Implantable Cardioverter-defibrillator Programming Research Articles

Programmed Ventricular Stimulation: Risk Stratification and Guiding Antiarrhythmic Therapies.

Electrophysiologic testing with programmed ventricular stimulation (PVS) has been utilized to induce ventricular tachycardia (VT), thereby improving risk stratification for patients with ischemic and nonischemic cardiomyopathies and determining the effectiveness of antiarrhythmic therapies, especially catheter ablation. A variety of procedural aspects can be modified during PVS in order to alter the sensitivity and specificity of the test including the addition of multiple baseline pacing cycle lengths, extrastimuli, and pacing locations. The definition of a positive result is also critically important, which has varied from exclusively sustained monomorphic VT (>30 seconds) to any ventricular arrhythmia regardless of morphology. In this review, we discuss the history of PVS and evaluate its role in sudden cardiac death risk stratification in a variety of patient populations. We propose an approach to future investigations that will capitalize on the unique ability to vary the sensitivity and specificity of this test. We then discuss the application of PVS during and following catheter ablation. The strategies that have been utilized to improve the efficacy of intraprocedural PVS are highlighted during a discussion of the limitations of this probabilistic strategy. The role of noninvasive programmed stimulation is also reviewed in predicting recurrent VT and informing management decisions including repeat ablations, modifications in antiarrhythmic drugs, and implantable cardioverter-defibrillator programming. Based on the available evidence and guidelines, we propose an approach to future investigations that will allow clinicians to optimize the use of PVS for risk stratification and assessment of therapeutic efficacy.

The impact of supraventricular arrhythmias on the outcomes of guideline-compliant implantable cardioverter defibrillator programming.

Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2)GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4)NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality. Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030). Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias.

Antitachycardic Therapy of ICD in Patients with Multiple Morphologies of Monomorphous Ventricular Tachycardia Refractory to Therapy

The article presents a description of a clinical case of a patient with structural myocardial pathology (postinfarction cardiosclerosis) with recurrent paroxysmal sustained monomorphic ventricular tachycardia (VT) refractory to the nominal recommended ICD (implantable cardioverter defibrillator) settings; as well as discusses the shortcomings of existing standard algorithms for antitachycardia pacing (ATP) of implantable cardioverter defibrillators and potential ways to increase its efficiency. The refractoriness of recurrent paroxysms of ventricular tachycardia to ATP therapy increases the risk of repeated ICD shocks.
 Despite the existence of universal recommendations for ICD programming and ATP therapy, there is a need in clinical practice for individualized ATP programming in patients refractory to nominal settings. Increasing the number of ATP series and changing algorithms enables to increase the efficiency of ATP up to 8089%. Refractoriness to standard ATP settings may be also overcome by using alternative ATP pacing algorithms (Ramp, Burst-plus, or Ramp-plus instead of Burst), changing the pacing interval, ATP sequence duration, pacing type, and even adding 12 extra stimuli, as well as using data from the previous intracardiac electrophysiological heart test.
 The presented clinical case of a patient with postinfarction cardiosclerosis and paroxysmal stable monomorphic VT (SM-VT) of several morphologies demonstrates that the arrhythmogenic substrate after myocardial infarction changes for a long time without new stenoses in large coronary arteries and without new episodes of acute coronary syndrome, as well as generates several different morphologies of VT from one scar (with different heart rates) and the effect on hemodynamics. The efficiency of early ATP pacing may differ for VT of various morphologies, which makes it reasonable to use alternative pacing algorithms (in addition to the standard Burst sequences recommended by the 2019 Consensus on ICD programming) and testing possible ATP algorithms during ablation of monomorphic VT, including during preventive VT ablation before ICD implantation.

Reduction in defibrillation threshold by modifications to the subcutaneous implantable-cardioverter defibrillator coil

The subcutaneous implantable cardioverter defibrillator (S-ICD) is approved as an alternative to the traditional transvenous ICD (T-ICD). The S-ICD has higher average defibrillation threshold (DFT) than the T-ICD, related primarily to greater distance from shocking coil to ventricular myocardium with the S-ICD. The S-ICD therefore utilizes a larger device capable of generating an 80J shock, compared to 35-40J maximal shock output typical for T-ICDs, and defibrillation efficacy testing is generally recommended for the S-ICD 1 Wilkoff B, Fauchier L, Stiles M, et al. 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing. Heart Rhythm 2016;13;e50-86. Google Scholar . We previously published computer modeling of predictors of defibrillation efficacy with the S-ICD, which determined that minimal fat underlying the S-ICD coil and generator (reducing shock impedance), and posterior generator position (better directing the shock vector across the ventricles), are predictors of lower DFT 2 Heist E. Belalcazar A. Stahl W. et al. Determinants of Subcutaneous Implantable Cardioverter-Defibrillator Efficacy. J Am Coll Cardiol EP. 2017; 3: 405-414 Google Scholar . Those findings formed the basis for the PRAETORIAN score, which is utilized in clinical S-ICD implantation to reduce DFT 3 Quast A.-F.B.E. Baalman S.W.E. Brouwer T.F. et al. A novel tool to evaluate the implant position and predict defibrillation success of the subcutaneous implantable cardioverter-defibrillator: The PRAETORIAN score. Heart Rhythm. 2018; 16: 403-410 Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar . A previously published computer modeling study examined the impact of dual S-ICD electrodes and electrode arrays, as well as variations in generator and lead location; results demonstrated reduced DFT with some configurations compared to the standard S-ICD 4 Jolley M. Stinstra J. Tate J. et al. Finite Element Modeling of Subcutaneous Implantable Defibrillator Electrodes in an Adult Torso. Heart Rhythm. 2010; 7: 692-698 Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar . In this current study, we performed computer modeling to determine whether design modifications to the S-ICD coil could result in reductions to S-ICD DFT.

Syncope in ICD recipients: a single centre experience.

There is little evidence of the impact of syncope in implantable cardioverter-defibrillator (ICD) patients in routine community hospital care. This single-centre retrospective study sought to evaluate the incidence and prognostic significance of syncope in consecutive ICD patients. Data were collected on consecutive patients undergoing first ICD implantation between January 2009 and December 2019. The primary endpoints were the first occurrence of all-cause syncope, all-cause mortality, and all-cause hospitalization. Multivariate Cox proportional hazard models were used to identify risk factors associated with syncope and to analyse the subsequent risk of mortality and hospitalization. 1003 patients (58% primary prevention) were included in the final analysis. During a mean follow-up of 1519 ± 1055 days, 106 (10.6%) experienced syncope, 304 died (30.3%), and 477 (47.5%) were hospitalized for any cause. In an analysis adjusted for baseline variables, the first occurrence of syncope was associated with a significantly increased risk of mortality (HR 2.82, P < 0.001) and the first occurrence of hospitalization (HR 2.46, P = 0.002). Syncope in ICD recipients is common and associated with a poor prognosis irrespective of baseline variables and ICD programming. The occurrence of syncope is associated with a significant increase in the risk of mortality and hospitalization.

Outcome and safety of intraoperative defibrillation testing during device replacement: the Simpler trial.

Intraoperative defibrillation testing (DT) during implant or replacement of implantable cardioverter-defibrillators (ICDs) has been a matter of debate for many years. This debate was put to rest by the Simple and Nordic ICD trials, and the practice of testing during new implantations has essentially been almost abandoned. Old registries demonstrated an increased incidence of significant findings in DT during replacements. The aim of the present study was to evaluate frequency of significant findings and safety of DT in subjects undergoing device replacement. A prospective observational multi-centre study included consecutive patients undergoing ICD generator replacement. The primary outcome was a failure to terminate induced ventricular fibrillation (VF) with a single shock 10 J below the maximal capacity of the device. Secondary outcomes included complications of DT. Patients were followed-up at 1- and 6-months post-procedure. A total of 92 patients were eligible, and consented to the study, of which 84 underwent DT during battery replacement. The median age was 68 years and 79.8% were males. Induction of VF was successful in 84 patients as was a successful conversion on the first attempt in all. There were no procedure-related complications. During follow up one patient had two appropriate ICD shock events. In four patients, ICD programming was changed. None suffered inappropriate shock. There was no evidence of lead malfunction. Two deaths occurred, none of which was related to arrhythmia. The present study found DT was not associated with complications in patients undergoing ICD generator replacement but produced no clinically important information.

Programming of implantable cardioverter defibrillators for primary prevention: outcomes at centers with high vs. low concordance with guidelines.

While ICD therapy reduction programming strategies are recommended in current multi-society guidelines, concerns remain about a possible trade-off between the benefits of ICD therapy reduction and failure to treat episodes of ventricular arrhythmias. The study is to evaluate the outcomes of primary prevention patients followed in centers with high and low concordance with the 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. Consecutive patients with primary prevention ICD implantation from two centers between 2014 and 2016 were included. One center was classified as high guideline concordance center (HGC) with 47% (146/310) of patients with initial ICD concordant with the guidelines, and the other center was classified as low guideline concordance center (LGC) with only 1% (2/178) of patients with guideline-concordant initial ICD programming. Cox proportional hazard models were used to assess risk of first ICD therapy (ATP or shock), first ICD shock, and mortality. A total of 488 patients were included (mean age, 66 ± 13years). During a mean follow-up of 1.9 ± 0.9years, patients followed at HGC were 63% less likely to receive any ICD therapy (adjusted HR [aHR] 0.37, 95% CI 0.42-0.99). There were no significant differences in the rate of first ICD shock (aHR 0.72, 95% CI 0.34-1.52) or mortality (aHR 1.19, 95% CI, 0.47-3.05). Compared to primary prevention patients followed at LGC, primary prevention ICD patients followed at HGC received a significantly lower rate of ICD therapy, mainly from ATP reduction, without a difference in mortality during follow-up.

Long-term clinical course and prognostic factors of heart failure with reduced ejection fraction (HFrEF) patients underwent primary prophylactic implantable cardioverter defibrillator (ICD)

Abstract Background For decades, ICD is a well-established therapy for improving prognosis of structural heart disease with severe cardiac dysfunction, and ICD for primary prophylaxis against sudden cardiac death were routinely provided. However, long-term prognosis and clinical course are different in each individual patient with an ICD, and it is moreover unclear what kind of factors might have influences on their clinical outcomes. Purpose The aim of this study is to clarify long-term prognosis and predictors of future major adverse cardiac events (MACEs) in HFrEF patients with an ICD as primary prophylaxis in Japanese population. Methods We retrospectively analyzed our ICD database. Patients underwent primary prophylactic ICD implantation from 2006 to 2020 at our institute and met the criteria of ICD recommendation of the latest Japanese guideline. Its requirements are receiving optimal medication therapy, symptomatic heart failure (New York Heart Association classification II or greater), and severe cardiac dysfunction (left ventricular ejection fraction (LVEF) is 35% or less). Additionally, prior NSVT is considered Class I ICD recommendation. In the case of ischemic cardiomyopathy (ICM), ICD implantation was done at least 40 days after myocardial infarction and at least 90 days after revascularization. MACEs were defined as composite outcome of cardiovascular death, heart failure hospitalization, and appropriate ICD therapies. Results A total of 148 consecutive patients were enrolled (male, 120 (81%); age, 62.1±11.8 years; LVEF, 23.0±5.86%; left ventricular end-diastolic diameter (LVDd), 67.6±9.26mm; paroxysmal or persistent atrial fibrillation (AF), 38 (26%); NSVT, 113 (76%); use of class III antiarrhythmic drugs, 48 (32%); ICM, 49 (33%); cardiac resynchronization therapy (CRT), 63 (43%)). One hundred twenty patients (81%) were programmed with a shock-only zone over 200 beats per minute. The median follow-up duration was 58.5 months. Among those 148 patients, MACEs were occurred to 60 patients (41%). As a result of dividing all patients into two groups by the occurrence of MACE, LVEF and LVDd were worse in MACE(+) group, whereas, MACE(−) had greater number of co morbidities. The results of cox-regression analysis showed LVDd (HR: 1.07, 95% CI: 1.03–1.12, p&amp;lt;0.001), AF (HR: 2.88, 95% CI: 1.56–5.31, p&amp;lt;0.001) and ICM (HR: 1.78, 95% CI: 1.00–3.16, p=0.049) were the independent predictors of MACEs (Table). However, initial ICD programming was not related to the occurrence of MACE. Conclusions The incidence of MACEs in patients with an ICD and severe HFrEF was substantially high in this Japanese population. Etiology of ICM, left ventricle size, and AF were the potential risk factors for future MACEs. Funding Acknowledgement Type of funding sources: None.

Effect of Novel Programming on Inappropriate Implantable Cardioverter-Defibrillator Therapy in Patients With Very Low Ejection Fraction (from A MADIT-RIT)

The Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy showed a significant reduction in the risk of inappropriate therapy in patients with a programmed high-rate cutoff ≥200 beats per minute or delayed therapy for events ≥170 beats per minute compared with conventional programming. We aimed to characterize outcomes by left ventricular ejection fraction (LVEF) ranges for patients with high-rate, delayed, or conventional implantable cardioverter-defibrillator programming. We assessed the effect of LVEF (LVEF &lt;15%, LVEF 15% to 25%, LVEF &gt;25%) on the risk of inappropriate conventional implantable cardioverter-defibrillator therapy and death in Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy. Inappropriate therapies and death were independently evaluated by the adjudication committee. Statistical methods involved Kaplan-Meier time-to-event graphs and Cox proportional hazards regression analyses. The study involved 140 patients (9%) with LVEF 15%, 585 with LVEF 15% to 25% (39%), and 774 with LVEF &gt;25% (52%). High-rate or delayed programming significantly reduced the risk of inappropriate therapy compared with conventional programming in patients with all LVEFs (p &lt;0.001 for all LVEF). Patients with LVEF &lt;15% had an exceptional 97% lower risk of inappropriate therapy, with high-rate programming than conventional programming (hazard ratio 0.028, p=0.001), without an increase in mortality. High-rate and delayed programming is superior to conventional programming in all LVEF ranges, without adverse effects.

Stereotactic Radioablation for Ventricular Tachycardia in the Setting of Electrical Storm.

Stereotactic body radiotherapy (SBRT) has been reported as a safe and efficient therapy for treating refractory ventricular tachycardia (VT) despite optimal medical treatment and catheter ablation. However, data on the use of SBRT in patients with electrical storm (ES) is lacking. The aim of this study was to assess the clinical outcomes associated with SBRT in the context of ES. This retrospective study included patients who underwent SBRT in the context of ES from March 2020 to March 2021 in one tertiary center (CHU Lille). The target volume was delineated according to a predefined workflow. The efficacy was assessed with the following end points: sustained VT recurrence, VT reduced with antitachycardia pacing, and implantable cardioverter defibrillator shock. Seventeen patients underwent SBRT to treat refractory VT in the context of ES (mean 67±12.8 age, 59% presenting ischemic heart disease, mean left ventricular ejection fraction: 33.7± 9.7%). Five patients presented with ES related to incessant VT. Among these 5 patients, the time to effectiveness ranged from 1 to 7 weeks after SBRT. In the 12 remaining patients, VT recurrences occurred in 7 patients during the first 6 weeks following SBRT. After a median 12.5 (10.5-17.8) months follow-up, a significant reduction of the VT burden was observed beyond 6 weeks (-91% [95% CI, 78-103]), P<0.0001). The incidence of implantable cardioverter defibrillator shock and antitachycardia pacing was 36% at 1 year. SBRT is associated with a significant reduction of the VT burden in the event of an ES; however, prospective randomized control trials are needed. In patients without incessant VT, recurrences are observed in half of patients during the first 6 weeks. VT tolerance and implantable cardioverter defibrillator programming adjustments should be integrated as part of an action plan defined before SBRT for each patient.

Improving adoption of evidence-based implantable cardioverter defibrillator programming: A single-center experience.

Strategic implantable cardioverter-defibrillator (ICD) programming, with the use of high-rate detection zones and long detection times, can significantly reduce nonessential ICD therapy and mortality, 1 Khan P. Jahagirdar N. Laybourn M. et al. Generic ICD programming and outcomes. Pacing Clin Electrophysiol. 2021; 44: 1995-2004 Crossref PubMed Scopus (1) Google Scholar and its use is supported by consensus guidelines. 2 Wilkoff B.L. Fauchier L. Stiles M.K. et al. 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing. Heart Rhythm. 2016; 13: e50-e86 Abstract Full Text Full Text PDF PubMed Scopus (150) Google Scholar Despite the published data and guideline recommendations, the implementation of strategic programming into clinical practice has been modest. 3 Varma N. Jones P. Wold N. et al. How well do results from randomized clinical trials and/or recommendations for implantable cardioverter-defibrillator programming diffuse into clinical practice? Translation assessed in a national cohort of patients with implantable cardioverter- defibrillators (ALTITUDE). J Am Heart Assoc. 2019; 8e007392 Google Scholar How best to improve the adoption of shock reduction programming is unclear. Here we describe our approach to improve ICD programming and its impact on the uptake of evidence-based programming at King's College Hospital (KCH), London.

Delayed detection programming significantly reduces inappropriate ICD therapies in patients with left-ventricular assist devices

Abstract Funding Acknowledgements Type of funding sources: None. Background Implantation of a left ventricular assist device (LVAD) is an established therapy for end-stage heart failure, either as bridge to transplantation or as destination therapy. Virtually all LVAD patients carry an implantable cardioverter-defibrillator (ICD) for primary or secondary prevention. The risk of ventricular tachyarrhythmias is significant in LVAD patients, but so is the burden of supraventricular tachycardia and the ensuing risk of inappropriate ICD therapies. The present retrospective study sought to quantify the impact of standard ICD programming vs. a ICD programming with long detection delays on the occurrence of inappropriate ICD therapies. Methods and results We retrospectively identified 337 consecutive patients (292 male, mean age 54.2 ± 12.3 years) who received a continuous-flow LVAD at our institution. Median follow-up duration was 2.3 (IQR 1.3, 3.7) years. Heart failure etiology was ischemic cardiomyopathy in 155 patients (46.0 %) and non-ischemic dilated cardiomyopathy in 150 (44.5 %). Other etiologies accounted for 32 patients (9.4 %). ICDs implanted at the time of LVAD implantation were single chamber devices in 176 patients (52.2 %), dual chamber devices in 45 patients (13.4 %), and CRT-D in 116 patients (34.4 %) A total of 2228 ICD-treated arrhythmia episodes occurred in 153 patients. 2066 (92.6 %) episodes were appropriate interventions for ventricular arrhythmias. 162 (7.3 %) treatments were inappropriate due to supraventricular tachyarrhythmias (n=115; 71.4 %), sinus tachycardia (n=15; 9.3 %) or oversensing (n=21; 12.9%). We retrospectively compared a standard programming (number of intervals for detection [NID] in the slowest therapy zone ≤ 40) and a long delay programming (NID &amp;gt; 40) and investigated the time to the first inappropriate therapy. A total of 285 patients were programmed to NID ≤ 40 at the first ICD interrogation after LVAD implant, 47 were programmed to NID &amp;gt; 40. Therapies were inactive in the remaining 5 patients. Median NID was 30 (IQR 23, 35) in the standard programming group and 60 (IQR 50, 76) in the long delay group, with similar rates for detection (median cycle lengths 340 [IQR 330, 350] ms and 330 [IQR 322, 340] ms for standard and long delay, respectively). Long delay programming was associated with significantly higher freedom from inappropriate therapies during follow-up (Hazard ratio 0.14, p [log rank] 0.027). No significant difference was observed between groups with regard to time to first appropriate therapy. Conclusion A number of intervals for detection greater than 40 in the slowest therapy zone was associated with a significantly increased freedom from inappropriate therapies in this large retrospective single-center cohort of LVAD patients with an ICD and should be considered as the default ICD programming strategy in this population.

Intraoperative defibrillation testing during replacements of implantable cardioverter-defibrillators: The Simpler trial

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Maurice Kahn Foundation via the Mayo- Sheba Collaboration Fund. Background The need for intraoperative defibrillation testing (DFT) during implant and/or replacement of implantable cardioverter-defibrillators (ICDs) has been a matter of debate for many years. This debate was put to rest by the Simple and the Nordic ICD trials, and the practice of testing during new implantations has practically been nearly abandoned. Nevertheless, induction of VF for testing purposes (VFT) may still have an important role in selective populations at risk for defibrillation failure, who were not included in the SIMPLE and Nordic trials. One such population includes those who undergo device replacements. Old registries demonstrated an increased incidence of significant findings in VFT during replacements. In the present study, we sought to test this observation. Objectives Evaluate frequency of significant findings and the safety of VFT in subjects undergoing device replacement. Methods A prospective observational multi-center study of VFT included consecutive patients undergoing ICD generator replacement in 5 centers in Israel, Europe, and the US. All centers followed the same VFT protocol. The primary outcome was defined as failure to terminate induced VF with a single shock at 10 Joules below the maximal capacity of the device. Secondary outcomes included complications of VFT. Patients were followed-up at 1 month and 6 months post-procedure. Data collection included documentation of any peri-operative complications and clinical endpoints (occurrence of appropriate shock, inappropriate shocks, lead failure, need for re-intervention, and infection). Results A total of 92 patients were eligible, and consented for the study, of which 84 underwent DFT during battery replacement. The median age was 68 years and 79.8% were male subjects. Induction of VF was successful in all 84 patients as well as VFT with a successful conversion on first attempt. During follow up one patient had two appropriate ICD shock events. In four patients, the ICD programming was changed. None suffered an inappropriate shock. There was no evidence of lead malfunction. A total of two deaths occurred, none of which were related to the device. Conclusion The present study found VFT was not associated with complications in patients undergoing ICD/CRTD generator replacement but produced no clinically important information.

Outcomes Following Standardized Implantable Cardioverter-defibrillator Reprogramming.

Multiple randomized controlled trials have demonstrated that programming implantable cardioverter-defibrillators (ICDs) with longer detection intervals and higher detection rates results in significant reductions in the delivery of inappropriate therapy without increasing the number of adverse events. Despite these findings, however, implementation of this evidence-based programming, particularly in previously implanted ICDs, remains inconsistent throughout the United States, with significant provider-dependent variability. We developed an institutionally standardized ICD reprogramming protocol for primary prevention ICDs utilizing high detection rates and long detection intervals, then prospectively evaluated outcomes in patients programmed with this protocol compared to a historical cohort. A total of 193 patients with primary prevention ICDs underwent standardized reprogramming and were monitored over a 1-year period. A historical cohort of 254 patients with ICD with non-standardized programming implanted prior to initiation of the standardized protocol were used as a comparison group. The primary outcomes were rates of appropriate or inappropriate ICD therapy. Secondary outcomes were rates of syncope, emergency department (ED) or urgent care (UC) visits, hospitalization, and death. All patients seen in the device clinic who qualified for device standardization were reprogrammed according to the previously developed evidence-based, institutionally standardized protocol. Patients who underwent standardized reprogramming had a lower prevalence of inappropriate therapy compared to the historical cohort (0% vs. 2.4%, P = .04); the prevalence of appropriate therapy was also lower in the reprogrammed group (4.1% vs. 7.1%) but not to a statistically significant degree (P = .19). There was a lower prevalence of syncope in the reprogrammed group (0% vs. 2.8%, P = .02). No significant difference in the prevalence of ED or UC utilization (37.8% vs. 33.9%, P = .39) or mortality (4.1% vs. 3.5%, P = .74) was found. Prospective standardized reprogramming of new and previously implanted primary prevention ICDs with high-rate detection and longer detection intervals may be an effective method to obtain high adherence to evidence-based reprogramming and reduce rates of inappropriate device therapies without a significant impact on appropriate therapies or mortality.

Evolution of Devices to Prevent Sudden Cardiac Death: Contemporary Clinical Impacts.

Implantable cardioverter defibrillators (ICDs) are recommended for primary and secondary prevention of sudden cardiac death and were first implanted more than 40 years ago. The addition of cardiac resynchronization improved outcomes in the heart failure population and is now an important part of optimized therapy for this population. In this review, we will address patient selection, risk stratification, and outcomes after ICD placement and technological improvements. Gender disparities in referral and outcomes will be discussed. Far from early technologies with limited pacing capabilities and no antitachycardia pacing (ATP), we have now moved to complex devices with the addition of ATP/ATP during charging, cardiac resynchronization therapy, remote monitoring, and improved battery longevity. The requirement for defibrillation testing at time of implantation has changed and in most implants are not required as part of new clinical guidelines. As the components most likely to fail are the leads, and many complications arise from the intravascular components, extravascular ICDs were developed, the subcutaneous ICD is now an option for many patients, and substernal devices are under clinical trials. Because shocks are associated with worse outcomes, optimized ICD programming is now recommended, with the benefit of reducing appropriate and inappropriate shocks with a decrease in mortality and no increase in the syncopal events. All these improvements will have a positive effect on patient outcomes and quality of life, and new technologies will be developed in the future.

Trends in implantable cardioverter-defibrillator programming practices and its impact on therapies: Insights from a North American Remote Monitoring Registry 2007-2018.

Recent evidence has revealed the utility of prolonged arrhythmia detection duration and increased rate cutoff to reduce implantable cardioverter-defibrillator (ICD) therapies. Data on real-world trends in ICD programming and its impact on outcomes are limited. The purpose of this study was to evaluate trends in ICD programming and its impact on ICD therapy using a large remote monitoring database. A retrospective analysis of patients with ICD implanted from 2007 to 2018 was conducted using the de-identified Medtronic CareLink database. Data on ICD programming (number of intervals to detection [NID] and therapy rate cutoff) and delivered ICD therapies were collected. Among 210,810 patients, the proportion programmed to a rate cutoff of ≥188 beats/min increased from 41% to 49% and an NID of ≥30/40 increased from 17% to 67% before May 2013 vs after February 2016. Programming to a rate cutoff of ≥188 beats/min, a ventricular fibrillation (VF) NID of ≥30/40, or a combined rate cutoff of ≥188 beats/min and VF NID of ≥30/40 were associated with reductions in ICD therapy. The largest reductions in ICD therapy occurred when the combination of rate cutoff ≥ 188 beats/min and VF NID ≥ 30/40 was programmed (antitachycardia pacing: hazard ratio [HR] 0.35; 95% confidence interval [CI] 0.34-0.36; P< .001; shocks: HR 0.67; 95% CI 0.65-0.69; P < .001; and antitachycardia pacing/shocks: HR 0.43; 95% CI 0.42-0.44; P < .001). Despite evidence supporting the use of prolonged detection duration and high rate cutoff, implementation of shock reduction programming strategies in real-world clinical practice has been modest. The use of evidence-based ICD programming is associated with reduced ICD shocks over long-term follow-up.

Implantable Cardioverter Defibrillators in Infants and Toddlers: Indications, Placement, Programming, and Outcomes

Limited data exist regarding implantable cardioverter defibrillator (ICD) usage in infants and toddlers. This study evaluates ICD placement indications, procedural techniques, programming strategies, and outcomes of ICDs in infants and toddlers. This is a single-center retrospective review of all patients ≤3 years old who received an ICD from 2009 to 2021. Fifteen patients received an ICD at an age of 1.2 years (interquartile range [IQR], 0.1-2.4; 12 [80%] women; weight, 8.2 kg [IQR, 4.2-12.6]) and were followed for a median of 4.28 years (IQR, 1.40-5.53) or 64.2 patient-years. ICDs were placed for secondary prevention in 12 patients (80%). Diagnoses included 8 long-QT syndromes (53%), 4 idiopathic ventricular tachycardias/ventricular fibrillations (VFs; 27%), 1 recurrent ventricular tachycardia with cardiomyopathy (7%), 1 VF with left ventricular noncompaction (7%), and 1 catecholaminergic polymorphic ventricular tachycardia (7%). All implants were epicardial, with a coil in the pericardial space. Intraoperative defibrillation safety testing was attempted in 11 patients (73%), with VF induced in 8 (53%). Successful restoration of sinus rhythm was achieved in all tested patients with a median of 9 (IQR, 7.3-11.3) J or 0.90 (IQR, 0.68-1.04) J/kg. Complications consisted of 1 postoperative chylothorax and 3 episodes of feeding intolerance. VF detection was programmed to 250 (IQR, 240-250) ms with first shock delivering 10 (IQR, 5-15) J or 1.1 (IQR, 0.8-1.4) J/kg. Three patients (20%) received appropriate shocks for ventricular tachycardia/VF. No patient received an inappropriate shock. There were 2 (13%) ventricular lead fractures (at 2.6 and 4.2 years post-implant), 1 (7%) pocket-site infection, and 2 (13%) generator exchanges. All patients were alive, and 1 patient (7%) received a heart transplant. ICDs can be safely and effectively placed for sudden death prevention in infants and toddlers with good midterm outcomes.

Имплантируемые кардиовертеры-дефибрилляторы в профилактике внезапной сердечной смерти: технические аспекты и дальнейшие перспективы применения. Что нужно знать практикующему врачу?

Currently, the prevention of sudden cardiac death (SCD) is an urgent issue as never, i.e., more than a half of patients with cardiovascular disorders die suddenly, one third of patients are young and middle-aged adults. The primary preventive strategy of SCD is an implantable cardioverter defibrillator (ICD) due to the lack of highly effective and, more important, safe antiarrhythmics. Forty years after the first ICD insertion, SCD is still the cause of more than 5 million of deaths annually worldwide. Therefore, a real need for ICD is significantly higher than the number of insertions. Meanwhile, primary physicians are not aware of this preventive tool. This paper reviews current approaches to ICD use for the primary and secondary prevention of SCD, types of ICDs, selection of electrode insertion sites, relevant aspects of ICD programming to detect and addresses arrhythmias by antitachycardial pacing or shock discharge, standards for outpatient follow-up after ICD insertion, distant monitoring and telemetry, and future perspectives of ICD insertion. KEYWORDS: sudden cardiac death, implantable cardioverter defibrillator, distant monitoring, perspectives. FOR CITATION: Talibullin I.V., Lebedeva N.B., Parfenov P.G., Mamchur S.E. Implantable cardioverter defibrillators for the prevention of sudden cardiac death: technical aspects and future perspectives. What a practitioner needs to know? Russian Medical Inquiry. 2022;6(1):21– 25 (in Russ.). DOI: 10.32364/2587-6821-2022-6-1-21-25.

Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: Analysis of All Appropriate Therapy in the PRAETORIAN Trial.

The PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) showed noninferiority of subcutaneous implantable cardioverter defibrillator (S-ICD) compared with transvenous implantable cardioverter defibrillator (TV-ICD) with regard to inappropriate shocks and complications. In contrast to TV-ICD, S-ICD cannot provide antitachycardia pacing for monomorphic ventricular tachycardia. This prespecified secondary analysis evaluates appropriate therapy and whether antitachycardia pacing reduces the number of appropriate shocks. The PRAETORIAN trial was an international, investigator-initiated randomized trial that included patients with an indication for implantable cardioverter defibrillator (ICD) therapy. Patients with previous ventricular tachycardia <170 bpm or refractory recurrent monomorphic ventricular tachycardia were excluded. In 39 centers, 849 patients were randomized to receive an S-ICD (n=426) or TV-ICD (n=423) and were followed for a median of 49.1 months. ICD programming was mandated by protocol. Appropriate ICD therapy was defined as therapy for ventricular arrhythmias. Arrhythmias were classified as discrete episodes and storm episodes (≥3 episodes within 24 hours). Analyses were performed in the modified intention-to-treat population. In the S-ICD group, 86 of 426 patients received appropriate therapy, versus 78 of 423 patients in the TV-ICD group, during a median follow-up of 52 months (48-month Kaplan-Meier estimates 19.4% and 17.5%; P=0.45). In the S-ICD group, 83 patients received at least 1 shock, versus 57 patients in the TV-ICD group (48-month Kaplan-Meier estimates 19.2% and 11.5%; P=0.02). Patients in the S-ICD group had a total of 254 shocks, compared with 228 shocks in the TV-ICD group (P=0.68). First shock efficacy was 93.8% in the S-ICD group and 91.6% in the TV-ICD group (P=0.40). The first antitachycardia pacing attempt successfully terminated 46% of all monomorphic ventricular tachycardias, but accelerated the arrhythmia in 9.4%. Ten patients with S-ICD experienced 13 electrical storms, versus 18 patients with TV-ICD with 19 electrical storms. Patients with appropriate therapy had an almost 2-fold increased relative risk of electrical storms in the TV-ICD group compared with the S-ICD group (P=0.05). In this trial, no difference was observed in shock efficacy of S-ICD compared with TV-ICD. Although patients in the S-ICD group were more likely to receive an ICD shock, the total number of appropriate shocks was not different between the 2 groups. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.

Single- vs dual-chamber ICDs to prevent from inappropriate shocks: the debate is still alive

Abstract Background The efficacy of dual-chamber implantable cardioverter defibrillators (ICDs) in preventing from inappropriate shocks (IS) is still a matter of debate. Purpose To compare the risk of IS among single- and dual-chamber ICDs in a cohort of heart failure (HF) patients carrying a prophylactic device. We aimed to focus on the relationship between programming and discriminators, and the risk of IS in a large cohort. Methods All HF patients with left ventricle ejection fraction &amp;lt;35% undergoing a prophylactic ICD-only implant were collected from the multicentre, prospective and nationwide UMBRELLA study. ICD programming was performed according to regular clinical practice at each site and. ICD setting and arrhythmic events occurring during the study period were automatically stored through the remote monitoring system. An experts committee analysed in a blinded manner all electrograms coming from the arrhythmic events. Results From 2006 to 2015, 782 patients implanted with an ICD were analysed (537 patients (68.7%) with single-chamber ICDs and 245 patients (31.3%) with dual-chamber ICDs). During a mean follow-up of 4.35±2 years, 109 IS were delivered in 49 patients. IS occurred in 7.8% (n=42) of patients carrying single-chamber ICDs and in 2.9% (n=7) of dual-chamber carriers (p=0.001). A propensity score matched analysis was performed. The matched cohort was composed by 110 well-balanced (regarding baseline characteristics and programming) patients. In the weighted sample, dual-chamber ICDs were related to lower rates of IS (Figure 1) as compared to single-chamber devices (0.9% vs. 11.8%, p≤0.001). Among programming the following ICD settings correlated to lower risk of IS: ≥30 of 40 intervals detection within ventricular fibrillation (VF) zone (HR=0.47; p=0.018), a programmed ATP-capable zone enabled through VF zone (HR=0.54; p=0.038), morphology discriminator (Wavelet®) (HR=0.42; p=0.032), and the specific dual-chamber discriminator (PR Logic®) (HR=0.28; p=0.004). After multivariable Cox regression analysis including clinical variables and device settings, PR Logic® discriminator was the only programming parameter independently related to a lower risk of IS (HR=0.18, CI 0.06–0.48, p=0.001). Conclusions In our nationwide cohort of primary prevention ICD-only patients, dual-chamber devices were associated with a lower risk of IS. ICDs equipped with PR Logic® discriminator might be useful to prevent from IS. Funding Acknowledgement Type of funding sources: None. Programming in the matched populationFigure 1