implantable cardioverter defibrillator (ICD) in this patient population remain scarce. We aimed to describe long-term follow-up of TOF patients implanted with ICD through a nationwide French registry. Nationwide French Registry including all TOF patients with an ICD initiated in 2010 by the French Institute of Health and Medical Research. The primary time to event endpoint was the time from ICD implantation to first appropriate ICD therapy. Clinical events were centrally adjudicated by a blinded committee. A total of 165 patients (mean age 42.2 ± 13.3 years, 70.1% males) were included from 40 centers, including 104 (63.0%) in secondary prevention. During a median (IQR) follow-up of 6.8 (2.5–11.4) years, 78 (47.3%) patients received at least one appropriate ICD therapy. The annual incidence of the primary outcome was 10.5% (7.1% and 12.5% in primary and secondary prevention, respectively, P = 0.03). Overall, 71 (43.0%) patients presented with at least one ICD complication, including inappropriate shocks in 42 (25.5%) patients and lead dysfunction in 36 (21.8%) patients. Among 61 (37.0%) primary prevention patients, the annual rate of appropriate ICD therapies was 4.1%, 5.3%, 9.5%, and 13.3% in patients with respectively no, one, two, or ≥ three guideline-recommended risk factors. QRS fragmentation was the only independent predictor of appropriate ICD therapies (HR 3.47, 95% CI 1.19–10.11), and its integration in a model with current criteria increased the 5-year time-dependent area under the curve from 0.68 to 0.81 (P = 0.006) (Fig. 1). Patients with TOF and an ICD experience high rates of appropriate therapies, including those implanted in primary prevention. The considerable long-term burden of ICD-related complications, however, underlines the need for careful candidate selection. A combination of easy-to-use criteria including QRS fragmentation might improve risk stratification.

Device-related infection in de novo transvenous implantable cardioverter-defibrillator Medicare patients

Cardiac device infection is a serious complication of implantable cardioverter-defibrillator (ICD) placement and requires complete device removal with accompanying antimicrobial therapy for durable cure. Recent guidelines have highlighted the need to better identify patients at high risk of infection to assist in device selection. To estimate the prevalence of infection in de novo transvenous (TV) ICD implants and assess factors associated with infection risk in a Medicare population. A retrospective cohort study was conducted using 100% Medicare administrative and claims data to identify patients who underwent de novo TV-ICD implantation (July 2016-December 2017). Infection within 720 days of implantation was identified using ICD-10 codes. Baseline factors associated with infection were identified by univariable logistic regression analysis of all variables of interest, including conditions in Charlson and Elixhauser comorbidity indices, followed by stepwise selection criteria with a P ≤ .25 for inclusion in a multivariable model and a backwards, stepwise elimination process with P ≤ .1 to remain in the model. A time-to-event analysis was also conducted. Among 26,742 patients with de novo TV-ICD, 519 (1.9%) developed an infection within 720 days post implant. While more than half (54%) of infections occurred during the first 90 days, 16% of infections occurred after 365 days. Multivariable analysis revealed several significant predictors of infection: age <70 years, renal disease with dialysis, and complicated diabetes mellitus. The rate of de novo TV-ICD infection was 1.9%, and identified risk factors associated with infection may be useful in device selection.

Efficacy and safety of implantable cardioverter-defibrillator implantation in pediatric tachycardia cases

Objective: To analyze the indication, efficacy and complications of implantable cardioverter-defibrillator (ICD) implantation in children with severe tachycardia. Methods: The retrospective study collected the clinical data of 6 patients who accepted ICD implantation in Shanghai Children's Medical Center from January 2009 to January 2020. The etiologies of tachycardia, procedure of the ICD implantation and the operation associated complications were analyzed. Results: The 6 patients aged from 6 years and 5 months to 16 years and 2 months, and their weight were from 15.4 kg to 49.8 kg. Three patients were diagnosed with long QT syndrome, and the remaining three with catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy and lethal cardiac channelopathy, respectively. All the patients suffered from drug-resistant ventricular tachycardia or ventricular vibration before the operation. After the ICD implantation, 3 patients had electric storm, which was alleviated after analgesics-sedatives treatment with chlorpromazine, dexmedetomidine or midazolam combined with fentanyl, as well as reset of the ICD parameters and support from psychological consultation. The other 3 patients did not undergo any complications as the above comprehensive strategies were given after the operation prophylactically. All patients continued anti-arrhythmic medicine after the operation and all survived at the end of the follow-up period lasted from 1 month to 7 years. Two patients had ventricular tachycardia (VT) and ventricular vibration, which were successfully recognized and defibrillated by ICD. Conclusions: ICD implantation is safe and effective in children and adolescent patients. The electric storm may happen after operation, which could be prevented by the comprehensive strategies including appropriate ICD parameter-setting, analgesics-sedatives treatment and psychological support.

Long-Term Follow-Up of Patients With Tetralogy of Fallot and Implantable Cardioverter Defibrillator: The DAI-T4F Nationwide Registry.

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and sudden cardiac death represents an important mode of death in these patients. Data evaluating the implantable cardioverter defibrillator (ICD) in this patient population remain scarce. A Nationwide French Registry including all patients with tetralogy of Fallot with an ICD was initiated in 2010 by the French Institute of Health and Medical Research. The primary time to event end point was the time from ICD implantation to first appropriate ICD therapy. Secondary outcomes included ICD-related complications, heart transplantation, and death. Clinical events were centrally adjudicated by a blinded committee. A total of 165 patients (mean age, 42.2±13.3 years, 70.1% males) were included from 40 centers, including 104 (63.0%) in secondary prevention. During a median (interquartile range) follow-up of 6.8 (2.5-11.4) years, 78 (47.3%) patients received at least 1 appropriate ICD therapy. The annual incidence of the primary outcome was 10.5% (7.1% and 12.5% in primary and secondary prevention, respectively; P=0.03). Overall, 71 (43.0%) patients presented with at least 1 ICD complication, including inappropriate shocks in 42 (25.5%) patients and lead dysfunction in 36 (21.8%) patients. Among 61 (37.0%) patients in primary prevention, the annual rate of appropriate ICD therapies was 4.1%, 5.3%, 9.5%, and 13.3% in patients with, respectively, 0, 1, 2, or ≥3 guidelines-recommended risk factors. QRS fragmentation was the only independent predictor of appropriate ICD therapies (hazard ratio, 3.47 [95% CI, 1.19-10.11]), and its integration in a model with current criteria increased the 5-year time-dependent area under the curve from 0.68 to 0.81 (P=0.006). Patients with congestive heart failure or reduced left ventricular ejection fraction had a higher risk of nonarrhythmic death or heart transplantation (hazard ratio, 11.01 [95% CI, 2.96-40.95]). Patients with tetralogy of Fallot and an ICD experience high rates of appropriate therapies, including those implanted in primary prevention. The considerable long-term burden of ICD-related complications, however, underlines the need for careful candidate selection. A combination of easy-to-use criteria including QRS fragmentation might improve risk stratification. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03837574.

Medicolegal Evaluation of the Case of Implantable Cardioverter Defibrillator (ICD) Lead Fracture Due to Domestic Violence

There has been an increase in sudden cardiac death in recent years. Lately, implantable cardioverter defibrillator (ICD) is a device which is used to prevent sudden cardiac death. Some problems may occur in the device as a result of trauma. Lead fracture constitutes one of these problems. In the literature, blunt trauma-related ICD complications, particularly lead fracture, seem to be very rare. In this case report, we evaluated a female patient who was exposed to a blunt trauma while getting pulled her left arm by her ex-husband and to some inappropriate shocks due to lead fracture, in medicolegal aspect. In case, a lead fracture occurred by pulling her left arm without chest trauma. It is aimed to take importance that even a mild violence might cause life-threating, severe clinical outcome.