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

Plasma microrna expression profile for reduced ejection fraction in dilated cardiomyopathy

The left ventricular (LV) ejection fraction (EF) is key to prognosis in dilated cardiomyopathy (DCM). Circulating microRNAs have emerged as reliable biomarkers for heart diseases, included DCM. Clinicians need improved tools for greater clarification of DCM EF categorization, to identify high-risk patients. Thus, we investigated whether microRNA profiles can categorize DCM patients based on their EF. 179-differentially expressed circulating microRNAs were screened in two groups: (1) non-idiopathic DCM; (2) idiopathic DCM. Then, 26 microRNAs were identified and validated in the plasma of ischemic-DCM (n = 60), idiopathic-DCM (n = 55) and healthy individuals (n = 44). We identified fourteen microRNAs associated with echocardiographic variables that differentiated idiopathic DCM according to the EF degree. A predictive model of a three-microRNA (miR-130b-3p, miR-150-5p and miR-210-3p) combined with clinical variables (left bundle branch block, left ventricle end-systolic dimension, lower systolic blood pressure and smoking habit) was obtained for idiopathic DCM with a severely reduced-EF. The receiver operating characteristic curve analysis supported the discriminative potential of the diagnosis. Bioinformatics analysis revealed that miR-150-5p and miR-210-3p target genes might interact with each other with a high connectivity degree. In conclusion, our results revealed a three-microRNA signature combined with clinical variables that highly discriminate idiopathic DCM categorization. This is a potential novel prognostic biomarker with high clinical value.

Health Care Costs After Cardiac Arrest in the United States

BACKGROUND

This study was designed to estimate the costs of index hospitalizations after cardiac arrest in the United States.

METHODS AND RESULTS

We used the US Nationwide Inpatient Sample (2003-2012) to identify patients with cardiac arrest. Log transformation of inflation-adjusted cost was determined for care to patient outcomes. Overall, an estimated 1 387 396 patients were hospitalized after cardiac arrest. The mean age of the cohort was 66 years, 45% were women, and the majority were white. Inpatient procedures included coronary angiography (15%), percutaneous coronary intervention (7%), intra-aortic balloon pump (4.4%), therapeutic hypothermia (1.1%), and mechanical circulatory support (0.1%). The rates of therapeutic hypothermia increased from zero in 2003 to 2.7% in 2012 (P<0.001). Both hospital charges and inflation-adjusted cost increased linearly over time. In a multivariate analysis, predictors of inflation-adjusted cost included large hospital size, urban teaching hospital, and length of stay. Among comorbidities, atrial fibrillation or fluid and electrolytes imbalance was most associated with cost. Among selected interventions, the cost was significantly increased with automatic implantable cardioverter defibrillators (odds ratio, 1.83; P<0.001), intra-aortic balloon pump (odds ratio, 1.50; P<0.001), hypothermia (odds ratio, 1.28; P<0.001), and extracorporeal membrane oxygenation (odds ratio, 2.38; P<0.001).

CONCLUSIONS

In the period between 2003 and 2012, postcardiac arrest hospitalizations resulted in a steady rise in associated health care cost, likely related to increased length of stay, medical procedures, and systems of care. Although targeted cost containment for postarrest interventions may reduce the finance burden, there is an increasing need for funding research into prediction and prevention of cardiac arrest, which offers greater societal benefit.

Racial and ethnic healthcare disparities in patients undergoing laser lead extraction

BACKGROUND

The rate of cardiovascular implantable electronic device infections (CIEDIs) has mirrored or exceeded the increased use of implantable cardiac devices in the United States. The presence of racial and ethnic disparities associated with CIEDIs has not been published. Our aim is to describe the presence of racial and ethnic disparities with respect to the management of CIEDIs.

METHODS

We reviewed a prospective single-center registry for patients undergoing removal of an implantable cardiac device between 1/2004 and 1/2016. 1173 consecutive patients underwent device extraction. 699 patients were identified as having an infection, 305 were identified as Caucasian and 394 were minorities (91 African Americans, 303 Hispanics). Patients had pre-operative transesophageal echocardiograms (TEEs) and collection of blood and exudate cultures. All underwent complete hardware extraction; leads were removed through the use of locking stylets and traction or laser extraction. En-bloc capsulectomy was performed with intraoperative specimen collection from pocket tissue, exudate, lead tips, and vegetations.

RESULTS

Minority patients were: younger (67.9 ± 14.5 years vs 72.4 ± 13.2 years), had a higher proportion of male gender, diabetes, and chronic renal failure (p < 0.001). Minorities experienced a higher rate of complications during extraction and a longer hospitalization (15.3 ± 9.9 days versus 17.4 ± 13.4 days, p < 0.001). There was no significant difference between the proportion of types of infection in both groups.

CONCLUSION

Minority patients with CIEDIs experienced more procedural complications during extraction and had a significantly longer length of index hospitalization than Caucasian patients.

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.

Disparity Between Indications for and Utilization of Implantable Cardioverter Defibrillators in Asian Patients With Heart Failure

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are lifesaving devices for patients with heart failure (HF) and reduced ejection fraction. However, utilization and determinants of ICD insertion in Asia are poorly defined. We determined the utilization, associations of ICD uptake, patient-perceived barriers to device therapy and, impact of ICDs on mortality in Asian patients with HF.

METHODS AND RESULTS

Using the prospective ASIAN-HF (Asian Sudden Cardiac Death in Heart Failure) registry, 5276 patients with symptomatic HF and reduced ejection fraction (HFrEF) from 11 Asian regions and across 3 income regions (high: Hong Kong, Japan, Korea, Singapore, and Taiwan; middle: China, Malaysia, and Thailand; and low: India, Indonesia, and Philippines) were studied. ICD utilization, clinical characteristics, as well as device perception and knowledge, were assessed at baseline among ICD-eligible patients (EF ≤35% and New York Heart Association Class II-III). Patients were followed for the primary outcome of all-cause mortality. Among 3240 ICD-eligible patients (mean age 58.9±12.9 years, 79.1% men), 389 (12%) were ICD recipients. Utilization varied across Asia (from 1.5% in Indonesia to 52.5% in Japan) with a trend toward greater uptake in regions with government reimbursement for ICDs and lower out-of-pocket healthcare expenditure. ICD (versus non-ICD) recipients were more likely to be older (63±11 versus 58±13 year; P<0.001), have tertiary (versus ≤primary) education (34.9% versus 18.1%; P<0.001) and be residing in a high (versus low) income region (64.5% versus 36.5%; P<0.001). Among 2000 ICD nonrecipients surveyed, 55% were either unaware of the benefits of, or needed more information on, device therapy. ICD implantation reduced risks of all-cause mortality (hazard ratio, 0.71; 95% confidence interval, 0.52-0.97) and sudden cardiac deaths (hazard ratio, 0.33; 95% confidence interval, 0.14-0.79) over a median follow-up of 417 days.

CONCLUSIONS

ICDs reduce mortality risk, yet utilization in Asia is low; with disparity across geographic regions and socioeconomic status. Better patient education and targeted healthcare reforms in extending ICD reimbursement may improve access.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov/ct2/show/NCT01633398. Unique identifier: NCT01633398.

A roadmap for evaluating the use and value of durable ventricular assist device therapy

Heart failure is a disease characterized by profound human suffering with limitations in survival despite treatment with guideline-directed medical therapies. Patients with heart failure frequently progress to advanced stages and often require cardiac transplantation or implantation of left ventricular assist devices (LVADs) to extend survival and improve quality of life. As the number of suitable heart donors, number of experienced medical centers and patient comorbidities place restrictions on the feasibility of cardiac transplantation, implantation of LVADs has emerged as a more frequently applied treatment as either a bridge to transplantation or as permanent therapy. Considerable data have documented improvements in survival, functional status and quality of life offered by LVADs, however, few studies have focused on identifying: (1) determinants of LVAD use across medical centers, (2) the relationship between the determinants of LVAD use and value (defined as quality divided by cost), and (3) how determinants of LVAD use are influenced or impacted by vulnerable populations. We propose a conceptual model that integrates the main determinants of LVAD utilization, which include technology, insurance coverage, market-, provider- and patient-level factors. We propose this paradigm as a necessary prerequisite for understanding LVAD usage and value. This conceptual framework provides a broader view for future studies, which are needed to inform emerging healthcare policies that influence dissemination of this expensive but life-prolonging medical therapy.

Long-term outcomes of heart failure patients who received primary prevention implantable cardioverter-defibrillator: An observational study

Background

Implantable cardioverter-defibrillator (ICD) therapy is indicated for selected heart failure patients for the primary prevention of sudden cardiac death. Little is known about the outcomes in patients selected for primary prevention device therapy in the northern region of New Zealand.

Method

Heart failure patients with systolic dysfunction who underwent primary prevention ICD/cardiac resynchronization therapy-defibrillator (CRT-D) implantation between January 1, 2007, and June 1, 2015, were included. Complications, mortality, and hospitalization events were reviewed.

Results

Three hundred and eighty-five primary prevention devices were implanted (269 ICD, 116 CRT-D). Mean age at implant was 59.1 ± 11.4 years. Mean duration of follow-up was 3.64 ± 2.17 years. The commonest cause of death was heart failure (41.8%). Only 2 patients died from sudden arrhythmic death. The 5-year heart failure mortality rate was 6%, whereas the 5-year sudden arrhythmic death rate was 0.3%. Heart failure hospitalizations were commoner in those who received ICD than CRT-D (67.7% vs 25.8%, P < .001). Maori patients have low implant rates (14%) with relatively high rates of admissions with heart failure and ventricular arrhythmia admissions.

Conclusions

Even in appropriately selected heart failure patients who received primary prevention devices, only a small percentage died as a result of sudden arrhythmic death. CRT-D should be the device of choice where appropriate in heart failure patients. Significant challenges remain to improve access to device therapy and maximize benefit to those who do get implanted.

Employment Status and Sick Leave After First-Time Implantable Cardioverter Defibrillator Implantation: Results From the COPE-ICD Trial

BACKGROUND

In the Copenhagen Outpatient Programme-Implantable Cardioverter Defibrillator (COPE-ICD) Trial, a positive effect from a cost-saving, comprehensive cardiac rehabilitation program was found on physical and mental health in patients with ICDs.

OBJECTIVE

In the context of the COPE-ICD Trial, the aims of this study is to investigate (a) employment status after ICD implantation, (b) the number of sick days related to ICD implantation, (c) differences in employment status and sick days between rehabilitation and usual care groups, and (d) predictors of employment status and sick leave.

METHOD

Patients with first-time ICD implantation were randomized to comprehensive cardiac rehabilitation or usual care. One year after ICD implantation, patients answered questions about employment status and sick leave. Differences were tested using the Student t test and the χ test. Predictors of employment status and sick leave were tested using logistic regression and linear regression models.

RESULT

A total of 196 patients were randomized. The questionnaire was completed by 138 patients (70%). In total, 47% had worked before ICD implantation. After 1 year, 81% were still working and their mean (SD) number of sick days was 33.8 (58.3). Age 60 years or younger and secondary ICD indication were predictors of working after 1 year. Patients with secondary ICD indication had more sick days and patients who were not married had fewer sick days.

CONCLUSION

Most patients who worked before ICD implantation returned to work after the ICD was placed. Those who were married and had an ICD for secondary prevention took more sick days after the ICD than did those without these characteristics. Those who were younger and have a secondary indication ICD were more likely to be working 1 year after ICD implantation.

Potential eligibility of congenital heart disease patients for subcutaneous implantable cardioverter-defibrillator based on surface electrocardiogram mapping

AIMS

The eligibility of complex congenital heart disease (C-CHD) patients for subcutaneous implantable cardioverter-defibrillator (S-ICD) has yet to be determined. The aim of this study was to determine in C-CHD patients: (i) the S-ICD eligibility, (ii) the most effective sensing vector, (iii) the impact of posture change on screening eligibility, and (iv) the impact of using two vs. six postures for screening. Adults with structurally normal hearts were used as controls.

METHODS AND RESULTS

The Boston Scientific ECG screening tool was used to determine eligibility for S-ICD in two and six different postures in 30 patients with C-CHD and 10 controls. Statistical significance was determined using Fisher's exact test. In total, 1440 bipolar vectors were collected. The mean age was 36.3 years, 57% subjects were men. Over all 86.7% of C-CHD patients and 100% controls (P > 0.05) met S-ICD eligibility. In controls, the primary vector (PV) was the most effective, and the alternate vector (AV) was least effective. In C-CHD patients, the AV was comparable to the PV. Posture change did not significantly affect S-ICD eligibility in C-CHD patients and controls (P > 0.05). Screening with six postures vs. two did not significantly affect S-ICD eligibility of C-CHD patients (83% vs. 87%, P > 0.05) or controls (90% vs. 100% P = >0.05).

CONCLUSION

No significant differences were observed between S-ICD eligibility in C-CHD patients and controls. The AV and PV are most suitable in C-CHD patients. No significant impact of postural change was observed for S-ICD eligibility between the two groups. No significant difference was observed in S-ICD eligibility when screening using two or six postures in both groups.

Gaps in Medical and Device Therapy for Patients with Left Ventricular Systolic Dysfunction: The EchoGap Study

Objectives:

To assess gaps between guidelines and medicine prescription/dosing and referral for defibrillator therapy in patients with left ventricular systolic dysfunction (LVSD).

Methods:

Outpatient echocardiography reports at an academic hospital centre were screened and outpatients with LVEF<40% were included. A questionnaire was mailed to the patients’ physician, querying prescription/dosing of ACE-inhibitors (ACEi), angiotensin receptor blockers (ARB) and beta-blockers (BB). Patients with LVEF<30% had additional questions on implantable cardiac defibrillator (ICD) referral.

Results:

Mean age was 69.6+/-12.2 years and mean LVEF was 29.7+/-6.5%. ACEi and/or ARB prescription rate was 260/309(84.1%) versus 256/308(83.1%) for BB (p=NS for comparison). Of patients on ACEi, 77/183(42.1%) were on target dose, compared to 7/45(15.5%) for ARB and 9/254(3.5%) for BB (p<0.01). Of 171/309 patients (55.3%) with LVEF<30%, 72/171(42.1%) had an ICD and 16/171(9.4%) were referred for one.

Conclusion:

Prescription rates of evidence-based HF medicines are relatively high in outpatients with LVSD referred for echocardiography at this Canadian academic medical centre; however, the proportion of patients at target doses was modest for ACEi and low for ARB and BB. Approximately half of patients who qualify for ICD by EF alone have one or were referred. Important reasons for patients with LVSD not on evidence-based therapy were identified.

Clinical reminders to providers of patients with reduced left ventricular ejection fraction increase defibrillator referral: a randomized trial

BACKGROUND

Many patients who are candidates for implantable cardioverter defibrillators (ICDs) are not referred for potential implantation. We sought to determine if a simple provider reminder would increase referrals.

METHODS AND RESULTS

We identified consecutive patients from January 2007 through July 2010 in the VA Palo Alto Health Care System with a left ventricular ejection fraction<35% on echocardiography. Patients were excluded using available administrative data only (no chart review) if they were known to have an ICD, if they were ≥80 years old, or if they did not have a current primary care or cardiology provider within the system. We randomized patients to no intervention or a clinical note to the provider in the medical record. The outcomes were referral for consideration of defibrillator implantation (primary) and documented discussion (secondary). Of 330 patients with left ventricular ejection fraction≤35%, 128 were known to have an ICD, 85 were no longer followed in the healthcare system, and 28 were ≥80 years old, leaving 89 patients to be randomized. Forty-six patients were randomized to intervention and 43 to control. Eleven of 46 (24%) intervention patients were referred for consideration of ICD implantation during the following 6 months versus 1 of 43 (2%) control patients (P=0.004). Overall, 31 of 46 (67%) intervention patients versus 19 of 43 (44%) control patients had documentation discussing potential candidacy for defibrillators (P=0.05).

CONCLUSIONS

In patients with low left ventricular ejection fraction, a simple electronic medical record-based intervention directed to their providers improved the rates of referral for ICD implantation.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01217827.

Implementation of guidelines for implantable cardioverter-defibrillator therapy in clinical practice: Which patients do benefit?

PURPOSE

Based on multiple large clinical trials conducted over the last decades guidelines for implantable cardioverter-defibrillator (ICD) implantations have been evolving. The increase in primary prophylactic ICD implantations challenges us to be critical towards the indications in certain patient populations.

METHODS

We retrospectively collected patient characteristics and rates of appropriate and inappropriate ICD therapy, appropriate and inappropriate ICD shock and mortality of all patients who received an ICD in the University Medical Center Utrecht (UMCU) over the years 2006-2011.

RESULTS

A total of 1075 patients were included in this analysis (74 % male, mean age 61 ± 13 years, left ventricular ejection fraction 30 ± 13 %); 61 % had a primary indication and 58 % had ischaemic heart disease. During a mean follow-up period of 31 ± 17 months, 227 of the patients (21 %) received appropriate ICD therapy (149 (14 %) patients received an appropriate ICD shock). Females, patients with a primary prophylactic indication and patients with non-ischaemic heart disease experienced significantly less ICD therapy. Only a few patients (54, 5 %) received inappropriate ICD therapy; 33 (3 %) patients received an inappropriate ICD shock. Fifty-five patients died within one year after ICD implantation and were therefore, in retrospect, not eligible for ICD implantation.

CONCLUSION

Our study confirms the benefit of ICD implantation in clinical practice. Nevertheless, certain patients experience less benefit than others. A more patient-tailored risk stratification based on electrophysiological parameters would be lucrative to improve clinical benefit and cost-effectiveness.

COPE-ICD: patient experience of participation in an ICD specific rehabilitation programme

PURPOSE

Evaluating rehabilitation programmes from the patient's perspective is much needed, as the patients are the most important stakeholders in the health care system. A comprehensive rehabilitation programme, COPE-ICD programme, consists of exercise training and nursing consultations during a one year period post ICD implantation. The purpose of this paper is to describe the experience and meaning of participating in a comprehensive ICD-specific rehabilitation programme.

METHODS

Qualitative interviews were conducted with 10 patients representing the participating population, and later transcribed. The analysis was inspired by Ricoeur's theory of interpretation, which consists of three levels: naive reading, structured analysis and critical interpretation and discussion.

RESULTS

The overall concept was that participating in the COPE-ICD programme meant feeling inspired and secure through individualized care. Four themes emerged: Knowledge: patients gained much needed understanding; Physical attention: patients interpreted body signals and adjusted their exercise behaviour; Trust: patients regained trust, felt secure and dared to live again; Strategies of living: patients' coping was supported through reflection and professional dialogue, and they dealt with the risk of shock or death.

CONCLUSION

Participating in an ICD-specific rehabilitation programme can make patients feel inspired and secure through individualized care. They discover that they have to rethink some of their strategies of living and they gain support in the reflection and coping needed for that. Patients gain insight and they develop a special physical attention whereby they continue healthy activities through interpreting body signals and adjusting exercise behaviour. They learn to trust their body again.

Geographic variation in implantable cardioverter-defibrillator use and heart failure survival

BACKGROUND

Implantable cardioverter-defibrillators and cardiac resynchronization therapy-defibrillators (ICD/CRT-Ds) are evidence-based preventative treatments for many patients with heart failure (HF), yet large numbers of eligible patients remain untreated. It is uncertain if localities with more frequent ICD/CRT-D use have had better rates of HF survival.

OBJECTIVES

To determine if US Hospital Referral Regions (HRRs) with larger increases in the rate of ICD/CRT-D utilization during 2002 to 2007 also had commensurate increases in HF survival.

RESEARCH DESIGN

Retrospective cohort.

PARTICIPANTS

Medicare beneficiaries age 66 to 80 nonelectively hospitalized for HF from 2002 to 2007.

MEASURES

Each HRR's annual ICD/CRT-D rate was estimated from the cohort's Medicare procedure claims. Survival duration was determined from Medicare mortality records. HRR-year-level panel regression models were estimated to assess whether an HRR's ICD/CRT-D rate predicted HF survival, adjusting for baseline differences in survival across HRRs and secular trends.

RESULTS

A total of 883,002 HF patients were propensity-score matched within HRR across 2002 to 2007. Across HRRs, growth in ICD/CRT-D use among such patients varied from 1 to 12 percentage points. Regression models indicated that a 1 percentage point increase in an HRR's ICD/CRT-D utilization among hospitalized HF patients was associated with an increase in 1-year survival of 0.12% [95% confidence interval (CI), 0.03%-0.21%, P=0.009] and with a 0.26% increase in HF survival at 2 years (95% CI, 0.14%-0.37%, P<0.001).

CONCLUSIONS

Localities with greater increases in ICD/CRT-D utilization from 2002 to 2007 also had greater improvements in HF survival. Areas with persistently low ICD/CRT-D use may be good targets for programs designed to increase the evidence-based use of defibrillators.

Combined cardiac magnetic resonance imaging and C-reactive protein levels identify a cohort at low risk for defibrillator firings and death

BACKGROUND

Annually, ≈80,000 Americans receive guideline-based primary prevention implantable cardioverter-defibrillators (ICDs), but appropriate firing rates are low. Current selection criteria for ICDs rely on left ventricular ejection fraction, which lacks sensitivity and specificity. Because scar-related myocardial tissue heterogeneity is a substrate for life-threatening arrhythmias, we hypothesized that cardiac magnetic resonance identification of myocardial heterogeneity improves risk stratification through (1) its association with adverse cardiac events independent of clinical factors and biomarker levels and (2) its ability to identify particularly high- and low-risk subgroups.

METHODS AND RESULTS

In 235 patients with chronic ischemic and nonischemic cardiomyopathy with a left ventricular ejection fraction of ≤35% undergoing clinically indicated primary prevention ICD implantation, gadolinium-enhanced cardiac magnetic resonance was prospectively performed to quantify the amount of heterogeneous myocardial tissue (gray zone [GZ]) and dense core scar. Serum high-sensitivity C-reactive protein (hsCRP) and other biomarkers were assayed. The primary end point was appropriate ICD shock for ventricular tachycardia/fibrillation or cardiac death, which occurred in 45 (19%) patients at a 3.6-year median follow-up. On univariable analysis, only diuretics, hsCRP, GZ, and core scar were associated with outcome. After multivariable adjustment, GZ and hsCRP remained independently associated with outcome (P<0.001). Patients in the lowest tertile for both GZ and hsCRP (n=42) were at particularly low risk (0.7% per year event rate), whereas those in the highest tertile for both GZ and hsCRP (n=32) had an event rate of 16.1% per year, P<0.001.

CONCLUSIONS

In a cohort of primary prevention ICD candidates, combining a myocardial heterogeneity index with an inflammatory biomarker identified a subgroup with a very low risk for adverse cardiac events, including ventricular arrhythmias. This novel approach warrants further investigation to confirm its value as a clinical risk stratification tool. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00181233.

T-wave alternans in apparently healthy subjects and in different subsets of patients with ischaemic heart disease

AIMS

Microvolt T-wave alternans (TWA) predicts arrhythmic risk in patients with ischaemic heart disease (IHD). While TWA has widely been assessed by the spectral method, it has been poorly characterized in healthy people as well as in IHD patients by the modified moving average (MMA) method.

METHODS AND RESULTS

We enrolled 729 consecutive subjects, referred for exercise stress test (EST). T-wave alternans was assessed by the MMA method, considering all 12 electrocardiogram (ECG) leads (TWA_tot) or the 6 ECG pre-cordial leads only (TWA_prec). Patients were divided into five groups: (i) no history of IHD and normal EST (Group 1); (ii) no history of IHD but positive EST (Group 2); (iii) ischaemic heart disease without any acute myocardial infarction [AMI (Group 3)]; (iv) old AMI (Group 4); (v) recent AMI (Group 5). T-wave alternans values >95th percentile of those measured in Group 1 were considered 'abnormal'. The 95th percentile of TWA values in Group 1 was 75 µV for TWA_tot and 65 µV for TWA_prec. T-wave alternans values and prevalence of abnormal TWA increased from Groups 1-2 to Group 5 (P< 0.00001 for both). Group 4 and Group 5, compared with Group 1, showed a significant higher prevalence of abnormal values of TWA_tot [odds ratio (OR) 1.70 (P= 0.002), and 2.07 (P= 0.01), respectively] and TWA_prec [OR 1.51 (P= 0.02) and 2.37 (P= 0.003), respectively] at multivariable analysis. In IHD patients EST-induced ischaemia did not influence TWA; in AMI patients, impaired left ventricular function was associated with higher TWA values.

CONCLUSIONS

In healthy people, TWA_tot and TWA_prec were ≤75 and ≤65 µV, respectively, in 95% of subjects. In IHD patients TWA values were higher compared with healthy individuals; a history of AMI was independently associated with abnormal TWA values.

Cardiac resynchronization therapy: a cost or an investment?

Cost-effectiveness estimates can help optimize use of available financial resources and this is especially relevant for implementation of cardiac resynchronization therapy (CRT), given the high upfront costs and the timescale of expected benefits. All available cost-effectiveness estimates for devices with (CRT-P) or without (CRT-D) a defibrillator are based on results of randomized trials of selected patients, with a relatively brief follow-up. Extrapolation suggests that the cost effectiveness of CRT may become more favourable as time horizons increase. Using a lifetime time horizon and comparison with optimal medical therapy, the cost effectiveness of both CRT-P and CRT-D appears to meet the $50 000/QALY benchmark commonly used for health-care interventions in the USA, as well as similar thresholds used in Europe. The absence of direct comparisons of the efficacy/effectiveness of CRT-P and CRT-D hampers cost-effectiveness comparisons, and so clinical judgment in the context of current evidence supporting the benefits of cardioverter-defibrillators may provide a rational basis for choosing between CRT-P and CRT-D. Efforts are currently being dedicated to improve CRT response rates by improved patient selection and, reasonably, any improvement in this field will translate into improved effectiveness, and therefore into improved cost effectiveness. The extended longevity of CRT devices will also positively impact cost-effectiveness estimates.

Safety of nerve conduction studies in patients with implantable cardioverter-defibrillators

OBJECTIVE

A patient with an implantable cardioverter-defibrillator (ICD) may suffer from neuromuscular disorders and may need to undergo a nerve conduction study (NCS). However, a NCS may be a source of electromagnetic interference (EMI). The aim of the present study was to investigate whether the interference from NCS used in a standardised test protocol affects ICD function.

METHODS

Twenty patients (19 males; mean age of 59.8±9.9 years) with implantable ICDs (eight with integrated and 12 with true bipolar leads), treated with amiodarone and with symptoms suggesting neuropathy were included. NCS were conducted using repetitive stimulation with frequency of 2 Hz and single, rectangular pulses of intensity up to 100 mA. Stimulation was performed in standard sites including proximal sites in the arm.

RESULTS

The impulses generated NCS were not detected by the ICD, irrespective of the site, rate or stimulus intensity.

CONCLUSIONS

Standardised test protocol for an NCS is safe in patients with an ICD regardless of the leads type.

SIGNIFICANCE

Current guidelines which limitate the NCS in patients with ICD may be the subject of revision.

COPE-ICD: a randomised clinical trial studying the effects and meaning of a comprehensive rehabilitation programme for ICD recipients -design, intervention and population

Background

Growing evidence exists that living with an ICD can lead to fear and avoidance behaviour including the avoidance of physical activity. It has been suggested that psychological stress can increase the risk of shock and predict death. Small studies have indicated a beneficial effect arising from exercise training and psychological intervention, therefore a large-scale rehabilitation programme was set up.

Methods/Design

A mixed methods embedded experimental design was chosen to include both quantitative and qualitative measures. A randomised clinical trial is its primary component. 196 patients (power-calculated) were block randomised to either a control group or intervention group at a single centre. The intervention consists of a 1-year psycho-educational component provided by two nurses and a 12-week exercise training component provided by two physiotherapists. Our hypothesis is that the COPE-ICD programme will reduce avoidance behaviour, sexual dysfunction and increase quality of life, increase physical capability, reduce the number of treatment-demanding arrhythmias, reduce mortality and acute re-hospitalisation, reduce sickness leading to absence from work and be cost-effective. A blinded investigator will perform all physical tests and data collection.

Discussion

Most participants are men (79%) with a mean age of 58 (range 20-85). Most ICD implantations are on primary prophylactic indication (66%). 44% is NYHA II. Mean walk capacity (6MWT) is 417 m. Mean perception of General Health (SF-36) is PCS 42.6 and MCS 47.1.

A large-scale ICD rehabilitation trial including psycho-educational intervention and exercise training has been initiated and will report findings starting in 2011.

Trial Registration

ClinicalTrials.gov: NCT00569478

Out-of-hospital cardiac arrests in young adults in Melbourne, Australia-adding coronial data to a cardiac arrest registry

AIM

We aim to describe the coronial findings of young adults where the out-of-hospital cardiac arrest (OHCA) aetiology was 'presumed cardiac'.

METHODS

Presumed cardiac aetiology OHCAs occurring in young adults aged 16-39 years were identified using the Victorian Ambulance Cardiac Arrest Registry (VACAR) and available coronial findings reviewed.

RESULTS

We identified 841 young adult OHCAs where the Utstein aetiology was 'presumed cardiac'. Of these 740 died and 572 (77%) OHCAs were matched to coroner's findings. On review of the coroner's cause of death, 230 (40.2%) had a 'confirmed cardiac' aetiology, 221 (38.6%) were proven 'non-cardiac', 97 (17%) were inconclusive and 24 (4.2%) cases remained 'open'. 'Confirmed cardiac' causes of OHCA were ischemic heart disease (n=126, 55%), cardiomegaly (n=26, 11.3%), cardiomyopathy (n=25, 11%), congenital heart disease (n=15, 6.5%), cardiac tamponade due to dissecting thoracic aorta aneurysm (n=10, 4.3%), myocarditis (n=8, 3.5%), arrhythmia (n=7, 3%), others (n=13, 5.7%). 'Non-cardiac' causes of OHCA were epilepsy/sudden unexplained death in epilepsy (SUDEP) (n=56, 25%), pulmonary embolism (n=29, 13%), subarachnoid haemorrhage (n=17, 7.7%), other intracranial bleed (n=7, 3.2%), pneumonia (n=17, 7.7%), DKA (n=16, 7.2%), other complications of diabetes mellitus (n=8, 3.6%), complications of obesity (n=9, 4%), haemorrhage (n=12, 5.4%), sepsis (n=8, 3.6%), peritonitis (n=6, 2.7%), aspiration (n=6, 2.7%), renal failure (n=5, 2.3%), asthma (n=5, 2.3%), complications of anorexia (n=3) and alcohol abuse (n=2), thyrotoxicosis (n=2), meningitis (n=1) and others (n=12). Compared with coroner's diagnosed 'non-cardiac' OHCAs, 'confirmed cardiac' were more likely to be witnessed (41% vs 23%, p≤0.01), receive bystander CPR (35% vs 20%, p≤0.001), have a shockable rhythm (27% vs 6.3%, p<0.001) and have EMS attempted resuscitation (62% vs 44%, p<0.001).

DISCUSSION

Linking OHCA registries with coronial databases for aetiology of the arrest will improve the quality of the data and should be considered by all OHCA registries, particularly for young adult OHCA.

Implantation and patient profiles for pacemakers and cardioverter-defibrillators in France (2008-2009)

BACKGROUND

An ageing population and the extension of indications will in all probability result in an increasing number of cardiac device implantations.

METHODS

Patients implanted in 2008 and 2009 were identified by means of the French National Hospital Discharge database to establish the implantation rate and the National Health Insurance (NHI) Information System database for patient profiles (76% of the population).

RESULTS

Of the 64,306 pacemaker implantations (1003.7 per million inhabitants [pmi]) in 2009, 21.4% were single chamber, 75.4% double chamber and 3.2% triple chamber (CRT-P). Of the 9028 cardioverter-defibrillator implantations (140.8 pmi) in 2009, 30.1% were single chamber, 27.5% double chamber and 42.5% triple chamber (CRT-D), accounting for 65% of cardiac resynchronization therapy (CRT) implants. Among NHI beneficiaries, 58.6% of cardioverter-defibrillators were implanted for primary prevention. Between 2008 and 2009, CRT-P implantations increased by 8.8% and CRT-D implantations by 29.3%. Regional variations in implantation rates were observed regarding single-chamber pacemakers (15-33%) and CRT-D among CRT (46.2-73.8%). Pacemaker implantations cost €158.4 million overall, 4.5% of which was for CRT-P; cardioverter-defibrillator implantations cost €96 million, 49% of which was for CRT-D. For NHI beneficiaries, 11.9% of CRT-P patients and 6.5% of CRT-D patients already had a device of the same type implanted in the 3 preceding years.

CONCLUSION

The results confirm the increase in cardioverter-defibrillator implantations in France. The implantation rate remains lower than that in the USA but falls within the European average. Reasons behind significant regional variations in implantation rates need further study.

Definition of performance metrics and methods for screening for sudden cardiac arrest risk at a tertiary care medical center

PURPOSE

The purpose of this study is to describe the results of manual and automatic electronic medical record-based screening of patients at risk of sudden cardiac arrest (SCA) based on measurements of left ventricular ejection fraction (LVEF).

METHODS

Counseling regarding SCA risk and implantable cardioverter defibrillator (ICD) therapy is underutilized in patients with reduced LVEF. We developed and implemented an electronic medical record (EMR)-based system for screening of such patients to improve care. In phase one, manual screening of electronic records and LVEF databases was initially performed by trained cardiac device nurses. In phase two, records were screened automatically by a customized program, and candidate patient records were sent to cardiac device nurses for final review and disposition.

RESULTS

In phase one, 2,531 patients with LVEF ≤35% were identified over 398 days. Manual EMR review showed that 1,918 patients (76%) received appropriate counseling regarding SCA risk, received ICDs, or had disqualifying comorbidities. In phase two, 1,081 patients with LVEF ≤35% were identified after automatic screening of 44,672 echocardiograms and EMR over 251 days. Of these, 513 patients (58%) received appropriate counseling regarding SCA risk, received ICDs, or had disqualifying comorbidities.

CONCLUSIONS

These data detail the utilization of consultation regarding SCA risk and ICDs in patients with reduced LVEF at a tertiary care center with ready access to arrhythmia specialists. Notification of primary providers of reduced LVEF with recommendation for consultation was not effective in improving patient care.

Do physicians' attitudes toward implantable cardioverter defibrillator therapy vary by patient age, gender, or race?

BACKGROUND

Implantable cardioverter defibrillator (ICD) therapy improves survival of patients with systolic heart failure. We assessed whether physicians' recommendation for ICD therapy varies as a function of patient age, gender, race, and physician's specialty.

METHODS

We surveyed a random sample (n = 9969) of U.S. physicians who are active members of the American College of Cardiology (ACC). We asked participants about their likelihood to recommend ICD therapy in 4 clinical scenarios that randomly varied patient age, gender, race, and ICD indication (guideline Class I, Class IIa, Class III, and Class I in a noncompliant patient).

RESULTS

Responses were received from 1210 physicians (response rate 12%), of whom 1127 met the study inclusion criteria. Responders and nonresponders had similar demographics. In responding to hypothetical clinical scenarios, physicians were less likely to recommend an ICD to older patients (≥80 vs 50 years) (P < 0.01) but were unaffected by gender or race for all class indications. Compared with non-electrophysiologists (EPs), EPs were significantly more likely to recommend an ICD for a Class I indication (92.4% vs 81.4%; P < 0.01), but they were not more likely to offer an ICD for a Class III indication (0.4% vs 0.6%; P = 0.95).

CONCLUSIONS

Based on survey responses, physicians were equally willing to offer an ICD to men and women and to whites and blacks, but were less likely to offer an ICD to an older patient even when indicated by practice guidelines. Electrophysiologists (EPs) more often adhered to practice guideline recommendations on ICD therapy compared with non-EPs.

Addressing disparities in sudden cardiac arrest care and the underutilization of effective therapies

Sudden cardiac arrest (SCA) is the most common cause of death in the Unites States. Despite its major impact on public health, significant challenges exist at the patient, provider, public, and policy levels with respect to raising more widespread awareness and understanding of SCA risks, identifying patients at risk for SCA, addressing barriers to SCA care, and eliminating disparities in SCA care and outcomes. To address many of these challenges, the Duke Center for the Prevention of Sudden Cardiac Death at the Duke Clinical Research Institute (Durham, NC) held a think tank meeting on December 7, 2009, convening experts on this issue from clinical cardiology, cardiac electrophysiology, health policy and economics, the US Food and Drug Administration, the Centers for Medicare and Medicaid Services, the Agency for Health Care Research and Quality, and device and pharmaceutical manufacturers. The specific goals of the meeting were to examine existing educational tools on SCA for patients, health care providers, and the public and explore ways to enhance and disseminate these tools; to propose a framework for improved identification of patients at risk of SCA; and to review the latest data on disparities in SCA care and explore ways to reduce these disparities. This article summarizes the discussions that occurred at the meeting.

Omega-3 Index and sudden cardiac death

Sudden cardiac death (SCD) is an unresolved health issue, and responsible for 15% of all deaths in Western countries. Epidemiologic evidence, as well as evidence from clinical trials, indicates that increasing intake and high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) protect from SCD and other major adverse cardiac events. Levels of EPA+DHA are best assessed by the Omega-3 Index, representing the red cell fatty acid content of EPA+DHA. Work is in progress that will further define the value of the Omega-3 Index as a risk factor for SCD, other cardiac events, and as target for treatment with EPA+DHA.

Implementation of device therapy (cardiac resynchronization therapy and implantable cardioverter defibrillator) for patients with heart failure in Europe: changes from 2004 to 2008

AIMS

Heart failure (HF) patients increasingly receive device therapy, either an implantable cardioverter defibrillator (ICD) or a biventricular pacemaker, also called cardiac resynchronization therapy (CRT), or a CRT device with an ICD (CRT-D). However, epidemiological data on the use of device therapy in Europe are limited.

METHODS AND RESULTS

Data on implantation rates for conventional pacemakers, ICD, CRT, and CRT-D in 15 Western European countries were obtained from the Eucomed Registry for the 5-year period 2004-2008. Implantation of conventional pacemakers increased by 9% in Europe over the 5 years (reaching 907/million in 2008) and there were significant differences between countries. Implantable cardioverter defibrillator implantations increased by 75% from 80/million in 2004 to 140/million in 2008, and differences between countries were larger than those for conventional pacemakers. Implantation rates for CRT-P alone increased slightly from 2004 to 2006, but remained at 25/million thereafter in Europe overall. The total number of CRT implants (CRT-P and -D) markedly increased from 46/million in 2004 to 99/million in 2008 (115%), but this was mainly due to more CRT-D implants, i.e. an increase in the proportion of CRT-D (from 55% in 2004 to 75% in 2008). Implantation rates for ICD, CRT, and CRT-D remained markedly different throughout the study period between countries.

CONCLUSION

Implantation rates of devices for HF, in particular ICD and CRT-D, have increased significantly between 2004 and 2008 in Europe, but there remain major differences between countries.