Risk of failure of transvenous implantable cardioverter-defibrillator leads

Cardiovascular implantable electronic device lead safety: Harnessing real-world remote monitoring data for medical device evaluation

BACKGROUND

Current methods to identify cardiovascular implantable electronic device lead failure include postapproval studies, which may be limited in scope, participant numbers, and attrition; studies relying on administrative codes, which lack specificity; and voluntary adverse event reporting, which cannot determine incidence or attribution to the lead.

OBJECTIVE

The purpose of this study was to determine whether adjudicated remote monitoring (RM) data can address these limitations and augment lead safety evaluation.

METHODS

Among 48,191 actively monitored patients with a cardiovascular implantable electronic device, we identified RM transmissions signifying incident lead abnormalities and, separately, identified all leads abandoned or extracted between April 1, 2019, and April 1, 2021. We queried electronic health record and Medicare fee-for-service claims data to determine whether patients had administrative codes for lead failure. We verified lead failure through manual electronic health record review.

RESULTS

Of the 48,191 patients, 1170 (2.4%) had incident lead abnormalities detected by RM. Of these, 409 patients had administrative codes for lead failure, and 233 of these 409 patients (57.0%) had structural lead failure verified through chart review. Of the 761 patients without administrative codes, 167 (21.9%) had structural lead failure verified through chart review. Thus, 400 patients with RM transmissions suggestive of lead abnormalities (34.2%) had structural lead failure. In addition, 200 patients without preceding abnormal RM transmissions had leads abandoned or extracted for structural failure, making the total lead failure cohort 600 patients (66.7% with RM abnormalities, 33.3% without). Patients with isolated right atrial or left ventricular lead failure were less likely to have lead replacement and administrative codes reflective of lead failure.

CONCLUSION

RM may strengthen real-world assessment of lead failure, particularly for leads where patients do not undergo replacement.

Transvenous or subcutaneous implantable cardioverter defibrillator: a review to aid decision-making

The implantable cardioverter-defibrillator (ICD) is a proven treatment for preventing sudden cardiac death. Transvenous leads are associated with significant mortality and morbidity, and the subcutaneous ICD (S-ICD) addresses this. However, it is not without limitations, in particular the absence of anti-tachycardia pacing. The decision of which device is most suitable for an individual patient is often complex. Here, we review the relative merits and weaknesses of both the transvenous and S-ICD. We summarise the available evidence for each device in particular patient cohorts, namely: ischaemic and non-ischaemic cardiomyopathy, idiopathic ventricular fibrillation, Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy.

FRAGILE: FRench Attitude reGistry in case of ICD LEad replacement

AIMS

FRench Attitude reGistry in case of ICD LEad replacement (FRAGILE) registry was set-up to describe the attitude in different French institutions in case of implantable cardioverter-defibrillator (ICD) lead replacement, extraction, or abandonment and to compare outcomes in both groups.

METHODS AND RESULTS

Prospective observational study comparing two attitudes in case of ICD lead replacement, extraction, or abandonment. Primary endpoint describes the attitude in different French centres, collect parameters that may influence the decision. Secondary endpoint compares early and mid-term (2 years) complications in both groups.Between April 2013 and April 2017, 552 patients were included in 32 centres. 434 (78.6%) were male, mean patient's age was 60.3 ± 14.4 years. In 56.9% of the cases, the decision was to explant the lead. Patients in the extraction group were younger than in the abandonment group (56.7 ± 14.5 vs. 65 ± 12.7 P < 0.0001) and less likely to have comorbidities (46.5% vs. 58.3% of the patients P = 0.022). The mean lead dwelling time was significantly longer in the abandonment group as compared with the extraction group (7.6 ± 3.9 vs. 5.2 ± 3.1 years, P < 0.0001). There was no statistical difference between both groups concerning early and 2 years complications.

CONCLUSION

In this registry, the strategy in case of non-infected ICD lead replacement was mainly influenced by patient's age and comorbidities and lead dwelling time. No difference was observed in outcomes in both strategies.

Long-term follow-up of abandoned transvenous defibrillator leads: a nationwide cohort study

AIMS

Commonly, a dysfunctional defibrillator lead is abandoned and a new lead is implanted. Long-term follow-up data on abandoned leads are sparse. We aimed to investigate the incidence and reasons for extraction of abandoned defibrillator leads in a nationwide cohort and to describe extraction procedure-related complications.

METHODS AND RESULTS

All abandoned transvenous defibrillator leads were identified in the Danish Pacemaker and ICD Register from 1991 to 2019. The event-free survival of abandoned defibrillator leads was studied, and medical records of patients with interventions on abandoned defibrillator leads were audited for procedure-related data. We identified 740 abandoned defibrillator leads. Meantime from implantation to abandonment was 7.2 ± 3.8 years with mean patient age at abandonment of 66.5 ± 13.7 years. During a mean follow-up after abandonment of 4.4 ± 3.1 years, 65 (8.8%) abandoned defibrillator leads were extracted. Most frequent reason for extraction was infection (pocket and systemic) in 41 (63%) patients. Procedural outcome after lead extraction was clinical success in 63 (97%) patients. Minor complications occurred in 3 (5%) patients, and major complications in 1 (2%) patient. No patient died from complication to the procedure during 30-day follow-up after extraction.

CONCLUSION

More than 90% of abandoned defibrillator leads do not need to be extracted during long-term follow-up. The most common indication for extraction is infection. Abandoned defibrillator leads can be extracted with high clinical success rate and low risk of major complications at high-volume centres.

Security millimetre wave body scanner safe for patients with leadless pacemakers or subcutaneous implantable cardioverter-defibrillators

PURPOSE

This study was designed to evaluate the electromagnetic interference (EMI) effects and safety of the new security screening millimetre wave body scanners (MWBSs) for patients with rare cardiac implantable electronic devices (CIEDs).

METHODS

We identified 73 patients with either entirely subcutaneous implantable cardioverter-defibrillators (S-ICD) or leadless pacemakers (LPM) attending routine device follow-up. CIED programming was optimised for the detection of EMI occurrence, and high-voltage therapy was disabled. Patients then underwent millimetre wave body scans under continuous ECG monitoring. Scanning was performed at the recommended distance as well as in close proximity to the scanner emulating accidental exposure. CIED function was observed for EMI effects.

RESULTS

There were no episodes of inhibition of pacing in the leadless pacemaker subgroup, no oversensing in the S-ICD subgroup and no spontaneous device reprogramming in any group. There was no change in pacing or sensing thresholds, and S-ICD vector eligibility remained unchanged after scanning with the MWBS. No CIEDs were identified by the MWBS during the study.

CONCLUSION

No EMI events were detected during the use of MWBSs by patients with either S-ICDs or LPMs. This data should be reassuring for patients suggesting that they can undergo security body scans without worries or disclosure of their CIED status.

Management and Outcomes of Transvenous Pacing Leads in Patients Undergoing Transcatheter Tricuspid Valve Replacement

OBJECTIVES

The aim of this study was to determine the prevalence of pacemaker lead-related complications following transcatheter tricuspid valve replacement (TTVR).

BACKGROUND

The rate of permanent pacemaker implantation following tricuspid valve (TV) surgery is high, and many patients have transvenous leads. The feasibility, safety, and outcomes of subsequently performing TTVR in the setting of transvenous pacemaker leads have not been established.

METHODS

The VIVID (Valve-in-Valve International Database) registry was used to review 329 patients who underwent TTVR following TV repair or replacement. Patients were subdivided into 3 cohorts for intergroup comparisons: no lead, epicardial lead, and transvenous lead (entrapped or not entrapped during the TTVR procedure).

RESULTS

Of 329 patients who underwent TTVR, 128 (39%) had prior pacing systems in place, 70 with epicardial and 58 with transvenous leads. A total of 31 patients had leads passing through the TV. Three patients had the right ventricular (RV) lead extracted prior to TTVR. The remaining 28 patients had the RV lead entrapped between the transcatheter TV implant and the surgical valve (n = 22) or the repaired TV (n = 6). One patient had displacement of the RV lead during the procedure, and 2 experienced lead failure during follow-up. Overall, there was no significant difference in the cumulative incidences of competing outcomes (death, TV reintervention, TV dysfunction) between patients with and those without pacing leads or entrapped RV leads.

CONCLUSIONS

TTVR in the setting of trans-TV pacemaker leads without lead extraction or re-replacement can be performed safely with a low risk for complications, offering an alternative to surgical TV replacement.

Active Surveillance of the Implantable Cardioverter-Defibrillator Registry for Defibrillator Lead Failures

BACKGROUND

Several defibrillator leads have been recalled due to early lead failure leading to significant patient harm. Confirming the safety of contemporary defibrillator leads is essential to optimizing treatment for patients receiving implantable cardioverter-defibrillators (ICDs). We therefore sought to assess the comparative long-term safety of the 4 most commonly implanted ICD leads within the National Cardiovascular Data Registry ICD Registry.

METHODS AND RESULTS

A propensity-matched survival analysis of the ICD Registry was performed evaluating 4 contemporary ICD leads in patients receiving an ICD system for the first time. All patients in the ICD Registry aged ≥18 years who underwent an implant of an ICD between April 1, 2011 and March 31, 2016 were included. Monitoring of safety began with ICD implant and continued up to 5 years. A meaningful difference in ICD failure rate was defined as twice (or more) the lead failure rate observed in the propensity-matched comparator patients. Among the 374 132 patients who received a new ICD implant, no safety alerts were triggered for the primary safety end point of lead failure for any of the high energy leads studied. Estimated rates of freedom from lead failure at 5 years ranged from 97.7% to 98.9% for the 4 high-energy leads of interest.

CONCLUSIONS

Though limited by incomplete long-term outcomes ascertainment, active surveillance of the ICD Registry suggests that there were no meaningful differences in the rate of ICD high-energy lead survival for the 4 most commonly used high-energy ICD leads.

Incidence of myopotential induction in subcutaneous implantable cardioverter-defibrillator patients: Is the oversensing issue really solved?

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has established its role in the prevention of sudden cardiac death in a defined population. Inappropriate shocks and device malfunction in S-ICD therapy may be caused by myopotential (MP) oversensing.

OBJECTIVE

The purpose of this study was to systematically evaluate a cohort of consecutive S-ICD patients for MP inducibility.

METHODS

After S-ICD implantation, all vectors (primary [PrimV], secondary [SecV], alternative [AltV]) were analyzed during isometric chest press (ICP), lifting and holding a 20-kg weight, and side plank exercise (SPE), supporting the body weight on the left arm. When MPs were induced, signal classification was assessed: adequate noise detection, induced undersensing (R waves classified as noise), and oversensing (noise annotated as R waves). In case of noise induction in the current vector, device reprogramming to a noise-free vector was done.

RESULTS

We systematically assessed 41 patients. In nearly all patients (90.2%), MPs were inducible. ICP was the most potent inductor of MPs. Whereas SecV (70.7%) and AltV (75.6%) were most vulnerable during ICP, PrimV was most affected during SPE (51.2%). In only a few cases did the S-ICD software distinguish correctly between MPs and QRS. MPs predominantly led to undersensing (up to 65.9%), but in up to 22% of patients MP-induced oversensing occurred but did not lead to tachycardia detection. No relation was seen between S-ICD lead and generator position and MP inducibility.

CONCLUSION

Induction of MPs during physical exercise was observed frequently. Although in most cases MP noise led to undersensing, oversensing events were commonly observed.

Effectiveness of single- vs dual-coil implantable defibrillator leads: An observational analysis from the SIMPLE study

INTRODUCTION

Dual-coil leads (DC-leads) were the standard of choice since the first nonthoracotomy implantable cardioverter/defibrillator (ICD). We used contemporary data to determine if DC-leads offer any advantage over single-coil leads (SC-leads), in terms of defibrillation efficacy, safety, clinical outcome, and complication rates.

METHODS AND RESULTS

In the Shockless IMPLant Evaluation study, 2500 patients received a first implanted ICD and were randomized to implantation with or without defibrillation testing. Two thousand and four hundred seventy-five patients received SC-coil or DC-coil leads (SC-leads in 1025/2475 patients; 41.4%). In patients who underwent defibrillation testing (n = 1204), patients with both lead types were equally likely to achieve an adequate defibrillation safety margin (88.8% vs 91.2%; P = 0.16). There was no overall effect of lead type on the primary study endpoint of "failed appropriate shock or arrhythmic death" (adjusted HR 1.18; 95% CI, 0.86-1.62; P = 0.300), and on all-cause mortality (SC-leads: 5.34%/year; DC-leads: 5.48%/year; adjusted HR 1.16; 95% CI, 0.94-1.43; P = 0.168). However, among patients without prior heart failure (HF), and SC-leads had a significantly higher risk of failed appropriate shock or arrhythmic death (adjusted HR 7.02; 95% CI, 2.41-20.5). There were no differences in complication rates.

CONCLUSION

In this nonrandomized evaluation, there was no overall difference in defibrillation efficacy, safety, outcome, and complication rates between SC-leads and DC-leads. However, DC-leads were associated with a reduction in the composite of failed appropriate shock or arrhythmic death in the subgroup of non-HF patients. Considering riskier future lead extraction with DC-leads, SC-leads appears to be preferable in the majority of patients.

Frequency of Need for Antitachycardia or Antibradycardia Pacing or Cardiac Resynchronization Therapy in Patients With a Single-Chamber Implantable Cardioverter-Defibrillator

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is unable to deliver antitachycardia pacing (ATP), bradycardia pacing, and cardiac resynchronization therapy (CRT). However, little is known about the proportion of patients that develop the need for 1 of these features. We evaluated the potential suitability for a S-ICD at the time of first replacement in a cohort of patients with a transvenous single-chamber device who did not need bradycardia pacing at the time of implantation. The study cohort consisted of patients who received a transvenous single-chamber ICD between 1998 and September 2017. The primary end point was a combined end point of the need for atrial or ventricular pacing, development of a CRT indication, or termination of ventricular arrhythmias by ATP delivery. During a mean follow-up of 5.6 ± 1.9 years, 78 of 254 patients (31%) reached the primary end point. The 7 years' cumulative S-ICD suitability rate was 65.6% (95% confidence interval [CI] 58.5% to 71.7%). Event rates were 9.5% (95% CI 6.5% to 13.9%) at 1-year follow-up, and 28.0% (95% CI 22.8% to 34.2%) at 5 years' follow-up. For individual end points, incidence rates were 1.8 (95% CI 1.2 to 2.6) per 100-patient-years for CRT, 0.3 (95% CI 0.1 to 0.8) per 100-patient-years for pacing-dependency, and 4.9 (95% CI 3.8 to 6.3) per 100-patient-years for appropriate ATP therapy. No baseline variables for predicting S-ICD unsuitability were found. In conclusion, at the time of the first replacement, 69% of the patients with a single-chamber device would have been clinically eligible for the S-ICD. Incidence rates of developing a bradycardia pacing and CRT indication are low.

Evaluation of recurrent ventricular tachyarrhythmias in patients who survived out-of-hospital cardiac arrest due to ventricular fibrillation: eligibility for subcutaneous implantable defibrillator therapy

Purpose

The subcutaneous implantable defibrillator (S-ICD) was developed to avoid complications related to transvenous leads. A trade-off with the S-ICD is the inability to deliver antitachycardia pacing (ATP). Data is scarce about the recurrence and characteristics of ventricular tachyarrhythmias (VTa) during a follow-up in survivors of out-of-hospital cardiac arrest due to ventricular fibrillation (OHCA-VF). The aim of the study is to determine the characteristics of VTa triggering ICD therapy in order to assess whether survivors of OHCA-VF are eligible candidates for the S-ICD.

Methods

All OHCA-VF patients who received a transvenous ICD were identified, 378 patients, age 57 ± 14 years, predominantly male (76%) with ischemic heart disease (58%). Arrhythmic endpoints were appropriate ICD therapies for any ventricular arrhythmia.

Results

Over a median follow-up of 4.5 years, 690 VTa in 91 patients (24%) were terminated by ICD therapy; 70% of patients had < 5 VTa with ICD therapy. VTa with cycle length ≤ 300 ms were mainly (82%) treated by shock, while 83% of VTa with cycle length > 300 ms were treated by ATP. The presence of a remote myocardial infarction (OR 2.07; 95% CI 1.08–3.97) and LVEF ≤ 0.35 (OR 2.09; 95% CI 1.09–4.00) were significantly associated with the occurrence of VTa with cycle length > 300 ms.

Conclusion

S-ICD implantation may be reasonable in survivors of OHCA-VF who present without a remote myocardial infarction and LVEF > 35%.

Device updates successfully reduce T‑wave oversensing and inappropriate shocks in subcutaneous ICD patients

Aims

To analyse the impact of device and software updates on the prevention of T‑wave oversensing (TWOS) and inappropriate shocks (IS) in subcutaneous ICD (S-ICD) patients.

Background

TWOS is a feared complication after implantation. It may lead to harmful IS. To date, specific strategies to reduce these events are lacking.

Methods

In this retrospective single-centre trial we analysed 146 S‑ICD patients who were implanted between 2010 and 2016. In all eligible consecutive patients (n = 139), follow-up of at least 6 weeks was studied. The incidence of TWOS/IS was analysed in patients receiving a 2^nd generation S‑ICD (Emblem-S-ICD) between 2014 and 2016 (Emblem). Their outcome was compared with a control group (SQ) treated with the SQ1010 device between 2010 and 2014, who were followed up for a maximum of 2 years. Furthermore, to test if the software update SMR8 reduces inappropriate shocks in the SQ1010-S-ICD population, the incidence of TWOS/IS was evaluated before and after update installation.

Results

Basic characteristics and indications for S‑ICD implantation were similar in both groups. However, the cumulative incidence of TWOS/IS was significantly decreased in Emblem vs. SQ (SQ: 15.4%, n = 14/91 vs. Emblem 4.2%, n = 2/48; p = 0.049). Furthermore, with regards to the SQ population we also observed a trend towards a significant reduction of TWOS/IS after installation of the software update SMR8 in 2014 (before update: 13.4%, n = 11/82 vs. after update: 4.6%, 3/65, p = 0.07).

Conclusion

2^nd generation devices but probably also the SMR8 software update reduce the incidence of TWOS/IS in S‑ICD patients.

Evaluation of a novel automatic screening tool for determining eligibility for a subcutaneous implantable cardioverter-defibrillator

BACKGROUND

The manufacturer has developed a new ECG screening tool to determine eligibility for the subcutaneous ICD (S-ICD), the "automatic screening tool" (AST), which may render manual ECG-screening unnecessary. The aim of the study was to determine the eligibility for the S-ICD using two methods (manual ECG-screening versus AST) in different patient categories including patients with cardiomyopathy, congenital heart disease and inherited primary arrhythmia syndrome.

METHODS

We prospectively evaluated the ECG suitability for an S-ICD in consecutive patients at our outpatient clinic between February and June 2017. The primary endpoint of the study was ECG eligibility defined as at least 1 successful vector in both supine and sitting postures.

RESULTS

A total of 254 patients (167 men; mean age 45 ± 16 years) were screened using both methods. Overall, there was a high ECG eligibility using either method (93% versus 92%, P = 0.45). Overall agreement between both methods was 94%. Patients with hypertrophic cardiomyopathy (HCM) more often had a failed screening test using either test in comparison to the patients without HCM (manual: odds ratio [OR] 3.3, 95% confidence interval [CI] 1.2-9.3, P = 0.02; AST: OR 3.0, 95% CI 1.2-7.6, P = 0.02).

CONCLUSION

AST showed a high agreement with manual ECG-screening for S-ICD. Overall there was a high ECG eligibility for S-ICD, although patients with HCM had a lower passing rate irrespective of the screening method.

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.

Neointimal fibrotic lead encapsulation - Clinical challenges and demands for implantable cardiac electronic devices

Every tenth patient with a cardiac pacemaker or implantable cardioverter-defibrillator implanted is expected to have at least one lead problem in his lifetime. However, transvenous leads are often difficult to remove due to thrombotic obstruction or extensive neointimal fibrotic ingrowth. Despite its clinical significance, knowledge on lead-induced vascular fibrosis and neointimal lead encapsulation is sparse. Although leadless pacemakers are already available, their clinical operating range is limited. Therefore, lead/tissue interactions must be further improved in order to improve lead removals in particular. The published data on the coherences and issues related to lead associated vascular fibrosis and neointimal lead encapsulation are reviewed and discussed in this paper.

Implantation of subcutaneous implantable cardioverter defibrillators in Europe: results of the European Heart Rhythm Association survey

AIMS

The purpose of this European Heart Rhythm Association (EHRA) survey is to provide an overview of the current use of subcutaneous cardioverter defibrillators (S-ICDs) across a broad range of European centres.

METHODS AND RESULTS

A questionnaire was sent via the internet to centres participating in the EHRA electrophysiology research network. Questions included standards of care and policies used for patient management, indications, and techniques of implantation of the S-ICDs. In total, 52 centres replied to the questionnaire. More than one-fourth of the responding centres does not implant the S-ICD (n = 14, 27%). The majority reported to have implanted <10 (50%) or 10-29 (23%) S-ICDs during the last 12 months. Lack of reimbursement (25%), non-availability (19%), and cost of the device (25%) seem to limit the use of the S-ICD. The most commonly reported indications for S-ICD implantation are a difficult vascular access (82%), a history of previous complicated transvenous ICD (8O%), young age (69%), or an anticipated higher risk of infection (63%). Inappropriate therapies were the most frequently reported major problems (38%), but the majority of respondents (51%) never encountered any issue after an S-ICD implantation. Most of the respondents (83%) anticipate significant increase of S-ICD use within the next 2 years.

CONCLUSION

This survey provides a contemporary insight into S-ICD implantation and management in the European electrophysiology centres, showing different approaches, depending on local policies. Cost issues or lack of reimbursement strongly influence the dissemination of the device. However, most respondents retain that S-ICD use will significantly increase in a very short time.

Entirely subcutaneous defibrillator and complex congenital heart disease: Data on long-term clinical follow-up

AIM

To describe the long-term follow-up of patients with complex congenital heart disease who underwent subcutaneous implantable cardiac defibrillator (S-ICD), focusing on local complications, appropriate and inappropriate shocks.

METHODS

Patients with complex congenital heart disease underwent S-ICD implant in two centers with the conventional technique. Data at follow-up were retrieved from clinical notes and institutional database.

RESULTS

Eight patients were implanted in two centres between 2010 and 2016. Median age at implant was 37.5 years (range 13-57). All patients who were deemed suitable for S-ICD implant passed the pre-procedural screening. Three patients were previously implanted with a anti-bradycardia device, one of whom with CRT. In one patient the device was explanted due to local infection. During the total median follow-up of 874 d, one patient had an appropriate and one inappropriate shock triggered by fast atrial tachycardia. None of the patients had inappropriate shocks secondary to T wave oversensing or electrical interference with anti- bradycardia devices.

CONCLUSION

S-ICD appears to be effective and safe in patients with complex congenital heart disease.

Implantable cardioverter defibrillator management: an update

Implantable cardioverter defibrillator (ICD) is the cornerstone of primary and secondary prevention of sudden cardiac death. In 35 years of technologic improvement and clinical trials, there has been a continuous increase in implantation rate. Purpose of this review is to point out and discuss every aspect related to actual ICD management, investigating implantation procedure and predischarge care, office and remote monitoring follow-up, diagnostic evaluations, management of patients with suspected therapies or malfunctions, heart failure, surgery, radiotherapy and endoscopic procedures. Also, ICD backface such as infections and other complications will be discussed. Finally, we will focus on interesting future perspectives for this setting of patients.

Mobile health in cardiology: a review of currently available medical apps and equipment for remote monitoring

INTRODUCTION

Recent developments in implantable cardioverter-defibrillators (ICDs) and smartphone technology have increased the possibilities for remote monitoring. It is the purpose of this review to give an overview of these new possibilities.

AREAS COVERED

Remote monitoring in ICD allows for early detection of lead fractures and remote follow-up of patients. Possible limitations are the lack of standardization and the possible unsafety of the data stored on the ICD. Secondly, remote monitoring of health parameters using smartphone compatible wearables and smartphone medical apps is addressed. Possible limitations include the fact that the majority of smartphone apps are unregulated by the regulatory authorities and privacy issues such as selling of app-generated data to third parties. Lastly, clinical studies with smartphone apps are discussed. Expert commentary: New technologies in ICDs and smartphones have the potential to be used for remote monitoring. However, unreliability of smartphone technology, inadequate legislation and lack of reimbursement impede implementation.

First clinical experience of the safety and feasibility of total subcutaneous implantable defibrillator in an Asian population

AIMS

The safety and feasibility of a subcutaneous implantable cardioverter-defibrillator (S-ICD) has been demonstrated in the treatment of life-threatening ventricular tachyarrhythmias (VT). Nonetheless, its safety and feasibility in an Asian population with smaller body-build is unclear.

METHODS AND RESULTS

Twenty-one Asian patients who underwent S-ICD from 1 April 2014 to 2 February 2015 in five institutions in Hong Kong and Singapore were retrospectively reviewed. Twenty-one patients with a mean age of 50.0 ± 14.1 years (range 29-77 years, 82.6% male) were included. Among them, 17 (81.0%) were Chinese, 3 (14.3%) were Malay, and 1 (4.8%) was Indian. Their mean body mass index was 23.0 ± 4.0 kg/m(2). An S-ICD was implanted for primary and secondary prevention in 13 (61.9%) and 8 (38.1%) patients, respectively. The indications included Brugada syndrome (n = 6, 28.6%), ischaemic cardiomyopathy (CMP, n = 6, 28.6%), dilated CMP (n = 4, 19.0%), hypertrophic CMP (n = 2, 9.5%), and idiopathic ventricular fibrillation (n = 2, 9.5%). Three patients (14.3%) had prior infected transvenous ICD. There were no acute complications but eight wound complications (persistent wound bleeding requiring intervention = 2; delayed wound healing: upper sternal wound = 3; generator site = 1; local wound infection = 2) were observed in six (28.2%) patients. After a mean follow-up of 107.2 ± 81.3 days (range of 14-254 days), one patient underwent three successful appropriate shocks for treatment of VTs. No inappropriate therapy was documented.

CONCLUSION

Our initial experience shows that S-ICD is a feasible treatment for VT among an Asian population with smaller body-build. There was nonetheless a relatively high rate of wound complications.

Transvenous Implantable Cardioverter-Defibrillator (ICD) Lead Performance: A Meta-Analysis of Observational Studies

BACKGROUND

Despite the widespread use of implantable cardioverter-defibrillators (ICDs) in clinical practice, concerns exist regarding ICD lead durability. The performance of specific lead designs and factors determining this in large populations need clarification.

METHODS AND RESULTS

The Medline, Embase, and Cochrane Collaboration databases were searched for studies including ≥2 of the most commonly implanted leads. The Mantel-Haenszel random-effects model was used. Seventeen studies were selected, including a total of 49 871 patients-5538 implanted with Durata (St. Jude Medical Inc), 10 605 with Endotak Reliance (Boston Scientific), 16 119 with Sprint Quattro (Medtronic Corp), 11 709 with Sprint Fidelis (Medtronic Corp), and 5900 with Riata (St. Jude Medical Inc)-with follow-up of 136 509 lead-years. Although the Durata lead presented a numerically higher rate, no statistically significant differences in the mean incidence of lead failure (0.29%-0.45% per year) were observed in comparison of the 3 nonrecalled leads. A higher event rate was documented with the Riata (1.0% per-year increase) and Sprint Fidelis (>2.0% per-year increase) leads compared with nonrecalled leads. An indication of increased incidence of Durata lead failure versus Sprint Quattro and Endotak Reliance leads was observed in 1 of 3 included studies, allowing for comparison of purely electrical lead failure, but this requires further evaluation.

CONCLUSIONS

Endotak Reliance (8F), Sprint Quattro (8F), and Durata (7F) leads displayed low annual incidence of failure; however, long-term follow-up data are still scarce. More data are needed to clarify the performance and safety of the Durata lead.

Lead Integrity Alert Is Useful for Assessment of Performance of Biotronik Linox Leads

INTRODUCTION

Medtronic's Lead Integrity Alert (LIA) software algorithm is useful for detecting abnormal parameters across various ICD-lead families. However, its utility in the assessment of the Biotronik Linox™ family of high-voltage (HV) leads is unknown.

METHODS

We conducted a retrospective cohort study to assess the performance of the LIA algorithm to detect abnormalities and lead failure in Linox ICD-leads. All LIA-enabled Medtronic devices connected to an active Linox lead were included. The alerts were adjudicated by 2 blinded electrophysiologists and correlated with clinical data.

RESULTS

Between 2008 and 2012, data from 208 patients with 564 patient-years of follow-up were available for analysis. The median follow-up duration was 32 (IQR 21-41 months). Twenty-one LIA triggers were noted in 20 different patients. The median delay until a positive LIA was 32 months (IQR 21-41 months) postimplant with a 5-year lead survival free from LIA of 76%. Ninety-five percent (19/20) LIA alerts were true lead failures. The most common LIA triggers were short V-V intervals (85%) and nonsustained ventricular tachycardia (85%). Abrupt changes of the ICD-lead impedance occurred in 5/20 triggers. Inappropriate ICD-shocks were strongly associated with a positive LIA (30% vs. 7.4%; P = 0.006). Of the explanted Linox leads 53% had visible abnormalities. The sensitivity, specificity, and positive predictive value for lead failure in the presence of a LIA trigger were 87%, 99.5%, and 95.2%, respectively.

CONCLUSIONS

A positive LIA trigger in Biotronik Linox ICD-leads is highly predictive of lead failure. LIA is useful in ongoing surveillance of lead performance.

Longevity of the Subcutaneous Implantable Defibrillator

Background—

The recent advent of subcutaneous implantable cardioverter defibrillators (S-ICDs) has provided investigators with a safe and effective new therapy in patients at risk of sudden cardiac death. At present, no data are available with regard to the longevity of these new devices. This study evaluated the longevity of the S-ICD system.

Methods and Results—

All patients enrolled in the European Regulatory Trial were included in the analysis. During follow-up, time and causes of device replacement or explantation were assessed and categorized. Device longevity was estimated using Kaplan–Meier analysis. Fifty-five patients were followed for a median of 5.8 years. During follow-up, 26 (47%) patients underwent device replacement and 5 (9%) underwent device explantation. Median time to replacement was 5.0 years (Q1–Q3, 4.4–5.6 years). Replacement was caused by battery depletion in 25 patients (92%), of which 5 within 1.5 years because of premature battery depletion, and by infection in 1 patient (2%). Replacement for a transvenous ICD system was required in 4 patients (7%) because of ineffective defibrillation in 1 (0.003 per patient-year), need for resynchronization therapy in 2 (0.01 per patient-year), and for antibradycardia pacing in 1 (0.003 per patient-year). At 5 years follow-up, 71% of devices were still in service.

Conclusions—

This study provides the first estimate of S-ICD system longevity since its introduction in clinical practice. Median longevity of the first generation S-ICD system was 5.0 years. The majority of devices were replaced because of battery depletion.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01117792.

Biventricular pacing and coronary sinus ICD lead implantation in a patient with a mechanical tricuspid valve replacement

A 49-year-old man was admitted with symptomatic, sustained monomorphic ventricular tachycardia. He had a previous history of AMP-kinase disease associated with hypertrophic cardiomyopathy and complete heart block, and a pre-existing dual chamber pacemaker. He also had a mechanical tricuspid valve replacement and mitral valve replacement, for severe tricuspid regurgitation from right ventricle (RV) lead-induced injury to the tricuspid valve and a fibroblastoma on the mitral valve. His pre-existing RV lead was maintained between the prosthetic valve annulus and the native annulus. Inability to place an implantable cardioverter-defibrillator (ICD) in the RV due to the presence of a mechanical tricuspid valve replacement represented a rare but challenging clinical scenario. Surgical epicardial lead placement or the use of a subcutaneous ICD (S-ICD) were possible alternatives. Traditional ICD lead placement was favored because of the broad QRS from RV pacing meaning that use of the S-ICD was not possible due to failure of the electrocardiogram to lie within the bounds of the screening template, and the perceived high risk of repeat thoracotomy. We describe the technique for ICD lead placement in a mid-lateral cardiac venous branch of the coronary sinus with the ability to deliver anti-tachycardia pacing and cardiac resynchronization. To our knowledge this is the first report of an ICD in the mid-lateral cardiac vein, with cardiac resynchronization. <Learning objective: This case describes the technique for implantable cardioverter-defibrillator placement in the coronary sinus with biventricular pacing in a patient with a mechanical tricuspid and pre-existing right ventricular endocardial lead. This technique represents a viable alternative to repeat thoracotomy and surgical lead placement, where the risks of complication, prolonged hospital stay and lead failure are high. It also offers the ability to deliver anti-tachycardia pacing and cardiac resynchronization.>.

Subcutaneous implantable cardioverter-defibrillator implantation in a patient with a left ventricular assist device already in place

A 56-year-old man with ischemic cardiomyopathy, a biventricular implantable cardioverter-defibrillator (ICD), and a left ventricular assist device (LVAD) developed a pocket hematoma and infection after an ICD generator change. The biventricular ICD was extracted, and the patient was given a full course of antibiotics. Because he had no indications for bradycardia pacing or biventricular pacing, he was implanted with a subcutaneous ICD under full anticoagulation. There was no interference in sensing or shock delivery from the ICD. The LVAD readings were unchanged during and after the procedure. The patient had an uneventful postoperative course, and both devices were functioning normally. To our knowledge, this is the first reported case of the implantation of a subcutaneous ICD in the presence of an LVAD. This report illustrates that both devices can be implanted successfully in the same patient. In addition, the subcutaneous ICD minimizes the risk of bloodstream infections, which can be fatal in patients who have life-supporting devices such as an LVAD.

The clinical course of patients with implantable cardioverter-defibrillators: Extended experience on clinical outcome, device replacements, and device-related complications

BACKGROUND

Large randomized trials demonstrated the beneficial effect of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) treatments in selected patients. Data on long-term follow-up of patients outside the setting of clinical trials are scarce.

OBJECTIVE

The aim of this study was to evaluate the long-term outcome of ICD and CRT-D recipients.

METHODS

All patients who underwent ICD (n = 1729 [57%]) or CRT-D (n = 1326 [43%]) implantation at the Leiden University Medical Center since 1996 were evaluated. Follow-up visits were performed every 3-6 months, and events were registered. Cumulative incidence curves of device therapy and device-related complications were adjusted for the competing risk of all-cause mortality.

RESULTS

After a median follow-up of 5.1 years (25th-75th percentile 3.1-7.8 years), 842 patients (28%) died. The cumulative incidence of all-cause mortality was 49% (95% confidence interval [CI] 45%-54%) in ICD recipients after 12 years of follow-up and 55% (95% CI 52%-58%) in CRT-D recipients after 8 years of follow-up. A total of 1081 patients (35%) received appropriate defibrillator therapy. The cumulative incidence of appropriate therapy in ICD patients was 58% (95% CI 54%-62%) after 12 years of follow-up and 39% (95% CI 35%-43%) in CRT-D patients after 8 years of follow-up. Twelve-year cumulative incidences of adverse events were 20% (95% CI 18%-22%) for inappropriate shock, 6% (95% CI 5%-8%) for device-related infection, and 17% (95% CI 14%-21%) for lead failure.

CONCLUSION

After long-term follow-up of ICD (12 years) and CRT-D (8 years) recipients, 49% of ICD recipients and 55% of CRT-D recipients had died. Appropriate ICD therapy was received by the majority (58%) of ICD recipients and by almost 40% of CRT-D recipients.