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Objective: It is not clear whether patients who received an implantable cardioverter-defibrillator (ICD) for primary prevention should undergo device replacement if they never experienced an appropriate ICD therapy during the first generator longevity. This study evaluated the incidence and predictors of appropriate ICD therapy after device replacement in this specific population. Methods: From two large prospective ICD registries, we identified all primary prevention patients who had a first ICD replacement without previous appropriate ICD therapy. Cox regression analysis was used to identify predictors of appropriate ICD therapy. Results: Of 403 primary prevention patients needing first ICD replacement, 275 patients (68%) had not received previous appropriate ICD therapy. Patients without previous appropriate ICD therapy before first ICD replacement (mean age at replacement 62±12 years, 75% male) had a mean follow-up of 86±24 months after the initial implantation and 30±24 months after device replacement. Following replacement, 3-year cumulative incidence of appropriate ICD therapy was 13.7% (95% CI 8.6 to 18.8%). No predictive factors associated with appropriate ICD therapy after replacement could be identified in spite of including seven clinically relevant factors. Conclusions: A considerable number of primary prevention patients without previous appropriate ICD therapy before first ICD replacement received appropriate ICD therapy after replacement. As there were no predictors of appropriate ICD therapy after replacement, replacing an ICD is still recommended in all primary prevention patients despite the lack of appropriate ICD therapy during first battery service life. [ABSTRACT FROM AUTHOR]

Objective: The implantable cardioverter defibrillator (ICD) is very effective in the prevention of sudden cardiac death, but its benefit is impaired by competing risks. A simple risk model to predict mortality was designed for patients with primary prevention and ischaemic cardiomyopathy. We aimed to apply this score to a general ICD population. Methods: This retrospective registry study included all patients in whom an ICD was implanted at a tertiary referral hospital. Risk factors were age >70 years, QRS width >120 ms, atrial fibrillation, New York Heart Association Functional Classification class >2 and glomerular filtration rate <60 mL/min/1.73 m². Kaplan- Meier curves were constructed according to the presence of 0, 1, 2 and >2 risk factors. Results: The cohort consists of 1032 patients, 881 (86%) were men, mean age was 61±14 years and mean follow-up 66±46 months. 256 patients (25%) died 58 ±41 months after implant. The setting was secondary prevention in 498 patients (48%). No risk factors was present in 32% of patients, 1 in 27%, 2 in 20% and >2 in 21%, respectively. There was a significant and comprehensible relation between risk score and mortality. Cumulative survival was 82% in patients with 0 risk factors, 63% in those with 1, 41% in those with 2 and 23% in those with >2 risk factors (p < 0.0001). ICD therapies were documented in 421 patients (41%) without correlation to risk factors. Conclusions: In a mixed population of primary and secondary preventive ICD carriers, application of a simple risk score predicts long-term mortality but not appropriate use of the ICD. [ABSTRACT FROM AUTHOR]

Remote monitoring is useful for management of implantable cardioverter defibrillator (ICD) patients regarding detection of arrhythmias and probable device or lead failure. We report the case of a patient who died suddenly while being on remote monitoring. The ICD was not retrieved postmortem. Even though clinical circumstances were suspicious of an arrhythmic death, this was excluded due to a distinctive manufacturer feature of the system. (PACE 2012; 35:e280-e283) [ABSTRACT FROM AUTHOR]

Aims The aim of this study was to determine the relationship between improved ejection fraction (EF) and occurrence of arrhythmias in patients with cardiac resynchronization therapy devices with defibrillator function (CRT-D). The hypothesis was that patients who experienced a marked improvement in EF also had fewer appropriate defibrillator interventions. Methods and results We analysed data of 270 patients from2 prospective registries with follow-up of ≥12 months and echocardiography performed ≥8 months after CRT-D implantation. The discriminator was whether left ventricular ejection fraction (LVEF) improved to >35% [cut-off for primary prevention implantable cardioverter-defibrillator (ICD) implantation]. Mean age was 61 ± 11 years, LVEF 22 ± 5%, and follow-up 40 ± 22 months. Ischaemic cardiomyopathy was present in 48%, and secondary prevention indication was present in 25%. Implantable cardioverter-defibrillator interventions were delivered to 35% of patients. Echocardiography (20 ± 15 months after implantation) showed an improvement in LVEF from 22% (SD 5.4%) to 30% (SD 9.8%). Improvement to >35% was seen in 21% of patients. Those who improved to >35% had fewer ICD interventions than those who did not (23 vs.38%; P-value 0.03). Analysing only patients with a primary prevention indication and stratifying again in patients with and without improvement of LVEF to >35%, the latter had highly significant more ICD-therapies (6 vs. 31%; P-value 0.0008). Conclusion Patients with CRT-D for primary prevention, whose LVEF improved to >35% during mid-term follow-up, are at low risk of first ICD therapies beyond year 1. If similar findings are reported in other patient cohorts, this might impact on decision-making at the time of battery depletion. [ABSTRACT FROM AUTHOR]

Current guidelines have indicated an implantable cardioverter-defibrillator (ICD) for patients with severe idiopathic dilated cardiomyopathy, for both primary and secondary prevention. Compared to coronary artery disease, the overall benefit has been smaller. A more refined risk assessment, using the left ventricular ejection fraction (LVEF) and prevention mode (primary/secondary), is still needed to guide ICD implantation. Patients included in 2 large ICD registers were analyzed regarding the appropriate therapies and improvement of LVEF, overall and in subgroups of prevention mode and LVEF <20% versus >20%. Overall, 349 patients were included; 70% were men, the mean age was 54 years, and the mean follow-up was 33 months. Cardiac resynchronization therapy (CRT) was used in 57%, and secondary prevention was present in 30%. ICD therapies were delivered to 33% of the patients, in most for ventricular tachycardia. Patients receiving an ICD for secondary prevention and non-CRT were more likely to have arrhythmic events (both p <0.05). The cumulative event rates at 5 years were 53% for secondary and 33% for primary prevention (p <0.001). Depending on the prevention mode and LVEF status (<20% vs >20%), the event rates ranged from 30% to 76%. The mean LVEF improved by 10%, independently of the stimulation mode (CRT 22% to 31%, non-CRT 26% to 35%; p <0.0001). A persistent improvement to >35% was seen in only 25% of CRT patients but in 45% of non-CRT patients (p = 0.004). In conclusion, the results from the present study have demonstrated that in patients with idiopathic dilated cardiomyopathy, the potential for LVEF improvement is considerable and that the rate of ICD interventions strongly depends on the prevention mode and LVEF. These findings could be the basis for additional risk stratification tools. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac resynchronization defibrillator (CRT‐D) as primary prevention is known to reduce mortality. At the time of replacement, higher age and comorbidities may attenuate the benefit of implantable cardioverter‐defibrillator (ICD) therapy. The purpose of this study was to evaluate the progression of comorbidities after implantation and their association with mortality following CRT‐D generator replacement. In addition, a risk score was developed to identify patients at high risk for mortality after replacement. Methods and Results: We identified patients implanted with a primary prevention CRT‐D (n = 648) who subsequently underwent elective generator replacement (n = 218) from two prospective ICD registries. The cohort consisted of 218 patients (median age: 70 years, male gender: 73%, mean left ventricular ejection fraction [LVEF]: 36 ± 11% at replacement). Median follow‐up after the replacement was 4.2 years during which 64 patients (29%) died and 11 patients (5%) received appropriate ICD shocks. An increase in comorbidities was observed in 77 patients (35%). The 5‐year mortality rate was 41% in patients with ≥2 comorbidities at the time of replacement. A risk score incorporating age, gender, LVEF, atrial fibrillation, anemia, chronic kidney disease, and history of appropriate ICD shocks at time of replacement accurately predicted 5‐year mortality (C‐statistic 0.829). Patients with a risk score of greater than 2.5 had excess mortality at 5‐year postreplacement compared with patients with a risk score less than 1.5 (57% vs. 6%; p <.001). Conclusion: A simple risk score accurately predicts 5‐year mortality after replacement in CRT‐D patients, as patients with a risk score of greater than 2.5 are at high risk of dying despite ICD protection. [ABSTRACT FROM AUTHOR]

Beat A. Schaer and Annina S. Vischer respond to a letter to the editor submitted in response to their article "A Plea for the Delivery of High-Voltage Shocks During Implantable Cardioverter-Defibrillator Replacement or System Upgrade", which was published in a 2012 issue of the "Canadian Journal of Cardiology".

The Seattle Heart Failure Model (SHFM) is a validated multivariate risk prediction model for mortality in patients with heart failure, using widely available clinical variables. The aim of this study was to assess the performance of the SHFM when applied to patients with heart failure who received cardiac resynchronization therapy devices with defibrillation. A total of 413 patients were identified from 2 prospective implantable cardioverter-defibrillator registries who received cardiac resynchronization therapy devices with defibrillation for the primary prevention of sudden death. Baseline laboratory and clinical data were entered in the SHFM to calculate predicted survival. The end point was all-cause mortality. During a median follow-up period of 2.8 years, 78 patients died and 9 underwent heart transplantation. Observed versus predicted 5-year mortality rates were 11.6% versus 11.4%, 21.5% versus 22.1%, and 41.4% versus 46.1% by ascending tertile of Seattle Heart Failure Score, respectively. No systematic or substantial errors of risk estimation were observed. Discrimination was excellent; the C-statistic ranged from 0.78 at 1-year follow-up to 0.70 at 5-year follow-up, and the Hosmer-Lemeshow chi-square statistic was 0.87 (p = 0.65). In conclusion, in patients with heart failure who received cardiac resynchronization therapy devices with defibrillation, the SHFM offers adequate discrimination of risk for all-cause mortality and estimation of mortality risk without substantial or systematic errors. [Copyright &y& Elsevier]

Background: Due to high failure rates, Medtronic withdrew the Sprint Fidelis lead (SFL) from the market. Passive fixation lead models exhibited better survival than active models, but most studies have limited follow‐up. Aim of this study was to give insights into passive lead survival with a follow‐up of 10 years. Methods: In two large Swiss centers, patients with passive SFLs were identified and data from routine implantable cardioverter defibrillator (ICD) follow‐ups were collected. Patients were censored at time of death, last device interrogation (if lost to follow‐up), time of lead revision (in non‐SFL‐related problems), or at database closure (31th December 2017). We defined lead failure as any of the following: lead fracture with inappropriate discharge; sudden increase in low‐voltage impedance to >1500 or high‐voltage impedance to >100 Ω; >300 nonphysiological short VV‐intervals. Results: We identified 145 patients. Age at implant was 60 ± 12 years with a median follow‐up of 10.2 (interquartile range [IQR]: 5.0‐11.2) years. Thirty‐five percent of patients died after 5.4 ± 2.7 years. A total of 19 leads (13%) failed after 6.7 ± 3.2 years (range: 1.2‐12.0). Overt malfunction with shocks existed in four patients (3%). Cumulative lead survival was 93.1% at 6, 88.2% at 8, 83.8% at 10, and 77.6% at 11 years, respectively, with 35% of implanted leads under monitoring at 10 years. Lead survival fits best a Weibull distribution with accelerating failure rates (k = 1.95, 95% CI 1.32‐2.87, P < 0.001). Conclusions: During very long‐term follow‐up, failure rate of the passive SFL shows an increase resulting in an impaired lead survival of 84% at 10 years. [ABSTRACT FROM AUTHOR]

Background Studies have shown that remote patient monitoring (RPM) of implantable cardioverter defibrillators (ICDs) is at least comparable to in-clinic follow-up with regard to clinical outcomes and might be cost-effective, yet RPM is not standard clinical practice within Europe. Better insight into the patient perspective on RPM may aid in its acceptance, implementation, and reimbursement. This narrative review (1) summarizes existing evidence on the impact of RPM on patient-reported outcomes and (2) discusses future directions in examining the patient perspective. Methods and Results Literature review indicated that only five randomized trials on RPM in ICD patients included patient-reported outcomes, with inconclusive results. Observational studies show a trend toward good patient satisfaction and acceptation of RPM. Yet, results should be interpreted with caution due to a number of limitations including a potential selection bias, use of generic/nonvalidated questionnaires, relatively short follow-up durations, and a lack of subgroup identification. Conclusion Although RPM seems to be safe, effective, timely, and efficient, the patient perspective has received little attention so far. The scarce evidence on patient-reported outcomes in RPM studies seems to be positive, but future trials with a follow-up of ≥12 months and validated patient-reported outcome measures are needed. The REMOTE-CIED study from our group is the first prospective randomized controlled trial primarily designed to examine the patient perspective on RPM, and is powered to identify characteristics associated with RPM satisfaction and benefit. Results are expected in 2018 and will add valuable information to the current evidence. [ABSTRACT FROM AUTHOR]

Background Many patients receiving an implantable cardioverter-defibrillator (ICD) also have atrial fibrillation (AF). Shock testing during ICD implantation carries a potential risk of cardioversion to sinus rhythm (SR) and thrombembolic events. We aimed to analyze the recurrence of AF after cardioversion to SR during ICD shock testing. Methods A total of 555 consecutive patients referred to a tertiary hospital in Switzerland for ICD implantation or generator exchange between 02/2002 and 03/2010 were screened for AF. Fifty-seven patients who were in AF at the time of ICD shock testing were included. Results Forty-four patients (77%) were successfully cardioverted from AF to SR. Type of AF (persistent, not permanent 64 vs 31% of cardioverted patients) was the only predictor. Thirty-nine patients (89%) experienced a recurrence of AF/atrial flutter after a median of 54 days (interquartile range 35-251 days). The only predictor for recurrence of AF was previous AF declared as permanent. No ischemic stroke occurred during hospitalization for the procedure. Conclusions For patients in AF undergoing shock testing at the time of ICD implant, there is a high chance of cardioversion from AF to SR, but there is also a high risk of early recurrence. Decisions regarding long-term anticoagulation should not be based on the heart rhythm immediately following shock testing. [ABSTRACT FROM AUTHOR]

Role of Defibrillation Threshold Testing. Introduction: Defibrillation threshold (DFT) testing has been performed to prove functionality of the implantable cardioverter defibrillator (ICD). Over the past years it has become increasingly controversial because of possible morbidity and mortality. The goal of this study was to determine unsuccessful shock testing and report strategies used to overcome these problems. Methods and Results: A total of 314 patients with a de novo implantation of an ICD and 127 patients receiving a generator exchange were identified retrospectively. All patients underwent defibrillation threshold testing after induction of VF using a low-energy T-wave shock during the intervention, 2 shock tests after de novo implantations, 1 after generator change. A safety margin of 10 J or more was requested. Seven (2.3%) patients in the de novo group and 2 patients (1.4%) in the generator exchange group could not be defibrillated using the standard approach. All of those patients had either chronic amiodarone therapy, secondary prevention or a cardiac resynchronization therapy device (CRT). In univariate analysis, amiodarone therapy, dilated cardiomyopathy, and lower ejection fraction were predictors of failure. Conclusion: Our study's results as well as a review of the current literature favor shock testing, especially in patients with specific risk factors as mentioned above. (J Cardiovasc Electrophysiol, Vol. 24, pp. 437-441, April 2013) [ABSTRACT FROM AUTHOR]

Background: The wearable cardioverter defibrillator (WCD) uses surface electrodes to detect arrhythmia before initiating a treatment sequence. However, it is also prone to inappropriate detection due to artefacts. Objective: The aim of this study is to assess the alarm burden in patients and its impact on clinical outcomes. Methods: Patients from the nationwide Swiss WCD Registry were included. Clinical characteristics and data were obtained from the WCDs. Arrhythmia recordings ≥30 s in length were analysed and categorized as VT/VF, atrial fibrillation (AF), supraventricular tachycardia (SVT) or artefact. Results: A total of 10653 device alarms were documented in 324 of 456 patients (71.1%) over a mean WCD wear-time of 2.0 ± 1.6 months. Episode duration was 30 s or more in 2996 alarms (28.2%). One hundred and eleven (3.7%) were VT/VF episodes. The remaining recordings were inappropriate detections (2736 (91%) due to artefacts; 117 (3.7%) AF; 48 (1.6%) SVT). Two-hundred and seven patients (45%) had three or more alarms per month. Obesity was significantly associated with three or more alarms per month (p = 0.01, 27.7% vs. 15.9%). High alarm burden was not associated with a lower average daily wear time (20.8 h vs. 20.7 h, p = 0.785) or a decreased implantable cardioverter defibrillator implantation rate after stopping WCD use (48% vs. 47.3%, p = 0.156). Conclusions: In patients using WCDs, alarms emitted by the device and impending inappropriate shocks were frequent and most commonly caused by artefacts. A high alarm burden was associated with obesity but did not lead to a decreased adherence. [ABSTRACT FROM AUTHOR]