Prevalence and mortality of patients with myocardial infarction and reduced left ventricular ejection fraction in a defined community: Relation to the second multicenter automatic defibrillator implantation trial

Prophylactic implantable cardioverter-defibrillator in the very elderly

Aims

Current guidelines do not propose any age cut-off for the primary prevention implantable cardioverter-defibrillator (ICD). However, the risk/benefit balance in the very elderly population has not been well studied.

Methods and results

In a multicentre French study assessing patients implanted with an ICD for primary prevention, outcomes among patients aged ≥80 years were compared with <80 years old controls matched for sex and underlying heart disease (ischaemic and dilated cardiomyopathy). A total of 300 ICD recipients were enrolled in this specific analysis, including 150 patients ≥80 years (mean age 81.9 ± 2.0 years; 86.7% males) and 150 controls (mean age 61.8 ± 10.8 years). Among older patients, 92 (75.6%) had no more than one associated comorbidity. Most subjects in the elderly group got an ICD as part of a cardiac resynchronization therapy procedure (74% vs. 46%, P < 0.0001). After a mean follow-up of 3.0 ± 2 years, 53 patients (35%) in the elderly group died, including 38.2% from non cardiovascular causes of death. Similar proportion of patients received ≥1 appropriate therapy (19.4% vs. 21.6%; P = 0.65) in the elderly group and controls, respectively. There was a trend towards more early perioperative events (P = 0.10) in the elderly, with no significant increase in late complications (P = 0.73).

Conclusion

Primary prevention ICD recipients ≥80 years in the real world had relatively low associated comorbidity. Rates of appropriate therapies and device-related complications were similar, compared with younger subjects. Nevertheless, the inherent limitations in interpreting observational data on this particular competing risk situation call for randomized controlled trials to provide definitive answers. Meanwhile, a careful multidisciplinary evaluation is needed to guide patient selection for ICD implantation in the elderly population.

Body Mass Index and Sudden Cardiac Death in Japanese Patients After Acute Myocardial Infarction: Data From the JCAD Study and HIJAMI-II Registry

Background

Although an “obesity paradox” exists in patients after myocardial infarction, the association between obesity and the risk of sudden cardiac death (SCD) is limited. The aim of this study was to determine whether obesity is associated with an increased risk of SCD in Japanese survivors of acute myocardial infarction.

Methods and Results

Pooled data from 2 cohort studies in Japan, JCAD (Japanese Coronary Artery Disease) study and the Heart Institute of Japan Acute Myocardial Infarction‐II (HIJAMI‐II) registry, comprising of 6216 patients (mean age 65±11 years, 75.2% male) with acute myocardial infarction who were discharged alive, were studied. The patients were categorized into the following body mass index (BMI) groups at baseline according to the World Health Organization classification for Asian populations: BMI <18.5 kg/m² (n=335), 18.5 to 23 kg/m² (n=2371), 23 to 27.5 kg/m² (n=2823), and ≥27.5 kg/m² (n=687). The main outcomes were all‐cause mortality and SCD. During an average follow‐up period of 3.6±1.4 years, all‐cause mortality was 10.1%, and SCD was 1.2%. Patients with BMI <18.5 kg/m² had the highest rate of all‐cause mortality (adjusted hazard ratio, 1.61; 95% confidence interval, 1.20–2.16), but high BMI (≥27.5 kg/m²) was not associated with mortality compared with patients in the group with BMI ≥18.5 and <23 kg/m². However, the long‐term risk of SCD was increased in the group with BMI ≥27.5 kg/m² (adjusted hazard ratio, 2.97; 95% confidence interval, 1.24–7.15). Multivariate analysis revealed that BMI ≥27.5 kg/m² was associated with an increased risk of SCD (hazard ratio, 2.78; 95% confidence interval, 1.35–5.74).

Conclusions

Obesity (BMI ≥27.5 kg/m²) was associated with the risk of SCD in Japanese patients after myocardial infarction, although an obesity paradox was found for all‐cause mortality.

Device Therapies Among Patients Receiving Primary Prevention Implantable Cardioverter-Defibrillators in the Cardiovascular Research Network

BACKGROUND

Primary prevention implantable cardioverter-defibrillators (ICDs) reduce mortality in selected patients with left ventricular systolic dysfunction by delivering therapies (antitachycardia pacing or shocks) to terminate potentially lethal arrhythmias; inappropriate therapies also occur. We assessed device therapies among adults receiving primary prevention ICDs in 7 healthcare systems.

METHODS AND RESULTS

We linked medical record data, adjudicated device therapies, and the National Cardiovascular Data Registry ICD Registry. Survival analysis evaluated therapy probability and predictors after ICD implant from 2006 to 2009, with attention to Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups: left ventricular ejection fraction, 31% to 35%; nonischemic cardiomyopathy <9 months' duration; and New York Heart Association class IV heart failure with cardiac resynchronization therapy defibrillator. Among 2540 patients, 35% were <65 years old, 26% were women, and 59% were white. During 27 (median) months, 738 (29%) received ≥1 therapy. Three-year therapy risk was 36% (appropriate, 24%; inappropriate, 12%). Appropriate therapy was more common in men (adjusted hazard ratio [HR], 1.84; 95% confidence interval [CI], 1.43-2.35). Inappropriate therapy was more common in patients with atrial fibrillation (adjusted HR, 2.20; 95% CI, 1.68-2.87), but less common among patients ≥65 years old versus younger (adjusted HR, 0.72; 95% CI, 0.54-0.95) and in recent implants (eg, in 2009 versus 2006; adjusted HR, 0.66; 95% CI, 0.46-0.95). In Centers for Medicare and Medicaid Services Coverage With Evidence Development analysis, inappropriate therapy was less common with cardiac resynchronization therapy defibrillator versus single chamber (adjusted HR, 0.55; 95% CI, 0.36-0.84); therapy risk did not otherwise differ for Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups.

CONCLUSIONS

In this community cohort of primary prevention patients receiving ICD, therapy delivery varied across demographic and clinical characteristics, but did not differ meaningfully for Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups.

Validation of Health Event Capture in the Marshfield Epidemiologic Study Area

OBJECTIVE

In this study, health event capture is broadly defined as the degree to which a group of people use a particular provider network as their primary source of health care services. The Marshfield Epidemiologic Study Area (MESA) is a valuable resource for population-based health research, but the completeness of health event capture has not been validated in recent years. Our objective was to determine the current level of outpatient and inpatient health event capture by Marshfield Clinic (MC) facilities and affiliated hospitals for people living within MESA.

DESIGN

A stratified sample survey with strata defined by MESA region (Central or North) and age group (<18 years or ≥18 years).

SETTING

24 ZIP codes in central and northern Wisconsin, USA.

PARTICIPANTS

2,485 individuals participated of the 4,313 sampled cohort members residing in MESA Central (N=61,041) and MESA North (N=25,906) on February 22, 2011.

METHODS

A health care utilization survey was mailed to a random sample stratified by age group and MESA region. Telephone interviews were attempted for nonrespondents. The survey requested information on sources of outpatient care and overnight hospital admissions. Population proportions representing health event capture metrics and corresponding 95% confidence intervals (CI) were estimated with analytic weights applied to account for the survey design.

RESULTS

Among those with an outpatient visit during the past 24 months, the most recent visit of an estimated 93% (95% CI, 91% - 94%) was at a MC facility. The most recent admission of an estimated 93% (95% CI, 90% - 96%) of those hospitalized in the past 24 months was at a hospital affiliated with MC. The proportion admitted to MC affiliated hospitals was higher for residents of MESA Central (97%) compared to MESA North (83%).

CONCLUSION

A high proportion of outpatient visits and inpatient admissions in MESA Central and MESA North are accessible in the MC electronic health record. This pattern of high health event capture has been demonstrated since the inception of MESA in 1991. The results from this study validate and support the continued use of MESA for population-based epidemiologic and clinical research.

Atrial flutter versus atrial fibrillation in a general population: differences in comorbidities associated with their respective onset

OBJECTIVE

Determine and compare the prevalence of known risk factors for cardiovascular disease among unselected individuals presenting with their first ever episode of atrial flutter (AFL) and atrial fibrillation (AF).

STUDY DESIGN AND SETTING

We evaluated 11 pre-selected clinical variables including age, sex, smoking history and other potential cardiac risk factors. Using the resources of the Marshfield Epidemiologic Study Area, a population-based database, all newly diagnosed cases of either AFL or AF in the region during a 4-year period were identified.

RESULTS

Among the 472 incident cases, 76 (16.1%) had AFL and 396 (83.9%) had AF. Compared to those with AF, subjects with AFL were more likely to have had a history of chronic obstructive pulmonary disease (25% vs. 12%, P = 0.006), heart failure (28% vs. 17%, P = 0.05), and smoking (49% vs. 37%, P = 0.06). Hypertension, on the other hand, was more common among individuals with AF (63% vs. 47%, P = 0.01).

CONCLUSION

This study represents the first report to evaluate potential differences in the conditions associated with the development of AFL versus AF. Research into the mechanisms of atrial arrhythmogenesis may lead to improved preventive and therapeutic interventions.

Gender differences in procedure-related adverse events in patients receiving implantable cardioverter-defibrillator therapy

BACKGROUND

Women are at higher risk than men for adverse events with certain invasive cardiac procedures. Our objective was to compare rates of in-hospital adverse events in men and women receiving implantable cardioverter- defibrillator (ICD) therapy in community practice.

METHODS AND RESULTS

Using the National Cardiovascular Data Registry ICD Registry, we identified patients undergoing first-time ICD implantation between January 2006 and December 2007. Outcomes included in-hospital adverse events after ICD implantation. Multivariable analysis assessed the association between gender and in-hospital adverse events, with adjustment for demographic, clinical, procedural, physician, and hospital characteristics. Of 161,470 patients, 73% were male, and 27% were female. Women were more likely to have a history of heart failure (81% versus 77%, P<0.01), worse New York Heart Association functional status (57% versus 50% in class III and IV, P<0.01), and nonischemic cardiomyopathy (44% versus 27%, P<0.01) and were more likely to receive biventricular ICDs (39% versus 34%, P<0.01). In unadjusted analyses, women were more likely to experience any adverse event (4.4% versus 3.3%, P<0.001) and major adverse events (2.0% versus 1.1%, P<0.001). In multivariable models, women had a significantly higher risk of any adverse event (OR 1.32, 95% CI 1.24 to 1.39) and major adverse events (OR 1.71, 95% CI 1.57 to 1.86).

CONCLUSIONS

Women are more likely than men to have in-hospital adverse events related to ICD implantation. Efforts are needed to understand the reasons for higher ICD implantation-related adverse event rates in women and to develop strategies to reduce the risk of these events.