Implantable Cardioverter-defibrillator Generator Research Articles

Patients' Perspectives Regarding Generator Exchanges of Implantable Cardioverter Defibrillators.

Shared decision-making is mandated for patients receiving primary prevention implantable cardioverter defibrillators (ICDs). Less attention has been paid to generator exchange decisions, although at the time of generator exchange, patients' risk of sudden cardiac death, risk of procedural complications, quality of life, or prognosis may have changed. This study was designed to explore how patients make ICD generator exchange decisions. Emory Healthcare patients with primary prevention ICDs implanted from 2013 to 2021 were recruited to complete in-depth interviews exploring perspectives regarding generator exchanges. Interviews were conducted in 2021. Transcribed interviews were qualitatively coded using multilevel template analytic methods. To investigate benefit thresholds for pursuing generator exchanges, patients were presented standard-gamble type hypothetical scenarios where their ICD battery was depleted but their 5-year risk of sudden cardiac death at that time varied (10%, 5%, and 1%). Fifty patients were interviewed; 18 had a prior generator exchange, 16 had received ICD therapy, and 17 had improved left ventricular ejection fraction. As sudden cardiac death risk decreased from 10% to 5% to 1%, the number of participants willing to undergo a generator exchange decreased from 48 to 42 to 33, respectively. Responses suggest that doctor's recommendations are likely to substantially impact patients' decision-making. Other drivers of decision-making included past experiences with ICD therapy and device implantation, as well as risk aversion. Therapeutic inertia and misconceptions about ICD therapy were common and represent substantive barriers to effective shared decision-making in this context. Strong defaults may exist to continue therapy and exchange ICD generators. Updated risk stratification may facilitate shared decision-making and reduce generator exchanges in very low-risk patients, especially if these interventions are directed toward clinicians. Interventions targeting phenomena such as therapeutic inertia may be more impactful and warrant exploration in randomized trials.

Successful defibrillation testing in patients undergoing elective subcutaneous implantable cardioverter-defibrillator generator replacement.

After implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD), a defibrillation test (DFT) is performed to ensure that the device can effectively detect and terminate the induced ventricular arrhythmia. Data on DFT efficacy at generator replacement are scarce with a limited number of patients and conflicting results. This study evaluates conversion efficacy during DFT at elective S-ICD generator replacement in a large cohort from our tertiary centre. Retrospective data of patients who underwent an S-ICD generator replacement for battery depletion with subsequent DFT between February 2015 and June 2022 were collected. Defibrillation test data were collected from both implant and replacement procedures. PRAETORIAN scores at implant were calculated. Defibrillation test was defined unsuccessful when two conversions at 65 J failed. A total of 121 patients were included. The defibrillation test was successful in 95% after the first and 98% after two consecutive tests. This was comparable with success rates at implant, despite a significant rise in shock impedance (73 ± 23 vs. 83 ± 24 Ω, P < 0.001). Both patients with an unsuccessful DFT at 65 J successfully converted with 80 J. This study shows a high DFT conversion rate at elective S-ICD generator replacement, which is comparable to conversion rates at implant, despite a rise in shock impedance. Evaluating device position before generator replacement may be recommended to optimize defibrillation success at generator replacement.

Defibrillator exchange in the elderly.

Implantable cardioverter-defibrillator (ICD) therapy in elderly patients is controversial because survival benefits might be attenuated by nonarrhythmic causes of death. The purpose of this study was to investigate the outcome of septuagenarians and octogenarians after ICD generator exchange (GE). A total of 506 patients undergoing elective GE were analyzed to determine the incidence of ICD shocks and/or survival after GE. Patients were divided into a septuagenarian group (age70-79 years) and an octogenarian group (age ≥80 years). The primary endpoint was death from any cause. Secondary endpoints were survival after appropriate ICD shock and death without experiencing ICD shocks after GE ("prior death"). The association of the ICD with all-cause mortality and arrhythmic death was determined for septuagenarians and octogenarians. Comparing both groups, similar left ventricular ejection fraction (35.6% ± 11.2% vs 32.4% ± 8.9%) and baseline prevalence of New York Heart Association functional class III or IV heart failure (17.1% vs 14.7%) were found. During the entire follow-up period of the study, 42.5% of patients in the septuagenarian group died compared to 79% in the octogenarian group (P<.01). Prior death was significantly more frequent in both age groups than were appropriate ICD shocks. Predictors of mortality were common in both groups and included advanced heart failure, peripheral arterial disease, and renal failure. In clinical practice, decision-making for ICD GE among the elderly should be considered carefully for individual patients.

Risk of ventricular arrhythmias following implantable cardioverter-defibrillator generator change in patients with recovered ejection fraction: Implications for shared decision-making.

Guidelines indicate primary-prevention implantable cardioverter-defibrillators (ICDs) for most patients with left ventricular ejection fraction (LVEF) ≤ 35%. Some patients' LVEFs improve during the life of their first ICD. In patients with recovered LVEF who never received appropriate ICD therapy, the utility of generator replacement upon battery depletion remains unclear. Here, we evaluate ICD therapy based on LVEF at the time of generator change, to educate shared decision-making regarding whether to replace the depleted ICD. We followed patients with a primary-prevention ICD who underwent generator change. Patients who received appropriate ICD therapy for ventricular tachycardia or ventricular fibrillation (VT/VF) before generator change were excluded. The primary endpoint was appropriate ICD therapy, adjusted for the competing risk of death. Among 951 generator changes, 423 met inclusion criteria. During 3.4 ± 2.2 years follow-up, 78 (18%) received appropriate therapy for VT/VF. Compared to patients with recovered LVEF > 35% (n = 161 [38%]), those with LVEF ≤ 35% (n = 262 [62%]) were more likely to require ICD therapy (p = .002; Fine-Gray adjusted 5-year event rates: 12.7% vs. 25.0%). Receiver operating characteristic analysis revealed the optimal LVEF cutoff for VT/VF prediction to be 45%, the use of which further improved risk stratification (p < .001), with Fine-Gray adjusted 5-year rates 6.2% versus 25.1%. Following ICD generator change, patients with primary-prevention ICDs and recovered LVEF have significantly lower risk of subsequent ventricular arrhythmias compared to those with persistent LVEF depression. Risk stratification at LVEF 45% offers significant additional negative predictive value over a 35% cutoff, without a significant loss in sensitivity. These data may be useful during shared decision-making at the time of ICD generator battery depletion.

PO-04-068 STEREOTACTIC ARRHYTHMIA RADIOTHERAPY DOES NOT ALTER TECHNICAL IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR FUNCTION: DETAILED SAFETY RESULTS OF THE PROSPECTIVE STARNL-1 TRIAL

Stereotactic arrhythmia radiotherapy (STAR) is a new potential treatment for patients with therapy-refractory ventricular tachycardia (VT). During STAR, the pro-arrhythmic substrate receives high-dose irradiation in a single fraction. Inherently, part of the implantable cardioverter-defibrillator (ICD) lead tips, leads and the site of lead insertion receive radiotherapy dose as well. This may directly, or indirectly due to induced fibrosis at the site of lead insertion, affect technical ICD functioning. To evaluate the effects of STAR on technical ICD functioning. The STARNL-1 was a prospective, single arm, pre-post intervention study. Patients with recurrent VT despite high doses of anti-arrhythmic drugs and after one or more catheter ablation(s) were considered therapy-refractory. Six patients were treated with a single radiotherapy dose of 25 Gy to the pro-arrhythmic substrate. Per protocol, ICD battery longevity and ICD parameters lead impedance, lead sense, and lead capture of the atrial/ventricular leads were collected from ICD readouts pre-therapy, within the first 24 hours after therapy and at 3 and 12 months after therapy. During targeting, the ICD generator was considered an organ at risk. The ICD leads and lead tips were not taken into account, therefore the ICD lead tips were retrospectively delineated to calculate the received radiotherapy dose. Since this study was not powered for statistical comparison of ICD parameters, ICD parameters were described. All six patients were male (age 54-83 years) and suffered from ischemic cardiomyopathy (left ventricular ejection fraction 24-52%). Four patients completed 12-month follow-up. Five patients had a dual-chamber ICD and one patient had a single-chamber ICD. The ICD generator received a median radiotherapy dose of 0.01 Gy (range 0.00-0.12 Gy), the atrial lead a median radiotherapy dose of 3.9 Gy (range 0.7-7.2 Gy), and the ventricular lead a median radiotherapy dose of 16.8 Gy (range 0.2-24.7 Gy). There was no sudden drop in battery longevity during follow-up. As can be appreciated from Table 1, atrial and ventricular lead impedance, sensing and capture were not altered during 12-month follow-up. Figure 1 shows a line graph of the ventricular lead impedance. STAR for VT does not alter technical ICD functioning within the first 12 months after treatment.Tabled 1ICD parameter results.ICD parameterPre-therapyWithin 24h after therapy3m12mAtrial lead impedance, Ohm419 (330-550)419 (310-550)433 (340-490)404 (390-440)Atrial lead sensing, mV1.8 (0.6-5.0)3.3 (0.9-5.0)2.0 (0.5-5.0)1.6 (0.6-5.0)Atrial lead capture, V0.69 (0.38-1.00)0.56 (0.50-1.00)0.56 (0.38-1.00)0.56 (0.38-0.75)Ventricular lead impedance, Ohm499 (390-766)465 (350-867)455 (360-838)460 (390-737)Ventricular lead sensing, mV12.0 (7.2-19.4)12.0 (11.7-20.1)12.0 (4.4-20.3)11.9 (11.7-19.9)Ventricular lead capture, V1.00 (0.63-3.50)0.88 (0.63-3.50)1.00 (0.63-3.88)0.88 (0.50-2.50)All parameters are provided as median (range). Open table in a new tab

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

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

23 IMPLANTABLE CARDIOVERTER DEFIBRILLATOR (ICD) EXPLOSION AFTER GUNSHOT: WHEN DEVICE PROTECTS TWICE

Abstract A 70 years old man presented to the emergency department with “accidental” gunshot wound at left hemithorax and left shoulder/arm. Initial clinical assessment showed stable vital signs and implantable cardioverter defibrillator(ICD) protruding outside from large wound in the infraclavicular region. The ICD, previously implanted for secondary prevention of ventricular tachycardia, appeared burned and the battery was exploded. Urgent chest computed tomography scan was performed with evidence of left omeral displaced fracture, large hematoma without arterial injury and many shotgun pellets in left shoulder/arm. The ICD generator was disconnected from passive fixation leads and removed. Patient was stabilized and omeral fracture was fixed. Following leads extraction was successfully performed in hybrid operating room with cardiac surgery standby considering the difficulty of the procedure, the type of leads (double coil, passive fixation) and the risk of complications. The patient was discharged home in good clinical conditions after re-implantation of novel ICD in right infraclavicular region. Emerging technologies are promising in making lead extractions safer and more accessible for patients worldwide. This clinicl case report will provide the most up-to-date indications and procedural approaches for lead extractions and insight on the future trends in this field.

Time course of oversensing and impedance changes in developing implantable cardioverter-defibrillator lead fracture.

Pace-sense conductors comprise a pacing coil to the tip electrode and cable to the ring-electrode. Implantable cardioverter-defibrillator (ICD) lead-monitoring diagnostics include pacing impedance (direct current resistance [DCR]) and measures of oversensing. How they change as fractures progress is unknown. To characterize the relationship between oversensing, impedance, and structural changes in ICD leads developing pace-sense conductor fractures. We performed bending tests on 39 leads connected to ICD generators in an electrolyte bath with simulated electrograms. DCR was recorded every 3 minutes; electrograms were telemetered continuously. Twenty-two leads were tested to develop partial or complete fracture criteria confirmed by imaging, using DCR or DCR variability measured by standard deviation (σDCR). Results are reported for 17 other test leads. Initial oversensing occurred with partial pacing coil fracture vs complete ring cable fracture and correlated with bending-induced DCR peaks. These peaks were too small to be detected by clinical impedance measurements and were characterized by small increases in σDCR (≥0.5 Ω). Impedance threshold alerts occurred at complete pacing coil fracture but only later for ring cable fractures. The oversensing alert triggered before device-detected ventricular fibrillation more frequently than impedance alerts (94% vs 17%; P = .00002). In conductor fracture, early oversensing corresponds to partial pacing coil fracture or complete ring cable fracture and correlates with transient bending-induced impedance increases, which are detected by impedance variability but too small to trigger clinical impedance alerts. This explains why clinical oversensing alerts provide more warning for device-detected ventricular fibrillation than impedance alerts and suggests how to improve impedance diagnostics based on short-term variability.

Abstract 9500: Patients’ Perspectives Regarding Generator Exchanges of Implantable Cardioverter-Defibrillators

Background: Shared decision-making (SDM) is mandated for patients receiving primary prevention implantable cardioverter-defibrillators (ICD). Less attention has been paid to ICD generator exchange (GE) decisions. At the time of GE, patients’ risk of sudden cardiac death (SCD), risk of procedural complications, quality of life, or prognosis may have changed. This study was designed to explore how patients view GE decisions. Methods: In-depth interviews about perspectives regarding GE decisions were conducted with patients who had primary prevention ICDs implanted at Emory Healthcare from 2013-2021. Patients were also presented a hypothetical scenario where their ICD battery was depleted but their risk of SCD over 5 years at the time of battery depletion varied (10%, 5%, 1%). Patients were asked about their willingness to undergo GE under each of these conditions. Transcribed interview text was qualitatively coded using a multilevel template analytic method. Results: Fifty patients were interviewed, of whom 19 had a prior GE, 16 had no prior ICD therapies and 14 had improved left ventricular ejection fraction. Overall, even with low SCD risk, patients’ willingness to undergo a GE remained high (Figure). If their doctor recommended deferring GE, 15/49 patients still would not defer a GE. Many patients reported not relying on risk/benefit estimates to make GE decisions. Most also reported deferring the decision to their doctor, and many exhibited significant therapeutic inertia. One patient stated, “since I’m already wired for it⋯wouldn’t make sense to disregard it.” Conclusion: Strong default preferences push patients towards a GE. Risk stratifying patients for SCD at the time of GE may facilitate SDM and may reduce GE in very low-risk patients. However, even at 1% risk of SCD, which would not meet thresholds for ICD therapy, most patients would choose GE. This highlights provision of risk information alone seems unlikely to drive substantially different GE decisions.

Implantable Cardioverter-defibrillator Magnetic Interference by the iPhone 12: Is It Clinically Significant?

The iPhone 12 series (Apple, Inc., Cupertino, CA, USA) contains a circular array of magnets around a central charging coil (compatible with “Magsafe” technology). The device was recently reported to have magnetic interference with implantable cardioverter-defibrillators (ICDs). We sought to test the electromagnetic interference of the iPhone 12 in inhibiting life-saving therapies of ICDs in clinical settings. After obtaining written informed consent, an iPhone 12 was placed over the device generators of 17 patients in the ICD clinic. Device interrogation was performed immediately before and after placing the iPhone over the ICD generator to evaluate for any inhibition of device therapies. To emulate a real-world scenario, the iPhone 12 was not placed directly over the skin above the device generator but instead was positioned over the patients’ clothes. None of the device interrogations revealed interruption of device therapies due to the iPhone. We concluded that, despite the iPhone having shown in vitro interference of ICD functioning, its effects are not clinically relevant in vivo. Larger studies need to be performed to confirm this finding and guide safety recommendations regarding the use of iPhones containing magnets by patients with implanted ICDs.

Survival Probability and Survival Benefit Associated With Primary Prevention Implantable Cardioverter-Defibrillator Generator Changes.

BackgroundAs patients derive variable benefit from generator changes (GCs) of implantable cardioverter‐defibrillators (ICDs) with an original primary prevention (PP) indication, better predictors of outcomes are needed.Methods and ResultsIn the National Cardiovascular Data Registry ICD Registry, patients undergoing GCs of initial non‐cardiac resynchronization therapy PP ICDs in 2012 to 2016, predictors of post‐GC survival and survival benefit versus control heart failure patients without ICDs were assessed. These included predicted annual mortality based on the Seattle Heart Failure Model, left ventricular ejection fraction (LVEF) >35%, and the probability that a patient's death would be arrhythmic (proportional risk of arrhythmic death [PRAD]). In 40 933 patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs (age 67.7±12.0 years, 24.5% women, 34.1% with LVEF >35%), Seattle Heart Failure Model–predicted annual mortality had the greatest effect size for decreased post‐GC survival (P<0.0001). Patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs with LVEF >35% had a lower Seattle Heart Failure Model–adjusted survival versus 23 472 control heart failure patients without ICDs (model interaction hazard ratio, 1.21 [95% CI, 1.11–1.31]). In patients undergoing GCs of initial noncardiac resynchonization therapy PP ICDs with LVEF ≤35%, the model indicated worse survival versus controls in the 21% of patients with a PRAD <43% and improved survival in the 10% with PRAD >65%. The association of the PRAD with survival benefit or harm was similar in patients with or without pre‐GC ICD therapies.ConclusionsPatients who received replacement of an ICD originally implanted for primary prevention and had at the time of GC either LVEF >35% alone or both LVEF ≤35% and PRAD <43% had worse survival versus controls without ICDs.

Defibrillator generator replacements in patients with left ventricular assist device support: The risks of hematoma and infection.

The majority (89%) of left ventricular assist device (LVAD) patients have an implantable cardioverter-defibrillator (ICD) in place. Due to the advances of modern-day LVAD therapy, more patients are on support for longer. This inevitably leads to more LVAD patients facing ICD generator battery depletion. Until now, there are insufficient data regarding periprocedural risks of generator replacements in a high-risk group like the LVAD cohort. A retrospective, single-center analysis of pocket-related outcomes of all ICD generator replacements in LVAD and Non-LVAD patients between January 2014 and December 2018. The primary outcome was the combined endpoint of clinically significant pocket hematoma and/or cardiac implantable electronic device (CIED) infection in the first 6 months after ICD generator exchange. The clinically significant hematoma was defined as hematoma requiring reoperation, prolongation of hospitalization, or interruption of anticoagulation. The cumulative incidence function was calculated for the primary endpoint. Two hundred seventy-seven patients underwent ICD generator exchange in our clinic in this time. Of these, 251 patients had a complete 6-month follow-up regarding clinically significant pocket hematomas and pocket infections. One hundred ninety patients had no LVAD, and 61 patients were on LVAD support. The rate of the primary combined endpoint clinically significant pocket hematoma and/or CIED infection was 3.5 times higher in LVAD patients compared to the non-LVAD cohort (event rate 39.14 vs 11.07 per 100 patient-years, p=0.048). Clinically significant pocket hematomas necessitating revision occurred nearly 4 times more often in the LVAD group (p=0.042). Pocket device infection rates were around 16 times higher in LVAD patients compared to non-LVAD patients (p=0.002). Compared to Non-LVAD patients, LVAD patients exhibit a relevant higher rate of clinically significant pocket hematoma and CIED infection after ICD generator exchange. This information should additionally be considered in the decision-making process regarding the indication for ICD generator exchange.

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

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

PO-707-07 SUDDEN CARDIAC DEATH AND APPROPRIATE DEFIBRILLATOR THERAPIES IN PATIENTS WITH IMPROVED EJECTION FRACTION &gt;35%

Implantable cardioverter-defibrillators (ICDs) and CRT-defibrillator (CRT-D) improve survival in indicated patients with left ventricular ejection fraction (LVEF) less than 35%. Approximately 75% of patients with ICD implantation for primary prevention do not experience an appropriate ICD Tachyarrhythmia Therapy (ITT) in the initial generator lifespan. The role of continued arrhythmia monitoring and therapies(and need for generator change) in those with improved left ventricular ejection fraction(LVEF) is not well studied. Evaluation of rates of ITT and incidence of sudden cardiac death(SCD) among patients with improved LVEF>35% after defibrillator placement. A retrospective study of patients who underwent CRT-D and ICD implantation for primary prevention was done. Patients >18 years of age with ischemic(ICM) or non-ischemic cardiomyopathy(NICM) with an initial EF<35%, and who had an improvement in LVEF post-implantation were included. Patients whose LVEF remained <35% after implantation were excluded. We stratified the patients based on their improved EF, as 36-45%, 46-55%, and >55%, respectively. Of 337 patients evaluated, LVEF improved >35% in 79 patients. The mean age for the study population was 59 ± 15 years; NICM was the etiology for heart failure in 65.8% of patients. Over a median follow-up of 73 months, LVEF improved to 36-45% in 44 patients, 46-55% in 25 patients, and > 55% in 10 patients. Eight patients died during the follow-up; none from sudden cardiac death. Overall, patients with NICM received more appropriate therapies than ICM patients. Of 41 ITT events in NICM, 85% occurred in patients before EF improvement >35% (OR 8.0,95% CI: 1.12-56.79). 60% of the ITT events in ICM group were observed before EF improved >35%. Patients with NICM whose EF improved to >45 % were more likely to receive inappropriate than appropriate therapies. No events were reported in either NICM or ICM groups after LVEF improvement beyond 55%(Table 1). Among patients who receive an ICD for primary prevention, most events occurred before EF improvement. Among patients with NICM, patients experienced only inappropriate therapies once their EF improved >45%. Larger prospective studies are needed to evaluate the necessity of ICD generator change in this subgroup.

Implantable cardioverter-defibrillators and the older patient: the Dutch clinical practice

Balance between benefit and burden of implantable cardioverter-defibrillator (ICD) therapy is more debatable in older patients, compared to younger patients. Of around 6000 yearly implanted ICDs in the Netherlands, 1:4 is received by patients ≥75 years. We aimed to evaluate the current clinical practice in the Netherlands for ICD implants and generator replacements, with a special focus on the older ICD patients. Cardiologists from all Dutch ICD implanting centres (n = 28) were interviewed. Questions aimed to evaluate outpatient care, pre-operative patient assessment, end-of-life-care counselling, evaluation of social and cognitive wellbeing, clinical evaluation of all patients prior to ICD replacement, and the consideration of the option to downgrade or not replace a device. Implanting cardiologists from all 28 implanting centres were approached for an interview. Response rate was 86%. Management appeared diverse. An age ≥80 years was consistently reported as incentive for more extensive patient evaluation. Patients were invited for counselling prior to device replacements in only the minority (46%) of hospitals. Downgrade or non-replacement was performed in rare cases. End-of-life care discussions were not standard procedure in 67% of the hospitals. Evaluation of social and cognitive wellbeing of patients was based solely on the general clinical impression of the physician in 83%, or not at all assessed in 8% of the centres. A structured framework for care and evaluation of cognitive and/or physical limitations is currently absent in most hospitals. At time of ICD (re-)evaluation, several factors may be considered before deciding on (continuation of) ICD therapy: patient preferences and comorbidity, the need for pacemaker therapy, primary vs. secondary prevention, procedural risks, and patient preferences.

Prospective evaluation of health status, quality of life and clinical outcomes following implantable defibrillator generator exchange.

BACKGROUNDLittle is known about health status and quality of life (QoL) after implantable cardioverter-defibrillator (ICD) generator exchange (GE).METHODSWe prospectively followed patients undergoing first-time ICD GE. Serial assessments of health status were performed by administering the 36-Item Short Form Survey (SF-36).RESULTSMean age was 67.5 ± 14.3 years, left ventricle ejection fraction (LVEF) was 36.5% ± 15.0% and over 40% of the cohort had improved LVEF to > 35% at the time of GE. SF-36 scores were significantly worse in physical/general health domains compared to domains of emotional/social well-being ( P < 0.001 for each comparison). Physical health scores were significantly worse among those with medical comorbidities including diabetes, chronic obstructive pulmonary disease and atrial fibrillation. Mean follow-up was 1.6 ± 0.5 years after GE. Overall SF-36 scores remained stable across all domains during follow-up. Survival at 3 years post-GE was estimated at 80%. Five patients died during follow-up and most deaths were adjudicated as non-arrhythmic in origin. Four patients experienced appropriate ICD shocks after GE, three of whom had LVEF which remains impaired LVEF (i.e., < 35%) at the time of GE. CONCLUSIONPatients undergoing ICD GE have significantly worse physical health compared to emotional/social well-being, which is associated with the presence of medical comorbidities. In terms of clinical outcomes, the incidence of appropriate shocks after GE among those with improvement in LVEF is very low, and most deaths post-procedure appear to be non-arrhythmic in origin. These data represent an attempt to more fully characterize the spectrum of QoL and clinical outcomes after GE.

Lead dislodgement after a very long-term period of cardiac implantable electronic device implantation.

A 74‐year‐old man was admitted for a second replacement of a transvenous implantable cardioverter‐defibrillator (ICD) generator at 15 years after implantation. Postoperatively, electrocardiographic monitoring showed atrial lead malfunction. Chest X‐ray revealed that the tip of the active fixation atrial lead was dislocated. We present a case of atrial lead dislodgement after a very long‐term period of an ICD implantation.

Defibrillation success after subcutaneous implantable cardioverter-defibrillator generator replacement is not affected by impedance increase

Abstract Funding Acknowledgements Type of funding sources: None. Background Routine defibrillation testing during implant and replacement of the subcutaneous implantable cardioverter-defibrillator (S-ICD) is recommended per current guidelines. Recently, concerns have been raised about an increase in shock impedance and consequent shock failure during defibrillation testing in S-ICD patients undergoing a generator replacement. Purpose We aim to describe the defibrillation success rate in relation to the shock impedance in patients undergoing S-ICD generator replacement in our large tertiary center. Methods In this retrospective analysis, data from replacement procedures were collected from all patients who underwent an S-ICD generator replacement in our center from June 2014 to December 2020. Defibrillation testing was performed with at least one shock of ≤65J, and a successful shock was defined as terminating the ventricular arrhythmia within 5 seconds after the shock. Results A total of 133 patients underwent an S-ICD generator replacement, 5.8 ± 0.9 years after initial implant. Reasons for replacement were: reaching of elective replacement indicator (n = 119), early battery depletion (n = 9), complaints of generator pocket (n = 3) and device malfunction (n = 2). Defibrillation testing was performed in 111 patients (86.5%) undergoing a replacement procedure. Shock impedance data from both the implant and replacement procedure were available in 101 patients. The median shock impedance of these patients during their replacement procedure was significantly higher than during their implant, 79Ω (IQR 66-94) and 66Ω (IQR 57.5-81) respectively (Z = -5.552, p &amp;lt; 0.001). Despite the higher shock impedance, first shock during defibrillation testing was successful in 105/111 patients (94.6%), with a success rate of 97.3% after two attempts. In the remaining three patients, the ventricular arrhythmia could only be terminated with a 80J shock. This was the case during both their initial implant and their replacement procedure. Shock impedance increase between implant and replacement was not significantly higher in patients with a successful first shock compared to patients with an unsuccessful first shock (Δ+11.1 ± 20.0Ω versus Δ+12.7 ± 27.6Ω, p = 0.86). Conclusion In this large retrospective analysis, we have shown a first shock success rate during S-ICD generator replacement of 94.6%, which is similar to the success rate of defibrillation testing after initial implant. After multiple attempts, defibrillation testing success rate was 100%. Even though the median shock impedance during replacement was significantly higher than during the initial implant, there was no difference in impedance increase in patients with a successful shock compared to patients with an unsuccessful shock. Abstract Figure. Defibrillation success

Electromagnetic interference from left ventricular assist device in patients with transvenous implantable cardioverter-defibrillator.

Many advanced heart failure patients have both a left ventricular assist device (LVAD) and an implantable cardioverter-defibrillator (ICD). This study examines incidence, clinical impact, and management of LVAD-related EMI. We performed a three-center retrospective analysis of transvenous ICD implanted patients with LVAD implanted between January 1, 2005 and December 31, 2020. The primary outcome was EMI after LVAD implantation, categorized as LVAD-related noise or telemetry interference. The rate of LVAD-related EMI among the 737 patients (mean age 58.6 ± 12.8 years) studied was 5.0%. Telemetry interference (1.5%) compromised ICD interrogation in all patients. This was resolved successfully with use of a metal shield, encased wand, radiofrequency tower, different ICD programmer or by increasing distance between ICD programmer and LVAD (n=6). ICD replacement was required to reestablish successful communication in three patients. LVAD-related noise (3.5%) led to oversensing (n=4), inappropriate mode switches (n=4), noise reversion (n=3), inhibition of pacing (n=2), inappropriate detection as atrial fibrillation (AF) (n=2) and inappropriate detection as ventricular tachycardia (VT) and/or ventricular fibrillation (VF) (n=2). This noise interference persisted (n=3), resolved spontaneously (n=16), resolved with programming change (n=6) or required lead revision (n=1). EMI from LVAD impacts ICD function, although, the incidence rate is low. Physicians implanting both, LVAD in patients with ICD (more common) or ICD in patients with LVAD, should be aware of possible interferences. Telemetry failure not resolved by metal shielding was overcome by ICD generator replacement to a different manufacturer. In most cases, LVAD-related noise resolves spontaneously.

Predictors of appropriate shock after generator replacement in patients with an implantable cardioverter defibrillator.

Implantable cardioverter defibrillators (ICDs) are indicated for the primary prevention of sudden cardiac death in patients with reduced left ventricular ejection fraction (LVEF). The ongoing risk/benefit profile of an ICD at generator replacement is unknown. This study aimed to identify predictors of appropriate ICD shocks and therapies after first ICD generator replacement, and its procedure-related complications. We conducted a multicenter, retrospective cohort study including patients with primary prevention ICDs who underwent generator replacement between April 2005 and July 2015 at three Canadian centers. The primary and secondary outcomes were appropriate ICD shock and any appropriate ICD therapy, respectively. Procedure-related complication rates were also reported. Of the 219 patients in the cohort, 61 (28%) experienced an appropriate shock while 40 (18%) experienced appropriate antitachycardia pacing over a median follow up of 2.2 years. Independent predictors of appropriate ICD shocks included: LVEF at time of replacement (adjusted odds ratio [OR] 0.4 per 10% increase in LVEF, P<.001), a history of appropriate ICD shocks prior to replacement (OR 4.9, P<.001), and a history of inappropriate ICD shocks (OR 4.2, 95%, P<.002). Similar predictors were identified for the secondary outcome of any appropriate ICD therapy. Device-related complications were reported in 25 (11%) patients, with 1 (0.5%) resulting in death, 14 (6.3%) requiring site re-operation, and 6 (2.7%) requiring cardiac surgical management. Not all primary prevention ICD patients undergoing generator replacement will require appropriate device therapies afterwards. Generator replacement is associated with several risks that should be weighed against its anticipated benefit. A comprehensive assessment of the risk-benefit profile of patients undergoing generator replacement is warranted.