Cost Advantage of Dual-Chamber Versus Single-Chamber Cardioverter-Defibrillator Implantation

Comparative Effectiveness of Implantable Defibrillators for Asymptomatic Brugada Syndrome: A Decision-Analytic Model

Background Optimal management of asymptomatic Brugada syndrome (BrS) with spontaneous type I electrocardiographic pattern is uncertain. Methods and Results We developed an individual-level simulation comprising 2 000 000 average-risk individuals with asymptomatic BrS and spontaneous type I electrocardiographic pattern. We compared (1) observation, (2) electrophysiologic study (EPS)-guided implantable cardioverter-defibrillator (ICD), and (3) upfront ICD, each using either subcutaneous or transvenous ICD, resulting in 6 strategies tested. The primary outcome was quality-adjusted life years (QALYs), with cardiac deaths (arrest or procedural-related) as a secondary outcome. We varied BrS diagnosis age and underlying arrest rate. We assessed cost-effectiveness at $100 000/QALY. Compared with observation, EPS-guided subcutaneous ICD resulted in 0.35 QALY gain/individual and 4130 cardiac deaths avoided/100 000 individuals, and EPS-guided transvenous ICD resulted in 0.26 QALY gain and 3390 cardiac deaths avoided. Compared with observation, upfront ICD reduced cardiac deaths by a greater margin (subcutaneous ICD, 8950; transvenous ICD, 6050), but only subcutaneous ICD improved QALYs (subcutaneous ICD, 0.25 QALY gain; transvenous ICD, 0.01 QALY loss), and complications were higher. ICD-based strategies were more effective at younger ages and higher arrest rates (eg, using subcutaneous devices, upfront ICD was the most effective strategy at ages 20-39.4 years and arrest rates >1.37%/year; EPS-guided ICD was the most effective strategy at ages 39.5-51.3 years and arrest rates 0.47%-1.37%/year, and observation was the most effective strategy at ages >51.3 years and arrest rates <0.47%/year). EPS-guided subcutaneous ICD was cost-effective ($80 508/QALY). Conclusions Device-based approaches (with or without EPS risk stratification) can be more effective than observation among selected patients with asymptomatic BrS. BrS management should be tailored to patient characteristics.

Outcomes of single- or dual-chamber implantable cardioverter defibrillator systems in Japanese patients

Background

There are no criteria for selecting single- or dual-chamber implantable cardioverter defibrillators (ICDs) in patients without a pacing indication. Recent reports showed no benefit of the dual-chamber system despite its preference in the United States. As data on ICD selection and respective outcomes in Japanese patients are scarce, we investigated trends regarding single- and dual-chamber ICD usage in Japan.

Methods

Data from a total of 205 ICD recipients with structural heart disease (median age, 63 years) in two Japanese university hospitals were reviewed. Patients with bradycardia with a pacing indication and permanent atrial fibrillation at implantation were excluded.

Results

Single- and dual-chamber ICDs were implanted in 36 (18%) and 169 (82%) patients, respectively. Non-ischemic cardiomyopathy dominated both groups. Seventeen dual-chamber patients developed atrial pacing-dependency over 4.5 years, and it developed immediately after implantation in 14. Although preoperative testing showed no sign of bradycardia in these patients, their pacing rate was set higher than it was in patients who were pacing-independent (61 vs. 46 paces per min, p<0.01). Two single-chamber patients (5%) underwent atrial lead insertion.

While inappropriate shock equally occurred in both groups (7 vs. 21 patients, single- vs. dual-chamber, P=0.285), device-related infection occurred only in dual-chamber patients (0 vs. 9 patients, P=0.155). No differences in death or heart failure hospitalization were observed between groups.

Conclusions

Dual-chamber ICDs were four-fold more common in Japanese patients without a pacing indication. No benefit over single-chamber ICD was observed. Newly developed atrial pacing-dependency seemed to be limited and could have been overestimated due to higher pacing rate settings in dual-chamber patients.

Clinical Outcomes of Single- versus Dual-Chamber Implantable Cardioverter Defibrillators: Lessons from the Israeli ICD Registry

OBJECTIVE

To compare the clinical outcomes of a single- versus dual-chamber ICD for primary prevention of sudden cardiac death in a large, national ICD registry.

METHODS

Data were collected from the prospective Israeli ICD Registry. Baseline characteristics and clinical outcomes including mortality, admissions for heart failure (HF), and ICD therapy were compared between the two groups.

RESULTS

A total of 1,125 subjects, 37% with a single-chamber and 63% with a dual-chamber ICD, constructed the baseline cohort. Approximately 80% had ischemic heart disease (IHD). Mean follow-up was 22 months, mean ejection fraction was 30%, and mean QRS width was 103 milliseconds in both groups. During follow-up, there were no significant differences in the rate of mortality, admissions for HF, appropriate or inappropriate therapy, or in time to any of the clinical outcomes. Using multivariate analysis, single-chamber ICD was not associated with increased risk of death or admission for HF. In a subgroup of patients with IHD, single-chamber ICD was associated with a higher rate of inappropriate therapy.

CONCLUSIONS

In this large retrospective population-based cohort, dual-chamber ICD showed no benefit in reducing the incidence of death or HF admissions, whereas in a subgroup of patients with IHD, single-chamber ICD was associated with increased inappropriate therapy. Further prospective studies are necessary to assess the benefit of dual-chamber ICD in reducing the rate of inappropriate therapy.

The cost effectiveness of implantable cardioverter defibrillators: a systematic review of economic evaluations

BACKGROUND

Sudden cardiac death (SCD) is the most common cause of death in developed countries, with more than 3 million people dying yearly. Implantable cardioverter defibrillators (ICDs) are considered to be an effective treatment in the primary and secondary prevention of SCD; however, their cost is considerable and this poses questions regarding whether they are worth the investment relative to less expensive pharmacotherapy.

OBJECTIVE

The aim of this systematic review is to investigate existing evidence regarding the cost effectiveness of ICD therapy and to identify the key drivers of cost effectiveness, for the purpose of informing interested policy and decision makers.

METHODOLOGY

A systematic review of the literature concerning the cost effectiveness of ICDs was undertaken. Electronic databases, including PubMed, Cochrane and Health Economic Evaluations Database were searched based on appropriate terms and their combinations. Economic evaluation studies that examined the cost effectiveness of ICDs were selected and 34 were included for evaluation.

RESULTS

Findings from the present analysis show that ICD therapy, in properly selected patients who are at high risk of sudden cardiac death, is associated with similar or better cost-effectiveness ratios compared with other well accepted conventional treatments. The cost effectiveness of ICDs is influenced by several factors, including ICD efficacy and safety, impact on patient quality of life, device original implantation cost, frequency and cost of battery replacement, patient demographics and risk profile and analysis time horizon.

CONCLUSION

ICDs may represent a cost-effective option relative to pharmacotherapy in appropriately selected patient groups. The cost-effectiveness ratios appear to be at acceptable and comparable levels to other established treatments in cardiovascular and non-cardiovascular diseases. However, cost effectiveness is highly related to several factors and hence economic efficiency is highly dependent on conditions that need to be fulfilled for each individual case in medical practice. The aforementioned factors and technological advances imply that to ensure cost-effective use of ICD therapy, continuous research is needed.

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

IMPORTANCE

Randomized trials of implantable cardioverter-defibrillators (ICDs) for primary prevention predominantly used single-chamber devices. In clinical practice, patients often receive dual-chamber ICDs, even without clear indications for pacing. The outcomes of dual- vs single-chamber devices are uncertain.

OBJECTIVE

To compare outcomes of single- and dual-chamber ICDs for primary prevention of sudden cardiac death.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of admissions in the National Cardiovascular Data Registry's (NCDR) ICD registry from 2006-2009 that could be linked to Centers for Medicare & Medicaid Services fee-for-service Medicare claims data. Patients were included if they received an ICD for primary prevention and did not have a documented indication for pacing.

MAIN OUTCOMES AND MEASURES

Adjusted risks of 1-year mortality, all-cause readmission, heart failure readmission, and device-related complications within 90 days were estimated with propensity-score matching based on patient, clinician, and hospital factors.

RESULTS

Among 32,034 patients, 12,246 (38%) received a single-chamber device and 19,788 (62%) received a dual-chamber device. In a propensity-matched cohort, rates of complications were lower for single-chamber devices (3.51% vs 4.72%; P < .001; risk difference, -1.20 [95% CI, -1.72 to -0.69]), but device type was not significantly associated with 1-year mortality (unadjusted rate, 9.85% vs 9.77%; hazard ratio [HR], 0.99 [95% CI, 0.91 to 1.07]; P = .79), 1-year all-cause hospitalization (unadjusted rate, 43.86% vs 44.83%; HR, 1.00 [95% CI, 0.97-1.04]; P = .82), or hospitalization for heart failure (unadjusted rate, 14.73% vs 15.38%; HR, 1.05 [95% CI, 0.99-1.12]; P = .19).

CONCLUSIONS AND RELEVANCE

Among patients receiving an ICD for primary prevention without indications for pacing, the use of a dual-chamber device compared with a single-chamber device was associated with a higher risk of device-related complications and similar 1-year mortality and hospitalization outcomes. Reasons for preferentially using dual-chamber ICDs in this setting remains unclear.

Predictors of pacemaker dependence and pacemaker dependence as a predictor of mortality in patients with implantable cardioverter defibrillator

BACKGROUND

The prevalence, predictors, and survival for the development of pacemaker dependence (PD) in patients implanted with an implantable cardioverter defibrillator (ICD) are unknown.

METHODS

This was a retrospective analysis of 1,550 consecutive patients with ICD implantation at a single center from 1996 to 2008 with a mean of 4.2 ± 3.4 years. Patients with implant intrinsic heart rates less than 40 beats/min (n = 48) and cardiac resynchronization therapy (n = 444) were excluded leaving 1,058 patients in this study. PD was defined as an intrinsic rhythm <40 beats/min after inhibiting the pacemaker, <50 beats/min with transient symptoms of dizziness relieved by resumption of pacing and right ventricle pacing despite algorithms to promote intrinsic conduction at the 3 monthly follow-up ICD clinic visits. Multivariate regression and Cox proportional hazard models were used for analysis.

RESULTS

The mean age was 64 ± 13 years; 79% were male with a primary indication for the ICD in 57%. PD occurred in 142 (13.4%) of patients, with a mean time to PD of 2.6 ± 1.9 years. PD was associated with a 48% increased odds for mortality versus non-PD ICD patients during the mean follow-up time of 4.2 ± 3.4 years (adjusted odds ratio = 1.48 [95% confidence interval 1.080-2.042]; P = 0.015). Older age, a history of atrial fibrillation, amiodarone use, and secondary prevention were the strongest predictors for the development of PD.

CONCLUSIONS

In this single-center ICD cohort, the development of PD was not uncommon and was associated with decreased survival.

Variation in use of dual-chamber implantable cardioverter-defibrillators: results from the national cardiovascular data registry

BACKGROUND

Among patients without an indication for a pacemaker, current evidence is inconclusive whether a dual-chamber implantable cardioverter-defibrillator (ICD) is superior to a single-chamber ICD. The current use of dual-chamber ICDs is not well characterized.

METHODS

We conducted a cross-sectional study exploring hospital-level variation in the use of dual-chamber ICDs across the United States. Patients receiving a primary prevention ICD from 2006 through 2009 without a documented indication for a pacemaker were included. Multivariate hierarchical logistic regression was used to explore patient, health care provider, and physician factors related to the use of a dual-chamber device.

RESULTS

Dual-chamber devices were implanted in 58% of the 87,115 patients without a pacing indication among 1293 hospitals, with hospital rates ranging from 0% in 33 centers to 100% in 109 centers. In multivariate analysis, geographic region was a strong independent predictor of dual-chamber device use, ranging from 36.4% in New England (reference region) to 66.4% in the Pacific region (odds ratio [OR], 5.25; 95% CI, 3.35-8.21). Hospital clustering was assessed using a median OR which was 3.96, meaning that 2 identical patients at different hospitals would have nearly a 4-fold difference in their chance of receiving a dual-chamber ICD.

CONCLUSIONS

Use of dual-chamber ICDs for the primary prevention of sudden cardiac death among patients without an indication for permanent pacing varies markedly at the hospital level in the United States. This is a clear example of how practice can vary independent of patient factors.

Dual-chamber implantable cardioverter-defibrillator selection is associated with increased complication rates and mortality among patients enrolled in the NCDR implantable cardioverter-defibrillator registry

OBJECTIVES

The aim of this study was to compare single- versus dual-chamber implantable cardioverter-defibrillator (ICD) implantation and complication rates in a large, real-world population.

BACKGROUND

The majority of patients enrolled in ICD efficacy trials received single-chamber devices. Although dual-chamber ICDs offer theoretical advantages over single-chamber defibrillators, the clinical superiority of dual-chamber models has not been conclusively proven, and they may increase complications.

METHODS

The National Cardiovascular Data Registry ICD Registry was used to examine the association between baseline characteristics and device selection in 104,049 patients receiving single- and dual-chamber ICDs between January 1, 2006, and December 31, 2007. A longitudinal cohort design was then used to determine in-hospital complication rates.

RESULTS

Dual-chamber devices were implanted in 64,489 patients (62%). Adverse events were more frequent with dual-chamber than with single-chamber device implantation (3.17% vs. 2.11%, p < 0.001), as was the rate of in-hospital mortality (0.40% vs. 0.23%, p < 0.001). After adjusting for demographics, medical comorbidities, diagnostic test data, and ICD indication, the odds of any complication (odds ratio: 1.40; 95% confidence interval: 1.28 to 1.52; p < 0.001) and in-hospital mortality (odds ratio: 1.45; 95% confidence interval: 1.20 to 1.74; p < 0.001) were increased with dual-chamber versus single-chamber ICD implantation.

CONCLUSIONS

In this large, multicenter cohort of patients, dual-chamber ICD use was common. Dual-chamber device implantation was associated with increases in periprocedural complications and in-hospital mortality compared with single-chamber defibrillator selection.

Atrial pacing or ventricular backup-only pacing in implantable cardioverter-defibrillator patients

BACKGROUND

The need for pacing support in typical ICD patients is unknown.

OBJECTIVE

This study sought to determine whether atrial pacing with ventricular backup pacing is equivalent to ventricular backup pacing only in implantable cardioverter-defibrillator (ICD) patients.

METHODS

We randomized 1,030 patients from 84 sites with indications for ICDs, with sinus rhythm, and without symptomatic bradycardia to atrial pacing with ventricular backup at 60 beats/min (518) or ventricular backup pacing at 40 beats/min (512). The primary end points were time to death, heart failure hospitalization (HFH), and heart failure-related urgent care (HFUC).

RESULTS

Follow-up was 2.4 ± 0.8 years when the trial was stopped for futility. There were 355 end point events (103 deaths, 252 HFH/HFUC) in 194 patients favoring ventricular backup pacing (event-free rate 77.7% vs. 80.3% for atrial pacing at 30 months; hazard ratio 1.14, upper confidence bound 1.59, prespecified noninferiority threshold 1.21), therefore equivalence between pacing arms was not demonstrated. Overall HFH/HFUC rates were slightly higher during atrial pacing (event-free rate 85.4% vs. 86.4% for ventricular backup pacing). Exploratory analyses revealed that the difference in HFH/HFUC rates was largely seen in patients with a PR interval ≥230 ms. There were no differences between groups for atrial fibrillation, ventricular tachycardia/ventricular fibrillation, quality of life, or echocardiographic measurements. Fewer patients in the atrial pacing group were reported to develop an indication for bradycardia pacing (3.7% vs. 7.3%, P = .0053).

CONCLUSION

Equivalence between atrial pacing and ventricular backup pacing only could not be demonstrated.

CLINICAL TRIALS IDENTIFIER

NCT00281099.

[Sandwiched between the single- and triple-chamber ICD: do we still need the dual-chamber ICD?]

Since it has been shown that adverse events are more frequent with dual-compared to single-chamber ICDs in patients with heart failure, and since the importance of prevention of unnecessary right ventricular pacing and the success of biventricular pacing have been demonstrated in numerous studies, the need for dual-chamber ICD systems has to be reassessed. The development of these systems was accompanied by expectations of improved hemodynamics in patients with bradycardia, a reduced incidence of atrial fibrillation, inappropriate therapies, and bradycardia-associated ventricular tachyarrhythmias. Single-chamber ICDs should be used restrictively and with great caution in patients with (sinus-) bradycardia and heart failure, since a relevant proportion of these patients is at risk of hemodynamic deterioration. Even if the proportion of patients with proven pacemaker syndrome is so small that it does not reach the level of statistical significance in large studies, a small percentage of patients with hemodynamic deterioration due to VVI pacing is still clinically (and economically) intolerable. Since the development of bradycardia or symptomatic chronotropic incompetence (e.g., due to amiodarone) is difficult to predict, it seems reasonable to use the indication for dualchamber systems liberally. However, the systematic prevention of unnecessary right ventricular pacing is crucial if dual-chamber ICDs are used. If advanced tachycardia discrimination algorithms and careful, individual programming are used, dual-chamber ICDs are superior in the prevention of inappropriate therapies. Additionally, dualchannel electrograms allow a more reliable interpretation of stored tachycardia episodes. In summary, dual-chamber systems represent a valuable improvement of ICD therapy but require thorough programming to convey their advantage.

Tools and strategies for the reduction of inappropriate implantable cardioverter defibrillator shocks

Implantable cardioverter defibrillators (ICDs) have been shown to provide a survival benefit in patients at high risk of sudden cardiac death. A major problem associated with ICD therapy is the occurrence of inappropriate shocks which impair patients' quality of life and may also be arrhythmogenic. Despite recent technological advances, the incidence of inappropriate shocks remains high, thus posing a challenge that we have to meet. In the present review we summarise the available tools and the strategies that can be followed in order to reduce inappropriate ICD shocks.

Is dual-chamber programming inferior to single-chamber programming in an implantable cardioverter-defibrillator? Results of the INTRINSIC RV (Inhibition of Unnecessary RV Pacing With AVSH in ICDs) study

BACKGROUND

The INTRINSIC RV (Inhibition of Unnecessary RV Pacing with AVSH in ICDs) study tested the hypothesis that dual-chamber rate-responsive (DDDR) with atrioventricular search hysteresis (AVSH) 60-130 programming is not inferior to single-chamber (VVI)-40 programming in an implantable cardioverter defibrillator with respect to all-cause mortality and heart failure hospitalizations using an equivalence margin of 5%.

METHODS AND RESULTS

At 108 centers, 1530 patients with an implantable cardioverter defibrillator indication received a VITALITY AVT (Guidant Corporation, St. Paul, Minn) implantable cardioverter defibrillator programmed consistently to DDDR AVSH 60-130 for the first week. Of those, 988 patients with <20% right ventricular pacing at 1 week were randomized to DDDR AVSH 60-130 or to VVI-40 programming. Among those randomized, 502 were assigned to DDDR AVSH and 486 to VVI. Groups were similar with regard to coronary disease (68%), gender (21% female), and New York Heart Association functional class >I (79%). A total of 32 patients (6.4%) in the DDDR AVSH arm and 46 patients (9.5%) in the VVI arm died or were hospitalized for heart failure during a mean follow-up of 10.4 months (relative risk=0.67, P=0.072 in favor of DDDR AVSH). DDDR AVSH was not inferior to VVI programming (P<0.001). All-cause mortality was not significantly different between the DDDR AVSH arm (3.6%) and the VVI arm (5.1%; P=0.23). The mean percent right ventricular pacing in the DDDR AVSH arm was 10% (median 4%) versus 3% (median 0%) in the VVI arm.

CONCLUSIONS

In the INTRINSIC RV trial, among those randomized, DDDR AVSH was associated with similar outcomes as with VVI backup pacing.

The Managed Ventricular Pacing? Versus VVI 40 Pacing (MVP) Trial: Clinical Background, Rationale, Design, and Implementation

BACKGROUND

Implantable cardioverter defibrillators (ICDs) reduce mortality among appropriately selected patients who have had or are at risk for life-threatening ventricular arrhythmia. Right ventricular apical (RVA) pacing has been implicated in worsening heart failure and death. The optimal pacemaker mode for bradycardia support while minimizing unnecessary and potentially harmful RVA pacing has not been determined.

METHODS

The Managed Ventricular pacing vs. VVI 40 Pacing Trial (MVP) is a prospective, multicenter, randomized, single-blind, parallel, controlled clinical trial designed to establish whether atrial-based dual-chamber managed ventricular pacing mode (MVP) is equivalent or superior to back-up only ventricular pacing (VVI 40) among patients with standard indications for ICD therapy and no indication for bradycardia pacing. The MVP Trial is designed with 80% power to detect a 10% reduction in the primary endpoint of new or worsening heart failure or all-cause mortality in the MVP-treated group. Approximately 1,000 patients at 80 centers in the United States, Canada, Western Europe, and Israel will be randomized to MVP or VVI 40 pacing after successful implantation of a dual-chamber ICD. Heart failure therapies will be optimized in accordance with evidence-based guidelines. Prespecified secondary endpoints will include ventricular arrhythmias, atrial fibrillation, new indication for bradycardia pacing, health-related quality of life, and cost effectiveness. Enrollment began in October 2004 and concluded in April 2006. The study will be terminated upon recommendation of the Data Monitoring Committee or when the last patient enrolled and surviving has reached a minimum 2 years of follow-up.

CONCLUSION

The MVP Trial will meet the clinical need for carefully designed prospective studies to define the benefits of atrial-based dual-chamber minimal ventricular pacing versus single-chamber ventricular pacing in conventional ICD patients.