Association of single- vs dual-chamber ICDs with mortality, readmissions, and complications among patients receiving an ICD for primary prevention

Appropriateness of implantable cardioverter-defibrillator device implants in the United States

BACKGROUND

The appropriate use criteria (AUCs) are a diverse group of indications aimed to better evaluate the benefits of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy.

OBJECTIVE

The purpose of this study was to quantify the proportion of ICD and cardiac resynchronization therapy with defibrillator (CRT-D) implants as appropriate, may be appropriate (MA), or rarely appropriate (RA) on the basis of the AUC guidelines.

METHODS

This is a multicenter retrospective study of patients within the National Cardiovascular Data Registry undergoing ICD implantation between April 2018 and March 2019 at >1500 US hospitals. The appropriateness of ICD implants was adjudicated using the AUC.

RESULTS

Of 309,318 ICDs, 241,438 were primary prevention implants (78.1%) and 67,880 secondary prevention implants (21.9%); 243,532 (79%) were mappable to the AUC. For primary prevention, 185,431 ICDs (96.4%) were appropriate, 5660 (2.9%) MA, and 1205 (0.6%) RA. For secondary prevention, 47,498 ICDs (92.7%) were appropriate, 2581 (5%) MA, and 1157 (2.3%) RA. A significant number of RA devices were implanted in patients with New York Heart Association class IV heart failure who were ineligible for advanced therapies (53.9%) and those with myocardial infarction within 40 days (18.1%). The appropriateness of the pacing lead was more variable, with 48,470 dual-chamber ICD implants (62%) being classified as appropriate, 29,209 (37.4%) MA, and 448 (0.6%) RA. Among CRT-D implants, 63,848 (82.2%) were appropriate, 9900 (12.7%) MA, and 3940 (5.1%) RA for left ventricular pacing. A total of 99,754 implants were deemed appropriate but excluded from Centers for Medicare & Medicaid Services National Coverage Determination. More than 92% of hospitals had an RA implant rate of <4%.

CONCLUSION

In this large national registry, 95% of mappable ICD and CRT-D implants were considered appropriate, with <2% of RA implants. Nearly 100,000 appropriate implants are excluded by Centers for Medicare & Medicaid Services National Coverage Determination.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Predicting long-term survival after de novo cardioverter-defibrillator implantation for primary prevention: A population based study

Background

Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death in patients with left ventricular dysfunction. While short-term mortality benefit of ICD insertion has been established in landmark randomized controlled trials, little is known about the long-term outcomes of patients with ICDs in clinical practice. In this paper, we describe the long-term survival of patients following de novo ICD implantation for primary prevention in clinical practice and determine the factors which help predict survival after ICD implant.

Methods

Retrospective population-based study of all patients receiving a de novo ICD for primary prevention in Ontario, Canada from 2007 to 2011 using the Ontario ICD Database housed within ICES. Simple random selection was used to split the population into a derivation and internal validation cohort in a ratio of 2:1. Cox proportional hazards regression was used to determine predictors of interest and predict 10-year survival, model performance was assessed using calibration and validation.

Results

In the derivation cohort (n = 3399), mean age was 65.3 years (standard deviation [SD] = 11.0), 664 patients were female (19.5 %) and 2344 patients (69.0 %) had ischemic cardiomyopathy. Ten year survival was 45.7 % (95 % confidence interval [CI] 44.0 %-47.4 %). The final prediction model included age, sex, disease factors (ischemic vs nonischemic cardiomyopathy, left ventricular ejection fraction) and patient factors (symptoms, comorbidities), and biomarkers at the time of ICD assessment. This model had good discrimination and calibration in derivation (0.79, 95 % CI 0.77, 0.81) and validation samples (0.78, 95 % CI 0.76, 0.79).

Conclusions

A combination of demographic and clinical factors determined at baseline can be used to predict 10-year survival in patients with implantable cardioverter-defibrillators with good accuracy. Our findings help to identify individuals at risk of long-term mortality and may be useful in targeting future prevention strategies to enhance longevity in this high-risk population.

Single- Versus Dual-Chamber Implantable Cardioverter-Defibrillator for Primary Prevention of Sudden Cardiac Death in the United States

Background Routine addition of an atrial lead during an implantable cardioverter-defibrillator (ICD) implantation for primary prevention of sudden cardiac death, in patients without pacing indications, was not shown beneficial in contemporary studies. We aimed to investigate the use and safety of single- versus dual-chamber ICD implantations in these patients. Methods and Results Using the National Inpatient Sample database, we identified patients with no pacing indications who underwent primary-prevention ICD implantation in the United States between 2015 and 2019. Sociodemographic and clinical characteristics, as well as in-hospital complications, were analyzed. Multivariable logistic regression was used to identify predictors of in-hospital complications. An estimated total of 15 940 patients, underwent ICD implantation for primary prevention of sudden cardiac death during the study period, 8860 (55.6%) received a dual-chamber ICD. The mean age was 64 years, and 66% were men. In-hospital complication rates in the dual-chamber ICD and single-chamber ICD group were 12.8% and 10.7%, respectively (P<0.001), driven by increased rates of pneumothorax/hemothorax (4.6% versus 3.4%; P<0.001) and lead dislodgement (3.6% versus 2.3%; P<0.001) in the dual-chamber ICD group. Multivariable analyses confirmed atrial lead addition as an independent predictor for "any complications" (odds ratio [OR], 1.1 [95% CI, 1.0-1.2]), for pneumo/hemothorax (odds ratio, 1.1 [95% CI, 1.0-1.4]), and for lead dislodgement (odds ratio, 1.3 [95% CI, 1.1-1.6]). Conclusions Despite lack of evidence for clinical benefit, dual-chamber ICDs are implanted for primary prevention of sudden cardiac death in a majority of patients who do not have pacing indication. This practice is associated with increased risk of periprocedural complications. Avoidance of routine implantation of atrial leads will likely improve safety outcomes.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

New atrial arrhythmia occurrence in single chamber implantable cardioverter defibrillator patients: A real-world investigation

INTRODUCTION

A current limitation of single chamber implantable cardioverter defibrillators (ICDs) is the lack of an atrial lead to reliably detect atrial fibrillation (AF) episodes. A novel ventricular based atrial fibrillation (VBAF) detection algorithm was created for single chamber ICDs to assess R-R variability for detection of AF.

METHODS

Patients implanted with Visia AF™ ICDs were prospectively enrolled in the Medtronic Product Surveillance Registry from December 15, 2015 to January 23, 2019 and followed with at least 30 days of monitoring with the algorithm. Time to device-detected daily burden of AF ≥ 6 min, ≥6 h, and ≥23 h were reported. Clinical actions after device-detected AF were recorded.

RESULTS

A total of 291 patients were enrolled with a mean follow-up of 22.5 ± 7.9 months. Of these, 212 (73%) had no prior history of AF at device implant. However, 38% of these individuals had AF detected with the VBAF algorithm with daily burden of ≥6 min within two years of implant. In these 80 patients with newly detected AF by their ICD, 23 (29%) had a confirmed clinical diagnosis of AF by their provider. Of patients with a clinical diagnosis of AF, nine (39%) were newly placed on anticoagulation, including five of five (100%) patients having a burden >23 h.

CONCLUSIONS

Continuous AF monitoring with the new VBAF algorithm permits early identification and actionable treatment for patients with undiagnosed AF that may improve patient outcomes.

Quality of observational studies of clinical interventions: a meta-epidemiological review

BACKGROUND

This meta-epidemiological study aimed to assess methodological quality of a sample of contemporary non-randomised clinical studies of clinical interventions.

METHODS

This was a cross-sectional study of observational studies published between January 1, 2012 and December 31, 2018. Studies were identified in PubMed using search terms 'association', 'observational,' 'non-randomised' 'comparative effectiveness' within titles or abstracts. Each study was appraised against 35 quality criteria by two authors independently, with each criterion rated fully, partially or not satisfied. These quality criteria were grouped into 6 categories: justification for observational design (n = 2); minimisation of bias in study design and data collection (n = 11); use of appropriate methods to create comparable groups (n = 6); appropriate adjustment of observed effects (n = 5); validation of observed effects (n = 9); and authors interpretations (n = 2).

RESULTS

Of 50 unique studies, 49 (98%) were published in two US general medical journals. No study fully satisfied all applicable criteria; the mean (+/-SD) proportion of applicable criteria fully satisfied across all studies was 72% (+/- 10%). The categories of quality criteria demonstrating the lowest proportions of fully satisfied criteria were measures used to adjust observed effects (criteria 20, 23, 24) and validate observed effects (criteria 25, 27, 33). Criteria associated with ≤50% of full satisfaction across studies, where applicable, comprised: imputation methods to account for missing data (50%); justification for not performing an RCT (42%); interaction analyses in identifying independent prognostic factors potentially influencing intervention effects (42%); use of statistical correction to minimise type 1 error in multiple outcome analyses (33%); clinically significant effect sizes (30%); residual bias analyses for unmeasured or unknown confounders (14%); and falsification tests for residual confounding (8%). The proportions of fully satisfied criteria did not change over time.

CONCLUSIONS

Recently published observational studies fail to fully satisfy more than one in four quality criteria. Criteria that were not or only partially satisfied were identified which serve as remediable targets for researchers and journal editors.

Two decades of implantable cardioverter defibrillator implantation and follow-up at a South African referral centre: trends, indications and long-term outcomes in a resource-limited setting

Background

More than two-thirds of cardiovascular deaths occur in low- and middle-income countries. Sudden cardiac deaths (SCD) from ventricular arrhythmias are an important cause of cardiovascular deaths. Implantable cardioverter defibrillators (ICD) are an important therapeutic strategy for detecting and terminating ventricular arrhythmias in patients at risk of SCD. The profile of patients treated with ICDs in South Africa is unknown. Further, with changing lines of evidence, the implantation trends are undetermined. The objectives of this study were to determine the profile of ICD recipients and implantation trends in a South African quaternary hospital.

Methods

This was a retrospective review of all patients implanted with ICDs at Groote Schuur Hospital from 01 January 1998 to 31 December 2020. A standardised data collection form was used to collect baseline demographic data, information on clinical presentation and ICD follow-up data for the history of ICD shock therapies.

Results

A total of 253 ICDs were implanted; 75% for secondary prevention and 25% for primary prevention. 67.2% of the implanted ICDs were single-chamber ICDs, dual-chamber ICDs were implanted in 12.3% and Cardiac resynchronisation with a defibrillator (CRT-D) in 20.6%. There was an upward trajectory of ICD implantations during the study period. Increasing numbers of dual-chamber devices and CRT-D were implanted over time. ICD recipients had a mean (standard deviation) age of 50 (14) years and were predominantly male (69%). Primary prevention ICD recipients were younger than secondary prevention recipients, with a mean (SD) age of 46 (14) years versus 51 (14) years, p = 0.019. The secondary prevention group presented with ventricular tachycardia in 81%, ventricular fibrillation in 13% and cardiopulmonary resuscitation without documented heart rhythm in 5.3% (10/190). After a median (interquartile range) follow-up of 44 (15; 93) months, there was an overall mortality rate of 16.2%, with no mortality difference between the primary and secondary prevention patient groups.

Conclusion

There is an increase in the annual number of ICDs implanted at a South African referral centre. ICDs are predominantly implanted for secondary prevention. However, over time the number of devices implanted for primary prevention is steadily increased. During follow-up, there was no mortality difference between the primary prevention and the secondary prevention groups.

The efficacy of single-lead implantable cardioverter-defibrillator with atrial sensing dipole to detect atrial fibrillation and to reduce inappropriate therapy according to atrial sensing ON or OFF: Rationale and design of the SMART-CONTROL study, a prospective multicenter randomized trial

BACKGROUND

Few studies have compared the efficacy of single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (VDD-ICD) and conventional single-chamber ICD from the aspect of atrial fibrillation (AF) detection or inappropriate ICD therapy reduction. In the SMART-CONTROL trial (NCT03932604), we primarily aim to investigate whether the atrial sensing capability of VDD-ICD is useful in AF detection and inappropriate therapy reduction by randomly activating or deactivating the atrial sensing function.

METHODS AND DESIGN

This study was designed as a prospective, multicenter, open-label, randomized trial to enroll 640 patients with no history of clinical AF or rhythm control for AF within 1 year who were undergoing the implantation of VDD-ICD system. Patients are assigned randomly to atrial sensing "ON" or "OFF" group, with crossover allowed during follow-up. The coprimary outcomes are the incidence of AF detection and inappropriate ICD therapy over a 2-year follow-up period. The secondary outcomes include non-AF atrial tachyarrhythmia, ventricular tachyarrhythmia with or without ICD therapy, thromboembolic events, bleeding, heart failure hospitalization, mortality, a composite of adverse cardiovascular events, and long-term atrial sensing stability or variability.

CONCLUSION

We expect that this trial can evaluate the efficacy of a single-lead ICD system on various clinical outcomes including AF detection and inappropriate therapy reduction, and ultimately provide guidance to selection of ICD system.

The utilization of atrial sensing dipole in single lead implantable cardioverter defibrillator for detection of new-onset atrial high-rate episodes or subclinical atrial fibrillation: A systematic review and meta-analysis

This meta-analysis aims to evaluate the performance of atrial sensing dipole in single lead implantable cardioverter defibrillator (VDD-ICD) recipients in particular diagnosing new-onset atrial high-rate episodes (AHREs) defined as rate threshold of 200 beats per minute, or subclinical atrial fibrillation (SCAF) defined as device-detected AF without symptoms. We comprehensively searched PubMed, Embase, and ClinicalTrials.gov. Studies comparing contemporary single- and dual-chamber ICD (VVI-/DDD-ICD) versus VDD-ICD were included. Restricted maximum likelihood method for random effect model and Mantel-Haenszel method for fixed effect model were used to estimate the effect size of new-onset AHREs, or SCAF detection in each group. Three prospective studies were identified and total of 991 participants were included. There were 330 (33.3%) in VDD-ICD and 661 (66.7%) in VVI-/DDD-ICD. Most (78%) participants were men. Median follow-up was from 365 days to 847 days. VDD-ICD has a higher likelihood of detecting AHREs or SCAF as compared to VVI-/DDD-ICD [(OR random effect : 2.6; 95% CI: 1.2, 5.8; p = .018); I-squared = 67.8%, p = .019]. This difference was more apparently seen in the comparison between VDD-ICD and VVI-ICD [(OR random effect: 3.8; 95% CI: 2.1, 6.6, p < .001), I-squared = 0.0%, p = .518]. The result is same as fixed effect. Rate of AHREs detection observed in VDD-ICD was not statistically different when compared to the only group with DDD-ICD from SENSE trial. In conclusion, this meta-analysis reveals that the use of floating atrial sensing dipole in VDD-ICD increases the detection of new-onset AHREs or SCAF when compared to VVI-ICD, with similar atrial sensing performance to DDD-ICD.

Strategies to Reduce Low-Value Cardiovascular Care: A Scientific Statement From the American Heart Association

Low-value health care services that provide little or no benefit to patients are common, potentially harmful, and costly. Nearly half of the patients in the United States will receive at least 1 low-value test or procedure annually, creating risk of avoidable complications from subsequent cascades of care and excess costs to patients and society. Reducing low-value care is of particular importance to cardiovascular health given the high prevalence and costs of cardiovascular disease in the United States. This scientific statement describes the current scope and impact of low-value cardiovascular care; reviews existing literature on patient-, clinician-, health system-, payer-, and policy-level interventions to reduce low-value care; proposes solutions to achieve meaningful and equitable reductions in low-value care; and suggests areas for future research priorities.

Trends in Use of Single- vs Dual-Chamber Implantable Cardioverter-Defibrillators Among Patients Without a Pacing Indication, 2010-2018

IMPORTANCE

Use of dual-chamber implantable cardioverter-defibrillator (ICD) systems among patients without a pacing indication is an example of low-value care given higher procedural risks, higher costs, and little evidence for benefit from an atrial lead. However, variation in the use of dual-chamber systems was present among patients without a pacing indication.

OBJECTIVE

To examine the temporal trends and hospital variation in use of single- and dual-chamber ICD implantation among patients without a pacing indication undergoing first-time ICD implantation.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter cross-sectional study was conducted using the US National Cardiovascular Data Registry ICD Registry. A total of 266 182 patients undergoing initial implantation of a single- or dual-chamber transvenous ICD without a bradycardia pacing indication, class I or II cardiac resynchronization therapy indication, or history of atrial fibrillation or atrial flutter were included. The study was conducted from April 1, 2010, to December 31, 2018; data analysis was performed from October 19, 2020, to January 5, 2022.

EXPOSURES

Implantation of a single- or dual-chamber ICD.

MAIN OUTCOMES AND MEASURES

Temporal trends among patients undergoing single- vs dual-chamber ICDs were determined using the Cochran-Armitage trend test, and hospital-level variation using adjusted hospital median odds ratios was examined.

RESULTS

A total of 266 182 patients (single-chamber ICD, 134 925; dual-chamber ICD, 131 257) were included in this analysis; mean (SD) age was 58.0 (14.0) years and 91 990 patients (68.2%) were men. The use of dual-chamber ICDs decreased from 64.7% (n = 15 694) in 2010 to 42.2% (n = 9762) in 2018 (P < .001). Adjusted for patient characteristics, the median hospital-level proportion of single-chamber ICDs increased from 42.9% (95% CI, 42.6%-45.0%) in 2010 to 50.0% (95% CI, 47.8%-51.0%) in 2018. The median odds ratio for the use of dual-chamber ICDs, adjusted for patient characteristics, was 1.6 (95% CI, 1.6-1.8) in 2010 and 1.5 (95% CI, 1.5-1.8) in 2018, indicating decreasing but persistent variation in use.

CONCLUSIONS AND RELEVANCE

In this national study of US patients undergoing first-time ICD implantation without a clinical indication for an atrial lead, the use of dual-chamber devices decreased. However, institutional variability in the use of atrial leads persists, suggesting differences in individual or institutional cultures of real-world practice and opportunity to reduce this low-value practice.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Atrial fibrillation associated with heart failure treated by a 2-lead CRT-DX system (BIO-AffectDX): Study design and clinical protocol

Background

Evidence to support use of cardiac resynchronization therapy (CRT) among patients with both heart failure (HF) and atrial fibrillation (AF) is largely limited to retrospective or post hoc subanalyses. Data from a prospectively enrolled and contemporary cohort are needed.

Objective

We aim to better characterize the changes from baseline in HF patients with concomitant AF subsequently implanted with a 2-lead CRT-DX system capable of sensing in the atrium, aggregating diagnostics, and delivering CRT therapy. The primary objective of this study is to evaluate the percentage of all HF subjects with an improvement in a clinical composite score from pre-CRT implant to 12 months.

Methods

The study is a US-based, prospective, observational multicenter clinical trial conducted at up to 50 sites and enrolling approximately 400 subjects with a follow-up period of 1 year. Multiple subject assessments, atrial rhythm status, and device interrogation will be collected at follow-up visits occurring at 3, 6, and 12 months postimplant.

Results

A Clinical Events Committee will adjudicate subject HF events, arrhythmia events, death events, and all device-classified ventricular tachycardia and ventricular fibrillation episodes with treatment that are collected throughout the follow-up period. Their decisions are based on independent physician review of the data from sites and device interrogation.

Conclusion

The BIO-AffectDX study aims to provide further insight into the expected outcomes from CRT treatment in patients with HF and AF.

Sacubitril/valsartan reduces indications for arrhythmic primary prevention in heart failure with reduced ejection fraction: insights from DISCOVER-ARNI, a multicenter Italian register

Aims

This sub-study deriving from a multicentre Italian register [Deformation Imaging by Strain in Chronic Heart Failure Over Sacubitril-Valsartan: A Multicenter Echocardiographic Registry (DISCOVER)-ARNI] investigated whether sacubitril/valsartan in addition to optimal medical therapy (OMT) could reduce the rate of implantable cardioverter-defibrillator (ICD) indications for primary prevention in heart failure with reduced ejection fraction (HFrEF) according to European guidelines indications, and its potential predictors.

Methods and results

In this observational study, consecutive patients with HFrEF eligible for sacubitril/valsartan from 13 Italian centres were included. Lack of follow-up or speckle tracking data represented exclusion criteria. Demographic, clinical, biochemical, and echocardiographic data were collected at baseline and after 6 months from sacubitril/valsartan initiation. Of 351 patients, 225 (64%) were ICD carriers and 126 (36%) were not ICD carriers (of whom 13 had no indication) at baseline. After 6 months of sacubitril/valsartan, among 113 non-ICD carriers despite having baseline left ventricular (LV) ejection fraction (EF) ≤ 35% and New York Heart Association (NYHA) class = II-III, 69 (60%) did not show ICD indications; 44 (40%) still fulfilled ICD criteria. Age, atrial fibrillation, mitral regurgitation > moderate, left atrial volume index (LAVi), and LV global longitudinal strain (GLS) significantly varied between the groups. With receiver operating characteristic curves, age ≥ 75 years, LAVi ≥ 42 mL/m2 and LV GLS ≥-8.3% were associated with ICD indications persistence (area under the curve = 0.65, 0.68, 0.68, respectively). With univariate and multivariate analysis, only LV GLS emerged as significant predictor of ICD indications at follow-up in different predictive models.

Conclusions

Sacubitril/valsartan may provide early improvement of NYHA class and LVEF, reducing the possible number of implanted ICD for primary prevention in HFrEF. Baseline reduced LV GLS was a strong marker of ICD indication despite OMT. Early therapy with sacubitril/valsartan may save infective/haemorrhagic risks and unnecessary costs deriving from ICDs.

Time to diagnosis of acute complications after cardiovascular implantable electronic device insertion and optimal timing of discharge within the first 24 hours

BACKGROUND

More than 3 million cardiovascular implantable electronic devices (CIEDs) are implanted annually. There are minimal data regarding the timing of diagnosis of acute complications after implantation. It remains unclear whether patients can be safely discharged less than 24 hours postimplantation.

OBJECTIVE

The purpose of this study was to determine the precise timing of acute complication diagnosis after CIED implantation and optimal timing for same-day discharge.

METHODS

A retrospective cohort analysis of adults 18 years or older who underwent CIED implantation at a large urban quaternary care medical center between June 1, 2015, and March 30, 2020, was performed. Standard of care included overnight observation and chest radiography 6 and 24 hours postprocedure. Medical records were reviewed for the timing of diagnosis of acute complications. Acute complications included pneumothorax, hemothorax, pericardial effusion, lead dislodgment, and implant site hematoma requiring surgical intervention.

RESULTS

A total of 2421 patients underwent implantation. Pericardial effusion or cardiac tamponade was diagnosed in 13 patients (0.53%), pneumothorax or hemothorax in 19 patients (0.78%), lead dislodgment in 11 patients (0.45%), and hematomas requiring surgical intervention in 5 patients (0.2%). Of the 48 acute complications, 43 (90%) occurred either within 6 hours or more than 24 hours after the procedure. Only 3 acute complications identified between 6 and 24 hours required intervention during the index hospitalization (0.12% of all cases).

CONCLUSION

Most acute complications are diagnosed either within the first 6 hours or more than 24 hours after implantation. With rare exception, patients can be considered for discharge after 6 hours of appropriate monitoring.

Epidemiology of cardiac implantable electronic device infections: incidence and risk factors

Cardiac implantable electronic device (CIED) infection is a potentially devastating complication of CIED procedures, causing significant morbidity and mortality for patients. Of all CIED complications, infection has the greatest impact on mortality, requirement for re-intervention and additional hospital treatment days. Based on large prospective studies, the infection rate at 12-months after a CIED procedure is approximately 1%. The risk of CIED infection may be related to several factors which should be considered with regards to risk minimization. These include technical factors, patient factors, and periprocedural factors. Technical factors include the number of leads and size of generator, the absolute number of interventions which have been performed for the patient, and the operative approach. Patient factors include various non-modifiable underlying comorbidities and potentially modifiable transient conditions. Procedural factors include both peri-operative and post-operative factors. The contemporary PADIT score, derived from a large cohort of CIED patients, is useful for the prediction of infection risk. In this review, we summarize the key information regarding epidemiology, incidence and risk factors for CIED infection.

Long-term complications in patients implanted with subcutaneous implantable cardioverter-defibrillators: Real-world data from the extended ELISIR experience

BACKGROUND

Recently, the Food and Drug Administration issued a recall for the subcutaneous implantable cardioverter-defibrillator (S-ICD) because of the possibility of lead ruptures and accelerated battery depletion.

OBJECTIVE

The aim of this study was to evaluate device-related complications over time in a large real-world multicenter S-ICD cohort.

METHODS

Patients implanted with an S-ICD from January 2015 to June 2020 were enrolled from a 19-institution European registry (Experience from the Long-term Italian S-ICD registry [ELISIR]; ClinicalTrials.gov identifier NCT0473876). Device-related complication rates over follow-up were collected. Last follow-up of patients was performed after the Boston Scientific recall issue.

RESULTS

A total of 1254 patients (median age 52.0 [interquartile range 41.0-62.2] years; 973 (77.6%) men; 387 (30.9%) ischemic) was enrolled. Over a follow-up of 23.2 (12.8-37.8) months, complications were observed in 117 patients (9.3%) for a total of 127 device-related complications (23.6% managed conservatively and 76.4% required reintervention). Twenty-seven patients (2.2%) had unanticipated generator replacement after 3.6 (3.3-3.9) years, while 4 (0.3%) had lead rupture. Body mass index (hazard ratio [HR] 1.063 [95% confidence interval 1.028-1.100]; P < .001), chronic kidney disease (HR 1.960 [1.191-3.225]; P = .008), and oral anticoagulation (HR 1.437 [1.010-2.045]; P = .043) were associated with an increase in overall complications, whereas older age (HR 0.980 [0.967-0.994]; P = .007) and procedure performed in high-volume centers (HR 0.463 [0.300-0.715]; P = .001) were protective factors.

CONCLUSION

The overall complication rate over 23.2 months of follow-up in a multicenter S-ICD cohort was 9.3%. Early unanticipated device battery depletions occurred in 2.2% of patients, while lead fracture was observed in 0.3%, which is in line with the expected rates reported by Boston Scientific.

Rate and impact on patient outcome and healthcare utilization of complications requiring surgical revision: Subcutaneous versus transvenous implantable defibrillator therapy

INTRODUCTION

Comparison data on management of device-related complications and their impact on patient outcome and healthcare utilization between subcutaneous implantable cardioverter-defibrillator (S-ICD) and transvenous ICD (TV-ICD) are lacking. We designed this prospective, multicentre, observational registry to compare the rate, nature, and impact of long-term device-related complications requiring surgical revision on patient outcome and healthcare utilization between patients undergoing S-ICD or TV-ICD implantation.

METHODS AND RESULTS

A total of 1099 consecutive patients who underwent S-ICD or TV-ICD implantation were enrolled. Propensity matching for baseline characteristics yielded 169 matched pairs. Rate, nature, management, and impact on patient outcome of device-related complications were analyzed and compared between two groups. During a mean follow-up of 30 months, device-related complications requiring surgical revision were observed in 20 patients: 3 in S-ICD group (1.8%) and 17 in TV-ICD group (10.1%; p = .002). Compared with TV-ICD patients, S-ICD patients showed a significantly lower risk of lead-related complications (0% vs. 5.9%; p = .002) and a similar risk of pocket-related complications (0.6 vs. 2.4; p = .215) and device infection (0.6% vs. 1.2%; p = 1.000). Complications observed in S-ICD patients resulted in a significantly lower number of complications-related rehospitalizations (median 0 vs. 1; p = .013) and additional hospital treatment days (1.0 ± 1.0 vs. 6.5 ± 4.4 days; p = .048) compared with TV-ICD patients.

CONCLUSIONS

Compared with TV-ICD, S-ICD is associated with a lower risk of complications, mainly due to a lower risk of lead-related complications. The management of S-ICD complications requires fewer and shorter rehospitalizations.

Long-term evaluation of sensing variability of a floating atrial dipole in a single‑lead defibrillator: The mechanistic basis of long-term stability of amplified atrial electrogram

BACKGROUND

A single‑lead implantable cardioverter-defibrillator (ICD) with a floating atrial dipole has been developed to enhance the diagnostic capability of atrial arrhythmias and to facilitate adjudication of arrhythmic events without the additional effort required for atrial lead insertion. However, there have been concerns about the long-term reliability of atrial sensing.

METHODS

We enrolled patients with the single-chamber ICD with atrial-sensing electrodes from 4 tertiary university hospitals in Korea. Minimal, maximal, and mean P wave amplitudes were collected at 3-6 months, 6-12 months, and 12-24 months after implantation. The difference between the minimal and maximal sensing amplitudes was calculated as an indicator of the variability of atrial sensing, while the atrial sensing stability was assessed using the mean amplitude.

RESULTS

A total of 86 patients were included for analysis. The variability of atrial sensing amplitudes significantly decreased at 12-24 months compared to 3-6 months (p = 0.01), while mean atrial amplitudes were stable throughout the mean follow-up duration of 17.4 months. Nine patients (10.5%) experienced inappropriate ICD therapy mostly due to misclassification of supraventricular tachycardia.

CONCLUSIONS

Under the hypothesis that sensing stability can be guaranteed as the variability decreases with time, we suggest that the concern about long-term sensing stability of a floating dipole can be abated with an ICD that has been implanted for over 2 years.

Impact of insurance status on ICD implantation practice patterns: Insights from the NCDR ICD registry

BACKGROUND

Whether insurance status influences practice patterns in implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) defibrillators, when indicated, is not known.

METHODS AND RESULTS

We analyzed the NCDR ICD Registry to evaluate associations of insurance status with guidelines-based receipt of CRT, as well as device-type, complication rates, and use of optimal medical therapy defined by guidelines. Among 798,028 patients with de novo ICD implants, we included only patients < 65 years (those older have Medicare) and excluded those admitted before 2006 (n=1,835) or with insurance coverage other than Medicare, Medicaid or private insurance (n=25,695) leaving 286,556 for analysis. Inverse probability of treatment weighting was used to control for imbalances between groups. Mean age was 53 years, 29% were female. Patients with private insurance and Medicare were more likely to receive CRT-D when indicated (79.6%, OR 1.19 95% CI 1.09-1.28, P <.001 and 78.5%, OR 1.11 95% CI 1.01-1.21 P = .03, respectively) compared to the uninsured (76.7%). The uninsured were also more likely than other groups to receive a single-chamber device. Complication rates did not differ. Uninsured patients were, however, more likely to receive optimal medical therapy, particularly in the subgroup receiving the implant for primary prevention.

CONCLUSIONS

In propensity-weighted analysis, uninsured patients are less likely to receive CRT when indicated but more likely to be receiving optimal medical therapy at discharge. Reasons for differences in device implantation practices based on insurance status require further study.

Dutch Outcome in Implantable Cardioverter-Defibrillator Therapy: Implantable Cardioverter-Defibrillator-Related Complications in a Contemporary Primary Prevention Cohort

Background

One third of primary prevention implantable cardioverter‐defibrillator patients receive appropriate therapy, but all remain at risk of defibrillator complications. Information on these complications in contemporary cohorts is limited. This study assessed complications and their risk factors after defibrillator implantation in a Dutch nationwide prospective registry cohort and forecasts the potential reduction in complications under distinct scenarios of updated indication criteria.

Methods and Results

Complications in a prospective multicenter registry cohort of 1442 primary implantable cardioverter‐defibrillator implant patients were classified as major or minor. The potential for reducing complications was derived from a newly developed prediction model of appropriate therapy to identify patients with a low probability of benefitting from the implantable cardioverter‐defibrillator. During a follow‐up of 2.2 years (interquartile range, 2.0–2.6 years), 228 complications occurred in 195 patients (13.6%), with 113 patients (7.8%) experiencing at least one major complication. Most common ones were lead related (n=93) and infection (n=18). Minor complications occurred in 6.8% of patients, with lead‐related (n=47) and pocket‐related (n=40) complications as the most prevailing ones. A surgical reintervention or additional hospitalization was required in 53% or 61% of complications, respectively. Complications were strongly associated with device type. Application of stricter implant indication results in a comparable proportional reduction of (major) complications.

Conclusions

One in 13 patients experiences at least one major implantable cardioverter‐defibrillator–related complication, and many patients undergo a surgical reintervention. Complications are related to defibrillator implantations, and these should be discussed with the patient. Stricter implant indication criteria and careful selection of device type implanted may have significant clinical and financial benefits.

Heart Disease and Stroke Statistics-2021 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2021 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors related to cardiovascular disease.

RESULTS

Each of the 27 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Rationale and feasibility of the atrioventricular single-lead ICD systems with a floating atrial dipole (DX) in clinical practice

Cardiac implantable electronic devices establish proper therapy for the prevention of sudden cardiac death, significantly reducing the morbidity and mortality of patients with arrhythmias and heart failure. It is well-known that the number of electrodes increases the risk of complications. To preserve the benefit of atrial sensing without the need to implant an additional lead, a single-lead ICD system with a floating atrial dipole (DX ICD lead) has been developed. Besides all of the potential benefits, the necessity of a reliable and stable atrial sensing via the floating dipole could be the main concern against the use of this lead type. In the current generation of DX devices, the specially filtered atrial signal seems to be high enough and stable over time, which is crucial in the early detection of atrial arrhythmias, discrimination between different forms of tachycardias in order to prevent inappropriate ICD therapy, and achieving an optimal atrioventricular and interventricular synchrony in patients with a two-lead CRT-DX system. The present review summarizes the benefits and potential drawbacks of the DX ICD systems based on the available literature, furthermore, proposes an evidence-based algorithm of ICD type selection.

No Association Between T-peak to T-end Interval on the Resting ECG and Long-Term Incidence of Ventricular Arrhythmias Triggering ICD Interventions

Background and Objectives

Potential of using the T-peak to T-end (TpTe) interval as an electrocardiographic parameter reflecting the transmural dispersion of ventricular repolarization (TDR) to identify patients (pts.) with higher risk of malignant ventricular arrhythmias (MVA) for better selection of candidates for implantable cardioverter-defibrillator (ICD) in primary prevention (PP) of sudden cardiac death (SCD) remains controversial. The primary objective of this study was to investigate the relationship between the TpTe interval in patient’s preimplantation resting 12-lead electrocardiogram (ECG) and the incidence of MVA resulting in appropriate ICD intervention (AI). The secondary objective was to assess its relationship to overall mortality.

Methods

A total of 243 consecutive pts. with severe left ventricular (LV) systolic dysfunction after myocardial infarction (MI) with a single-chamber ICD for PP of SCD from one implantation center were included. Excluded were all pts. with any other disease that could interfere with the indication of ICD implantation. Primarily investigated intervals were measured manually in accordance with accepted methodology. Data on ICD interventions were acquired from device interrogation during regular outpatient visits. Survival data were collected from the databases of health insurance and regulatory authorities.

Results

We did not find a significant relationship between the duration of the TpTe interval and the incidence of MVA (71.5 ms in pts. with MVA vs. 70 ms in pts. without MVA; p = 0.408). Similar results were obtained for the corrected TpTe interval (TpTec) and the ratio of TpTe to QT interval (76.3 ms vs. 76.5 ms; p = 0.539 and 0.178 vs. 0.181; p = 0.547, respectively). There was also no significant difference between the duration of TpTe, TpTec and TpTe/QT ratio in pts. groups by overall mortality (71.5 ms in the deceased group vs. 70 ms in the survivors group; HR 1.01; 95% CI, 0.99–1.02; p = 0.715, 76.3 ms vs. 76.5 ms; HR 1.01; 95% CI, 0.99–1.02; p = 0.208 and 0.178 vs. 0.186; p = 0.116, respectively).

Conclusion

This study suggests no significant association of overall or MVA-free survival with ECG parameters reflecting TDR (TpTe, TpTec) in patients with systolic dysfunction after MI and ICD implanted for primary prevention.

Comparison of transvenous vs subcutaneous defibrillator therapy in patients with cardiac arrhythmia syndromes and genetic cardiomyopathies

BACKGROUND

Inherited arrhythmia syndromes and genetic cardiomyopathies attribute in a significant proportion to sudden cardiac death. Implantable cardioverter defibrillators (ICDs) are the cornerstone in the prevention of sudden death in high-risk patients. However, ICD therapy is also associated with high rates of inappropriate shocks and/or device-related complications especially in young patients.

OBJECTIVE

To determine the outcome of high-risk patients with inherited arrhythmia syndromes and genetic cardiomyopathies comparing two defibrillator technologies.

METHOD

Between 2010 and 2018, 183 consecutive patients from two large German tertiary care centers were enrolled in the study. The majority of patients (83%) had either cardiac channelopathies or idiopathic ventricular fibrillation without cardiac structural abnormalities, while the remaining 17% had a genetic cardiomyopathy (HCM/ARVC). Eighty-six patients (47%) received a transvenous ICD (TV-ICD), while a subcutaneous ICD (S-ICD) was implanted in another 97 patients (53%).

RESULTS

During a mean follow-up of 4.3 years, 30 patients had an appropriate ICD therapy (annual rate 3.8%). Fifteen patients experienced an inappropriate shock (annual rate 1.9%). Lead failure occurred in 17 (9%) patients and was less frequent in the S-ICD group (OR 0.48, 95%CI 0.38-0.62). Adverse defibrillator events, defined as a composite of inappropriate shocks and lead failure requiring surgical revision were significantly lower in the S-ICD group as compared to the TV-ICD group (OR 0.55, 95%CI 0.41-0.72). There was a non-significant trend towards lower appropriate shocks in the S-ICD group, that in combination with all-cause shocks yielded in a significantly higher freedom of any shock in the S-ICD group (RR 39%, p = 0.003). No deaths occurred during follow-up.

CONCLUSION

The present data favor the use of the subcutaneous ICD for patients with inherited arrhythmia syndromes and genetic cardiomyopathies who do not need anti-bradycardia pacing.

Rate, Time Course, and Predictors of Implantable Cardioverter Defibrillator Infections: An Analysis From the SIMPLE Trial

Background

The number of implantable cardioverter defibrillator (ICD) infections is increasing due to an increased number of ICD implants, higher-risk patients, and more frequent replacement procedures, which carry a higher risk of infection. Reducing the morbidity, mortality, and cost of ICD-related infections requires an understanding of the current rate of this complication and its predictors.

Methods

The Shock Implant Evaluation Trial (SIMPLE) trial randomized 2500 ICD recipients to defibrillation testing or not. Over an average of 3.1 years, patients were seen every 6 months and examined for evidence of ICD infection, which was defined as requiring device removal and/or intravenous antibiotics.

Results

Within 24 months, 21 patients (0.8%) developed infection. Fourteen patients (67%) with infection presented within 30 days, 20 patients by 12 months, and only 1 patient beyond 12 months. Univariate analysis demonstrated that patients with primary electrical disorders (3 patients, P = 0.009) and those with a secondary prevention indication (13 patients, P = 0.0009) were more likely to develop infection. Among the 2.2% of patients who developed an ICD wound hematoma, 10.4% developed an infection. Among the 8.3% of patients requiring an ICD reintervention, 1.9% developed an infection.

Conclusions

This cohort of ICD recipients at high-volume centres have a low risk of device-related infection. However; strategies to reduce wound hematoma and the need for ICD reintervention could further reduce the rate of infection.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Subclinical atrial fibrillation detection with a floating atrial sensing dipole in single lead implantable cardioverter-defibrillator systems: Results of the SENSE trial

INTRODUCTION

Subclinical atrial fibrillation (AF), in the form of cardiac implantable device-detected atrial high rate episodes (AHREs), has been associated with increased thromboembolism. An implantable cardioverter-defibrillator (ICD) lead with a floating atrial dipole may permit a single lead (DX) ICD system to detect AHREs. We sought to assess the utility of the DX ICD system for subclinical AF detection in patients, with a prospective multicenter, cohort-controlled trial.

METHODS AND RESULTS

One hundred fifty patients without prior history of AF (age 59 ± 13 years; 108 [72%] male) were enrolled into the DX cohort and implanted with a Biotronik DX ICD system at eight centers. Age-, sex-, and left ventricular ejection fraction-matched single- and dual-chamber ICD cohorts were derived from a Cornell database and from the IMPACT trial, respectively. The primary endpoint were AHRE detection at 12 months. During median 12 months follow-up, AHREs were detected in 19 (13%) patients in the DX, 8 (5.3%) in the single-chamber, and 19 (13%) in the dual-chamber cohorts. The rate of AHRE detection was significantly higher in the DX cohort compared to the single-chamber cohort (P = .026), but not significantly different compared to the dual-chamber cohort. There were no inappropriate ICD therapies in the DX cohort. At 12 months, only 3.0% of patients in the DX cohort had sensed atrial amplitudes less than 1.0 mV.

CONCLUSION

Use of a DX ICD lead allows subclinical AF detection with a single lead DX system that is superior to that of a conventional single-chamber ICD system.

Single vs. dual chamber implantable cardioverter-defibrillators or programming of implantable cardioverter-defibrillators in patients without a bradycardia pacing indication: systematic review and meta-analysis

Aims

Implantable cardioverter-defibrillators (ICDs) are key in the prevention of sudden cardiac death, but outcomes may vary by type of device or programming [single chamber (SC) vs. dual chamber (DC)] in patients without a bradycardia pacing indication. We sought to meta-analyse patient outcomes of randomized trials of SC vs. DC devices or programming.

Methods and results

We searched PubMed, Embase, Scopus, Web of Science, and Cochrane trials databases for relevant studies excluding those published before 2000, involving children, or not available in English. Endpoints included mortality, inappropriate ICD therapies, and implant complications. Endpoints with at least three reporting studies were meta-analysed. We identified eight studies meeting inclusion criteria representing 2087 patients with 16.1 months mean follow-up. Mean age was 62.7 years (SD 1.92); in six studies reporting sex, most patients were male (85%). Comparing patients with a SC or DC ICD or programming, we found similar rates of mortality [odds ratio (OR) 0.95, 95% confidence interval (CI) 0.54-1.68; P = 0.86] and inappropriate therapies (OR 1.46, 95% CI 0.97-2.19; P = 0.07) in five and six studies, respectively. In three studies of SC vs. DC ICDs (but not programming) rates of pneumothorax and lead dislodgement were not different (OR 2.12, 95% CI 0.18-24.72; P = 0.55 and OR 0.87, 95% CI 0.32-2.47; P = 0.83, respectively).

Conclusion

In this meta-analysis of randomized controlled trials comparing SC vs. DC ICD device or programming, there was no significant difference in inappropriate therapies, mortality, pneumothorax, or lead dislodgement. Future studies should compare these devices over longer follow-up and in specific patient populations.

Important Parameters for Implantable Cardioverter Defibrillator Selection

The efficacy of implantable cardioverter defibrillators in reducing the risk of sudden cardiac death has been well established by several clinical trials. Several factors relating to device characteristics, patient attributes, and comorbidities should be considered when selecting the appropriate implantable cardioverter defibrillators for each patient. This review examines some of these issues.

Remote Monitoring of Implantable Cardioverter-Defibrillators, Cardiac Resynchronization Therapy and Permanent Pacemakers: A Health Technology Assessment

BACKGROUND

Under usual care, people with an implantable cardioverter-defibrillator (ICD), cardiac resynchronization therapy with or without a defibrillator (CRT-D and CRT-P, respectively), or a permanent pacemaker have follow-up in-person clinic visits. Remote monitoring of these devices allows the transfer of the information stored in the device so that it can be accessed by the clinic personnel via a secured website.

METHODS

We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for remote monitoring of ICDs, CRTs, and permanent pacemakers plus clinic visits compared with clinic visits alone. This is an update of a 2012 health technology assessment. In addition to the eligible randomized controlled trials (RCTs) from the 2012 publication, we included RCTs identified through a systematic literature search on June 1, 2017. We assessed the risk of bias of each study using the Cochrane risk of bias tool and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We conducted an economic evaluation to determine the cost-effectiveness of remote monitoring blended with in-clinic follow-up compared to in-clinic follow-up alone in patients with an ICD, a CRT-D, or a pacemaker. We determined the budget impact of blended remote monitoring in patients implanted with ICD, CRT-D, CRT-P, or pacemaker devices from the perspective of the Ontario Ministry of Health and Long-Term Care. To understand patient experiences with remote monitoring, we interviewed 16 patients and family members.

RESULTS

Based on 15 RCTs in patients with implanted ICDs or CRT-Ds, remote monitoring plus clinic visits resulted in fewer patients with inappropriate ICD shocks within 12 to 37 months of follow-up (moderate quality evidence; absolute risk difference -0.04 [95% confidence interval -0.07 to -0.01]), fewer total clinic visits (moderate quality evidence), and a shorter time to detection and treatment of events (moderate quality evidence) compared with clinic visits alone. There was a similar risk of major adverse events (moderate quality evidence).Based on 6 RCTs in patients with pacemakers, remote monitoring plus clinic visits reduced the arrhythmia burden (high quality evidence), the time to detection and treatment of arrhythmias (high quality evidence), and the number of clinic visits (moderate quality evidence]) compared with clinic visits alone. Here again, there was a similar risk of major adverse events (high quality evidence).Results from the economic evaluation showed that among ICD and CRT-D recipients, blended remote monitoring (remote monitoring plus in-clinic follow ups) was more costly (incremental value of $4,354 per person) and more effective, providing higher quality-adjusted life years (incremental value of 0.19), compared to in-clinic follow-up alone. Among pacemaker recipients, blended remote monitoring was less costly (with an incremental saving of $2,370 per person) and more effective (with an incremental value of 0.12 quality-adjusted life years) than with in-clinic follow-up alone. We estimated that publicly funding remote monitoring could result in cost savings of $14 million over the first five years.Participants using remote monitoring reported that these devices provide important medical and safety benefits in managing their heart condition. Remote cardiac monitoring provides patients and their family members with an increased freedom. Their belief that the device will help with earlier detection of technical or clinical problems reduces the amount of stress and distraction their condition causes in their lives.

CONCLUSIONS

Remote monitoring of ICDs, CRT-Ds, and pacemakers plus clinic visits resulted in improved outcomes without increasing the risk of major adverse events compared with clinic visits alone. Remote monitoring is a cost-effective option for patients implanted with cardiac electronic devices. Patients reported positive experiences using remote monitoring, and perceived that the device provided important medical and safety benefits.

Postpacing Interval During Right Ventricular Overdrive Pacing to Discriminate Supraventricular from Ventricular tachycardia

Introduction

Failure to differentiate supraventricular from ventricular arrhythmias is the most frequent cause of inappropriate implantable cardioverter-defibrillator (ICD) therapies. We hypothesized that the postpacing interval (PPI) after overdrive right ventricular pacing may differentiate ventricular (VT) from supraventricular tachycardia (SVT) such as sinus tachycardia, atrial flutter and atrial tachycardia. This hypothesis is based on the entrainment maneuver. Reentrant tachycardia circuit for VTs would haveshorter distance to RV apex than SVTs have, and the conduction time between a ventricular pacing site and the tachycardia origin is expected to be shorter in VTs than in SVTs.

Methods

220episodes from 38 patients with single chamber ICDs that RV overdrive pacing could not terminate or change the tachycardia cycle length (TCL) were retrospectively reviewed. Episodes were classified as VTs (n=115) and SVTs (n=105). TCLs, PPIs and PPI-TCL were compared between groups.

Results

The cycle length of VTs was shorter than SVTs (320.6±30.3 vs 366.5±40 ms, p=0.001). PPI and PPI-TCL of VTs were shorter than SVTs (504.7±128.3 vs 689.2±121.8 ms, p=0.001, 184±103 vs 322.6±106.6 ms, p=0.001; respectively). ROC curve analysis demonstrated a 525 ms cut-off value for PPI has 89% sensitivity and 57.4% specificity to predict inappropriate ICD therapies due to SVTs (AUC:0.852). Similarly, A PPI-TCL <195 ms favored VT as a diagnosis rather than SVT with a 90% sensitivity, and 51% specificity (AUC:0.838).

Conclusion

Analyzing of PPI during overdrive pacing from RV apex may discriminate supraventricular from ventricular tachycardia. This criterion may have a potential role in implantable devices that use a single ventricular lead.

Inappropriate shocks in single-chamber and subcutaneous implantable cardioverter-defibrillators: a systematic review and meta-analysis

AIMS

Single-chamber (VR-ICD) and subcutaneous (S-ICD) implantable cardioverter-defibrillators are effective to protect patients against sudden death but expose them to higher risk of inappropriate shock (IS). We sought to quantify the annual rate and influencing factors of ISs in VR- and S-ICDs from the literature.

METHODS AND RESULTS

PubMed, Embase, and Cochrane Library were searched for full text articles with IS rates. Poisson distribution estimated proportion of patients with ISs; rates were annualized based on follow-up duration. Random effects meta-analysis accounted for study-to-study variation. Out of 3264 articles, 16 qualified for the meta-analysis. Across studies, 6.4% [95% confidence interval (CI) 5.1-7.9%] of patients received an IS per year. Meta-regression analyses demonstrated that IS rates were lower in more recent studies [rate ratio (RR) per year: 0.93, 95% CI: 0.87-0.98; P = 0.01] and trended lower in studies with longer follow-up (RR per year: 0.78, 95% CI: 0.60-1.01; P = 0.06). Use of S-ICDs (RR: 1.81, 95% CI: 0.86-3.81; P = 0.12) and ventricular tachycardia zone programmed on (RR: 1.13, 95% CI: 0.65-1.97; P = 0.66) were not associated with a significantly increased change in risk. The IS rate observed in one of the more recent studies was significantly lower than predicted after accounting for covariates (RR: 0.29, 95% CI: 0.14-0.60; P < 0.001).

CONCLUSIONS

A comprehensive review of the literature shows that 6.4% of patients with ICDs experienced their first IS annually. One of the 16 studies was better than predicted with the lowest reported rate (1.9%) and could not be explained by timing of the study or other covariates.

Complications Associated With Implantable Cardioverter Defibrillators in Adults With Congenital Heart Disease or Left Ventricular Noncompaction Cardiomyopathy (From the NCDR® Implantable Cardioverter-Defibrillator Registry)

Patients with childhood heart disease are living longer and entering adulthood, and may undergo implantable cardioverter-defibrillator (ICD) implantation to reduce the risk of sudden death. We evaluated the characteristics of adult patients with congenital heart disease or left ventricular noncompaction cardiomyopathy (LVNC) in the National Cardiovascular Disease Registry ICD Registry and determined ICD-related in-hospital complications. Patients with LVNC or transposition of the great arteries, tetralogy of Fallot, Ebstein's anomaly, atrial septal defect, ventricular septal defect, or common ventricle were identified in the registry. In-hospital complications were compared among different diagnoses using the chi-square test for categorical variables and the F-test in analyses of variance for continuous variables. A total of 3,077 patients were identified. The mean age was 48.0 ± 16.0 years, and 39.9% were female. Single-chamber ICDs were implanted in 25.2%, dual chamber in 41.9%, and cardiac resynchronization in 30.8%. Intraprocedural or postprocedural complications occurred in 70 patients (2.3%); there were 6 in-hospital deaths (0.2%). The most frequent complications were acute lead dislodgments, pneumothorax, and hematomas. Patients with Ebstein's anomaly had the greatest complication rate (8.3%, p = 0.03). The complication rate was 1.55% in single-chamber devices, 1.86% in dual chamber, and 3.5% in cardiac resynchronization (p < 0.001). For initial implants, the complication rate was 2.55%, 1.62% in generator replacements, and 8.77% in lead revisions (p = 0.001). In conclusion, in this large contemporary adult cohort of congenital heart disease and LVNC patients who underwent ICD implant procedures, periprocedural complication rates were low. Lead-related risks predominated.

Comparison of Inappropriate Shocks and Other Health Outcomes Between Single- and Dual-Chamber Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death: Results From the Cardiovascular Research Network Longitudinal Study of Implantable Cardioverter-Defibrillators

BACKGROUND

In US clinical practice, many patients who undergo placement of an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death receive dual-chamber devices. The superiority of dual-chamber over single-chamber devices in reducing the risk of inappropriate ICD shocks in clinical practice has not been established. The objective of this study was to compare risk of adverse outcomes, including inappropriate shocks, between single- and dual-chamber ICDs for primary prevention.

METHODS AND RESULTS

We identified patients receiving a single- or dual-chamber ICD for primary prevention who did not have an indication for pacing from 15 hospitals within 7 integrated health delivery systems in the Longitudinal Study of Implantable Cardioverter-Defibrillators from 2006 to 2009. The primary outcome was time to first inappropriate shock. ICD shocks were adjudicated for appropriateness. Other outcomes included all-cause hospitalization, heart failure hospitalization, and death. Patient, clinician, and hospital-level factors were accounted for using propensity score weighting methods. Among 1042 patients without pacing indications, 54.0% (n=563) received a single-chamber device and 46.0% (n=479) received a dual-chamber device. In a propensity-weighted analysis, device type was not significantly associated with inappropriate shock (hazard ratio, 0.91; 95% confidence interval, 0.59-1.38 [P=0.65]), all-cause hospitalization (hazard ratio, 1.03; 95% confidence interval, 0.87-1.21 [P=0.76]), heart failure hospitalization (hazard ratio, 0.93; 95% confidence interval, 0.72-1.21 [P=0.59]), or death (hazard ratio, 1.19; 95% confidence interval, 0.93-1.53 [P=0.17]).

CONCLUSIONS

Among patients who received an ICD for primary prevention without indications for pacing, dual-chamber devices were not associated with lower risk of inappropriate shock or differences in hospitalization or death compared with single-chamber devices. This study does not justify the use of dual-chamber devices to minimize inappropriate shocks.