Performance of the subcutaneous implantable cardioverter-defibrillator in patients with a primary prevention indication with and without a reduced ejection fraction versus patients with a secondary prevention indication

Clinical impact of ECG change on oversensing of subcutaneous implantable cardioverter-defibrillators

BACKGROUND

Inappropriate shocks delivered from subcutaneous implantable cardioverter-defibrillators (S-ICD) are most frequently caused by cardiac oversensing. However, the predictors for oversensing of S-ICD remain unclear.

OBJECTIVE

We aimed to investigate the predictors for oversensing of S-ICD, especially clinical impact of ECG change.

METHODS

We retrospectively enrolled 99 consecutive patients who underwent S-ICD implantation between 2013 and 2021. Oversensing events were defined as inappropriate charge of the capacitors induced by cardiac or noncardiac signals other than tachycardia.

RESULTS

During a median 34 month (IQR 20-50 months) of the follow-up period, 11 of the 99 patients experienced 34 oversensing events and 4 patients received inappropriate shocks during their events. Six patients exhibited ECG changes (bundle branch block, 3; ventricular pacing, 1; inverted T wave, 1; poor R progression, 1) during follow-up period. Oversensing events were observed in four of the six patients with ECG changes (67%), and three patients underwent S-ICD removal because of inevitable shock. Contrastingly, among the remaining patients without ECG change, all 7 patients who experienced oversensing events could continue using S-ICD with reprogramming sensing vector and/or restriction of excessive exercise. Logistic regression analysis showed lower voltage of Sokolow-Lyon ECG (V₁S+V₅R) was the predictor of oversensing event among the patients without ECG change. When the cut off value was 2.1mV, the sensitivity, specificity, positive predictive value, and negative predictive value were 85.7%, 62.7%, 15.7%, and 98.1%, respectively.

CONCLUSION

Unavoidable oversensing resulting in S-ICD removal is caused by ECG changes. Oversensing in patients without ECG change can be managed.

Nomogram predicting death and heart transplantation before appropriate ICD shock in dilated cardiomyopathy

Aims

This study aimed to develop and validate a competing risk nomogram for predicting all‐cause mortality and heart transplantation (HT) before first appropriate shock in non‐ischaemic dilated cardiomyopathy (DCM) patients receiving implantable cardioverter‐defibrillators (ICD).

Methods and results

A total of 218 consecutive DCM patients implanted with ICD between 2010 and 2019 at our institution were retrospectively enrolled. Cox proportional hazards model was primarily built to identify variables associated with death and HT. Then, a Fine–Gray model, accounting for the appropriate shock as a competing risk, was constructed using these selected variables along with implantation indication (primary vs. secondary). Finally, a nomogram based on the Fine–Gray model was established to predict 1‐, 3‐, and 5‐year probabilities of all‐cause mortality and HT before first appropriate shock. The area under the receiver operating characteristic (ROC) curve (AUC), Harrell's C‐index, and calibration curves were used to evaluate and internally validate the performance of this model. The decision curve analysis was applied to assess its clinical utility. The 1‐, 3‐, and 5‐year cumulative incidence of all‐cause mortality and HT without former appropriate shock were 5.3% [95% confidence interval (CI) 2.9–9.9%], 16.6% (95% CI 11–25.0%), and 25.3% (95% CI 17.2–37.1%), respectively. Five variables including implantation indication, left ventricular end‐diastolic diameter, N‐terminal pro‐brain natriuretic peptide, angiotensin‐converting enzyme inhibitor/angiotensin receptor blocker, and amiodarone treatment were independently associated with it (all P < 0.05) and were used for constructing the nomogram. The 1‐, 3‐, and 5‐year AUC of the nomogram were 0.83 (95% CI 0.73–0.94, P < 0.001), 0.84 (95% CI 0.75–0.93, P < 0.001), and 0.85 (95% CI 0.77–0.94, P < 0.001), respectively. The Harrell's C‐index was 0.788 (95% CI 0.697–0.877, P < 0.001; 0.762 for the optimism‐corrected C‐index), showing the good discriminative ability of the model. The calibration was acceptable (optimism‐corrected slope 0.896). Decision curve analysis identified our model was clinically useful within the entire range of potential treatment thresholds for ICD implantation. Three risk groups stratified by scores were significantly different between cumulative incidence curves (P < 0.001). The identified high‐risk group composed 17.9% of our population and did not derive long‐term benefit from ICD.

Conclusions

The proposed nomogram is a simple, useful risk stratification tool for selecting potential ICD recipients in DCM patients. It might facilitate the shared decision‐making between patients and clinicians.

OUP accepted manuscript

Aims

To report 5-year outcomes of EFFORTLESS registry patients with early generation subcutaneous implantable cardioverter-defibrillator (S-ICD) devices.

Methods and results

Kaplan–Meier, trend and multivariable analyses were performed for mortality and late (years 2–5) complications, appropriate shock (AS) and inappropriate shock (IAS) rates. Nine hundred and eighty-four of 994 enrolled patients with diverse diagnoses (28% female, 48 ± 17 years, body mass index 27 ± 6 kg/m², ejection fraction 43 ± 18%) underwent S-ICD implantation. Median follow-up was 5.1 years (interquartile range 4.7–5.5 years). All-cause mortality was 9.3% (95% confidence interval 7.2–11.3%) at 5 years; 703 patients remained in follow-up on study completion, 171 withdrew including 87 (8.8%) with device explanted, and 65 (6.6%) lost to follow-up. Of the explants, only 20 (2.0%) patients needed a transvenous device for pacing indications. First and final shock efficacy for discrete ventricular arrhythmias was consistent at 90% and 98%, respectively, with storm episode final shock efficacy at 95.2%. Time to therapy remained unaltered. Overall 1- and 5-year complication rates were 8.9% and 15.2%, respectively. Early complications did not predict later complications. There were no structural lead failures. Inappropriate shock rates at 1 and 5 years were 8.7% and 16.9%, respectively. Self-terminating inappropriately sensed episodes predicted late IAS. Predictors of late AS included self-terminating appropriately sensed episodes and earlier AS.

Conclusion

In this diverse S-ICD registry population, spontaneous shock efficacy was consistently high over 5 years. Very few patients underwent S-ICD replacement with a transvenous device for pacing indications. Treated and self-terminating arrhythmic episodes predict future shock events, which should encourage more personalized device optimization.

Non-transvenous ICD therapy: current status and beyond

Subcutaneous implantable cardioverter/defibrillators (S-ICDs) have been developed to offer ICD treatment to patients without venous access to the heart and to overcome complications associated with transvenous leads, particularly lead fracture/insulation defects and endocarditis. Several studies and registries have demonstrated the feasibility and safety of S‑ICD in different groups of patients. Further developments in S‑ICD technology involve the combination with devices that can provide anti-bradycardia and anti-tachycardia pacing if needed. The extravascular ICD (EV-ICD) is a new system that similarly offers ICD therapy without a transvenous lead but uses a substernal instead of a subcutaneous lead to facilitate detection of ventricular fibrillation and to provide anti-tachycardia and also temporary anti-bradycardia pacing. The first animal but also clinical data on EV-ICDs have been published. This review discusses the current state, potential advantages and limitations, and future research of both S‑ICD and EV-ICD.

Secondary prevention of sudden cardiac death

The prevention and treatment of sudden cardiac death (SCD) remains a significant public health challenge. For patients with a history of sudden death attributable to ventricular arrhythmia, implantable cardioverter-defibrillator (ICD) therapy is a mainstay of treatment, although these patients remain at high risk for recurrent ventricular arrhythmia and defibrillator therapies. In this review, we summarize landmark clinical trials evaluating the efficacy of ICD therapy in secondary prevention patients, review clinical outcomes including mode of death in survivors of SCD, and highlight the role for systematic diagnostic evaluation. We additionally discuss the invasive electrophysiological management of these patients, including ICD selection and programming as well as the role and timing of antiarrhythmic drug therapy and catheter ablation. Finally, we frame future challenges and needs to advance the care for secondary prevention patients.

State-of-the-art consensus on non-transvenous implantable cardioverter-defibrillator therapy

Within the last decade, implantable cardioverter-defibrillator (ICD) systems with non-transvenous leads were developed in order to minimize complications related to the cardiovascular position of transvenous ICD leads. This national expert consensus gives an overview of potential indications for the implantation of non-transvenous ICD systems, and provides specific recommendations for implantation, follow-up, and complication management in patients with subcutaneous ICD. Regarding particular issues like the necessity for shock efficacy testing, or the clinical outcome as compared to transvenous ICD, randomized data are expected in the near future.

Subcutaneous implantable cardioverter defibrillator indication in prevention of sudden cardiac death in difficult clinical situations: A French expert position paper

The introduction of a new technology always raises questions about its place compared with the reference technology. The use of an implantable cardioverter defibrillator to prevent sudden cardiac death is now a widely proven technique, with a clear statement of its indication in the guidelines. More recently, a subcutaneous implantable cardioverter defibrillator has been introduced, and appears to be an attractive technique as it removes the need to implant a lead inside the right ventricle to treat the patient, which should dramatically decrease the risk of complications over time. Currently, only one model of subcutaneous implantable cardioverter defibrillator is available on the market; its indications are the same as for transvenous implantable cardioverter defibrillators, except for patients who need stimulation because of conduction disorders or ventricular tachycardias that can potentially be treated effectively by antitachycardia pacing. The different technical characteristics of transvenous versus subcutaneous implantable cardioverter defibrillators therefore raise the question of which to choose in different clinical settings. The experts who participated in the preparation of this manuscript had three meetings, organized by the company Boston Scientific. Each expert prepared the draft of a section corresponding to a clinical situation. The choice between transvenous versus subcutaneous implantable cardioverter defibrillator was then voted on by all the experts. The results of the votes are presented in this manuscript, as it seemed important to us to show the disparities of opinion that can exist in certain situations. The votes were cast independently and anonymously.

Incidence, mechanisms, and clinical impact of inappropriate shocks in patients with a subcutaneous defibrillator

Aims

Inappropriate shocks (IAS) remain a challenge for patients and physicians after implantation of the subcutaneous implantable cardioverter-defibrillator (S-ICD). The aims were to assess and characterize different patterns of IAS.

Methods and results

Two hundred and thirty-nine patients were implanted with an S-ICD between 2010 and 2018 for primary and secondary prevention. Follow-up data of at least 6 months were analysed. During a mean follow-up of 34.9 ± 16.0 months, a total of 73 shocks occurred in 38 patients (6%). Forty-three (59%) shocks were considered appropriate due to ventricular tachycardia/ventricular fibrillation, while 30 (41%) were inappropriate and occurred in 19 patients (8%). Myopotentials/noise was the most frequent cause of inappropriate shocks (n = 8), followed by T-wave oversensing (n = 6) and undersensing of the QRS, resulting in adaptation of the automatic gain control and inappropriate shock (n = 5). Seventy-four percent of all IAS occurred on the primary vector, while no IAS occurred on the alternate vector. In seven of eight patients (88%), IAS related to myopotentials have occurred on the primary sensing vector. Multivariate analysis identified taller patients, primary sensing vector and first-generation S-ICD device as predictors for IAS. SMART pass effectively reduced the occurrence of IAS in the second-generation S-ICD system.

Conclusion

Inappropriate therapies are less frequently observed on the alternate vector. The primary vector seems to be unfavourable with regard to oversensing caused by myopotentials. Inappropriate shocks were associated with an increased rate of rehospitalization but not mortality. These observations have implications for the prevention of inappropriate S-ICD shocks.

The subcutaneous implantable cardioverter-defibrillator in review

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a completely extrathoracic device that has recently been FDA approved for the prevention of sudden cardiac death in select populations. Although the transvenous implantable cardioverter defibrillator (TV-ICD) has a proven mortality benefit in multiple patient populations, there are significant risks both with implantation and years after its placement. The S-ICD may help prevent some of these complications. Currently, the S-ICD is typically implanted in patients with prior device infection or at an increased risk for an infection, younger patients with difficult venous access related to either hemodialysis or difficult cardiac anatomy, patients who live active lifestyles, and those who may outlive the TV-ICD leads. There is an absolute contraindication for S-ICD implantations for patients who need pacing either for ventricular tachycardia or bradycardia because this device cannot perform these functions. To date, there are no randomized controlled trial (RCT) data evaluating the safety and efficacy of this relatively new device. Observational studies of both the S-ICD alone and in comparison with the TV-ICD have showed promising results, including a decrease in lead-related and periprocedural complications as well as a high level of effectiveness at terminating ventricular arrhythmias. These analyses over time may have contributed to the evolution and comfortability with the S-ICD system, as physicians are more often referring for and/or implanting this device for patients with appropriate indications. Furthermore, inappropriate shock rates with the S-ICD have decreased over time especially with dual zone programming. This review summarizes the results of a multitude of observational studies with respect to patient selection for the S-ICD, complication rates, appropriate and inappropriate shock rates, and programming. This review also tackles current ongoing randomized trials. Although the results of ongoing trials will be helpful, there is still a continued need to evaluate the efficacy of the S-ICD in broader patient populations including patients with several comorbidities and older patients so that more patients can be considered for this potentially lifesaving device.

The subcutaneous implantable cardioverter-defibrillator: Current trends in clinical practice between guidelines and technology progress

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a valuable alternative to the conventional trans-venous ICD (TV-ICD) for the prevention of sudden cardiac death (SCD). Prospective registries showed that the S-ICD is safe and effective in treating ventricular tachyarrhythmias in high-risk patients without pacing indications. While in earlier studies patients implanted with S-ICDs were young and mostly affected by channelopathies, contemporary S-ICD cohorts include patients with severely impaired left ventricular function and significant comorbidities. This review focuses on S-ICD evidence-based use and highlights current gaps between guidelines recommendations and real-world clinical practice.

Feasibility of entirely subcutaneous ICD™ systems in patients with coronary artery disease

BACKGROUND

The subcutaneous ICD (S-ICD™) is an important advance in device therapy for the prevention of sudden cardiac death (SCD). Although current guidelines recommend S-ICD™ use, long-term data are still limited, especially in subgroups. Among several cardiac diseases that prone to SCD, coronary artery disease (CAD) carries several peculiarities that may hamper S-ICD™ therapy in this cohort. CAD can lead to an ischemic cardiomyopathy (ICM) with a reduced left-ventricular ejection fraction (LVEF) and bundle branch blocks, which can be difficult for ICD sensing and discrimination of arrhythmia. CAD is mainly driven by risk factors such as diabetes mellitus, which put these patients at an elevated risk for infectious complications of cardiac devices. Furthermore, in ICM myocardial scars are frequent and are a potential substrate for ventricular tachycardia, which may be accessible for antitachycardia pacing. At the moment, it remains unclear if there is a value of S-ICD™ therapy in this subgroup. Therefore, this study analysed patients with CAD.

MATERIALS AND METHODS

All S-ICD™ patients with CAD as the main indication for ICD implantation (n = 45 patients) in our large-scaled single-center S-ICD™ registry (n = 249 patients) were included in this study. Baseline characteristics, appropriate and inappropriate shocks, and complications were documented in a mean follow-up of 22.5 ± 8.3 months.

RESULTS

Primary prevention of SCD was the indication for implantation of an S-ICD™ in 28 patients (62%). Of all 45 patients with an overall mean age of 58.1 ± 11.4 years, 40 were male (88%). The mean LVEF was 37.7 ± 12.6%. Three episodes of ventricular arrhythmia (one monomorphic, one polymorphic, one ventricular fibrillation) were adequately terminated in three patients (7%). In only one patient, oversensing resulting in an inappropriate shock was observed, which could be managed by changing the sensing vector. 15 of the examined 45 patients previously had a transvenous ICD, which was explanted due to system-related infections. In only two patients, S-ICD™ was changed to transvenous ICD because of the need of antibradycardia stimulation. There were no S-ICD™ system-related infections.

CONCLUSION

The S-ICD™ seems to be a valuable option for the prevention of SCD in CAD patients. Patients with systemic infections of a transvenous ICD and, therefore, a need for an alternative might benefit from the absence of intracardiac leads as the S-ICD™ is safe and works flawlessly in these patients. Inadequate shock delivery was very rare, while every episode of ventricular arrhythmia was terminated by the first shock.

EHRA White Paper: knowledge gaps in arrhythmia management—status 2019

Clinicians accept that there are many unknowns when we make diagnostic and therapeutic decisions. Acceptance of uncertainty is essential for the pursuit of the profession: bedside decisions must often be made on the basis of incomplete evidence. Over the years, physicians sometimes even do not realize anymore which the fundamental gaps in our knowledge are. As clinical scientists, however, we have to halt and consider what we do not know yet, and how we can move forward addressing those unknowns. The European Heart Rhythm Association (EHRA) believes that scanning the field of arrhythmia / cardiac electrophysiology to identify knowledge gaps which are not yet the subject of organized research, should be undertaken on a regular basis. Such a review (White Paper) should concentrate on research which is feasible, realistic, and clinically relevant, and should not deal with futuristic aspirations. It fits with the EHRA mission that these White Papers should be shared on a global basis in order to foster collaborative and needed research which will ultimately lead to better care for our patients. The present EHRA White Paper summarizes knowledge gaps in the management of atrial fibrillation, ventricular tachycardia/sudden death and heart failure.

The modular cardiac rhythm management system: the EMPOWER leadless pacemaker and the EMBLEM subcutaneous ICD

Cardiac implantable electronic devices have been successfully treating patients with brady- and tachyarrhythmias for decades. However, there are still significant complications related to this therapy modality, many related to the transvenous lead. Paradigm-shifting technologies, such as the subcutaneous implantable cardioverter-defibrillator (S-ICD) and leadless cardiac pacemakers (LCP), have emerged to address these complications. The novel modular cardiac rhythm management (mCRM) system, consisting of a communicating antitachycardia pacing-enabled LCP and S‑ICD, is the first system to integrate wireless intrabody communication between devices to allow for coordination of leadless pacing and defibrillator therapy delivery. In this review, the design and concept of the mCRM system are presented and available evidence is summarized.

Risk Factors and Temporal Trends of Complications Associated With Transvenous Implantable Cardiac Defibrillator Leads

Background

The transvenous implantable cardioverter‐defibrillator (ICD) lead is the most common source of complications in a traditional ICD system. This investigation aims to determine the incidence, predictors, and costs associated with these complications using a large insurance database.

Methods and Results

Data from the OptumLabs™ Data Warehouse, which include diagnosis, physician and procedure codes, and claims from patient hospitalizations, were analyzed. Patients with a de novo ICD or cardiac resynchronization therapy defibrillator implanted from January 1, 2003, through June 30, 2015, were included; those who did not have continuous coverage beginning 1 year before implantation were excluded, resulting in 40 837 patients followed up over an average of 2.3±2.1 years. Patients were followed up until they had the procedure or their last active date in the database. Of 20 580 device procedures, 2165 (5.3%) and 771 (1.9%) had mechanical and infectious complications, respectively. The 5‐year rate of freedom from mechanical complication was 92.0% and 89.3% for ICDs and cardiac resynchronization therapy defibrillators, respectively. Infectious complications were more likely in patients with a history of atrial fibrillation, diabetes mellitus, and renal disease, and the risk increased with subsequent device procedures. Younger age, female sex, lack of comorbidities, and implantations between 2003 and 2008 were associated with more mechanical complications.

Conclusions

Incidence of mechanical and infectious complications of transvenous ICD leads over long‐term follow‐up is much higher in the real world than in clinical studies. In our study cohort, 1 of 4 transvenous ICD leads had mechanical complications when followed up to 10 years. The high rate of reintervention leads to additional complications.

Specific indications and clinical outcome in patients with subcutaneous implantable cardioverter-defibrillator (ICD) - A nationwide multicentre registry

BACKGROUND

Subcutaneous implantable cardioverter-defibrillators (S-ICD) are an innovative and less invasive alternative to transvenous ICD (TV-ICD) in selected patients. We aimed to investigate the underlying diseases and the specific indications for implanting S-ICD in clinical practice, as well as the prevalence of shock delivery and complications.

METHODS AND RESULTS

From December 2012, data of 236 patients (30,5% female; age 48,6±16,8years) were gathered from 12 centres in Austria. Follow-up data over a period of 1,7±1,1years were available for 231 patients (in total 359,2 patient-years). Predominant underlying diseases were ischemic cardiomyopathy (iCMP; 32,0%), idiopathic ventricular fibrillation (22,6%) and dilated cardiomyopathy (dCMP; 17,3%). The most frequent indications for implantation were sudden cardiac death survival (27,4%), primary prevention for iCMP (23,9%) and for dCMP (12,8%), and previous explantation of TV-ICD (12,4%). Appropriate shocks were documented in 16 patients (6,9%), iCMP being the predominant underlying disease. Arrhythmia conversion was successful in all patients, efficacy of the first shock was 96%. Inappropriate shock rate was 5,2%, predominantly caused by oversensing of T wave or artefacts. A device upgrade to an ICD system with pacing function was necessary in <1%. Clinical complications needing surgical revision occurred in 8 patients (3,5%).

CONCLUSIONS

S-ICD were mostly implanted for primary prevention, one fourth of our cases were sudden death survivors. Clinical and functional complication rate was relatively low. In conclusion, S-ICD is a safe and efficient alternative in a larger population of ICD candidates, when no cardiac pacing is needed. EC-number: C-136-17.

Spectrum and Outcome of Patients Who Have Undergone Implantation of an Implantable Cardioverter Defibrillator After Aborted-Sudden Cardiac Arrest

Most of implantable cardioverter defibrillator (ICD) secondary prevention studies have been published 2 decades ago. We aimed to describe a contemporary cohort of patients who have undergone implantation of an ICD after an aborted-sudden cardiac arrest (SCA). We retrospectively evaluated consecutive patients referred to our centers between 2005 and 2013. Predictors of overall mortality or heart transplant were analyzed using Cox proportional hazards models. A total of 250 patients (76.4% male, 48.7 ± 16.7 years) were included (mean follow-up = 49.6 ± 35 months). The presence of a structural heart disease (SHD) was considered as the primary cause of the aborted-SCA in 160 patients (64%). In 90 patients (36%), no SHD was observed, with patients much younger (40.9 ± 16.2 years vs 53.0 ± 15.5 years in the SHD group, p < 0.0001). The 5-year estimated rates of death or heart transplant were 14.3% and 5.2% in the group with and without SHD, respectively (hazard ratio = 4.65, 95% confidence interval 1.40 to 15.6, p = 0.014). The 5-year estimated rates of appropriate ICD therapy in the ventricular fibrillation zone were 16.7% and 25.1% in patients without and with SHD (p = 0.24), respectively. Only left ventricular ejection fraction remained independently associated with mortality or heart transplant (hazard ratio = 0.94, 95% confidence interval 0.90 to 0.97, p = 0.0004). Overall, 69 patients (27.6%) experienced at least 1 ICD-related complication. In conclusion, compared with secondary prevention pivotal studies, the current patients who have undergone implantation of an ICD after aborted-SCA are younger, with a high proportion of structurally normal hearts. Compared with patients without SHD, who depicted a relatively favorable outcome, patients with SHD present a fourfold higher risk of death during follow-up. Reduced left ventricular ejection fraction remains the major influencing factor.

Acute and Long-term Results After Contemporary Subcutaneous Implantable Cardioverter-defibrillator Implantation: A Single-center Experience

INTRODUCTION AND OBJECTIVES

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to the transvenous defibrillator. The incidence of complications is similar, with inappropriate shocks (IS) being more frequent than those occurring with contemporary programming of transvenous defibrillators. Several improvements have been implemented after the S-ICD was approved for use in Europe in 2009. This study reports the results of S-ICD use in a single center, whose experience began late, at the end of 2013.

METHODS

Prospective observational study including consecutive patients with defibrillator indication and no indication for either permanent pacing or cardiac resynchronization who underwent S-ICD implantation. Implant data and long-term follow-up were analyzed.

RESULTS

An S-ICD was implanted in 50 patients who were deemed suitable after electrocardiographic screening. The mean age was 46.9±15 (range, 15-78) years and 72% were male. Thirty eight percent had left ventricular ejection fraction ≤ 35%. The most frequent heart disease was ischemic heart disease (34%), followed by hypertrophic cardiomyopathy (18%). The intermuscular technique was used, with 3 incisions in 10% and 2 incisions in the remaining 90%. Ventricular fibrillation was induced in 49 patients, with 100% effectiveness in their conversion. After a mean follow-up of 18.1 (range, 2.3-44.8) months, there were no late complications requiring surgical revision, the rate of IS was 0%, and 1 patient (2%) experienced appropriate shocks.

CONCLUSIONS

Improvements in technology, implant technique and device programming, along with appropriate patient selection, have led to outstanding acute and long-term results, especially regarding the absence of both IS and complications requiring surgical revision.

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

BACKGROUND

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).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

A case of long QT syndrome: challenges on a bumpy road

Beta‐agonist treatment during pregnancy may unmask the diagnosis of long QT syndrome. The QT prolongation can result in functional AV block. A history of seizure and/or sudden death in a family member should raise suspicion of ventricular tachycardia. More than one mutation may coexist. Refusal of beta‐blocker therapy complicates risk stratification.