Utilization of implantable cardioverter-defibrillators in survivors of cardiac arrest in the United States from 1996 to 2001

Racial and Ethnic Disparities in Implantable Cardioverter-Defibrillator Utilization: A Contemporary Review

Purpose of review

Sudden cardiac arrest is associated with high morbidity and mortality. Despite having a disproportionate burden of sudden cardiac death (SCD), rates of primary and secondary prevention of SCD with implantable cardioverter-defibrillator (ICD) therapy are lower among eligible racially minoritized patients. This review highlights the racial and ethnic disparities in ICD utilization, associated barriers to ICD care, and proposed interventions to improve equitable ICD uptake.

Recent findings

Racially minoritized populations are disproportionately eligible for ICD therapy but are less likely to see cardiac specialists, be counseled on ICD therapy, and ultimately undergo ICD implantation, fueling disparate outcomes. Racial disparities in ICD utilization are multifactorial, with contributions at the patient, provider, health system, and structural/societal level.

Summary

Racial and ethnic disparities have been demonstrated in preventing SCD with ICD use. Proposed strategies to mitigate these disparities must prioritize care delivery and access to care for racially minoritized patients, increase the diversification of clinical and implementation trial participants and the healthcare workforce, and center reparative justice frameworks to rectify a long history of racial injustice.

Recurrent Out-of-Hospital Sudden Cardiac Arrest: Prevalence and Clinical Factors

BACKGROUND

Despite improvements in management following survival from sudden cardiac arrest (SCA) and wide availability of implantable cardioverter defibrillators for secondary prevention, a subgroup of individuals will suffer multiple distinct episodes of SCA. The objective of this study was to characterize and evaluate the burden of recurrent out-of-hospital SCA among survivors of SCA in a single large US community.

METHODS

SCA cases were prospectively ascertained in the Oregon Sudden Unexpected Death Study. Individuals that experienced recurrent SCA were identified both prospectively and retrospectively.

RESULTS

We ascertained 6649 individuals with SCA (2002-2020) and 924 (14%) survived to hospital discharge. Of these, 88 survivors (10%) experienced recurrent SCA. Of the nonsurvivors (n=5725), 35 had suffered a recurrent SCA. Of the total 123 SCA cases with recurrent SCA, >60% occurred at least 1 year after the initial SCA (median 23 months, range: 6 days to 31 years). SCA occurred despite a secondary prevention implantable cardioverter defibrillator in 22% (n=26). Prevalence of coronary disease (36% versus 25%), hypertension (69% versus 43%), diabetes (44% versus 21%), and chronic kidney disease (35% versus 14%) was significantly higher in recurrent SCA versus single SCA survivors (n=80, P=0.01). Among individuals with no secondary prevention implantable cardioverter defibrillators before recurrent SCA, the majority had apparently reversible etiologies identified at initial SCA, with one-quarter undergoing coronary revascularization and over half diagnosed with noncoronary cardiac etiologies.

CONCLUSIONS

At least 10% of SCA survivors had recurrent SCA, and a large subgroup suffered their repeat SCA despite treatment for an apparently reversible etiology. A renewed focus on careful assessment of cardiac substrate as well as management of coronary disease, hypertension, diabetes, and chronic kidney disease in SCA survivors could reduce recurrent SCA.

Efficacy of Implantable Cardioverter-defibrillators for Secondary Prevention of Sudden Cardiac Death in Patients with End-stage Renal Disease

End-stage renal disease (ESRD) constitutes a major burden on the health-care system in the United States, with more than 300,000 patients nationwide being treated with renal replacement therapy. Very few studies to date have evaluated the benefit of implantable cardioverter-defibrillator (ICD) implantation for secondary prevention in patients with ESRD. In this study, we evaluated the efficacy of secondary-prevention ICDs in reducing all-cause mortality in patients on dialysis using the United States Renal Data System (USRDS) database. We queried the USRDS for relevant data between 2004 and 2010. Patients with diagnoses of ventricular fibrillation (VF), ventricular tachycardia (VT), or sudden cardiac arrest (SCA) were included in the study. Patients were excluded from the analysis if they were younger than 18 years; had missing age, sex, or race/ethnicity information; had experienced myocardial infarction; or had an ICD in situ at the time of VF, VT, or SCA diagnosis. The primary endpoint of this study was to determine the efficacy of secondary-prevention ICDs in reducing all-cause mortality in patients on dialysis. A total of 1,442 patients (3.4%) with ESRD had ICD insertion. Patients who received an ICD were predominantly younger, white males with lower Charlson Comorbidity Index and with fewer cardiovascular events. Survival at two years was 53% among those with an ICD relative to 27% among those without an ICD. In this study, we observed a substantial decrease in mortality in patients receiving an ICD for secondary prevention when compared with a cohort of similar patients with a history of VF, VT, or SCA.

Disparity in implantable cardioverter defibrillator therapy among minority South Asians in the United Kingdom

OBJECTIVE

There are large geographical differences in implantable cardioverter defibrillator (ICD) implantation rates for reasons not completely understood. In an increasingly multiethnic population, we sought out to investigate whether ethnicity influenced ICD implantation rates.

METHODS

This was a retrospective, cohort study of new ICD implantation or upgrade to ICD from January 2006 to February 2019 in recipients of Caucasian or South Asian ethnicity at a single tertiary centre in the UK. Data were obtained from a routinely collected local registry. Crude rates of ICD implantation were calculated for the population of Leicestershire county and were age-standardised to the UK population using the UK National Census of 2011.

RESULTS

The Leicestershire population was 980 328 at the time of the Census, of which 761 403 (77.7%) were Caucasian and 155 500 (15.9%) were South Asian. Overall, 2650 ICD implantations were performed in Caucasian (91.9%) and South Asian (8.1%) patients. South Asians were less likely than Caucasians to receive an ICD (risk ratio (RR) 0.43, 95% CI 0.37 to 0.49, p<0.001) even when standardised for age (RR 0.75, 95% CI 0.74 to 0.75, p<0.001). This remained the case for primary prevention indication (age-standardised RR 0.91, 95% CI 0.90 to 0.91, p<0.001), while differences in secondary prevention ICD implants were even greater (age-standardised RR 0.49, 95% CI 0.48 to 0.50, p<0.001).

CONCLUSION

Despite a universal and free healthcare system, ICD implantation rates were significantly lower in the South Asian than the Caucasian population residing in the UK. Whether this is due to cultural acceptance or an unbalanced consideration is unclear.

Cluster Randomized Trial Examining the Impact of Automated Best Practice Alert on Rates of Implantable Defibrillator Therapy

Background:

Implantable cardioverter-defibrillators (ICDs) are indicated in patients with left ventricular ejection fraction ≤35%, but many eligible patients do not receive this therapy. In this cluster randomized trial, we investigated the impact of a best practice alert (BPA) through the electronic health records on the rates of electrophysiology referrals, ICD implantations, and all-cause mortality in severe cardiomyopathy patients.

Methods and Results:

Providers in the Heart and Vascular Institute (n=106) and in General Internal Medicine (n=89) were randomized to receive or not receive a BPA recommending consideration for ICD implantation. Patients belonging to the BPA and no BPA groups of providers were followed to the end points of electrophysiology referrals, ICD implantations, and all-cause mortality. Between 2013 and 2015, patients with reduced left ventricular ejection fraction were managed by 93 providers in the BPA (n=997 patients) and 102 providers in the no BPA (n=909 patients) groups. Patients in the 2 groups had comparable baseline characteristics. After a median follow-up of 36 months, 638 (33%) patients were referred to electrophysiology, 536 (27%) received an ICD, and 445 (23%) died. Patients in the BPA group were more likely to be referred to electrophysiology (hazard ratio=1.23; P =0.026), to receive ICD therapy (hazard ratio=1.35; P =0.006), and exhibited a trend towards slightly lower mortality (hazard ratio=0.85; P =0.091).

Conclusions:

Delivering a BPA through the electronic health record recommending to providers consideration of ICD implantation when the left ventricular ejection fraction is ≤35% improves the rates of electrophysiology referrals and ICD therapy in patients with severe left ventricular dysfunction.

Implantable Cardioverter Defibrillator Implantation Rates After Out of Hospital Cardiac Arrest: Are the Rates Guideline-Concordant?

BACKGROUND

Clinical practice guidelines recommend implantable cardioverter defibrillators (ICDs) for the secondary prevention of sudden death after a cardiac arrest not from a reversible cause, but "real world" implantation rates are not well described.

METHODS

Adults with out of hospital cardiac arrest attended by Emergency Medical Services are captured in the Toronto Regional RescuNET database. We analyzed those who survived to hospital discharge and collected data on age, sex, initial rhythm, ST-elevation myocardial infarction (STEMI) on presenting electrocardiogram (ECG), in-hospital revascularization, neurologic status (Modified Rankin Scale [MRS]) at discharge, and admission hospital type. To estimate 'indicated' ICD implantation rates, "likely ICD-eligible" patients were defined as having an initial shockable rhythm, no STEMI on presenting ECG, no revascularization, and good neurologic status (MRS 0-3). "Not likely ICD-eligible" patients were defined as having a STEMI on presenting ECG, revascularization, or poor neurologic status (MRS 4-5).

RESULTS

In the 1238 adults (2011-2014) analyzed, the overall ICD implantation rate was 23.9%. Two hundred fifty-six patients were "likely ICD-eligible," of whom 146 (57.0%) received an ICD. The implantation rate for "not likely ICD-eligible" patients was 16.7% (112 of 670). ICD eligibility could not be determined for 312 patients, of whom 38 (12.2%) received an ICD. Admission to a hospital with ICD implantation facilities was associated with a higher probability of ICD implantation (odds ratio, 2.85; 95% confidence interval, 1.40-5.82).

CONCLUSIONS

Postcardiac arrest ICD implantation rates in eligible patients are lower than expected. Implementation strategies to monitor guideline adherence after out of hospital cardiac arrest are warranted.

Effect of a Reminder Statement on Echocardiography Reports on Referrals for Implantable Cardioverter-Defibrillators for Primary Prevention

Numerous trials show the benefit of implantable cardioverter-defibrillators (ICDs) for primary prevention in patients with low ejection fraction (EF), a class I indication. However, underutilization is well documented. We retrospectively reviewed charts to see whether placing a reminder statement into echocardiogram reports for appropriate patients increased adherence to guidelines. From January through June 2013, a brief reminder of the ICD guidelines was automatically inserted into echocardiogram reports with EF ≤ 35% (reminder period). Charts were reviewed to determine if these patients (1) were referred to Electrophysiology (EP) within 6 months of the index echo and (2) received an ICD within 6 months of EP referral. Chart review of all patients who had an echocardiogram performed between March and August 2012 with an EF ≤ 35% provided a control period. More patients were referred to EP in the reminder period compared with control period, 68% (54 of 80) versus 51% (53 of 104), p = 0.03. There was also a higher rate of discussions in the reminder period between patients and physicians about ICD therapy (71% vs 54%, p = 0.02). Among patients appropriate for ICD, 52% of patients during the reminder period received an ICD versus 38% of patients during the control period (p = 0.11). A simple reminder statement on echocardiography reports led to a significant improvement in appropriate EP referrals and a trend toward increased ICD implantation in appropriate patients.

Primary Prevention of Sudden Cardiac Death With Device Therapy in Urban and Rural Populations

BACKGROUND

Implantable cardioverter defibrillators (ICDs) have shown benefit in reducing mortality in patients with heart failure, after myocardial infarction, and those with reduced ejection fraction. We sought to explore the use of this therapy in specialized heart function clinics, in rural and urban locations.

METHODS

This was a retrospective cohort study performed in 3 specialized heart function clinics in Nova Scotia, 2 of which were in rural locations. All patients with an initial left ventricular ejection fraction ≤ 35% were included from 2006 to 2011. Rates of referral, ICD implantation, and mortality were compared between urban and rural groups.

RESULTS

There were 922 patients included in the study; 636 patients in the urban clinic, 286 in the rural locations. Referral rates were higher in the urban clinic compared with the rural locations (80.4% vs 68.3%; P = 0.024). Refusal rates for referral were higher in the rural locations (13.7% vs 2.1%; P < 0.0001). Higher referral rates were associated with urban location (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.01-3.26; P = 0.047), and younger age (OR, 0.96; 95% CI, 0.93-0.99; P = 0.003); lower referral rates for women was observed (OR, 2.29; 95% CI, 1.13-4.63; P = 0.021). Mortality was significantly associated with older age, lack of referral, presence of comorbidities (renal failure, diabetes, peripheral vascular disease) and a rural location.

CONCLUSIONS

Specialized heart function clinics have a high rate of appropriate referral for primary prevention ICDs, but referral rates for this life-saving therapy remain lower in rural jurisdictions. This disparity in access to care is associated with increased mortality and might require particular attention to prevent unnecessary deaths.

Implantable cardioverter defibrillator and survival after out-of-hospital cardiac arrest due to acute myocardial infarction in Denmark in the years 2001-2012, a nationwide study

AIM

The purpose of this study was to describe the implantation of implantable cardioverter defibrillator after out-of-hospital cardiac arrest caused by myocardial infarction in Denmark 2001-2012 and subsequent survival.

METHODS

The Danish Cardiac Arrest Registry was used to identify patients ⩾18 years surviving to discharge without prior implantable cardioverter defibrillator. Information on cardioverter defibrillator implantation was obtained from the National Patient Registry.

RESULTS

We identified 974 myocardial infarction-out-of-hospital cardiac arrest patients surviving to hospital discharge, 130 of these patients (13%) had a cardioverter defibrillator implanted early (⩽40 days post-out-of-hospital cardiac arrest), 58 patients (6%) had late implantable cardioverter defibrillator (41-365 days post-out-of-hospital cardiac arrest). Odds of implantable cardioverter defibrillator implantation within one year were higher in patients receiving cardiopulmonary resuscitation (odds ratio (OR)_CPR: 1.99, confidence interval (CI): 1.23-3.22, p=0.01), and Charlson Comorbidity Index level 1, (OR_CCI1: 2.10, CI:1.25-3.49, p<0.01). Odds of a late implantable cardioverter defibrillator was higher in patients undergoing percutaneous coronary intervention (PCI) (OR_PCI: 3.67, CI: 1.35-9.97, p=0. 01). An early, but not late implantable cardioverter defibrillator was associated with increased survival (event time ratio_{Early ICD}: 1.45, CI: 1.11-1.90, p=0.01). Chronic heart failure, higher age groups, Charlson Comorbidity Index levels 1 to ⩾3 and male sex were associated with lower survival. Highest income was associated with higher survival.

CONCLUSION

Cardioverter defibrillator implantation rates in patients surviving an myocardial infarction-out-of-hospital cardiac arrest increased from 14% to 19% over the period. Of the total patient population, 13% had implantation earlier than recommended by guidelines, presumably as primary prevention of sudden cardiac death. Acute PCI and arrest later in the study period (increase one year) were predictors of late cardioverter defibrillator implantation. Early cardioverter defibrillator implantation was significantly associated with a long-term survival benefit, later implantation was not.

Geographic and Temporal Variation in Cardiac Implanted Electric Devices to Treat Heart Failure

BACKGROUND

Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings.

METHODS AND RESULTS

We identified new CRT with pacemaker (CRT-P) or defibrillator generators (CRT-D) implanted between 2008 and 2013 in the United States from a commercial claims database. For each implant, we characterized prior medication use, comorbidities, and geography. Among 17 780 patients with CRT devices (median age 69, 31% women), CRT-Ps were a small and increasing share of CRT devices, growing from 12% to 20% in this study period. Compared to CRT-D recipients, CRT-P recipients were older (median age 76 versus 67), and more likely to be female (40% versus 30%). Pre-implant use of β-blockers and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers was low in both CRT-D (46%) and CRT-P (31%) patients. The fraction of CRT-P devices among all new implants varied widely across states. Compared to the increasing national trend, the share of CRT-P implants was relatively increasing in Kansas and relatively decreasing in Minnesota and Oregon.

CONCLUSIONS

In this large, contemporary heart failure population, CRT-D use dwarfed CRT-P, though the latter nearly doubled over 6 years. Practice patterns vary substantially across states and over time. Medical therapy appears suboptimal in real-world practice.

Sudden cardiac death and chronic kidney disease: From pathophysiology to treatment strategies

Chronic kidney disease (CKD) patients demonstrate higher rates of cardiovascular mortality and morbidity; and increased incidence of sudden cardiac death (SCD) with declining kidney failure. Coronary artery disease (CAD) associated risk factors are the major determinants of SCD in the general population. However, current evidence suggests that in CKD patients, traditional cardiovascular risk factors may play a lesser role. Complex relationships between CKD-specific risk factors, structural heart disease, and ventricular arrhythmias (VA) contribute to the high risk of SCD. In dialysis patients, the occurrence of VA and SCD could be exacerbated by electrolyte shifts, divalent ion abnormalities, sympathetic overactivity, inflammation and iron toxicity. As outcomes in CKD patients after cardiac arrest are poor, primary and secondary prevention of SCD and cardiac arrest could reduce cardiovascular mortality in patients with CKD.

A Patient Presents with Longstanding, Severe LV Dysfunction. Is There a Role for Additional Risk Stratification Before ICD?

Increased longevity of patients with systolic heart failure caused by the use of implantable cardioverter-defibrillators (ICDs) is one of the most successful achievements in contemporary medicine. During the last 2 decades, the scientific community has striven to increase the benefits of ICD usage by specifying indications for primary prevention ICD implantation. Left ventricular ejection fraction is neither highly specific nor is it a highly sensitive risk marker of sudden cardiac death. The authors discuss risk-stratification approaches in different patient populations with structural heart disease and systolic heart failure.

Primary prevention implantable cardioverter-defibrillators in older racial and ethnic minority patients

BACKGROUND

Racial and ethnic minorities are under-represented in clinical trials of primary prevention implantable cardioverter-defibrillators (ICDs). This analysis investigates the association between primary prevention ICDs and mortality among Medicare, racial/ethnic minority patients.

METHODS AND RESULTS

Data from Get With The Guidelines-Heart Failure Registry and National Cardiovascular Data Registry's ICD Registry were used to perform an adjusted comparative effectiveness analysis of primary prevention ICDs in Medicare, racial/ethnic minority patients (nonwhite race or Hispanic ethnicity). Mortality data were obtained from the Medicare denominator file. The relationship of ICD with survival was compared between minority and white non-Hispanic patients. Our analysis included 852 minority patients, 426 ICD and 426 matched non-ICD patients, and 2070 white non-Hispanic patients (1035 ICD and 1035 matched non-ICD patients). Median follow-up was 3.1 years. Median age was 73 years, and median ejection fraction was 23%. Adjusted 3-year mortality rates for minority ICD and non-ICD patients were 44.9% (95% confidence interval [CI], 44.2%-45.7%) and 54.3% (95% CI, 53.4%-55.1%), respectively (adjusted hazard ratio, 0.79; 95% CI, 0.63-0.98; P=0.034). White non-Hispanic patients receiving an ICD had lower adjusted 3-year mortality rates of 47.8% (95% CI, 47.3%-48.3%) compared with 57.3% (95% CI, 56.8%-57.9%) for those with no ICD (adjusted hazard ratio, 0.75; 95% CI, 0.67%-0.83%; P<0.0001). There was no significant interaction between race/ethnicity and lower mortality risk with ICD (P=0.70).

CONCLUSIONS

Primary prevention ICDs are associated with lower mortality in nonwhite and Hispanic patients, similar to that seen in white, non-Hispanic patients. These data support a similar approach to ICD patient selection, regardless of race or ethnicity.

A meta-analysis of mortality in end-stage renal disease patients receiving implantable cardioverter defibrillators (ICDs)

Data on the effectiveness of implantable implantable cardioverter defibrillators (ICDs) with respect to reducing mortality in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) are lacking. The purpose of this meta-analysis was to compare the mortality of patients with ESRD who have received and not received an ICD. A search was conducted on January 31, 2013 of Medline, Cochrane, EMBASE, and Google Scholar. Studies were selected for inclusion based on the following criteria. 1) Randomized controlled trial. 2) ESRD patients with heart failure. 3) Device therapy (ICD, CRT-defibrillator [CRT-D]) used to treat heart failure. 4) Primary outcome is survival analysis. 5) Retrospective study if survival analysis was performed. The primary outcome was overall survival (OS), and the secondary outcome was 2-year survival. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated, and a χ2-based test of homogeneity was performed. Three studies were included in the analysis. The combined OR for OS was 2.245 (95% CI 1.871 to 2.685, P<0.001), indicating that patients with an ICD had a significantly higher OS than those without an ICD. The combined OR for 2-year survival was 2.312 (95% CI 1.921 to 2.784, P<0.001), indicating that patients with an ICD had a significantly higher 2-year survival rate than those without an ICD. The use of ICD in patients with ESRD is associated with an increase in the OS and the 2-year survival rate.

Sudden cardiac arrest in hemodialysis patients with wearable cardioverter defibrillator

Background

The survival outcome following a sudden cardiac arrest (SCA) in hemodialysis (HD) patients is poor regardless of whether an event takes place in or out of a dialysis center. The characteristics of SCA and post‐SCA survival with HD patients using a wearable cardioverter defibrillator (WCD) are unknown.

Methods

All HD patients who were prescribed a WCD between 2004 and 2011 and experienced at least one SCA event were included in this study. Demographics, clinical background, characteristics of SCA events were identified from the manufacturer's database. An SCA event was defined as all sustained ventricular tachycardia/fibrillation (VT/VF) or asystole occurring within 24 hours of the index arrhythmia episode. The social security death index was used to determine mortality after WCD use.

Results

A total of 75 HD patients (mean age = 62.9 ± 11.7 years, female = 37.3%) experienced 84 SCA events (119 arrhythmia episodes) while wearing the WCD. Sixty six (78.6%) SCA events were due to VT/VF and 18 (21.4%) were due to asystole. Most SCA episodes occurred between 09:00 and 10:00 (RR = 2.82, 95% CI [1.05, 7.62], P < 0.0001), followed by the 13:00–14:00 time interval (RR = 2.22, 95% CI [0.79, 6.21], P = 0.006). Acute 24‐hour survival was 70.7% for all SCA events; 30‐day and 1‐year survival were 50.7% and 31.4%, respectively. Women had a better post‐SCA survival than men (HR = 2.41, 95% CI [1.09, 5.36], P = 0.03).

Conclusions

The use of WCD in HD patients was associated with improved post‐SCA survival when compared to historical data.

Factors influencing the decision to ICD implantation in survivors of OHCA and its influence on long term survival

BACKGROUND

Knowledge is insufficient of the long-term benefit of an implantable cardioverter defibrillator (ICD) after out of hospital cardiac arrest (OHCA).

AIM

To describe the use and factors of importance for outcome in relation to ICD use among survivors of ventricular fibrillation (VF).

METHODS

In consecutive patients discharged alive after OHCA in Gothenburg between 1988 and 2008 the long-term prognosis was followed.

RESULTS

In all, there were 5443 OHCAs of which 1489 (27%) were hospitalized alive. Of those, 495 (33%) were discharged alive, of which 390 (79%) had shockable rhythm. The use of ICDs increased, but only 58 of 390 (15%) had an ICD. Among patients who received an ICD, the 2-year mortality was 2%, versus 25% of those who did not (p<0.0001). In follow-up (mean 5.5 years; maximum 10 years), the use of an ICD showed a borderline association with mortality (adjusted hazard ratio 0.49; 95% confidence interval, 024-1.01; p=0.052). Patients who had ICD were younger and had better cerebral function compared with patients without. Predictors for mortality were cerebral function at discharge, age, history of heart failure and myocardial infarction and no coronary angiography during hospitalization.

CONCLUSION

Among survivors of OHCA caused by VT/VF who had ICD during hospitalization only 2% died during the subsequent 2 years. The use of ICDs was low but increasing. Factors of importance for mortality were cerebral function at the time of discharge, age, history of heart failure and myocardial infarction and no coronary angiography during hospitalization.

Low rate of secondary prevention ICDs in the general population: multiple-year multiple-source surveillance of sudden cardiac death in the Oregon Sudden Unexpected Death Study

INTRODUCTION

Sudden cardiac death (SCD) is a large public health problem that warrants on-going evaluation in the general population. While single-year community-based studies have been performed there is a lack of studies that have extended evaluation to multiple years in the same community.

METHODS AND RESULTS

From the on-going Oregon Sudden Unexpected Death Study, we analyzed prospectively identified SCD cases in Multnomah County, Ore, (population ≈700,000) from February 1, 2002 to January 31, 2005. Detailed information ascertained from multiple sources (first responders, clinical records, and medical examiner) was analyzed. A total of 1,175 SCD cases were identified (61% male) with a mean age of 65 ± 18 years for men versus 70 ± 20 for women (P < 0.001). The overall incidence rate for the period was 58/100,000 residents/year. One-quarter (24.6%) was ≤ 55 years of age. The most common initial rhythm was ventricular tachycardia or fibrillation (39% of cases, survival 27%) followed by asystole (36%, survival 0.7%) and pulseless electrical activity (23%, survival 6%). Among subjects that underwent resuscitation, the rate of survival to hospital discharge was 12% and overall survival to hospital discharge irrespective of resuscitation was 8%. Of the 68 survivors, 16 (24%) received a secondary prevention ICD.

CONCLUSION

We report annualized SCD incidence from a multiple-year, multiple-source community-based study, with higher than expected rates of women and subjects age ≤ 55 years. The low implantation rate of secondary prevention ICDs is likely to be multifactorial, but there are potential implications for recalibration of the projected need for ICD implantation; larger and more detailed studies are warranted.

Influence of age on perioperative complications among patients undergoing implantable cardioverter-defibrillators for primary prevention in the United States

BACKGROUND- The majority of current implantable cardioverter-defibrillator (ICD) recipients are significantly older than those in the ICD trials. Data on periprocedural complications among the elderly are insufficient. We evaluated the influence of age on perioperative complications among primary prevention ICD recipients in the United States. METHODS AND RESULTS- Using the National Cardiovascular Data's ICD Registry, we identified 150 264 primary prevention patients who received ICDs from January 2006 to December 2008. The primary end point was any adverse event or in-hospital mortality. Secondary end points included major adverse events, minor adverse events, and length of stay. Of 150 264 patients, 61% (n=91 863) were 65 years and older. A higher proportion of patients ≥65 years had diabetes, congestive heart failure, atrial fibrillation, renal disease, and coronary artery disease. Approximately 3.4% of the entire cohort had any complication, including death, after ICD implant. Any adverse event or death occurred in 2.8% of patients under 65 years old; 3.1% of 65- to 69-year-olds; 3.5% of 70- to 74-year-olds; 3.9% of 75- to 79-year-olds, 4.5% of 80- to 84-year-olds; and 4.5% of patients 85 years and older. After adjustment for clinical covariates, multivariate analysis found an increased odds of any adverse event or death among 75- to 79-year-olds (1.14 [95% confidence interval, 1.03 to 1.25], 80-to 84-year-olds (1.22 [95% confidence interval, 1.10 to 1.36], and patients 85 years and older (1.15 [95% confidence interval, 1.01 to 1.32], compared with patients under 65 years old. CONCLUSIONS- Older patients had a modestly increased-but acceptably safe-risk of periprocedural complications and in-hospital mortality, driven mostly by increased comorbidity.

Patients, intimate partners and family experiences of implantable cardioverter defibrillators: qualitative systematic review

AIM

This paper is a report of an interpretive review of qualitative research on how an implantable cardioverter defibrillator affects adult recipients and their significant others.

BACKGROUND

An implantable cardioverter defibrillator detects pathological cardiac rhythms and automatically converts the rhythm with electrical counter shocks.

DATA SOURCES

A systematic literature search was conducted for qualitative research papers published between January 1999 and January 2009. PubMed, Medline, ISI Web of Knowledge and CINAHL databases were searched with the following key words: internal defibrillator, implantable defibrillator and qualitative research.

REVIEW METHODS

Twenty-two papers were included. The critical appraisal skills programme and prompts were used to appraise studies. Thematic analysis and synthesis approaches were used to interpret evidence.

FINDINGS

People with an implantable cardioverter defibrillator were found to experience physical, psychological and social changes. Shocks produce fear and anxiety, affecting relationships and sexual relations. The use of support groups and the use of the Internet are important in helping adjustment to an implantable cardioverter defibrillator. Women's responses to an implantable cardioverter defibrillator appear different than men's responses and include concerns about physical appearance and relationship issues. Postdischarge follow-up and educational programmes are still underdeveloped.

CONCLUSION

Patients need additional education, support and follow-up care after hospital discharge. Patients and significant others benefit from collaboration between patient associations and healthcare professional societies. Future research is needed to identify the specific challenges that women recipients face.

Secondary prevention in heart failure

Although most recent investigations into sudden cardiac death prevention in heart failure patients have been focused on primary prevention, secondary indications for defibrillators and medical therapy remain vitally important in this complex patient group. Antiarrhythmic therapy is currently used primarily as adjuvant therapy to implantable defibrillators. Secondary prophylaxis defibrillator trials have shown clear benefit in preventing recurrent sudden cardiac death, despite concern over inappropriate shocks and the potential detrimental effects of appropriate shocks. Device programming for secondary prophylaxis can help ameliorate these issues. This article discusses these issues as well as the continued underuse of defibrillators in specific populations.

Low referral pattern for implantable defibrillator therapy in a tertiary hospital: referral physician survey and Monte Carlo simulation

Although implantable cardioverter defibrillator (ICD) therapy is the standard of care for prevention of sudden cardiac death (SCD), its underutilization is a clinical concern. We performed a retrospective study on patients who underwent cardiac catheterization at a tertiary medical center to identify those who were eligible for ICD therapy as per the guidelines and those who actually received it as a part of treatment. Surprisingly, only 4.4% of eligible patients received ICD for SCD prevention. Assuming that the major cause of this underutilization of ICD therapy was low referral, we performed a structured survey among the referring physicians to assess specialists' availability, primary care physicians' role in ICD referral, patient management concerns, familiarity with ICD guidelines, and economics of ICD implantation. Physician response rate of the survey was 51% (35/68). Survey results showed that the common reasons for underreferral included nonavailability of electrophysiologists (34%), poor quality of life of patients (25.7%), patients not being on optimal therapy (25.7%), and low awareness (22.85%). Subsequently, a Monte Carlo simulation was used to assess a hypothetical survival of the study cohort, which showed that in an "ideal scenario" of ICD implantation, the mortality in the study cohort was decreased by 6.9% and 12.3% at 2- and 5-year follow-up, respectively. This study highlights the underutilization of ICDs and the referring physicians' approach to this therapy.

[The daily experience of the patient with an implantable cardioverter defibrillator]

OBJECTIVE

To describe the daily experience of patients with an automatic defibrillator (AD) implant and the adaptive changes of the patient.

METHOD

Qualitative and phenomenological research. Collection of data through; initially unstructured interview with half of the informants, semi-structured interviews through an open questions guide after the initial unstructured interviews and use of personal narratives of the informants. Analysis of the data using the Van Manen proposal.

RESULTS

We analysed the interviews of 10 participants. We collected socio-demographic variables and identified the following themes, which respond to the question "How is life with an AD": It is life "with the two sides of the coin," living in constant wait and uncertainty, accepting change, developing adaptation strategies, renegotiating relationships and sexuality and it is to live transformed.

CONCLUSIONS

The results of this study can be integrated into nurse clinical practice in areas such as valuation after discharge, changes in habits, control of treatment, notification of shocks, masking detection of symptoms and strategies that can jeopardise the bearer. Research needs to be developed that looks closer into the influence of other technological devices in people.

Predictors of early mortality in implantable cardioverter-defibrillator recipients

AIMS

Multiple trials have shown that implantable cardioverter defibrillators (ICDs) prolong survival in secondary and primary prevention populations. However, in spite of the efficacy of these devices in terminating life-threatening arrhythmias, total mortality remains high.

METHODS AND RESULTS

We evaluated 1703 patients (mean age: 67 +/- 12 years, 82% male) with conventional ICD indications, who were enrolled and followed between 2001 and 2004 at 128 US centres. Patients were followed for up to a year, and vital status was obtained for 1655 patients (97%, median follow-up: 377 days). There were 183 deaths within 1 year of ICD implantation (1-year mortality rate: 16%). Predictors of mortality included a history of atrial fibrillation (AF, P < 0.0001), diabetes (P = 0.0001), failure to use cholesterol-lowering medications (P < 0.001), use of digitalis and derivatives (P < 0.0001), use of diuretics (P < 0.0001), low body mass index (BMI, P < 0.0001), increasing age (P < 0.0001), low left ventricular ejection fraction (P < 0.0001), low activity hours (P < 0.0001), elevated resting heart rate (P = 0.014), low mean arterial pressure (MAP, P = 0.007), and poor functional status (New York Heart Association class, P < 0.0001). In multivariate modelling, AF (P < or = 0.001), diabetes (P = 0.004), BMI (P = 0.001), MAP (P = 0.040), and functional class (P = 0.006) predicted mortality.

CONCLUSION

In this population undergoing ICD implantation, poor functional status, low MAP, diabetes, low BMI, and AF were strongly associated with death within a year.

Depression and anxiety symptoms are associated with reduced dietary adherence in heart failure patients treated with an implantable cardioverter defibrillator

BACKGROUND

Heart failure (HF) patients treated with an implantable cardioverter defibrillator (ICD) are a growing patient population for whom the general treatment guidelines for HF still apply. Dietary recommendations, sodium and fluid restriction and daily weight monitoring, are a critical component of HF self-management. However, HF patients often report poor adherence to these recommendations. Studies that have investigated factors associated with poor diet adherence have focused on knowledge and beliefs. The current study extends previous research by examining the impact of psychosocial factors (depression, anxiety, and social support) on adherence to dietary recommendations in this growing subgroup of HF patients.

METHODS

Eighty-eight HF patients, with a mean age of 70 years, treated with an ICD (77% male) completed questionnaires assessing depression and anxiety symptoms, social support, and dietary adherence.

RESULTS

Most patients reported following dietary recommendations in the past week most of the time (63%), whereas only 16% of patients reported following dietary recommendations all of the time. Greater depression and anxiety symptoms were associated with poorer dietary adherence, whereas social support did not predict reported dietary adherence.

CONCLUSIONS

Findings suggest that many HF patients treated with an ICD do not comply with dietary recommendations. Depression and anxiety symptoms were found to be associated with worse dietary adherence, whereas social support was not related to adherence. Further research is needed to understand the role of social support in dietary adherence in HF patients.

Influence of patient age and sex on delivery of guideline-recommended heart failure care in the outpatient cardiology practice setting: findings from IMPROVE HF

BACKGROUND

The influence of patient age and sex on delivery of guideline-recommended heart failure (HF) therapies in contemporary outpatient settings has not been well studied. The Registry to Improve the Use of Evidence-Based Heart Failure Therapies in the Outpatient Setting (IMPROVE HF) is a prospective cohort study designed to characterize current management of outpatients with chronic HF and left ventricular ejection fraction < or =35%.

METHODS

Baseline data for eligible patients with systolic HF in a national registry of 167 US outpatient cardiology practices were collected by trained chart abstractors. Data were stratified and analyzed as male/female and by age tertiles with generalized estimating equation models constructed for 7 care measures.

RESULTS

A total of 15,381 patients were enrolled, with 8,770 (71.1%) of these male. Median age of female patients was 72.0 and 70.0 for males. Use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, aldosterone inhibitors, and cardiac resynchronization therapy was not significantly different between male and female patients, but rates for implantable cardioverter defibrillators, anticoagulation therapy for atrial fibrillation, and HF education were significantly lower for females. After adjusting for patient and practice characteristics, 3 of 7 measures significantly differed by patient sex, and 6 of 7 measures by age. Older patients, particularly older women, were significantly less likely to receive guideline-indicated HF therapies.

CONCLUSIONS

Patient age and sex were independently associated with reduced rates of some, but not all, HF therapies in outpatient cardiology practices. Older women are especially at risk. Further research is needed to understand the causes and consequences of these age- and sex-related differences in care.

Racial and gender trends in the use of implantable cardioverter-defibrillators among Medicare beneficiaries between 1997 and 2003

Differences in the use of implantable cardioverter-defibrillators (ICDs) have been reported, but the extent to which they have widened after the publication of major clinical trials supporting their use is unclear. Using data on Medicare beneficiaries, the authors determined annual age-standardized population-based utilization rates of ICDs for white men, black men, white women, and black women from 1997 to 2003. During the study period, overall use of ICDs increased most for white men (81.7-254.7 procedures per 100,000 from 1997 to 2003) and black men (38.0-151.7 procedures per 100,000), with white women (28.9-98.4 procedures per 100,000) and black women (18.2-77.3 procedures per 100,000) showing smaller increases in comparison. After adjustment with multivariable regression models, differences in utilization rates between whites and men widened compared with blacks and women between 1997 and 2003, a period when indications for ICD therapy have expanded.

Preventing tomorrow's sudden cardiac death today: dissemination of effective therapies for sudden cardiac death prevention

Because the burden of sudden cardiac death (SCD) is substantial, it is important to use all guideline-driven therapies to prevent SCD. Among those therapies is the implantable cardioverter defibrillator (ICD). When indicated, ICD use is beneficial and cost-effective. Unfortunately, studies suggest that most patients who have indications for this therapy for primary or secondary prevention of SCD are not receiving it. To explore potential reasons for this underuse and to propose potential facilitators for ICD dissemination, the Duke Center for the Prevention of SCD at the Duke Clinical Research Institute (Durham, NC) organized a think tank meeting of experts on this issue. The meeting took place on December 12 and 13, 2007, and it included representatives of clinical cardiology, cardiac electrophysiology, general internal medicine, economics, health policy, the US Food and Drug Administration, the Centers for Medicare and Medicaid Services, the Agency for Health care Research and Quality, and the device and pharmaceutical industry. Although the meeting was funded by industry participants, this article summarizing the presentations and discussions that occurred at the meeting presents the expert opinion of the authors.

Device therapies in the post-myocardial infarction patient with left ventricular dysfunction

The post-myocardial infarction (MI) patient with left ventricular dysfunction (LVD) is at risk for ventricular arrhythmias resulting in sudden cardiac death. In high-risk post-MI patients with a depressed left ventricular ejection fraction, prophylactic implantable cardioverter defibrillators (ICDs) may significantly improve survival. These benefits are in addition to those of optimal pharmacologic therapy, and ICD therapy should be considered the standard of care in these patients. Recent device trials have demonstrated the benefits of prophylactic ICD placement in patients who have been selected based on post-MI left ventricular systolic dysfunction alone. In addition, cardiac resynchronization therapy can improve the quality of life beyond that achievable with drug therapy alone and should be considered in patients with symptomatic heart failure with QRS prolongation. Further risk stratification studies of post-MI LVD patients will allow ICD therapy to be applied in a more cost-effective manner.

Outcome in African Americans and other minorities in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)

BACKGROUND

The SCD-HeFT demonstrated that implantable cardioverter/defibrillator (ICD) therapy significantly improved survival compared to medical therapy alone in stable moderately symptomatic heart failure patients with an ejection fraction < or = 35%. The purpose of this report is to describe the outcomes in African Americans (AAs) and other minorities.

METHODS

Of 2521 patients enrolled, 23% were minorities and 17% were AAs. Baseline demographic, clinical variables, socioeconomic status, and long-term outcomes were compared according to race. Two major prespecified subgroups were examined: heart failure cause (ischemic vs nonischemic) and New York Heart Association class (II vs III).

RESULTS

At baseline, compared to whites, AAs were younger and had more nonischemic heart failure, lower ejection fractions, worse New York Heart Association functional class, and higher prevalence of a history of nonsustained ventricular tachycardia. Comparable percentages of whites and AAs held paid jobs, but whites had a significantly higher educational level and household income (P = .001). Compliance with ICD implantation and medical therapy was comparable in both subgroups. No significant difference was observed in the rate of ICD discharge among whites and AAs. Adjusted mortality risk was significantly higher in AAs compared to whites (hazard ratio 1.27, P = .038). Mortality was equally reduced in both race groups receiving ICD therapy compared to placebo (hazard ratio 0.65 in AAs and 0.73 in whites).

CONCLUSIONS

Survival benefits from ICD therapy in SCD-HeFT were not dependent on race. In addition, in this clinical trial setting, there was no evidence that AAs were less willing to accept ICD therapy than whites.

"That's like an act of suicide" patients' attitudes toward deactivation of implantable defibrillators

OBJECTIVE

To understand potential patient barriers to discussions about implantable cardioverter defibrillator (ICD) deactivation in patients with advanced illness.

DESIGN

Qualitative focus groups.

PARTICIPANTS

Fifteen community-dwelling, ambulatory patients with ICDs assigned to focus groups based on duration of time since implantation and whether they had ever received a shock from their device.

APPROACH

A physician and a social worker used a predetermined discussion guide to moderate the groups, and each session was audiotaped and subsequently transcribed. Transcripts were analyzed using the method of constant comparison.

RESULTS

No participant had ever discussed deactivation with their physician nor knew that deactivation was an option. Patients expressed a great deal of anxiety about receiving shocks from their device. Participants discussed why they needed the device and expressed desire for more information about the device; however, they would not engage in conversations about deactivating the ICD. One patient described deactivation "like an act of suicide" and all patients believed that the device was exclusively beneficial. Patients also expressed a desire to have their physician make the decision about deactivation.

CONCLUSIONS

None of the patients in our study knew that they might need to deactivate their ICD as their health worsens. These community-dwelling outpatients were not willing to discuss the issue of ICD deactivation and their attitudes about deactivation might impede patients from engaging in these conversations. These findings are in contrast to findings in other advance care planning research and may be related to the unique nature of the ICD.

Improved Survival Associated with Prophylactic Implantable Defibrillators in Elderly Patients with Prior Myocardial Infarction and Depressed Ventricular Function: A MADIT-II Substudy

INTRODUCTION

We aim to evaluate the mortality benefit from defibrillator therapy in eligible elderly patients. Effective primary prevention of sudden cardiac death with implantable cardioverter defibrillators is well demonstrated in patients with coronary disease and depressed ventricular function.

METHODS AND RESULTS

Among 1,232 patients enrolled with prior infarct and left ventricular ejection fraction < or = 0.30, 204 were > or = 75 years old. Of these 204 patients, 121 underwent defibrillator implant. Relative to the younger patients, those > or = 75 years had a higher incidence of atrial fibrillation, elevated blood urea nitrogen (BUN), widened QRS, and lower use of beta-blockers and HMG-CoA reductase inhibitors. Relevant clinical covariates were similar in elderly patients randomized to conventional and defibrillator therapy. The hazard ratio for the mortality risk in patients > or = 75 years assigned to defibrillator implant compared with those in conventional therapy was 0.56 (95 confidence interval 0.29-1.08; P = 0.08) after a mean follow-up of 17.2 months. Comparatively, the hazard ratio in patients < 75 years assigned to defibrillator implant was 0.63 (0.45-0.88; P = 0.01) after 20.8 months. Elderly patients had similar reductions in quality of life (QoL) regardless of treatment randomization. Scores through Health Utilities Index Mark III (HUI) Questionnaire changes from baseline to 1 year were -0.22 for patients with conventional therapy versus -0.20 for patients with ICD, and -0.36 versus -0.27 at 2 years, respectively (P = NS).

CONCLUSION

The implantable defibrillator is associated with an equivalent reduction of mortality in elderly and younger patients, with no compromise in the QoL in the older age subjects.

Impact of race and gender on cardiac device implantations

BACKGROUND

Pacemakers and implantable cardioverter-defibrillators (ICDs) are established therapies for life-threatening cardiac arrhythmias. Biventricular pacemakers (BiVP) can improve heart failure in selected patients as well.

OBJECTIVE

This study sought to investigate the impact of gender and race on rates of implantation of pacemakers and ICDs in patients with reduced left ventricular ejection fraction (LVEF).

METHODS

Data were obtained from ADVANCENT, a prospective multicenter registry enrolling patients with LVEF < or = 40% between June 2003 and November 2004. a total of 26,264 patients from 106 us centers were enrolled. the mean age was 66.4 years; 71.5% were male and 81.9% were white; 10,394 subjects (39.6%) had devices implanted.

RESULTS

The overall rate of device implantation was higher in white subjects compared with nonwhite subjects (41.1% vs 32.5%, P <.0001). This was also true for the rates of implantation of all types of ICDs (28.6% vs 23.9%, P <.0001) and BiVP (11.2% vs 7.7%, P <.0001). After adjusting for age, gender, LVEF, New York Heart Association class, coronary artery disease, QRS duration, comorbidities, type of referring physician, and insurance type, nonwhite race remained an independent negative predictor of implantation of any device (odds ratio [OR] 0.86, 95% confidence interval [CI] 0.791 to 0.927), and any ICD (OR 0.88, 95% CI 0.817 to 0.964). Female gender was also independently associated with decreased implantation of any device (OR 0.70, 95% CI 0.66 to 0.76), and any ICD (OR 0.60, 95% CI 0.55 to 0.64).

CONCLUSION

In this large cohort with reduced LVEF, minorities and women were significantly less likely to receive device implants. These findings were most pronounced in nonwhite women, and could not be explained by disparities in demographic or clinical characteristics.

Use of implantable cardioverter defibrillators in Canadian and US survivors of out-of-hospital cardiac arrest

BACKGROUND

Cardiac arrest due to ventricular arrhythmia in the absence of a reversible cause or contraindication has been a class I indication for insertion of an implantable cardioverter defibrillator since 1998. We compared and contrasted the use of implantable cardioverter defibrillator therapy in Canada and the United States among adults who survived a cardiac arrest.

METHOD

Data on hospital separations from April 1, 1994 through March 31, 2003 were obtained from the Health Person-Oriented Information Database maintained by Statistics Canada and from the US National Hospital Discharge Survey on all patients with a primary diagnosis of cardiac arrest, ventricular fibrillation or ventricular flutter for the same 9-year period. We excluded all records of patients with a secondary diagnosis of acute myocardial infarction.

RESULTS

In Canada, 3793 patients survived to discharge after a cardiac arrest; 628 (16.6%) of these were implanted with a cardioverter defibrillator before discharge. The implant rate rose steadily from 5.4% in 1994/95 to 26.7% in 2002/03. In the United States, 23 688 (30.2%) of 78 538 such survivors received an implantable cardioverter defibrillator before discharge. Logistic regression analysis indicated that sex, age, fiscal year, the hospital's teaching status, hospital size and patient history of heart failure were positive predictors of implantable cardioverter defibrillator implantation. Age, renal failure, liver failure and cancer were negative predictors of receiving an implantable cardioverter defibrillator.

INTERPRETATION

The rate of use of implantable cardioverter defibrillator therapy for cardiac arrest survivors in Canada is increasing, but still is lower than the rate in the United States.

Inequitable distribution of implantable cardioverter defibrillators in Ontario

Objectives:Implantable cardioverter defibrillator (ICD) therapy reduces the risk of sudden death in patients with ischemic cardiomyopathy, but their novelty and cost may represent barriers to utilization. The objective of this study was to examine the influence of age, gender, place of residence, and socioeconomic status on rates of ICD implantation for the primary prevention of death.

Methods:We conducted a population-based retrospective cohort study involving the entire province of Ontario, Canada. Patients were eligible if they had survived following hospitalization for heart failure from 1 January 1993, to 31 March 2004, and previously sustained an acute coronary syndrome within 5 years. Patients with an existing ICD or a documented history of cardiac arrest were excluded, as were patients who died in the hospital. Primary outcome was ICD implantation.

Results:We identified 48,426 patients hospitalized for heart failure who survived to hospital discharge. Of these, 440 received an ICD, with a gradual 30-fold increase in implantation rates over the study period (.12–3.9 percent). ICD recipients were more likely to be men (odds ratio [OR] = 4.14; 95 percent confidence interval [CI], 3.24–5.30), younger than 75 years of age (OR = 3.19; 95 percent CI, 2.57–3.96), reside in a metropolitan area (OR = 1.42; 95 percent CI, 1.04–1.9), and live in a higher socioeconomic neighborhood (OR = 1.32; 95 percent CI, 1.08–1.61).

Conclusions:Among patients with heart failure and a previous myocardial infarction, ICD use is increasing in Ontario. However, the application of this technology is characterized by major sociodemographic inequities. The causes and consequences of the pronounced age and gender discrepancies, in particular, warrant further investigation.