Lead Failure Research Articles

Characterization of Outer Insulation in Long-Term-Implanted Leads.

Success of pacemakers and implantable cardioverter defibrillators may be limited by premature lead failure. Lead insulation polymers, such as polyurethane (PU) and polydimethylsiloxane (PDMS), are reported to degrade over time in vivo. PU is known to undergo oxidation, whereas PDMS undergoes surface hydrolysis. Previous studies have characterized polymer degradation in vitro, in animals or in short-term human study; however, complex effects of the biochemical and mechanical environment on the lead insulation can only be fully understood by evaluating long-term-implanted leads. Therefore, we established a retrieval program to systematically characterize the chemical and surface changes in 37 of 104 retrieved pacing and defibrillator leads, implanted for ≥5 yr. Fourier transform infrared (FTIR) spectroscopy was used for chemical analysis, and a scanning electron microscope was used for surface degradation evaluation. PDMS leads were investigated for changes in the ratio of Si-O-Si to Si-C peaks, whereas PU degradation was evaluated by changes in ether (C-O-C), carbonyl (C=O), methylene (C-H), and amino (C-N/N-H) peaks. Under SEM, PDMS showed enhanced roughness but no statistical increase in Si-O-Si bonds. PU showed uniform cracking throughout the lead body and statistical changes in each of the oxidation indicative peaks. Overall, both polymers showed surface changes in the physiological environment, but PU was the only material to show chemical changes. This work is a large-scale characterization study on long-term-implanted leads that confirmed PU oxidation but not hydrolysis of PDMS in vivo. It provides important insight for manufacturers when making design improvements and for surgeons when making decisions about lead implantation.

Failure rate and conductor externalization in the Biotronik Linox/Sorin Vigila implantable cardioverter-defibrillator lead

We observed a case of conductor externalization in a Biotronik Linox lead. The purpose of this study was to investigate lead performance of the Linox lead and the identical Sorin Vigila lead and prevalence of conductor externalization. We compared lead performance of all Linox and Vigila leads implanted at our center (BL group; n = 93) with that of all Boston Scientific Endotak Reliance leads (ER group; n = 190) and Medtronic Sprint Quattro leads (SQ group; n = 202) implanted during the same period. We screened all patients in the BL group for conductor externalization. We identified 8 cases of lead failures in the BL group (index case of conductor externalization, 6 cases of nonphysiological high-rate sensing, and 1 case of high-voltage conductor fracture). Prospective fluoroscopic screening of 98% of all active BL group cases revealed 1 additional case of conductor externalization. The median follow-up was 41, 27, and 29 months for the BL group, ER group, and SQ group, respectively; lead survival was 94.9%, 99.2%, and 100% at 3 years and 88%, 97.5%, and 100% at 5 years (P = .038 for BL group vs ER group and P = .007 for BL group vs SQ group using the log-rank test). Younger age at implant was an independent predictor of lead failure in the BL group (adjusted hazard ratio 0.85; 95% confidence interval 0.77-0.94; P = .001). At our center, survival of the Linox lead is 88% at 5 years and significantly worse than that of other leads. Conductor externalization is present in a minority of failed Linox leads. Younger age at implant is an independent predictor of Linox lead failure.

Long-Term Performance of the Riata/ST Implantable Cardioverter–Defibrillator Lead

Riata and Riata ST implantable cardioverter-defibrillator leads are prone to structural and electrical failure (EF). Our objective was to evaluate Riata/ST lead performance over a long-term follow-up. Of 184 patients having undergone Riata/ST and Riata ST Optim lead implantation from September 2003 to June 2008, 154 patients were evaluated for EF and radiographic conductor externalization (CE). Survival analysis for EF was performed for Riata/ST leads, both for failure-free lead survival and cumulative hazard. Subanalysis on 7Fr leads was performed to evaluate EF and CE rates both for different Riata ST lead management (monitoring vs proactive) and between Riata ST and Riata ST Optim leads. During a mean follow-up of 7 years, Riata/ST lead EF rate was 13% overall. Similar failure-free survival rate was noted for 7Fr as for 8Fr leads (log-rank, p = 0.63). Of all failed leads, 64% failed only after 5 years of follow-up. Compared with the absolute failure rate of 1.84% per device year, cumulative hazard analysis for leads surviving past 5 years revealed an estimated failure rate of 7% per year. No clinical or procedural predictors for EF were found. The subanalysis on 7Fr leads showed an excellent outcome both for a proactive lead management approach as for Optim leads. In conclusion, long-term survival of the Riata/ST lead is impaired with an accelerating EF risk over time. An initial exponential trend was followed by a linear lead failure pattern for leads surviving past 5 years, corresponding to an estimated 7% annual EF rate. These findings may have repercussions on the lead management strategy in patients currently surviving with a Riata/ST lead to prevent significant clinical events like inappropriate shocks or failed device interventions.

Single-coil and dual-coil defibrillator leads and association with clinical outcomes in a complete Danish nationwide ICD cohort

The best choice of defibrillator lead in patients with routine implantable cardioverter-defibrillator (ICD) is not settled. Traditionally, most physicians prefer dual-coil leads but the use of single-coil leads is increasing. The purpose of this study was to compare clinical outcomes in patients with single- and dual-coil leads. All 4769 Danish patients 18 years or older with first-time ICD implants from 2007 to 2011 were included from the Danish Pacemaker and ICD Register. Defibrillator leads were 38.9% single-coil leads and 61.1% dual-coil leads. The primary end point was all-cause mortality. Secondary end points were lowest successful energy at implant defibrillation testing, first shock failure in spontaneous arrhythmias, structural lead failure, and lead extraction outcomes. Single-coil leads were associated with lower all-cause mortality with an adjusted hazard ratio of 0.85 (95% confidence interval 0.73-0.99; P = .04). This finding was robust in a supplementary propensity score-matched analysis. However, dual-coil leads were used in patients with slightly higher preimplant morbidity, making residual confounding by indication the most likely explanation for the observed association between lead type and mortality. The lowest successful defibrillation energy was higher using single-coil leads (23.2 ± 4.3 J vs 22.1 ± 3.9 J; P < .001). No significant differences were observed for other secondary end points showing high shock efficacies and low rates of lead failures and extraction complications. Shock efficacy is high for modern ICD systems. The choice between single-coil and dual-coil defibrillator leads is unlikely to have a clinically significant impact on patient outcomes in routine ICD implants.

Abstract 19880: High Failure Rate of Linox Defibrillator Leads

Introduction: Recent lead failures have resulted in large recalls with a significant global impact, not only financially, but also physically and mentally for those carrying an implantable cardiac defibrillator (ICD). Following the introduction of the ‘Linox S’ and ‘Linox SD’ ICD leads in 2006 by manufacturer ‘Biotronik’, we observed several cases with early failure. The objective of this study was to determine the failure rate of ‘Biotronik Linox’ leads implanted at our centre, and to compare them with the performance of two comparators, the Durata (St. Jude Medical) and the Endotak (Boston Scientific) lead. Methods: As of 2012, all ‘Linox S or SD’ (n=408), Durata (model 7122, n=340) and Endotak (model 0125, 0138 and 0158, n=343) leads were identified form the Erasmus MC prospective ICD registry. Lead failure was defined by low/high-voltage impedance, failure to capture, sense or defibrillate, or the presence of non-physiological signals not due to external interference. Results: A total of 1091 high-voltage defibrillation leads were implanted between April 2000 and May 2012 in 1066 patients (78% males, median age 62 years). The median time from implantation to lead failure was 3.6 years (IQR, 1.5 to 4.8 years). ‘Linox’ leads demonstrated a sudden increase in failure at 3-3.5 years after implantation and their estimated failure rates were 5.5% and 10.1%, at 5 and 8 years after implantation, respectively. Durata and Endotak demonstrated gradual malfunction and failure rates were 2.1% and 2.1%, and 0.4% and 0.8%, at 5 and 8 years, respectively. The mechanism of failure was noise in the majority of failed leads (50%) followed by impedance out-of-range (29%). Conclusions: ‘Linox S/SD’ leads demonstrate a significant high failure rate. Remote monitoring is reasonable as electrical dysfunction (noise or impedance out-of-range) is observed in the majority of cases. National device safety and advisory committees worldwide might be facing a new challenge.

Abstract 11945: Indications and Outcomes Following Transvenous Extraction of ICD versus Pacemaker Leads

Introduction: Percutaneous transvenous lead extraction of cardiovascular implantable electronic devices (CIEDs) is increasingly common. Although ICD leads are widely considered to be more difficult to extract than pacemaker leads, there are few direct comparisons. Methods/Results: Using a cohort of 368 consecutive patients undergoing lead extraction (dwell time &gt;1 year) between 2005-2012, we compared baseline characteristics/outcomes in extractions involving pacing versus ICD leads. We defined major adverse events (MAE) as any events/complications that required procedural intervention, transfusion, or that resulted in death or serious harm during index hospitalization. Median age was 60.6 yrs and 29.6% were women. There were 136 (37%) pacing lead extractions and 232 (63%) ICD lead extractions. Pacing leads had a longer dwell time (6.14 yrs [IQR 1.2-10.9 ] versus 4.4 yrs [IQR 1.1-6.4], p&lt;0.001) and higher median LVEF (55% [IQR 35-55] vs. 30% [IQR 20-40], p&lt;0.001) compared with ICD lead patients. Indications for pacing and ICD lead extractions included sepsis/endocarditis (21.3% vs. 24.6%, p=0.48), pocket infection (40.4% vs. 34.9%, p=0.29), and lead failure (15.4% vs. 38.8%, p&lt;0.001). There were no significant differences between pacing and ICD lead extractions in median fluoroscopy time (5.5 vs. 8.5 minutes, p=0.86) or femoral bailout rate (4.4% vs. 5.2%, p=0.73). There were similar rates of all-cause MAE during index hospitalization (5.1% vs. 5.6%), death (2.2% vs 3.2%) and clinical success (97.0% vs. 97.0%, p=0.55) in pacemaker and ICD extractions, respectively. Conclusions: ICD leads are more commonly extracted relative to pacemaker leads, and this difference is driven by larger numbers of lead failure within ICD leads. Despite much longer dwell times, major adverse events were similar in pacing lead cases compared with ICD extractions.

Abstract 17084: Clinical Experience With the Subcutaneous Implantable Cardioverter Defibrillator in Paediatric Patients

Introduction: In pediatric patients prevention of Sudden Cardiac Death (SCD) using Implantable Cardioverter Defibrillators (ICD) is associated with a higher risk of complications than in the adult population. Surgical re-interventions due to infection, lead dislocation or migration and inappropriate shocks on intra and extracardiac oversensing are the most prevalent complications. The Subcutaneous ICD (S-ICD) has been introduces as a less invasive and extravascular alternative to overcome some of these complications. The scientific data that has led to the approval of the S-ICD did not include pediatric patients. Contradicting reports in small cohorts have been published on the effectiveness of S-ICD therapy in the pediatric population. We here report the largest pediatric cohort with the longest follow up to date where the S-ICD has been used for SCD prevention. Hypothesis: The S-ICD is safe and effective for the prevention of SCD in a diverse pediatric population. Methods: We retrospectively studied all consecutive pediatric patients (age&lt;18 yrs)that were implanted with a S-ICD in our center. Results: Fifteen S-ICDs were implanted in 14 patients (mean age 14, range 8-17), 71% were male, mean BMI was 18.8 (range 17.2-28.8), 57% had a secondary prevention indication, 77% had a genetic arrhythmia diagnosis and the median follow up was 21 months (range 1- 57). The first shock efficacy of induced and spontaneous episodes was 100% (n=13 and n =2 respectively). Inappropriate shocks due to intracardiac oversensing occurred in 3 (21%) patients. No lead failures or dislocations were observed. Two patients (14%) experienced a complication requiring re-intervention: one infection and one pocket erosion. After the pocket erosion the S-ICD has been successfully re-implanted. In one patient the S-ICD was removed after cardiac transplantation. None of the patients died during follow up. Conclusions: The S-ICD is safe and effective in a diverse pediatric populations. There was a very high efficacy of defibrillation therapy (100%) and a relative low and mild occurrence of complications. The S-ICD should be considered as a viable alternative for transvenous ICD's in pediatric patients.

Abstract 14872: Sensitivity of Cinefluoroscopy Compared With Visual Inspection of the Extracted Lead for Detection of Conductor Externalization of Riata/Riata St ICD Leads

Background: The Riata/Riata ST implantable cardioverter defibrillator (ICD) lead series (St Jude Medical, Sylmar, CA) is vulnerable to a characteristic insulation failure mechanism which results in conductor externalization (CE). This may be visible on cinefluoroscopy, however the sensitivity of this test is unknown when compared with direct visible inspection of extracted leads. Methods: We retrospectively reviewed the records of patients with Riata leads extracted at our center since 01/01/2011, and compared CE on fluoroscopic imaging before extraction with the visual appearance of the extracted lead ex vivo. Cinefluoroscopy of the Riata lead was performed in three planes: posteroanterior, left and right anterior oblique. CE was defined as a conductor that had breached the outer insulation material and was clearly visible outside the lead body on fluoroscopy. Ex vivo, CE was defined as externalization of the conductor cable(s) visible on inspection of the extracted lead with a corresponding linear insulation defect. Results: Of 424 patients with Riata leads 37(8.7%) patients underwent extraction with a mean implant duration of 6.24 years ±1.9 years. The indication for extraction was infection in 12 (32.4%); 7 (18.9%) for electrical or structural lead failure and other indications in 18 (48.6%). CE was evident on cinefluoroscopy in 8 (21.6%) patients before extraction including 2 (25%) leads extracted for electrical failure. Post extraction, CE was visible in an additional 3 (8.1%) leads including 1 (33%) extracted for electrical failure. Overall sensitivity was 72.7%. Conclusions: Cinefluoroscopy has suboptimal sensitivity for detection of CE in Riata ICD leads. The absence of CE on cinefluoroscopy does not imply that the outer insulation is structurally intact. Our results suggest that routine cinefluoroscopy of Riata/Riata ST leads is of limited utility.

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

BackgroundDespite 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 ResultsThe 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.ConclusionsEndotak 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.

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

Does implantation technique infl uence lead failure?

Objective We aimed to analyse whether diff erent lead implantation techniques infl uence lead failure based on implant duration.Methods and results Eighty-two transvenous leads were extracted due to lead failure. Median implant duration (MID) of the extracted leads was 68 months. Failed leads were retrospectively divided into 5 subgroups according to predefi ned technical procedural aspects, potentially triggering lead failure: venous approach, lead disorder in the generator pocket, sharp lead angulation, lead-lead interaction and number of leads in situ. The subgroupswere correlated to the MID and compared. The MID was 81 vs 59 months in medial vs lateral venous puncture (P = 0.453). In subgroups without/with lead disorder the MID was 59 vs 107 months (P = 0.006) and 57 vs 84 months (P = 0.012) in subgroups without/with sharp lead angulation, respectively. In subgroups without/with more than 1 lead-lead interaction the MID was 59 vs 81 months (P = 0.029) and 65 vs 86 months (P = 0.128) without/with more than 2 lead-lead interactions, respectively. In subgroups without/with more than 1 lead in situ the MID was 73 vs 67 months (P = 0.453), 81 vs 27 months (P = 0.296) in subgroups without/with more than 2 leads in situ and 68 vs 77 months (P = 0.264) in subgroups without/with more than 3 leads in situ, respectively.Conclusions Although, we were able to confi rm our hypothesis only partially, technical aspects of lead implantation technique should be kept in mind as a potential reason causing lead failure.

Pulse Generator Exchange Does Not Accelerate the Rate of Electrical Failure in a Recalled Small Caliber ICD Lead.

St. Jude Riata/Riata ST defibrillator leads (St. Jude Medical, Sylmar, CA, USA) were recalled by the Food and Drug Administration in 2011 for an increased rate of failure. More than 227,000 leads were implanted and at least 79,000 patients still have active Riata leads. Studies have examined clinical predictors of lead failure in Riata leads, but none have addressed the effect of implantable cardioverter defibrillator (ICD) generator exchange on lead failure. The purpose of this study is to assess the effect of ICD generator exchange on the rate of electrical failure in the Riata lead at 1 year. A retrospective chart review was conducted in patients who underwent implantation of a Riata/Riata ST lead at one center. Patients with a functioning Riata lead (with/without externalized conductor) at the time of ICD exchange were compared to controls with Riata leads implanted for a comparable amount of time who did not undergo generator replacement. Riata leads were implanted in 1,042 patients prior to the recall and 153 of these patients underwent generator exchange without lead replacement. Conductor externalization was noted in 21.5% of Riata leads in the ICD exchange cohort, which was not different from the control group (19.2%; P = 0.32). Two leads failed in the first year after generator replacement (1.5%) which did not significantly differ from the control group (2.0%; P = 0.57). At change-out, 54% received a commanded shock (18.6 ± 0.9 J) that did not result in any change in the high-voltage lead impedance (46.1 ± 1.1 ohms). Conductor externalization was seen frequently in our cohort of patients. ICD generator exchange did not accelerate the rate of Riata lead failure at 1 year. Although both the control and the change-out cohorts failed at a rate much greater than nonrecalled leads, generator exchange did not appear to add to the problem.

Predictors of Long-Term Survival Following Transvenous Extraction of Defibrillator Leads.

Little data exist on long-term outcomes following extraction of implantable cardioverter defibrillator (ICD) leads, particularly for noninfectious indications. We sought to identify predictors of long-term survival after ICD lead extraction. We retrospectively reviewed ICD lead extractions at our institution (n = 508). Procedural outcomes and long-term survival were ascertained by medical records review. Indication for lead extraction was infection in 32.5% and lead failure in 61.8%. Mean dwell time of the oldest extracted lead was 5.1 ± 5.9 years. Complete procedural success was achieved in 96.5% of cases. Major procedure-related complications occurred in 1.6% with six periprocedural deaths. During a mean follow-up of 866 ± 798 days, survival was significantly worse among patients with infection as the indication for extraction. At 1 year after extraction, survival among those with infection was 88.2%, compared to 95.0% in the lead failure cohort (P < 0.001). Procedural failure was a significant predictor of long-term mortality, even after excluding periprocedural deaths. In multivariate models, the presence of chronic kidney disease, increased number of leads requiring extraction, lower ejection fraction, and procedural failure were predictors of mortality. Despite high rates of procedural success, infectious indication for ICD lead extraction is associated with increased long-term mortality. In contrast, among patients undergoing extraction for lead failure, long-term survival was excellent. The presence of procedural failure was a significant predictor of long-term mortality. Further studies will be necessary to better understand the mechanisms by which procedural failure may adversely impact long-term outcomes.

Lead insulation failure, a serious complication: risk factors and management

“OUTSIDE-IN” ABRASIONS: A NEW PHENOMENA — MORE QUESTIONS THAN ANSWERS We may divide abrasions according to mechanism into “outside-in” and “inside-out” abrasions. The “outside-in” abrasions are well known in the pocket as the result of friction between leads or between the lead and the device, as well as in the venous system, with tearing surfaces among leads, first rib, and clavicle. However, “outside-in” abrasions most frequently appear in the intracardiac part of the lead and are associated with infective endocarditis (IE) [2]. The outer insulation abrasion remains electrically signless unless concomitant inner insulation failure occurs and in the device control both oversensing and undersensing may be observed [3]. The Banacha classification was established to morphologically describe abrasions analysed with an optical microscope, and to facilitate comparison and analysis. The classification distinguishes three levels of silicone in vivo damage: mild, moderate, and severe, all in two subtypes: a and b [2]. A severe abrasion with conductor exposure may be assessed clinically (Fig. 1A) [4]. Insulation abrasion more often concerned patients with sub-pectorally or abdominally implanted devices. Risk factors of intracardiac abrasions are implantation of two or more leads in the heart cavities, and in the case of atrial leads: passive fixation, longer mean dwell time (time from implantation), and three or more procedures proceeding lead extraction [2]. Severe abrasions with conductor exposure were associated with the number of extracted leads, dwell time, location of the lead in the coronary sinus, and excessive lead length in the cardiac chambers [4]. The most important observation was that, irrespective of the abrasion level of degradation in the intracardiac part of the lead, they were associated with IE development [2]. The process of outside-in abrasion may be INTRODUCTION Endocardial leads are the most important parts of cardiovascular implantable electronic device systems. The endocardial lead parts are located in the tissue of the pocket, in the venous system, and finally in the right heart cavities. The three different microenvironments present different impacts on lead body parts, especially the outermost insulation. Lead design also concerns the outer insulation, which has been evaluated since implantation of the first pacemaker. In the current paper we present the different mechanisms of insulation failure of the leads available on the market, and of leads that have been withdrawn from the market but still exist in living patients. The outer lead insulation may dictate the lead reliability. Silicone, polyurethane, fluoropolymers (PTFE, ETFE), and co-polymer silicone-polyurethane (Optim) are materials widely used as insulation of endocardial leads. Insulation breach and abrasions may occur anywhere along the lead. The lead parameters: abnormal sensing amplitudes, abnormal and variant pacing thresholds, and lead impedance abnormalities may be indicators of lead failure. The insulation characteristics of typical damage, lead failure symptoms, and lead management are crucial for patients, theirs doctors, scientists, and manufacturers.

ICD lead failure detection in chronic soaked leads.

Abrasion-induced insulation breach is a common failure mode of silicone-body, transvenous, implantable cardioverter defibrillator leads. It is caused either by external compression or internal motion of conducting cables. The present method of monitoring lead integrity measures low frequency conductor impedance. It cannot detect insulation failures until both the silicone lead body and inner fluoropolymer insulation have been breached completely, exposing conductors directly to blood or tissue. Even then the resistance changes are usually swamped by the baseline values. Thus the first clinical presentation may be either failure to deliver a life-saving shock or painful, inappropriate shocks in normal rhythm. We have previously presented a method for identifying early lead failure based on high frequency transmission line impedance measurements. That work used fresh leads in a liquid simulation bath; we have now demonstrated similar effects in leads soaked for 32 days and hence with saline-saturated silicone lead bodies.

Predictive factors of lead failure in patients implanted with cardiac devices

IntroductionLead failures (LFs) are one of the most common complications in patients implanted with cardiovascular implantable electronic devices. LFs often cause serious secondary complications such as inappropriate ICD shocks or asystole. This study aimed to identify the clinical factors associated with the occurrence of LFs. MethodsA total of 735 consecutive device implantations (mean age 67±15years, males 64%) performed at a single university hospital setting from 1997 to 2014 were included. The implanted devices consisted of 421 pacemakers, 250 implantable cardioverter defibrillators (ICD), 9 cardiac resynchronization therapy pacemakers (CRT-P), and 55 CRT defibrillators (CRT-D). The primary endpoint was the development of an LF. ResultsDuring a mean duration of 5.8±4.3years, 38 LFs developed in 31 patients (mean age 56±14years). LFs included 32 ICD (7 Sprint Fidelis, 2 Riata), and 6 pacing leads. Nine patients received inappropriate ICD shocks and 1 had syncope due to an LF. All patients underwent lead reinsertions with device replacements. Eight patients required opposite site implantations due to venous occlusions. The predictive factors of LFs were the age, male sex, taller body length, ICD vs. pacemaker, lesser lead number, extra-thoracic puncture of the axillary vein vs. a cut-down of the cephalic vein, use of recalled leads and patients with idiopathic ventricular fibrillation (IVF) and Brugada syndrome (BrS). ConclusionLFs occurred mainly with ICD leads. A lesser age, the puncture method, lead model, and diagnosis of IVF/BrS were associated with the development of LFs.

User-reported abrasion-related lead failure is more common with durata compared to other implantable cardiac defibrillator leads

Following increased rates of inside-out abrasion with the St Jude Medical Riata lead, the Durata implantable cardiac defibrillator (ICD) lead was introduced with modifications intended to increase abrasion resistance. Recent case reports have described insulation failures of the Durata. To determine if increased rates of abrasion-related failure are present with the Durata lead. The Food and Drug Administration Manufacturer and User Facility Device Experience database was queried for reports of insulation failure of the Durata lead from 2014. Comparison was made to other ICD leads. Incidence was estimated and case characteristics were compared. The estimated incidence of abrasion was significantly higher for the Durata lead than for the Boston Scientific Endotak or the Medtronic Quattro leads. The mode of abrasion was most often lead-to-can, as compared to "inside-out" abrasion with the Riata lead. Full-thickness abrasion was associated with failure to defibrillate or inappropriate therapy. Four patients had failure of therapy or death. The findings indicate higher rates of insulation failures of the Durata lead, despite design modifications. External abrasion from the pulse generator to the adjacent lead within the device pocket was the most common etiology. Shocks unmasked previously undetected abrasion, resulting in failure to defibrillate. Data are presented indicating a possible time dependency to abrasion risk. This limited query suggests need for ongoing scrutiny of Durata lead performance. Careful inspection of Durata leads at the time of ICD replacement is warranted, as are vigorous attempts to gather information about terminal events in patients with Durata leads.

Evaluation of the necessity for cardioverter-defibrillator implantation in elderly patients with Brugada syndrome.

The clinical characteristics and prognosis of elderly patients with Brugada syndrome (BrS) are largely unknown. The purpose of this study was to evaluate the risks and benefits of implantable cardioverter defibrillator (ICD) in elderly patients with BrS based on a long follow-up. A total of 120 BrS patients with ICD (90 for aborted sudden cardiac arrest or syncope, mean age, 46.6±12.2 years; 50 with age ≥60 years at the last follow-up) were included in this study. During 102±68 months of follow-up, 31 patients (26%) experienced appropriate shocks. Age at the first attack of ventricular fibrillation (VF) was <70 years in all patients (mean, 45.0±12.1 years), the incidence of VF decreased with age, and VF did not recur after 70 years of age except in 2 patients with ischemic heart disease. Eleven of 28 patients with supraventricular tachycardia experienced inappropriate shocks. These inappropriate shocks increased with age and reached a peak in patients who were in their sixties. Lead failures occurred in later stages after implantation in 10 of 120 patients (8%). Long-term follow-up of high-risk BrS patients with ICD showed a low incidence of VF in those aged >70 years. Considering the increasing risk of inappropriate shocks because of the relatively late onset of supraventricular tachycardia and lead failures, avoidance of ICD implantation, or replacement may be considered in elderly BrS patients who remain free from VF until 70 years of age.

ICD Therapy after Atrial Switch Repair for d-Transposition of the Great Arteries—German Multicenter Experience

Sudden cardiac death is the most common cause of late mortality after atrial switch repair for d-transposition of the great arteries. Experience with ICD therapy in these patients is limited. We conducted a multicenter cohort study to determine the current state of ICD therapy in atrial switch patients at adult congenital heart disease centers. Biometrical and clinical data as well as data on device implantation, programming, ICD discharges and complications of 33 patients from four centers were analyzed retrospectively. ICDs were implanted for primary/secondary prevention in 29 (88%) and 4 (12%) individuals, respectively. Median age at implantation was 27.5 years. 30 patients (91%) presented with NYHA ≤II at implantation. All patients with secondary prevention indication were classified as NYHA I. 21 (64%) individuals suffered from atrial reentrant tachycardia (ART). During median follow-up of 4.7 years, 5 appropriate ICD therapies were delivered in 2 (6%) patients with primary prevention indication. 12 inappropriate ICD discharges occurred in 8 patients (24%) due to ART (n = 6) or lead failure (n = 2). ICD related complications occurred in 9 patients (27%): lead dislodgment/failure in 7 patients, ICD infection in 2 (6%) patients. At implantation, heart failure as defined by NYHA classification was not advanced in the majority of patients. Appropriate discharges were only occasionally observed. Lead failure and ART were present in >20% of the patients and were frequent reasons for inappropriate ICD discharges. Facing these results, rigorous treatment of ART seems mandatory.

ICD leads

Implantable cardioverter-defibrillator (ICD) leads have to fulfill particular requirements: safe pacing and sensing, detection, and termination of ventricular tachyarrhythmias, if necessary by (multiple) high-energy shocks. At the same time, their implantation has to be simple, they need to provide excellent long-term stability and they must be completely and safely extractable. Numerous technical developments have enabled currently available ICD leads to fulfill these expectations to a high extent. However, some changes of lead design, materials, and manufacturing processes have led to increased lead failure, especially in two lead models (Medtronic Sprint Fidelis®, St. Jude Medical Riata®). The high rate of lead failure was identified only several years after market release, in part because there are no appropriate registries of ICD leads. This review presents background and developments of ICD lead technology and their association with the clinical usage of ICD therapy. To also benefit patients with only slightly-to-moderately increased risk of ventricular tachyarrhythmia, optimum ICD therapy requires optimal leads and sufficiently experienced implanters.