Implantable Cardiac Defibrillator Lead Failure and Management

Global LEADR pivotal trial results

BACKGROUND

Implantable cardioverter-defibrillators last longer, and interest in reliable leads with targeted lead placement is growing. The OmniaSecure™ defibrillation lead is a novel small-diameter, catheter-delivered lead designed for targeted placement, based on the established SelectSecure SureScan MRI Model 3830 lumenless pacing lead platform.

OBJECTIVE

This trial assessed safety and efficacy of the OmniaSecure defibrillation lead.

METHODS

The worldwide LEADR pivotal clinical trial enrolled patients indicated for de novo implantation of a primary or secondary prevention implantable cardioverter-defibrillator/cardiac resynchronization therapy defibrillator, all of whom received the study lead. The primary efficacy end point was successful defibrillation at implantation per protocol. The primary safety end point was freedom from study lead-related major complications at 6 months. The primary efficacy and safety objectives were met if the lower bound of the 2-sided 95% credible interval was >88% and >90%, respectively.

RESULTS

In total, 643 patients successfully received the study lead, and 505 patients have completed 12-month follow-up. The lead was placed in the desired right ventricular location in 99.5% of patients. Defibrillation testing at implantation was completed in 119 patients, with success in 97.5%. The Kaplan-Meier estimated freedom from study lead-related major complications was 97.1% at 6 and 12 months. The trial exceeded the primary efficacy and safety objective thresholds. There were zero study lead fractures and electrical performance was stable throughout the mean follow-up of 12.7 ± 4.8 months (mean ± SD).

CONCLUSION

The OmniaSecure lead exceeded prespecified primary end point performance goals for safety and efficacy, demonstrating high defibrillation success and a low occurrence of lead-related major complications with zero lead fractures.

Subcutaneous cardioverter defibrillator implanted intermuscularly in patients with end-stage renal disease requiring hemodialysis: 5-year follow-up

BACKGROUND

The aim of the present study was to evaluate the long-term safety and effectiveness of the subcutaneous implantable cardioverter defibrillator (S-ICD) when implanted intermuscularly in patients with end-stage renal disease and hemodialysis.

METHODS

This study is a retrospective analysis of 21 consecutive patients implanted with S-ICDs at three experienced centers in Germany with comorbid renal insufficiency requiring hemodialysis, as well as being at risk of sudden cardiac death. The S-ICD was placed intermuscularly in all patients. Follow-ups (FUs) were performed every 6 months.

RESULTS

The mean ± standard deviation FU duration was 60.0 ± 11.4 months, with a range of 39 to 78 months. There were no deaths due to arrhythmia, or device-associated infections and complications. Four patients (19.1%) died during FU due to respiratory insufficiency during dialysis, systolic heart failure, septic infection of the urogenital tract, and colorectal cancer, respectively. There were six non-device-related hospitalizations with a duration of 12.7 ± 5.1 days and a hospitalization rate of 4.1 per 100 patient years.

CONCLUSIONS

In the long-term FU of this small population of seriously compromised hemodialysis patients at risk of sudden cardiac death, the intermuscularly implanted S-ICD system was safe and effective. No arrhythmic complications, device-associated infections, or complications compromised survival. These data are encouraging and support testing in a larger group of similarly compromised patients.

Cellular excitability and ns-pulsed electric fields: Potential involvement of lipid oxidation in the action potential activation

Recent studies showed that nanosecond pulsed electric fields (nsPEFs) can activate voltage-gated ion channels (VGICs) and trigger action potentials (APs) in excitable cells. Under physiological conditions, VGICs' activation takes place on time scales of the order 10-100 µs. These time scales are considerably longer than the applied pulse duration, thus activation of VGICs by nsPEFs remains puzzling and there is no clear consensus on the mechanisms involved. Here we propose that changes in local electrical properties of the cell membrane due to lipid oxidation might be implicated in AP activation. We first use MD simulations of model lipid bilayers with increasing concentration of primary and secondary lipid oxidation products and demonstrate that oxidation not only increases the bilayer conductance, but also the bilayer capacitance. Equipped with MD-based characterization of electrical properties of oxidized bilayers, we then resort to AP modelling at the cell level with Hodgkin-Huxley-type models. We confirm that a local change in membrane properties, particularly the increase in membrane conductance, due to formation of oxidized membrane lesions can be high enough to trigger an AP, even when no external stimulus is applied. However, excessive accumulation of oxidized lesions (or other conductive defects) can lead to altered cell excitability.

Long-term outcomes of abandoned leads of cardiac implantable electronic devices

BACKGROUND

Evidence of the long-term outcomes of abandoned leads (ALs) in patients with cardiac implantable electronic devices (CIEDs) is scarce.

OBJECTIVE

This study aimed to investigate the long-term outcomes of ALs.

METHODS

This retrospective cohort study reviewed a single-center CIED registry of 2962 procedures performed from 1984-2018 and identified 130 patients with AL (AL group). We matched 2 controls without AL (by age, sex, device type, and device revision/removal date) to each patient with AL (n = 260) and compared CIED-related infection, venous thrombosis/stenosis, and all-cause mortality between groups using a Cox proportional hazard model analysis.

RESULTS

For a mean follow-up period of 11.2 ± 8.2 years, 14 (3.6%), 7 (1.8%), and 143 (36.7%) patients had a CIED-related infection, venous thrombosis/stenosis, or experienced all-cause mortality, respectively. The AL group had more comorbidities than the control group. Lead malfunction was the most common cause of abandonment (64.6%). After adjustment for covariates, no significant intergroup differences were noted in the risks of infection, venous thrombosis/stenosis, or all-cause mortality (adjusted hazard ratio [aHR] 2.52; 95% confidence interval [CI] 0.77-8.25; aHR 1.18; 95% CI 0.25-5.64; aHR 1.26; 95% CI 0.89-1.80, respectively). Patients with multiple ALs had increased risks of infection and all-cause mortality vs controls (aHR 8.61; 95% CI 2.13-34.84; aHR 2.42; 95% CI 1.17-5.00, respectively).

CONCLUSION

Patients with a single AL showed similar risks of CIED-related infections, venous thrombosis/stenosis, and all-cause mortality as those without ALs, whereas those with multiple ALs showed increased risks of infection and all-cause mortality.

Long-term follow-up of patients undergoing add-on pacing/sensing lead vs. ICD lead implantation for failed IS-1/DF-1 ICD leads: a single centre experience

BACKGROUND

Intracardiac defibrillator/cardioverter (ICD) is a cornerstone device for prevention of sudden cardiac death. Lead failure (LF) is one of the most important long-term complications. In this study, we sought to investigate mid-to-long term clinical, device and lead characteristics of patients who have undergone pacing sensing lead (PSL) implantation for an ICD LF and compare them to the patients who have undergone a new ICD lead implantation.

METHODS

In this retrospective, single centre, case-control study, we have screened all ICD patients presenting with LF. Patients with IS-1/DF-1 ICD leads with intact high-voltage conductor were included in the study group, while other patients were included in the control arm. Study group patients underwent PSL implantation, control group patients underwent ICD lead implantation.

RESULTS

Thirty patients were included in each arm of the study. The mean duration of follow-up after intervention was similar in both groups (47.6 months ± 20.4 vs. 46.1 months ± 25.7, p = .808). The total failure rate was not different between two groups (p = .640). Rate of high-voltage conductor disfunction was also similar between two arms: 1 (3.3%) in PSL arm and 0 in control arm (p = .303).

CONCLUSIONS

Addition of a PSL for IS-1/DF-1 ICD LF with normal high-voltage conductor measurements is a viable treatment option with similar long-term results to addition of a new ICD lead. This approach is potentially less costly, technically less demanding, and, in case of concomitant extraction procedure, associated with less acute complication risk.

Poorer outcomes associated with more invasive lead management strategies for Abbott Riata® leads: a large, multicenter experience

BACKGROUND

Over 100,000 Abbott Riata® were implanted in the United States before they were recalled in 2010. There are still a significant number of Abbott Riata® leads in use, and it is unclear how these leads should be managed at the time of generator change or lead malfunction. Although data comparing both Sprint Fidelis® and Abbott Riata® leads in this setting is available, there are no multicenter comparative studies of outcomes for various lead management strategies, including lead extraction (LE), lead abandonment/revision (LA), and generator change (GC) only at the time of device at elective replacement interval (ERI) for Abbott Riata® leads.

METHODS

A retrospective, multicenter study was undertaken to compare short-term outcomes (major complications-MC, death, extended or re-hospitalizations within 60 days-RH, lead malfunction-LM) and total outcomes (short-term outcomes & lead malfunction during follow-up) of patients with Riata® leads undergoing LE, LA, or GC.

RESULTS

152 patients (65 ± 13 years, 68% male) were followed for a mean 33 ± 30 months following intervention. Out of 166 procedures, 13 patients underwent LE, 16 patients underwent LA, and 137 patients underwent GC. There was 1 major complication in each group, yielding an event rate of 7.7% for LE, 6.3% for LA, and 0.7% for GC cohorts. There were significantly more short-term and total adverse outcomes in the group of patients getting LE and LA versus GC only (38.5% & 31.3% vs 7.3%, P < 0.001). Total Riata® lead dwell time follow-up was 17,067 months. A total of 3 Riata® lead malfunctions were noted during long-term follow-up. Inappropriate shocks were similar between LE 7.7% (1/13), LA 6.3% (1/16). and GC 11.0% (4/136); P = 0.57.

CONCLUSIONS

There were more short-term and total adverse outcomes in more invasive management strategies (LE and LA) versus GC alone. The failure rate of Riata® leads was substantially lower compared to previous reports. Therefore, we recommend only performing battery exchange when a device with an active Riata® lead is at ERI, unless there is malfunction of the Riata® lead noted on testing. There were significantly more short-term adverse outcomes in the lead extraction (5/13) and lead abandonment/revision (5/16) groups than the generator only (8/137) group (P < 0.001). GIB - Gastrointestinal bleed, CHF - congestive heart failure, NSTEMI - non-ST elevation MI.

Cardiac pacing and lead devices management: 25 years of research at EP Europace journal

AIMS

Cardiac pacing represents a key element in the field of electrophysiology and the treatment of conduction diseases. Since the first issue published in 1999, EP Europace has significantly contributed to the development and dissemination of the research in this area.

METHODS

In the last 25 years, there has been a continuous improvement of technologies and a great expansion of clinical indications making the field of cardiac pacing a fertile ground for research still today. Pacemaker technology has rapidly evolved, from the first external devices with limited longevity, passing through conventional transvenous pacemakers to leadless devices. Constant innovations in pacemaker size, longevity, pacing mode, algorithms, and remote monitoring highlight that the fascinating and exciting journey of cardiac pacing is not over yet.

CONCLUSION

The aim of the present review is to provide the current 'state of the art' on cardiac pacing highlighting the most important contributions from the Journal in the field.

Factors affecting insulation failure in reusable surgical devices

The purpose of this study was to investigate the associated factors of insulation failure (IF) in reusable endoscopic instruments. The insulation coating of reusable endoscopic instruments underwent routine visual checks, hand washing to remove visible stains, and mechanized sterilization. We recorded the cleaning number and usage period of all instruments. The instruments were tested for IF using a detector. IF was found in eight of 69 devices (11.6%). Examining by clinical specialty, we found IF in 4 of 28 gastrointestinal (14.3%), 3 of 20 gynecological (15.0%), 1 of 12 urological (8.3%), and none of the nine thoracic devices. The median distance from the tip to the damaged part was 5 cm (3-5 cm). In the IF and the intact groups, the period of use [7 years (6-8) versus 7 years (4-8), P = 0.90] and the number of cleanings [281 (261-323) versus 261 (179-320), P = 0.27] were not significantly different. The IF group included products of three different companies; however, six of the eight (75.0%) were from the same company. Cleaning methods and usage period have a lower impact on IF. The use of reusable forceps as a monopolar device was found to pose a higher risk, requiring regular assessments.

Performance of an implantable cardioverter-defibrillator lead family

BACKGROUND

Lead failure is the major limitation in implantable cardioverter-defibrillator (ICD) therapy. Long-term follow-up data for Biotronik Linox ICD leads are limited. Therefore, we analyzed the performance of all these leads implanted at our institution.

MATERIALS AND METHODS

All Linox and Linox Smart ICD leads implanted between 2006 and 2015 were identified. Lead failure was defined as electrical dysfunction (oversensing, abnormal impedance, exit block). Lead survival was described, according to Kaplan-Meier. Associations between lead failure and specific variables were examined. p < .05 was considered significant.

RESULTS

We included 417 ICD leads. The median follow-up time for Linox (n = 205) was 81 months and for Linox Smart (n = 212) 75 months. During that follow-up time, 30 Linox (14.6%) and 16 Linox Smart leads (7.6%) showed a malfunction. The 5-year lead survival probability was 97.4% for Linox and 95.2% for Linox Smart (log-rank test, p = .19). The 6- and 8-year lead survival probability for Linox was 93.6% and 84.6%, and for Linox Smart 93% and 91.9%. The only factor significantly associated with lead failure was younger patient age at implantation (hazard ratio/year: 0.97, 95% CI: 0.94-0.99, p = .002).

CONCLUSION

This relatively large study with a long follow-up period highlights a relevant failure rate of Biotronik Linox leads. The performance of Linox versus Linox Smart ICD leads was comparable. Although we show an acceptable 5-year lead survival probability, we observed a marked drop after just 1 more year of follow-up. In an era of improving heart failure survival probability, a prolonged follow-up of ICD leads is increasingly clinically relevant.

Practical Approaches to Transvenous Lead Extraction Procedures-Clinical Case Series

Transvenous lead extraction (TLE) is regarded as the first-line strategy for the management of complications associated with cardiac implantable electronic devices (CIEDs), when lead removal is mandatory. The decision to perform a lead extraction should take into consideration not only the strength of the clinical indication for the procedure but also many other factors such as risks versus benefits, extractor and team experience, and even patient preference. TLE is a procedure with a possible high risk of complications. In this paper, we present three clinical cases of patients who presented different indications of TLE and explain how the procedures were successfully performed. In the first clinical case, TLE was necessary because of device extravasation and suspicion of CIED pocket infection. In the second clinical case, TLE was necessary because occlusion of the left subclavian vein was found when an upgrade to cardiac resynchronization therapy was performed. In the last clinical case, TLE was necessary in order to remove magnetic resonance (MR) non-conditional leads, so the patient could undergo an MRI examination for the management of a brain tumor.

Risk factors for cardiac implantable electronic device infections: a nationwide Danish study

AIMS

Cardiac implantable electronic device (CIED) infection is a severe complication to modern management of cardiac arrhythmias. The CIED type and the type of surgery are recognized as risk factors for CIED infections, but knowledge of patient-related risk factors is scarce. This study aimed to identify lifelong patient-related risk factors for CIED infections.

METHODS AND RESULTS

Consecutive Danish patients undergoing a CIED implantation or reoperation between January 1996 and April 2018 were included. The cohort consisted of 84 429 patients undergoing 108 494 CIED surgeries with a combined follow-up of 458 257 CIED-years. A total of 1556 CIED explantations were classified as either pocket (n = 1022) or systemic CIED infection (n = 534). Data were cross-linked with records from the Danish National Patient Registry and the Danish National Prescription Registry. Using multiple-record and multiple-event per subject proportional hazard analysis, specific patient-related risk factors were identified but with several variations amongst the subtypes of CIED infection. CIED reoperations were associated with the highest risk of pocket CIED infection but also CIED type, young age, and prior valvular surgery [hazard ratio (HR): 1.62, 95% confidence interval (CI): 1.29-2.04]. Severe renal insufficiency/dialysis (HR: 2.40, 95% CI: 1.65-3.49), dermatitis (HR: 2.80, 95% CI: 1.92-4.05), and prior valvular surgery (HR: 2.09, 95% CI: 1.59-2.75) were associated with the highest risk of systemic CIED infections. Congestive heart failure, ischaemic heart disease, malignancy, chronic obstructive pulmonary disease, and temporary pacing were not significant at multivariate analysis.

CONCLUSION

Specific comorbidities and surgical procedures were associated with a higher risk of CIED infections but with variations amongst pocket and systemic CIED infection. Pocket CIED infections were associated with CIED reoperations, young age and more complex type of CIED, whereas systemic CIED infections were associated with risk factors predisposing to bacteraemia.

Prospective long-term follow-up of silicone-polyurethane–insulated implantable cardioverter-defibrillator leads

Background

Objective

Methods

Results

Conclusion

Interpreting device diagnostics for lead failure

Implantable cardioverter-defibrillators (ICDs) incorporate automated, lead-monitoring alerts (alerts) and other diagnostics to detect defibrillation lead failure (LF) and minimize its adverse clinical consequences. Partial conductor fractures cause oversensing, but pacing or high-voltage alerts for high impedance detect only complete conductor fracture. In both pacing and high-voltage insulation breaches, low-impedance alerts require complete breach with metal-to-metal contact. Oversensing alerts for pace-sense LF also require complete breach, but not metal-to metal contact. Electrograms (EGMs) from leads with confirmed fractures have characteristics findings. In insulation breach, however, oversensed EGMs reflect characteristics of the source signal. Oversensing alerts that operate on the sensing channel analyze R-R intervals for 2 patterns typical of LF but uncommon in other conditions: a rapidly increasing count of "nonphysiological" short intervals and rapid "nonsustained tachycardias." These alerts are sensitive but nonspecific. Alerts that compare sensing and shock channels define oversensing as sensed events that do not correlate temporally with EGMs on the shock channel. Their performance depends on implementation. Specific advantages and limitations are reviewed. Most ICDs measure impedance using subthreshold pulses. Patterns in impedance trends provide diagnostic information, whether or not an alert is triggered. Gradual increases in impedance do not indicate structural LF, but they may cause failed defibrillation if shock impedance is high enough. Because impedance-threshold alerts are insensitive, normal impedance trends never exclude LF, but an abrupt increase that triggers an alert almost always indicates a header connection issue or LF. Methods for discriminating connection issues from LF are reviewed.

Safety and feasibility of implanting a transvenous implantable cardioverter defibrillator (TV-ICD) in the left axilla

BACKGROUND

Transvenous implantable cardioverter defibrillator (TV-ICD) systems are commonly implanted in the left anterior chest because of an easier implantation and better defibrillation threshold. This study aimed to evaluate the safety and feasibility of left axillary implantations of TV-ICD systems.

METHODS

We performed left axillary TV-ICD implantations and compared that to the major complication rate and operation time of the conventional TV-ICD implantation site (left anterior chest). The electrical parameter trends were also assessed in the left axilla group.

RESULTS

Seventy-six consecutive patients were evaluated for the analysis. Thirty-one patients had their system implanted in the left axilla and the reasons for the implantations included 29 patients for cosmetic reasons and two for post-infection conditions. The operation time and major complication rate were similar between the two groups (left anterior chest vs. left axilla: 134±62.4 min vs. 114±33.5 min, p = .11, 1/45 patient, 2.2% [pocket hematoma] vs. 1/31 patient, 3.2% [lead dislodgement], p = .77). During the follow up period (4.9±2.3years), no lead interruptions were observed in either group. The electrical lead parameters at the time of the implantation and follow up were similar in the study group (R wave sensing 20.8±33.4 vs. 11.2±7.42 mv, p = .34; lead impedance 464±64.7 vs. 418±135ohm, p = .22; pacing threshold [at 0.4 ms] 1.0±0.76 vs. 1.21±0.93V, p = .49).

CONCLUSION

TV-ICD implantations in the left axilla were performed safely without increasing the operation time as compared to the conventional ICD implantation site. ICD implantations in the left axilla are an alternative in those not suitable for implanting TV-ICDs in the conventional implantation site.

Clinical and radiographic predictors of cardiovascular implantable electronic device lead failure at the time of initial implantation

OBJECTIVE

To assess the clinical and radiographic factors associated with lead failure by comparing subjects with lead failure within 10 years of implantation with an implant-year-matched group without lead failure.

METHODS

A case-control study with 49 subjects who received Cardiac Implantable Electronic Device (CIED) between January 1, 1999 and July 31, 2008 and developed lead failure within 10 years of implantation in a single center. The control group consisted of subjects (n = 54) with normally functioning leads matched one-to-one by implant year.

RESULTS

Among the failure group, the meantime from implantation to device lead failure was 4.70 ± 2.94 years. Older age at implantation was associated with a lower likelihood of lead failure (Odds Ratio (OR) = 0.28 (75 vs 42 years old), 95% CI 0.12-0.63, P = .002). A larger smallest loop diameter on the chest radiograph was also associated with a lower likelihood of lead failure (OR = 0.51 (31 vs 14 mm), 95% CI 0.27-0.97, P = .04). CIED type (defibrillator vs pacemaker) and Ottawa scores were not significantly associated with lead failure. Among lead-specific parameters, defibrillation lead vs pace-sense lead was associated with lead failure (OR = 3.91, 95% CI 1.95-7.81, P < .001).

CONCLUSIONS

Younger age, defibrillation leads, and small lead loops are associated with lead failure in CIEDs. Techniques to avoid tight loops in the pocket could potentially reduce the risk of lead failure and bear important implications for the implanting physician.

RF. Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from "bench to bedside", fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

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.

In vitro modeling accurately predicts cardiac lead fracture at 10 years

BACKGROUND

Development of a cardiac lead fracture model has the potential to differentiate well-performing lead designs from poor performing ones and could aid in future lead development.

OBJECTIVE

The purpose of this study was to demonstrate a predictive model for lead fracture and validate the results generated by the model by comparing them to observed 10-year implantable cardioverter-defibrillator lead fracture-free survival.

METHODS

The model presented here uses a combination of in vivo patient data, in vitro conductor fatigue test data, and statistical simulation to predict the fracture-free survival of cardiac leads. The model was validated by comparing the results to human clinical performance data from the Medtronic Sprint Fidelis (Minneapolis, MN) models 6931 (single coil, active fixation) and 6949 (dual coil, active fixation), as well as the Quattro model 6947 (dual coil, active fixation).

RESULTS

Median patient age in the single coil Fidelis 6931 population (64 years) was less than in the dual coil Fidelis 6949 and Quattro populations (68 years). Modeled and observed fracture-free survival for Quattro (>97%) was superior to that for Fidelis (<94%). The modeled survival agreed with the observed fracture-free survival data. The average model error was 0.3% (SD 1.2%).

CONCLUSION

This model for cardiac lead fracture-free survival using in vivo lead bending measurements and in vitro bench testing can be used to predict lead performance as observed by alignment with field survival data.

Sporadic high pacing and shock impedance on remote monitoring in hybrid implantable cardioverter-defibrillator systems: Clinical impact and management

BACKGROUND

Sporadic high impedance values without other anomalies detected by remote monitoring of hybrid cardiac implantable electronic device systems have been described recently. The clinical significance and related hazard of this phenomenon are not fully understood.

OBJECTIVE

The purpose of this study was to describe the prevalence, management, and outcomes associated with hybrid implantable cardioverter-defibrillator (ICD) systems.

METHODS

We collected data on patients with sporadic high lead impedance alert on remote monitoring who had undergone implantation with a hybrid ICD system between January 2015 and December 2019. Pacing thresholds, sensing and impedance values, and temporal pattern of impedance values were collected by remote monitoring, at implantation, and during an in-office visit.

RESULTS

Among 92 patients receiving a hybrid ICD, 15 (16.3%) had high impedance alert on remote monitoring (14 Boston Scientific and 1 St. Jude Medical ICD canisters paired with Medtronic or Biotronik DF-1 leads). Four patients had a cardiac resynchronization therapy-defibrillator (CRT-D), 7 a dual-chamber ICD, and 4 a single-chamber ICD. Three patients presented with high atrial lead impedance, 7 high right ventricular lead impedance, 1 high left ventricular impedance, and 2 high shock impedance values. All patients underwent follow-up by remote monitoring. Sporadic high impedance values were not associated with an adverse outcome or need for revision in all but 1 patient, who had continuously increasing pacing thresholds due to lead microfracture.

CONCLUSION

In the absence of clear signs of lead fracture or connection issues, sporadic high pacing and shock impedance in hybrid implantable defibrillator systems can be safely managed by close follow-up.

When an Implantable Cardioverter Defibrillator can Kill your Patient!

Inappropriate therapy due to noise oversensing caused a true ventricular fibrillation (VF) and a life-threatening event in a patient. A 19-year-old patient with surgically corrected congenital heart disease and systolic dysfunction had an implantable cardioverter defibrillator implanted for primary prevention in 2013. This patient was admitted at the Emergency Department in June 2018 after receiving eight shocks from the device on the same day, with a prolonged syncope after the third shock. Another noise-induced VF detection occurred, and two inappropriate shocks followed sequentially, causing true VF. Four appropriate shocks were subsequently needed until sinus rhythm was finally restored.

Cardiac resynchronization therapy with or without defibrillation: a long-standing debate

Cardiac resynchronization therapy (CRT) was shown to improve cardiac function, reduce heart failure hospitalizations, improve quality of life and prolong survival in patients with severe left ventricular dysfunction and intraventricular conduction disturbances, mainly left bundle branch block, on optimal medical therapy with ACE-inhibitors, β-blockers and mineralocorticoid receptor antagonists up-titrated to maximum tolerated evidence-based doses. CRT can be achieved by means of pacemaker systems (CRT-P) or devices with defibrillation capabilities (CRT-D). CRT-Ds offer an undoubted advantage in the prevention of arrhythmic death, but such an advantage may be of lesser degree in non-ischemic heart failure aetiologies. Moreover, the higher CRT-D hardware complexity compared to CRT-P may predispose to device/lead malfunctions and the higher current drainage may cause a shorter battery duration with consequent premature replacements and the well-known incremental complications. In a period of financial constraints, also device costs should be carefully evaluated, with recent reports suggesting that CRT-Ps may be favoured over CRT-Ds in patients with non-ischemic cardiomyopathy and no prior history of cardiac arrhythmias from a cost-effectiveness point of view. The choice between a CRT-P or a CRT-D device should be patient-tailored whenever straightforward defibrillator indications are not present. The Goldenberg score may facilitate this decision-making process in ambiguous settings. Age, comorbidities, kidney disease, atrial fibrillation, advanced functional class, inappropriate therapy risk, implantable device infections and malfunctions are factors potentially reducing the expected benefit from defibrillating capabilities. Future prospective, randomized controlled trials are warranted to directly compare the efficacy and safety of CRT-Ps and CRT-Ds.

Subcutaneous implantable cardioverter-defibrillator electrode fracture: Follow-up, troubleshooting, and evaluation

The subcutaneous-implantable cardioverter-defibrillator (S-ICD) and its electrode were developed to avoid long-term complications of transvenous leads in the vasculature. We report a case of unexpected, inappropriate S-ICD shocks due to oversensing of high-amplitude, nonphysiologic, electrical noise artifacts that were not preceded by high-impedance alerts or sensing electrogram noise detections. Following explant, high-magnification X-ray imaging of the S-ICD electrode demonstrated partial fracture of the distal sensing conductor located near a short radius bend in the electrode at the electrode-header interface. Clinicians should be aware of a potential for fatigue failure fracture of the S-ICD electrode. Recommendations for systematic S-ICD follow-up and troubleshooting are discussed.

Unexpected inhibition of bradycardia pacing due to oversensing in ICD lead fracture associated with spurious tachyarrhythmia detection and discharges

Ιn a 76-year old man with a dual-chamber ICD implanted five years ago, dizzy spells and significant bradycardia on Holter were not initially recognized as inhibition of bradycardia pacing, due to oversensing. Hospital admission was deemed necessary only after repetitive ICD shocks attributed to right ventricular pace-sense lead fracture. The need to ensure adequate ICD antibradycardia backup pacing in pacing-dependent patients when deleterious sensing errors occur, cannot be overemphasized.

A fatigue-resistant microcable for small diameter leads of active implantable medical devices

Reliability is a key-but-challenging requirement of active implantable medical devices. Implanted medical devices, such as leads, are exposed to tough environments in terms of corrosion and movement. Alongside good reliability, there is also a need for the size of medical implants to be reduced, both to minimize trauma and to enable sites that have hitherto been inaccessible to be reached, such as the tortuous venous collateral network of the left ventricle. Finally, specific electrical properties are required to adequately stimulate or sense specific regions within the human body. In this work, we present a composite microcable that combines small size with high electrical performance and long-term lead robustness. Combining multiple individually insulated electrical conductors in a microcable structure is perfectly suited for leads with multiple selectively contacted electrodes. The use of fine wires of 19 μm diameter enables the manufacture of a 7 × 7 microcable with an extremely small total diameter of less than 0.3 mm. In addition, the fine wires are composed of a core-shell metal-to-metal composite, which allows multiple advantages in one microcable: good X-ray visibility, high electrical conductivity, and very high fatigue resistance. The new MP35N®-Pt composite wire exhibits very strong lead robustness with good electrical conductivity. The fatigue test results presented were obtained by applying 90° bending under tensile load and show that the microcable has a 35-fold increase in high cycle fatigue robustness compared to standard PtIr20 leads. The resulting fracture surfaces were analyzed with scanning electron microscopy. Complementary results from conductivity measurements, X-ray visibility tests and mechanical testing have also been presented to illustrate the benefits of this newly developed composite microcable compared to state-of-the-art electrical conductors for medical implant applications.

Automated Implantable Cardioverter Defibrillator/Pacemaker Lead Fracture

Implanted artificial pacemakers are groundbreaking pieces of technology that have a vast array of medical benefits. However, as with other electronic devices, these implanted cardiac devices are not immune to failure. One of the most common failures are lead fractures, which can lead to conduction issues that result in inappropriate or insufficient electrical stimulation to the myocardium or other myocytes. The authors present a classic example of this type of artificial pacemaker failure, with the hospital course of a female patient presenting with erratic muscle contractions due to improper electrical impulse generation and conduction.

Dizziness during atrial antitachycardia pacing: What is the cause

A 74-year-old with a history of sinus node dysfunction and intermittent AV block s/p permanent pacemaker implant 6 years prior, complains of one episode of dizziness.

Unexpected high failure rate of a specific MicroPort/LivaNova/Sorin pacing lead

BACKGROUND

Pacing leads are the Achilles heel of pacemakers. Most manufacturers report a 3-year survival rate of >99% of their leads. We observed several failures of the Beflex/Vega leads (MicroPort, Shanghai, China; formerly Sorin/LivaNova).

OBJECTIVE

The purpose of this study was to investigate failure rates of Beflex/Vega leads.

METHODS

We analyzed the performance of Beflex/Vega leads implanted at our tertiary referral center. All-cause lead failures (any issues requiring reinterventions such as lead dislocations, cardiac perforations, and electrical abnormalities) were identified during follow-up. The Beflex/Vega lead was compared with a reference lead (CapSureFix Novus 5076, Medtronic, Minneapolis, MN) implanted within the same period and by the same operators.

RESULTS

A total of 585 leads were analyzed (382 Beflex/Vega and 203 CapSureFix Novus 5076 leads). Cumulative failure rate estimates were 5.2%, 6.3%, and 12.4% after 1, 2, and 3 years for the Beflex/Vega lead. This was worse compared to the reference lead (1.5%, 1.5%, 3.7% after 1, 2, and 3 years; P = .001). Early failure manifestations up to 3 months occurred at a similar rate (Beflex/Vega vs CapSureFix Novus 5076 lead: 1.3% vs 0.5% for dislocations; 1.3% vs 1.0% for perforations). During follow-up, electrical abnormalities such as noise oversensing (P = .013) and increased pacing thresholds (P = .003) became more frequent in the Beflex/Vega group. Electrical abnormalities were the most common failure manifestation 3 years after implantation in this group (9.4% vs 2.2% for the CapSureFix Novus 5076).

CONCLUSION

The failure rate of the Beflex/Vega lead of >10% after 3 years was higher than that of a competitor lead. This gives rise to concern since >135,000 such leads are active worldwide.

Chronic thromboembolic pulmonary hypertension secondary to implantable cardioverter defibrillator lead thrombus in a patient with Brugada syndrome: a rare complication requiring a multidisciplinary approach

We report the case of a 57-year-old male patient with prior syncope associated with sustained ventricular tachycardia in the setting of Brugada syndrome, who was submitted to implantation of a cardioverter defibrillator for secondary prevention. During follow-up, he presented a significant increase in lead impedance, and a transthoracic echocardiogram showed a mass attached to the lead. He was started on oral anticoagulation after infective endocarditis was excluded but nevertheless suffered repeated episodes of pulmonary embolism that led to severe chronic thromboembolic pulmonary hypertension. After heart team discussion, he was referred to pulmonary endarterectomy and replacement of the implantable cardioverter defibrillator with a subcutaneous device. This led to significant improvement of functional class and normalisation of pulmonary haemodynamics. More recently, he suffered syncope in the setting of ventricular fibrillation with appropriate shocks and was started on quinidine without further recurrence of arrhythmic episodes.

Endovascular Neuromodulation: Safety Profile and Future Directions

Endovascular neuromodulation is an emerging technology that represents a synthesis between interventional neurology and neural engineering. The prototypical endovascular neural interface is the Stentrode^TM, a stent-electrode array which can be implanted into the superior sagittal sinus via percutaneous catheter venography, and transmits signals through a transvenous lead to a receiver located subcutaneously in the chest. Whilst the Stentrode^TM has been conceptually validated in ovine models, questions remain about the long term viability and safety of this device in human recipients. Although technical precedence for venous sinus stenting already exists in the setting of idiopathic intracranial hypertension, long term implantation of a lead within the intracranial veins has never been previously achieved. Contrastingly, transvenous leads have been successfully employed for decades in the setting of implantable cardiac pacemakers and defibrillators. In the current absence of human data on the Stentrode^TM, the literature on these structurally comparable devices provides valuable lessons that can be translated to the setting of endovascular neuromodulation. This review will explore this literature in order to understand the potential risks of the Stentrode^TM and define avenues where further research and development are necessary in order to optimize this device for human application.

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.

Impedance in the Diagnosis of Lead Malfunction

Impedance is the ratio of voltage to current in an electrical circuit. Cardiovascular implantable electronic devices measure impedance to assess the structural integrity electrical performance of leads, typically using subthreshold pulses. We review determinants of impedance, how it is measured, variation in clinically measured pacing and high-voltage impedance and impedance trends as a diagnostic for lead failure and lead-device connection problems. We consider the differential diagnosis of abnormal impedance and the approach to the challenging problem of a single, abnormal impedance measurement. Present impedance provides a specific but insensitive diagnostic. For pacing circuits, we review the complementary roles of impedance and more sensitive oversensing diagnostics. Shock circuits lack a sensitive diagnostic. This deficiency is particularly important for insulation breaches, which may go undetected and present with short circuits during therapeutic shocks. We consider new methods for measuring impedance that may increase sensitivity for insulation breaches.

High shocking and pacing impedances due to defibrillation lead calcification

Purpose

We have reported the calcification of Endotak defibrillation leads that required replacement. The aim of this study was to assess calcified Endotak Reliance leads in the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database and compare them to calcified Sprint Fidelis, Sprint Quattro Secure, Riata, and Durata leads in MAUDE.

Methods

We searched the MAUDE database from 2008 to 2019 for defibrillation lead calcification using the terms “calcium,” “calcification,” and “calcified”. Included were explanted leads whose manufacturers found calcium on the shocking and/or pacing electrode.

Results

The MAUDE search identified 113 calcified defibrillation leads that qualified for the study, including 109 Endotak Reliance leads, 1 Sprint Quattro Secure lead, 2 Durata leads, 1 Riata ST lead, and no Sprint Fidelis lead. The sign of calcification was a gradual increase in shocking or pacing impedance. Average implant time was 7.4 ± 3.1 (range: 1.3–16.5) years. Only Endotak Reliance leads had shocking coil calcification (n = 72; 66.0%) and five (6.9%) of these failed defibrillation threshold (DFT) testing. Distal pacing electrode calcification affected 55 (50.4%) Endotak Reliance leads. The four other leads had pacing ring electrode calcification only.

Conclusion

Endotak Reliance defibrillation leads appear prone to shocking coil and/or distal pacing electrode calcification. High impedances may compromise defibrillation and pacing therapy. Patients who have these leads should be monitored; those exhibiting high shocking impedances should be considered for DFT testing. Lead replacement should be considered for pacemaker-dependent patients whose leads exhibit progressively high impedances.

High-voltage impedance rise; mechanism and management in patients with transvenous implantable cardioverter-defibrillators: a case series

Background

We describe a case series of patients for a gradual rise in daily, low-voltage sub-threshold measurement (LVSM) of shock (high-voltage, HV) impedance in a group of patients with Boston Scientific implantable cardioverter-defibrillators (ICDs) and investigate the cause of the abnormality.

Case summary

Six patients presented with a gradual rise in HV impedance above normal range (132.5 ± 20.8 Ω). Patients were young with a mean age of 29 ± 11 years, four patients had hypertrophic cardiomyopathy, one left ventricular non-compaction, and one long QT. All lead designs were silicon body with GORE polytetrafluoroethylene (ePTFE) coated coils, and a lower true shock impedance (TSI) was seen in all cases with full output synchronized shock. We compared the rate of HV impedance rise with our historical cohort of Boston ICDs using an unpaired t-test. The change in impedance per month was significantly higher amongst our six patients when compared with our cohort of Boston Scientific ICDs (3.2 ± 1.9 Ω/month vs. 0.0008 ± 0.005 Ω/month, P < 0.001). Patients were individually investigated and management discussed in a dedicated device multi-disciplinary team meeting (MDT).

Discussion

There are distinct differences between TSI and LVSM. The TSI is derived from a full output shock, whilst LVSM is calculated from a small current output. These cases highlight the inaccuracies of the LVSM measurement. The gradual rise in LVSM is significantly higher than the value for TSI in these patients we propose the most likely mechanism is encapsulation fibrosis surrounding the right ventricular shock coil. Management for these patients requires vigorous testing to rule out electrical failure, and replacement maybe necessary.

Methodology for creating a chronic osseointegrated neural interface for prosthetic control in rabbits

BACKGROUND

Chronic stability and high degrees of selectivity are both essential but somewhat juxtaposed components for creating an implantable bi-directional PNI capable of controlling of a prosthetic limb. While the more invasive implantable electrode arrays provide greater specificity, they are less stable over time due to compliance mismatch with the dynamic soft tissue environment in which the interface is created.

NEW METHOD

This paper takes the surgical approach of transposing nerves into bone to create neural interface within the medullary canal of long bones, an osseointegrated neural interface, to provide greater stability for implantable electrodes. In this context, we describe the surgical model for transfemoral amputation with transposition of the sciatic nerve into the medullary canal in rabbits. We investigate the capacity to create a neural interface within the medullary canal histolomorphologically. In a separate proof of concept experiment, we quantify the chronic physiological capacity of transposed nerves to conduct compound nerve action potentials evoked via an Osseointegrated Neural Interface.

COMPARISON WITH EXISTING METHOD(S)

The rabbit serves as an important animal model for both amputation neuroma and osseointegration research, but is underutilized for the exploration neural interfacing in an amputation setting.

RESULTS

Our findings demonstrate that transposed nerves remain stable over 12 weeks. Creating a neural interface within the medullary canal is possible and does not impede nerve regeneration or physiological capacity.

CONCLUSIONS

This article represents the first evidence that an Osseointegrated Neural Interface can be surgically created, capable of chronic stimulation/recording from amputated nerves required for future prosthetic control.

Comparison of the performance of implantable cardioverter-defibrillator leads among manufacturers

BACKGROUND

Leads are often considered the weakest link in implantable cardioverter-defibrillator (ICD) systems, and lead dysfunction is a major concern for ICD recipients. The aim of this study was to compare the lead performance from three different manufacturers.

METHODS

We retrospectively reviewed consecutive patients who underwent ICD system implantation at Chiba University Hospital, Japan, between March 2008 and September 2017. The following leads were implanted in our center: Durata (St. Jude Medical, St. Paul, MN, USA, now Abbott) (n = 105), Linox and Linox^Smart (Biotronik, Berlin, Germany) (n = 66), and Sprint Quattro (Medtronic, Minneapolis, MN, USA) (n = 126).

RESULTS

A total of 297 ICD leads were analyzed. Failure rates for Durata, Linox/Linox^Smart, and Sprint Quattro were 0.20%/patient year, 0.95%/patient year, and 1.84%/patient year, respectively, during a mean follow-up of 4.8, 6.4, and 3.0 years, respectively. The cumulative ICD lead survival probability was 98.9%, 100%, and 87.5%, after 5 years, respectively. The survival probability over the entire follow-up time as measured by the log-rank test was lower for Sprint Quattro leads than for either Durata (p = 0.011) or Linox/Linox^Smart (p = 0.028). The difference between Durata and Linox/Linox^Smart was not significant (p = 0.393).

CONCLUSIONS

In this single-center retrospective study, the performance of Sprint Quattro was lower than the performance of Linox/Linox^Smart and Durata leads. Large-scale, multi-center studies or manufacturer-independent registries may be necessary to confirm or reject self-reported survival probabilities from manufacturers' product performance reports.

Your Automated Implantable Cardioverter Defibrillator Is Not a Bulletproof Vest but It Might Save Your Life

A 43-year-old male was brought to the emergency department as the highest level trauma activation with complaints of chest and arm pain after sustaining gunshot wounds (GSW). Initial workup was notable for superficial GSWs to the left chest and upper extremity with direct impact to the patient’s automated implantable cardioverter defibrillator. The patient underwent replacement of the device without rewiring and was discharged home without complications.

Rate and predictors of electrical failure in non-recalled defibrillator leads

Background

Implantable cardioverter defibrillator (ICD) leads are considered as the ‘weakest link’ in defibrillator systems due to FDA recalls and advisories involving popular lead models from major manufacturers. The rate of electrical failure of ICD leads not implicated in a recall is however not well determined.

Methods

Medical records of patients implanted with ICDs at hospitals of the University of Pittsburgh Medical Center between 2002 and 2014 were analyzed. Leads were classified as having electrically failed if removed or replaced for reasons other than infection or heart transplantation. Patients were followed to endpoint of death or electrical lead failure.

Results

2410 consecutive ICD recipients (mean age 66 ± 13 years, women 22%, single/dual/biventricular-ICD 20%/44%/36%) were included. During a mean follow-up of 3.9 ± 3.3 years, 1272 patients (53%) died, 55 patients (2.3%) had ICD lead electrical failure, and 1052 (44%) patients were alive with functional leads at the time of last follow-up. Patients with failed leads had higher BMI (p = 0.07), better functional status (p = 0.04), higher serum creatinine (p = 0.004), wider QRS complex (p = 0.01), higher number of implanted leads (p = 0.06) and were more likely to have ischemic cardiomyopathy (p = 0.03). After adjusting for these variables in a binary logistic regression model, only a lower BMI, presence of non-ischemic cardiomyopathy, and a better functional status remained independently predictive of electrical failure.

Conclusions

Only 2.3% of non-recalled ICD leads experience electrical failure (annual failure rate of 0.6%). A higher patient functional status, lower BMI, and non-ischemic etiology of cardiomyopathy are independently associated with higher rates of ICD lead failure.

Iatrogenic Palpitations during Exercise in a Patient with a Dual Chamber Implantable Cardioverter-Defibrillator and Lead Dysfunction

Implantable cardioverter-defibrillators (ICDs) are an effective treatment to prevent sudden cardiac death; however, lead dysfunction is an important complication during the long-term follow-up period in ICD recipients. Careful device programming is required in accordance with the individual situation in patients with lead dysfunction. We herein present a patient in whom programming to AAI triggered palpitations during exercise.

Comparison of lead failure manifestation of Biotronik Linox with St. Jude Medical Riata and Medtronic Sprint Fidelis lead

PURPOSE

To compare lead failure manifestation and lead performance of the Biotronik Linox/Sorin Vigila defibrillator lead (Linox group) with the St. Jude Medical Riata/Riata ST (Riata group) and Medtronic Sprint Fidelis defibrillator leads (Fidelis group).

METHODS

We assessed the performance of all aforementioned leads implanted at our center and investigated the manifestation of lead failures.

RESULTS

Of 93 Linox, 86 Riata, and 81 Fidelis leads implanted at our center, 11 (12%), 22 (26%), and 25 (31%) leads failed during a median follow-up of 46, 61, and 84 months, respectively. Inappropriate shocks were delivered in 64% (Linox), 5% (Riata), and 32% (Fidelis) of lead failures; a device alert was noted in none (Linox), 5% (Riata), and 52% (Fidelis); and lead failure was a coincidental finding in 36% (Linox), 91% (Riata), and 16% (Fidelis) of cases (p < 0.001). Non-physiological high rate signals were observed in 73% (Linox), 27% (Riata), and 80% (Fidelis) of lead failures (p = 0.001) and damaged lead integrity was found in 36% (Linox), 73% (Riata), and 24% (Fidelis) of cases (p = 0.064). Lead survival at 5 years was 88%, 92%, and 71% for Linox, Riata, and Fidelis group, respectively.

CONCLUSIONS

The most frequent clinical manifestation of lead failure was inappropriate shocks for Linox, coincidental finding for Riata and device alert for Fidelis leads. Non-physiological high rate signals were frequently observed in Linox and Fidelis lead failures whereas in Riata lead failures, a damaged lead integrity was the predominant finding.

Overview of Lead Management

Lead management describes a comprehensive approach to cardiac implantable electronic device lead utilization, encompassing lead and device selection, vascular access, implant techniques, handling lead failures and recalls, managing infectious and other complications, and performing device and lead extraction. Device and lead selection should be based on the latest guidelines and the available data to choose the optimal device system for each patient. Lead extraction is a highly specialized procedure and should be carried out by a team of personnel extensively trained in the procedure at centers with cardiac surgical support.

Long-term performance of a pacing lead family: A single-center experience

BACKGROUND

The performance of Abbott/St. Jude Medical (Sylmar CA) Tendril pacing leads has not been well characterized.

OBJECTIVE

We sought to assess the performance of Tendril leads as compared with that of different pacing leads.

METHODS

We retrospectively identified patients implanted with the following leads: Tendril leads 1888 TC, 2088 TC, and 1688 TC, Medtronic (Fridely, MN) 4076 CapSureFix Novus, and Boston Scientific (Natick, MA) FINELINE II Sterox Pacing EZ leads (models 4469, 4470, and 4471). The primary end point was the incidence of lead malfunction assessed by Kaplan-Meier analysis.

RESULTS

During the study period, 9782 leads were implanted, including 8512 Tendril leads, 731 Medtronic 4076 CapSureFix Novus leads, and 539 FINELINE II leads. A total of 540 leads (5.5%) malfunctioned during a mean follow-up of 3.6 ± 2.9 years. Lead malfunction manifested predominantly as noise and/or low impedance (95%). Lead malfunction rates were significantly higher at 5 years for Tendril vs non-Tendril leads (7.0% vs 2.1%; P < .001). The highest rate of failure at 5 years was seen in the Tendril 1888 TC leads (9.9%), followed by Tendril 1688 (5.7%) and Tendril 2088 (5.2%) leads. In contrast, malfunction rates were significantly lower for the Medtronic 4076 (2.6%) and FINELINE II (1.7%) leads. During follow-up to 10 years, the incidence of lead malfunction for Optim-insulated Tendril leads (models 1888 TC and 2088 TC) was significantly higher than that for the non-Optim-insulated Tendril 1688 TC lead (24.5% vs 7.1%) (P = .008).

CONCLUSION

Tendril leads appear to have a higher rate of malfunction than do comparator leads. Optim insulation may partly explain the higher failure rate.