ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: Executive Summary

Role of the Electrocardiogram for Identifying the Development of Atrial Fibrillation

Atrial fibrillation (AF), a prevalent cardiac arrhythmia, is associated with increased morbidity and mortality worldwide. Stroke, the leading cause of serious disability in the United States, is among the important complications of this arrhythmia. Recent studies have demonstrated that certain clinical variables can be useful in the prediction of AF development in the future. The electrocardiogram (ECG) is a simple and cost-effective technology that is widely available in various healthcare settings. An emerging body of evidence has suggested that ECG tracings preceding the development of AF can be useful in predicting this arrhythmia in the future. Various variables on ECG especially different P wave parameters have been investigated in the prediction of new-onset AF and found to be useful. Several risk models were also introduced using these variables along with the patient's clinical data. However, current guidelines do not provide a clear consensus regarding implementing these prediction models in clinical practice for identifying patients at risk of AF. Also, the role of intensive screening via ECG or implantable devices based on this scoring system is unclear. The purpose of this review is to summarize AF and various related terminologies and explain the pathophysiology and electrocardiographic features of this tachyarrhythmia. We also discuss the predictive electrocardiographic features of AF, review some of the existing risk models and scoring system, and shed light on the role of monitoring device for screening purposes.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Evolving Concepts in Cardiac Physiologic Pacing in the Era of Conduction System Pacing

Cardiac physiologic pacing (CPP) has become a well-established therapy for patients with cardiomyopathy (left ventricular ejection fraction <35%) in the presence of a left bundle branch block. In addition, CPP can be highly beneficial in patients with pacing-induced cardiomyopathy and patients with existing cardiomyopathy expected to have a right ventricular pacing burden of >40%. The benefits of CPP with traditional biventricular pacing are only realized if adequate resynchronization can be achieved. However, left ventricular lead implantation can be limited by individual anatomic variation within the coronary venous system and can be adversely affected by underlying abnormal myocardial substrate (i.e., scar tissue), especially if located within the basal lateral wall. In the last 7 years the investigation of conduction system pacing (CSP) and its potential salutary benefits are being realized and have led to a rapid evolution in the field of cardiac resynchronization pacing. However, supportive evidence for CSP for patients eligible for cardiac resynchronization remains limited compared with data available for biventricular cardiac resynchronization, mostly derived from leading CSP investigative centers. In this review, we perform an up-to-date comprehensive review of the available literature on CPP.

Natural History of Nonsurgical Complete Atrioventricular Block in Children and Predictors of Pacemaker Implantation

BACKGROUND

Data on the natural history of complete atrioventricular block (CAVB) in children are scarce, and criteria for pacemaker (PM) implantation are based on low levels of evidence.

OBJECTIVES

This study aimed to evaluate the natural course and predictors of PM implantation in a nationwide cohort of pediatric patients with nonsurgical CAVB.

METHODS

All children with CAVB in the absence of structural heart disease presenting from 1977 to 2016 were retrospectively identified, yielding 95 subjects with a mean age of 4.05 years at the first presentation with a follow-up median of 0.80 years (IQR: 0.02-6.82 years). PM implantation was performed according to the available guidelines. Serial 24-hour Holter recordings and echocardiograms were reviewed. Predictors of PM implantation performed >1 month after the first presentation were evaluated.

RESULTS

The minimum and mean 24-hour heart rates and maximum RR intervals had a nonlinear correlation with age (P < 0.0001 for all). The left ventricular (LV) size was moderately increased, and the shortening fraction was normal in the majority throughout follow-up. PM implantation was performed in 62 patients (65.3%) reaching guideline criteria. The mean 24-hour heart rate at presentation was a predictor of subsequent PM implantation (HR: 0.938; 95% CI: 0.894-0.983; P = 0.003 per unit increase) regardless of age at presentation. Patients presenting with a mean 24-hour heart rate >58 beats/min (>75th percentile) had a high probability of freedom from PM within the subsequent 5 years (91.7% vs 44.4%; P < 0.001).

CONCLUSIONS

Pediatric patients with CAVB showed an age-dependent decrease in heart rate, moderate LV dilation, and preserved LV function. The probability of subsequent PM implantation could be predicted by the heart rate profile at presentation, defining a low-risk group and allowing for individualized follow-up.

Catheter ablation of ventricular tachycardia associated with structural heart disease: Current status and perspectives

Catheter ablation is an effective and safe treatment for ventricular tachycardia attributable to structural heart disease, reducing the risk of recurrent arrhythmias and defibrillator shock therapy. Advances in medical technology and an accumulation of data have led to the development of detailed guidelines. Successful ablation requires accurate identification of the arrhythmia substrate and effective delivery of radiofrequency energy to the target tissue. Modern practice requires use of traditional electrophysiological mapping processes such as entrainment mapping and three-dimensional activation sequence mapping in combination with newer functional mapping techniques for which there is growing support. Thorough non-invasive preoperative assessment is also necessary before an invasive procedure is undertaken. In this review, we summarize contemporary practice and recent randomized controlled trials underpinning the latest developments in mapping and ablation and discuss potential future developments in this field.

Pulmonary hypertension associated with congenital heart block and neonatal lupus syndrome: A series of four cases

OBJECTIVE

Neonatal lupus syndrome has multisystemic manifestations among which pulmonary involvement has been rarely reported. We describe the clinical presentation, management, and outcome of a series of four neonates who developed reversible pulmonary hypertension associated with auto-immune congenital complete heart block.

METHOD

Data from the French registry of neonatal lupus syndrome were retrospectively reviewed.

RESULTS

Between 2000 and March 2020, 231 children were included in the French registry, four/73 followed in our institution developed pulmonary hypertension. Diagnosis was suspected on transthoracic echocardiography at a median age of 42 days [range 10-58], and confirmed by right heart catheterization in all; 2 of them where paced at time of diagnosis and 2 were not. All had some degree of hypoxemia and respiratory distress. Hypoxemia was always reversible under O² et NO. Lung CT demonstrated ground glass anomalies in all. One patient had a lung biopsy consistent with pulmonary hypertension secondary to lung disease. Management included immunosuppressive therapy in 3 associated with sildenafil in 2. Pulmonary hypertension resolved in all at a median age of 4 weeks [range 3-6] after treatment initiation and after one year for the one child who did not receive specific treatment.

CONCLUSION

Clinical, hemodynamical, imaging and histological findings advocate for pulmonary hypertension associated with respiratory disease as a rare manifestation of neonatal lupus syndrome.

Mobile Health Monitoring of Cardiac Status

Cardiovascular diseases (CVDs) are responsible for more deaths than any other cause, with coronary heart disease and stroke accounting for two-thirds of those deaths. Morbidity and mortality due to CVD are largely preventable, through either primary prevention of disease or secondary prevention of cardiac events. Monitoring cardiac status in healthy and diseased cardiovascular systems has the potential to dramatically reduce cardiac illness and injury. Smart technology in concert with mobile health platforms is creating an environment where timely prevention of and response to cardiac events are becoming a reality.

Novel Device-Based Algorithm Provides Optimal Hemodynamics During Exercise in Patients With Cardiac Resynchronization Therapy

BACKGROUND

An adaptive cardiac resynchronization therapy (aCRT) algorithm has been described for synchronized left ventricular (LV) pacing and continuous optimization of cardiac resynchronization therapy (CRT). However, there are few algorithmic data on the effect of changes during exercise.Methods and Results:We enrolled 27 patients with availability of the aCRT algorithm. Eligible patients were manually programmed to optimal atrioventricular (AV) and interventricular (VV) delays by using echocardiograms at rest or during 2 stages of supine bicycle exercise. We compared the maximum cardiac output between manual echo-optimization and aCRT-on during each phase. After initiating exercise, the optimal AV delay progressively shortened (P<0.05) with incremental exercise levels. The manual-optimized settings and aCRT resulted in similar cardiac performance, as demonstrated by a high concordance correlation coefficient between the LV outflow tract velocity time integral (LVOT-VTI) during each exercise stage (Ex.1: r=0.94 P<0.0008, Ex.2: r=0.88 P<0.001, respectively). Synchronized LV-only pacing in patients with normal AV conduction could provide a higher LVOT-VTI as compared with manual-optimized conventional biventricular pacing at peak exercise (P<0.05).

CONCLUSIONS

The aCRT algorithm was physiologically sound during exercise by patients.

Arrhythmias in Congenital Heart Disease

Cardiac defects are the most common congenital defects, accounting for approximately 9 per 1000 births. Patients with structural heart disease related to congenital diseases are prone to develop intrinsic rhythm abnormalities as a result of altered physiology. In addition, they are at an increased risk of developing acquired arrhythmias secondary to the nature of surgical interventions done to improve physiologic function in the setting of these defects. Arrhythmia management and risk stratification pose particularly complex challenges to clinicians managing this population.

A Population-Based Study of Device Eligibility, Use, and Reasons for Nonimplantation in Patients at Heart Function Clinics

BACKGROUND

Implantable cardioverter defibrillator (ICD) therapy is lifesaving; however, real-world data regarding the proportion of patients eligible for a primary prevention ICD and subsequent use remain sparse. This study evaluated rates of primary prevention ICD eligibility and use among patients in heart function clinics (HFCs) and to identify reasons for nonimplantation.

METHODS

A retrospective study was performed of patients seen at HFCs in Alberta, Canada, from 2013 to 2015. Demographics, comorbidities, clinical indications, and reasons for nonimplantation were abstracted. Eligibility was defined according to the 2008 American College of Cardiology/American Heart Association/Heart Rhythm Society ICD, 2012 American College of Cardiology/American Heart Association/Heart Rhythm Society Focused Update, and 2013 Canadian Cardiovascular Society Cardiac Resynchronization Therapy guidelines. Logistic regression was used to calculate an odds ratio (OR) and 95% confidence interval (CI) for predictors of nonimplantation.

RESULTS

Among 1239 patients in HFCs, the median age was 70 years (interquartile range, 59-80), 67% were male, and the median left ventricular ejection fraction was 0.40 (interquartile range, 0.28-0.53). Overall, 45% of patients (n = 553) met guideline criteria for an ICD, and of those, 36% (n = 198) received a device. Among device nonrecipients, 52% (n = 185) had no documented reason for nonimplantation. The most common reason for nonimplantation among nonrecipients was patient preference (48%). Predictors associated with nonimplantation were age more than 75 years (OR, 1.92; 95% CI, 1.31-2.82) and history of cancer (OR, 2.26; 95% CI, 1.07-4.78). At 3 years follow-up, 27% of nonrecipients were deceased.

CONCLUSIONS

We found that one-third of patients who met guideline criteria received an ICD and that documentation for nonimplantation was poor.

Characteristics and Outcomes in Patients With Electrical Storm

Electrical storm (ES) is a life-threatening condition with diverse clinical presentation, caused by recurrent malignant ventricular arrhythmia--≥3 episodes of ventricular tachycardia (VT) or ventricular fibrillation within 24hours and is associated with high mortality. The aim of this study was analysis of clinical profile, treatment, and prognosis of patients with ES admitted to a high-volume cardiovascular center. We present results of a single-center, retrospective, ongoing observational registry enrolling consecutive patients presenting with ES admitted between 2006 and 2017. Clinical history, results of diagnostic investigations, and treatment were collected for all patients. Follow-up data were collected from hospital documentation, outpatient clinic, remote monitoring systems, and from data gathered from national health services. Registry enrolled 101 consecutive patients admitted with ES. Two-thirds of patients had ischemic cardiomyopathy. Mean left ventricle ejection fraction was 26%. In 56.4% of the patients coronary angiogram was performed and in 20.8% cases percutaneous coronary intervention was needed. 18.8% of the patients underwent VT ablation. 12-month mortality from first ES in our population was 21.8%. NYHA class III and IV, raised N-terminal fragment of prohormone B-type Natriuretic Peptide and creatinine levels, and lower hemoglobin levels were independent predictors of death. In conclusion, most patients admitted with ES have ischemic cardiomyopathy. Over 1/3 of the population had significant narrowing of at least one coronary artery with ES masking ischemia and underwent percutaneous coronary intervention. Nearly 1/5 of the patients were treated with VT ablation. 12-month mortality was high and exceeded 1/4 of patients with ES.

Active periodic electrograms in remote monitoring of pacemaker recipients: the PREMS study

AIMS

Remote monitoring (RM) is considered as a standard of care for pacemaker recipients. Remote monitoring systems provide calendar-based intracardiac electrogram recordings (IEGM) only with the current pacemaker settings (passive IEGM). PREMS (Pacemaker Remote Electrogram Monitoring Study), an observational, multicentre trial, prospectively evaluated the clinical value of an active IEGM (aIEGM), including three 10-s sections (passive IEGM, encouraged sensing, and encouraged pacing), compared to other RM data and to its passive IEGM section. Secondary objectives included the added value of the aIEGM to fully assess the sensing and pacing functions of each lead.

METHODS AND RESULTS

Patients were enrolled within 3 months after pacemaker implantation and followed until the first transmitted aIEGM, which was analysed together with all other RM data. In total, 567 patients were enrolled (79 ± 9 years, 62% men, 19% single-chamber, and 81% dual-chamber pacemakers). Of 547 aIEGMs transmitted in 547 patients, 161 [29.4%; 95% confidence interval (95% CI) 25.6-33.3%] indicated at least one anomaly non-detectable with certainty-or at all-on other RM data, including atrial arrhythmia, extrasystoles, undersensing, oversensing, and loss of capture. In 21.7% of cases the detected events deserved a corrective action. The sensing and pacing function of each lead could be fully assessed in 77.3% of aIEGM (95% CI 72.6-82.0%) vs. 15.5% (95% CI 11.4-19.6%) when considering only the passive IEGM section (P < 0.001).

CONCLUSION

An active IEGM improves the clinical value of remote pacemaker follow-up. Furthermore, compared to a passive IEGM, the aIEGM increases the capability to fully assess remotely the sensing and pacing functions.

A Population-Based Study of Adherence to Guideline Recommendations and Appropriate-Use Criteria for Implantable Cardioverter Defibrillators

Studies evaluating physician adherence to guideline recommendations for implantable cardioverter defibrillator (ICD) therapy are sparse, and none exist for the application of appropriate-use criteria (AUC) in clinical practice. As part of a quality improvement initiative, a review of all ICD procedures was performed from January 1, 2015 to December 31, 2016 in Alberta, Canada, to evaluate the proportion of patients receiving appropriate ICD therapy and to identify reasons for nonadherence. Our device-implant process involves an electrophysiologist or implanting cardiologist evaluation, reminders of ICD eligibility criteria on the device requisition, and peer-review consensus. Implants were classified according to the 2008 American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) ICD guidelines, 2013 Canadian Cardiovascular Society (CCS) Cardiac Resynchronization Therapy (CRT) guidelines, and 2013 AUC. There were 1,300 ICD procedures performed, and the mean age was 63.8 ± 12.9 years; 79% were male; the mean ejection fraction was 0.32 ± 0.13, and 69% were for primary prevention. Among all implants, < 1% were discordant with American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) recommendations. Among CRT implants, 10% were inconsistent with Canadian Cardiovascular Society (CCS) recommendations. According to AUC, 92% of implants were appropriate. Reasons for nonadherence to ACC/AHA/HRS recommendations included QRS width < 120 msec (n = 3), LVEF > 0.35 (n = 2) and recent myocardial infarction (MI) (n = 1). The most common reason for nonadherence to AUC was the absence of criteria for classification (n = 57, 4%). In this population-based study, we found that a process of specialist evaluation, eligibility reminders on device forms, and peer-review consensus may improve adherence to guideline recommendations and AUC for ICD therapy.

Quantifying the utilization of medical devices necessary to detect postmarket safety differences: A case study of implantable cardioverter defibrillators

PURPOSE

To estimate medical device utilization needed to detect safety differences among implantable cardioverter defibrillators (ICDs) generator models and compare these estimates to utilization in practice.

METHODS

We conducted repeated sample size estimates to calculate the medical device utilization needed, systematically varying device-specific safety event rate ratios and significance levels while maintaining 80% power, testing 3 average adverse event rates (3.9, 6.1, and 12.6 events per 100 person-years) estimated from the American College of Cardiology's 2006 to 2010 National Cardiovascular Data Registry of ICDs. We then compared with actual medical device utilization.

RESULTS

At significance level 0.05 and 80% power, 34% or fewer ICD models accrued sufficient utilization in practice to detect safety differences for rate ratios <1.15 and an average event rate of 12.6 events per 100 person-years. For average event rates of 3.9 and 12.6 events per 100 person-years, 30% and 50% of ICD models, respectively, accrued sufficient utilization for a rate ratio of 1.25, whereas 52% and 67% for a rate ratio of 1.50. Because actual ICD utilization was not uniformly distributed across ICD models, the proportion of individuals receiving any ICD that accrued sufficient utilization in practice was 0% to 21%, 32% to 70%, and 67% to 84% for rate ratios of 1.05, 1.15, and 1.25, respectively, for the range of 3 average adverse event rates.

CONCLUSIONS

Small safety differences among ICD generator models are unlikely to be detected through routine surveillance given current ICD utilization in practice, but large safety differences can be detected for most patients at anticipated average adverse event rates.

Development of Heart Failure From Transient Atrial Fibrillation Attacks in Responders to Cardiac Resynchronization Therapy

OBJECTIVES

This study aimed to clarify the clinical impact of transient atrial fibrillation (AF) attacks themselves and the efficacy of cardiac resynchronization therapy (CRT) in patients with intermittent AF.

BACKGROUND

The benefit of CRT in patients with intermittent AF, especially the effect of the AF attacks themselves, remains unclear.

METHODS

Among our cohort of 269 consecutive CRT patients, we compared the percent of biventricular pacing (BIVP%) and other clinical characteristics between patients with intermittent AF and those with sinus rhythm (SR).

RESULTS

During a median follow-up of 942 days (interquartile range: 379 to 1,464 days) a total of 22 patients, including 59% of CRT responders, developed heart failure (HF) due to a transient AF attack itself, and that accounted for 21% of all HF events. The BIVP% during the AF attacks was significantly lower than that during SR (p < 0.05). When compared to the SR groups, patients with intermittent AF had a significantly higher risk of developing HF or death (hazard ratio: 2.2; 95% confidence interval: 1.3 to 3.8). However, the patients who received a BIVP% of ≥90% during AF attacks were comparable to those with SR (hazard ratio: 1.2; 95% confidence interval: 0.4 to 3.0).

CONCLUSIONS

A substantial number of patients developed HF due to transient AF attacks themselves even in the CRT responders, and the reason was mainly due to the loss of the BIVP%.

Coronary vasospasm-induced polymorphic ventricular tachycardia: a case report and literature review

Introduction

Coronary vasospasm is an uncommon but important cause of myocardial ischaemia and ventricular arrhythmias.

Case presentation

In this report, we present a striking example of vasospasm manifesting as ST-segment elevation and ventricular tachycardia on Holter monitoring. Later, spasm occurred during a procainamide challenge performed for suspected Brugada syndrome. The patient underwent implantable cardioverter-defibrillator insertion and was successfully treated with oral calcium channel blocker.

Discussion

We review contemporary data regarding management and outcomes in coronary vasospasm and discuss the use of implantable defibrillator therapy in patients who have sustained a significant arrhythmic event.

Imaging-based predictors of permanent pacemaker implantation after transcatheter aortic valve replacement

BACKGROUND

Cardiac conduction abnormalities requiring permanent pacemaker (PPM) implantation are major complications of transcatheter aortic valve replacement (TAVR). We aimed to investigate whether the relationship between prosthetic valve size and cardiac-gated computed tomography (CT)-based aortic root complex measurements can aid in recognizing patients at risk for PPM implantation post-TAVR.

METHODS

We included 83 of 114 consecutive patients who underwent TAVR with the Edwards Sapien valve (Edwards Lifesciences, Irving, CA, USA) at our institution. We excluded patients with preexisting PPM, patients who required conversion to an open surgical procedure, and patients without CT data. We assessed the significance of various potential predictors of PPM placement post-TAVR.

RESULTS

Following TAVR, eight patients (9.6%) required PPM. Prosthetic valve to sinus of Valsalva (SOV) index was significantly higher in those patients requiring a PPM post-TAVR (84.1 ± 9.3 vs 76.8 ± 7.1, P  =  0.009).

CONCLUSIONS

The prosthetic valve size to diameter of SOV index was identified as a novel predictor of PPM implantation after TAVR.

Assessing physician knowledge regarding indications for a primary prevention implantable defibrillator and potential barriers for referral

BACKGROUND

Although there is clear evidence to demonstrate that primary prevention implantable defibrillators (ICDs) reduce mortality in high-risk patients, ICDs are underutilized. Limited data exist assessing referring physicians' knowledge about guideline indications and attitudes towards ICDs, which may influence decision for referral.

METHODS AND RESULTS

The Arrhythmia Working Group from the Alberta Cardiovascular and Stroke Strategic Clinical Network developed a web-based survey consisting of case scenarios regarding primary prevention ICD indications and a list of barriers for referral to aid in the design of a complex device care pathway. We invited referring physicians to participate in the survey including internists and cardiologists and cardiology residents. The survey was completed by 109 of 799 (response rate = 14%) of physicians. Of those, 55% were internists, 32% cardiologists, and 13% cardiology residents. The majority of physicians were male (62%), practicing in a university hospital (66%). Overall, complete guideline-concordant answers were provided by 34% of physicians. In multivariable analysis, predictors of complete guideline concordance were being a cardiologist (odd ratio [OR] 5.9, confidence interval [CI] 2.1-16.4, P = 0.001) and cardiology resident (OR 6.7, CI 1.7-27.3, P = 0.007). The most common barrier for referral for internists was lack of confidence in knowledge of guideline recommendations; while cardiologists reported concerns about cost-effectiveness and cardiology residents were most concerned with inappropriate shocks.

CONCLUSION

Knowledge regarding indications for primary prevention ICD is limited and varies significantly among referring physicians. The barriers for referral differ among physician groups and addressing these identified barriers may help to improve appropriate ICD utilization.

Venous Hemodialysis Catheters and Cardiac Implantable Electronic Devices: Avoiding a High-Risk Combination

End-stage renal disease is frequently accompanied by cardiac comorbidity that warrants treatment with a cardiovascular implantable electronic device (permanent pacemaker or implantable cardioverter-defibrillator). In the United States, chronic hemodialysis (HD) population, cardiac implantable devices are present in up to 10.5% of patients; a venous HD catheter is utilized for blood access in 18% of prevalent patients. The concomitant presence of a venous HD catheter and cardiovascular implantable device creates a high-risk circumstance, with potential for causing symptomatic central venous stenosis, and for developing complicated endovascular infection. This dangerous combination may be avoided for many patients by utilizing nondialysis methods for management of advanced chronic kidney disease, initiating dialysis without venous catheter access, or managing cardiac rhythm disorders without use of transvenous cardiac implantable electronic devices. In those situations where the combination of a venous HD catheter and cardiac implantable device is unavoidable, there are strategies to minimize duration of venous catheter access, and to reduce risks for infectious complications. It is essential for nephrologists and cardiologists to understand the indications, alternatives, and risks involved with venous HD access and cardiac implantable devices. Coordinated management of renal disease and cardiac rhythm disorders has potential to minimize risks, improve outcomes, and substantially reduce the cost of care.

Hospice in heart failure: why, when, and what then?

Hospice is a model of care for patients nearing the end of their lives that emphasizes symptom management, quality of life (QOL), and support of the patient and caregiving family through the death of the patient and the family's bereavement. It is associated with high patient and caregiver satisfaction and appears to not shorten lifespan for appropriately referred patients. Patients with advanced heart failure are being referred to hospice care more often than in the past, but the majority of deaths occur without this benefit. Hospice care in the USA is defined by the Medicare Hospice Benefit and associated regulations. Hospice is appropriate for patients with an expected survival prognosis of 6 months or less, and multiple predictive factors and tools are available to assist in prognostication. Management of symptoms and specific drug therapy options are discussed. For many patients, deactivation of electronic cardiac devices is appropriate when the goals of care are comfort and QOL. Ongoing collaboration of the referring physician with the hospice agency and staff offers opportunities for seamless and quality care.

Cost-Effectiveness Analysis of Iodine-123 Meta-Iodobenzylguanidine Imaging for Screening Heart Failure Patients Eligible for an Implantable Cardioverter Defibrillator in the USA

BACKGROUND

Many guideline-eligible heart failure (HF) patients do not receive a survival benefit from implantable cardioverter defibrillators (ICDs). Improved risk stratification may help to reduce costs and improve the cost effectiveness of ICDs.

OBJECTIVE

To estimate the potential outcomes, costs, and cost effectiveness of using iodine-123 meta-iodobenzylguanidine (I-mIBG) to screen HF patients eligible for an ICD.

METHODS

A decision-analytic model was developed to compare screening with I-mIBG imaging and no screening over 2-year and 10-year time horizons from a US payer perspective. Data on I-mIBG imaging and risk stratification were obtained from the ADMIRE-HF/HFX (AdreView Myocardial Imaging for Risk Evaluation in Heart Failure) trial. Data on ICD effectiveness for prevention of sudden cardiac death (SCD) were obtained from a meta-analysis. Costs of ICDs and costs of generator and lead procedures were obtained from the Agency for Healthcare Research and Quality National Inpatient Sample. Age-specific mortality was modeled using US life tables and data from the ACT (Advancements in ICD Therapy) Registry on risks of SCD and non-SCD mortality. Sensitivity analyses were conducted.

RESULTS

In the analysis, screening with I-mIBG imaging was associated with a reduction in ICD utilization of 21 %, resulting in a number needed to screen to prevent 1 ICD implantation of 5. Screening reduced the costs per patient by US$5500 and US$13,431 (in 2013 dollars) over 2 and 10 years, respectively, in comparison with no screening and resulted in losses of 0.001 and 0.040 life-years, respectively, over 2 and 10 years. Screening was decrementally cost effective, with savings of US$5,248,404 and US$513,036 per quality-adjusted life-year lost over 2 and 10 years, respectively. In subgroup analyses, cost savings were greater for patients with an ejection fraction (EF) of 25-35 % than for those with an EF <25 %.

CONCLUSIONS

According to the model, screening of guideline-eligible patients selected for ICDs with I-mIBG imaging may be cost effective and may help reduce costs associated with implantation of ICDs, with a minimal impact on survival.

A Rare Case of Renal Infarct due to Noncompaction Cardiomyopathy: A Case Report and Literature Review

Left ventricular noncompaction cardiomyopathy is a rare myocardial disorder which results from failure of left ventricle to compact in embryogenesis. We present a case of a 53-year-old female who came because of abdominal pain and was found to have renal infarct secondary to noncompaction cardiomyopathy.

Left ventricular sphericity independently predicts appropriate implantable cardioverter-defibrillator therapy

BACKGROUND

Whether echocardiographic markers of remodeling are associated with ventricular tachyarrhythmias is unknown.

OBJECTIVE

The purpose of this study was to determine whether a transthoracic echocardiographic (TTE) marker of spherical left ventricular (LV) remodeling is associated with appropriate implantable cardioverter-defibrillator (ICD) therapy in patients with primary prevention ICDs.

METHODS

From TTE images, we calculated sphericity index (SI), the ratio of biplane LV end-diastolic volume to the volume of a hypothetical sphere with a diameter of the LV end-diastolic length, and examined the relation between SI and therapy for ventricular tachyarrhythmias in 278 patients with primary prevention ICDs and in 50 controls without structural heart disease or ventricular arrhythmias.

RESULTS

SI in normal healthy adult subjects and in subjects receiving ICDs was 0.44 ± 0.02 and 0.65 ± 0.04, respectively (P <.001). Median time to first appropriate ICD therapy was significantly shorter in ICD patients with SI in the upper vs lower 50% of SI values (1.40 vs 2.38 years, P = .02 for conventional ICD patients; 1.54 vs 2.65 years, P = .02 for cardiac resynchronization therapy-defibrillator [CRT-D] patients). In multivariable Cox regression analysis, SI in the upper 50% was independently associated with appropriate ICD therapy after multivariable adjustment (hazard ratio 2.2, P = .03 for ICD cohort; hazard ratio 4.4, P = .01 for CRT-D cohort). SI was not associated with total mortality in either cohort.

CONCLUSION

SI is associated with appropriate ICD therapy, but not total mortality, in patients receiving primary prevention ICDs. These observations suggest spherical LV remodeling may predispose to ventricular arrhythmias. Furthermore, SI appears to add predictive accuracy for appropriate ICD therapy in patients with reduced ejection fraction.

Management of Arrhythmias in Cardiac Sarcoidosis

The prevalence of cardiac involvement in sarcoidosis is under-recognized and is associated with multiple complications, including conduction block, arrhythmias, and sudden death. The comparative roles of common therapies have been inadequately studied. The purpose of this review is to examine the literature regarding treatments utilized to manage arrhythmias associated with cardiac sarcoidosis.

[ICD therapy in the primary prevention of sudden cardiac death: Risk stratification and patient selection]

Without the concept of primary prevention of sudden cardiac death, therapy with implantable defibrillators would not have reached the current distribution and clinical importance. Most of the scientific evidence of the concept is based on clinical studies from 1996-2005. More than 75 % of all defibrillator implantations are currently indicated as primary prevention. Implantable converter-defibrillator (ICD) therapy in the primary prevention of sudden cardiac death was incorporated into scientific guidelines starting in 1998. The historical development of the indications for ICD therapy in the primary prevention of sudden cardiac death is presented, reflecting major results of controlled, randomized clinical studies and guideline discussions.

Sudden cardiac death in CKD patients

The risk of sudden cardiac death (SCD) is high in chronic kidney disease patients, and it increases with the progression of kidney function deterioration. The most common causes of SDC are the following: ventricular tachycardia, ventricular tachyarrhythmia, tachycardia torsade de pointes, sustained ventricular fibrillation and bradyarrhythmia. Dialysis influences cardiovascular system and results in hemodynamic disturbances as well as electrolyte shifts altering myocardial electrophysiology. Studies suggest that this procedure exerts both detrimental (poor volume control can exacerbate hypertension and left ventricle hypertrophy) and beneficial effects (associated with fluid removal and subsequent decrease in left ventricle stretch). Dialysis-related vulnerability to serious arrhythmias is the result of sudden shifts in fluid status and electrolytes, particularly potassium, which alter the physiological milieu. Also Ca(2+) ions, in which concentration alters during dialysis, are of key importance in the contraction of vascular smooth muscle cells and cardiac myocytes, thus exerting significant effects on hemodynamics. Due to the fact that SCD occurs with similar frequency in peritoneal dialysis and in hemodialysis patients, it seems that end-stage renal disease factors are more important than the specific ones associated with dialysis type. The results of randomized trials suggested that hemodialysis patients may not derive the same benefit of cardiovascular disease therapy including beta-blockers, calcium channel blockers and angiotensin-converting enzyme inhibitors as the general population with normal kidney function. Noninvasive tests used to stratify SCD risk in HD patients have poor positive value, and thus, combining tests including HRV, baroreceptor sensitivity and effectiveness index as well as its function indices and heart rate turbulence should be implemented. There are only few large randomized placebo-controlled trials assessing the influence of cardioprotective medications or implantable cardioverter defibrillator (ICD) implantation in dialysis patients on life quality and survival, and their results are sometimes contradictory. The decision concerning treatment and/or ICD implantation in this group of patients should be made on the basis of careful assessment of individual risk factors. Moreover, due to the high hazard of cardiovascular mortality including SCD in dialysis patients, physicians should concentrate on the early selection of high-risk patients, monitoring them and introduction of preventive measures.

Patients' perception of implantable cardioverter defibrillator deactivation at the end of life

BACKGROUND

Individualised care at the end of life requires professional understanding of the patient's perception of implantable cardioverter defibrillator deactivation.

AIM

The aim was to evaluate the evidence on patients' perception of implantable cardioverter defibrillator deactivation at end of life.

DESIGN

Systematic narrative review of empirical studies was published during 2008-2014.

DATA SOURCES

Data were collected from six databases, citations from relevant articles and expert recommendations.

RESULTS

In all, 18 studies included with collective population of n = 5810. Concept mapping highlighted three themes: (1) Diverse preferences regarding discussion and deactivation. Deactivation was rarely discussed pre-implantation, with some studies demonstrating patients' reluctance to discuss implantable cardioverter defibrillator deactivation at any stage. Two studies found the majority of patients valued such discussions. Diversity was reflected in patients' willingness to deactivate, ranging from 12% (n = 9) in Irish cohort to 79% (n = 195) in Dutch study. (2) Ethical and legal considerations were predominant in Canadian and American literature as patients wanted to contribute but felt the decision should be a doctor's responsibility. Advance directives were uncommon in Europe, and where they existed the implantable cardioverter defibrillator was not mentioned. (3) 'Living in the now' was evident as despite deteriorating symptoms many patients maintained a positive outlook and anticipated surviving more than 10 years. Several studies asserted living longer was more important than quality of life.

CONCLUSION

Patients regard the implantable cardioverter defibrillator as a complex and solely beneficial device, with little insight regarding its potential impact on a peaceful death. This review confirms the need for professionals to discuss with patients and families implantable cardioverter defibrillator functionality and deactivation at appropriate opportunities.

Adverse structural remodeling of the left ventricle and ventricular arrhythmias in patients with depressed ejection fraction

BACKGROUND

The relationship of life-threatening ventricular arrhythmias to specific patterns of adverse LV remodeling has not been reported. We examined the relationship of ventricular tachycardia and/or fibrillation (VT/VF) to the pattern of left ventricular (LV) structural remodeling and to the degree of LV dysfunction in patients with a low ejection fraction (EF).

METHODS AND RESULTS

Data from 127 patients with a low EF (≤0.45) and an implantable cardioverter-defibrillator (ICD) were examined and VT/VF identified by means of ICD device interrogation. Echocardiographic data were used to define LV structural remodeling (eccentric hypertrophy, concentric remodeling/hypertrophy, and normal geometry). VT/VF occurred in 26% of the 127 patients. VT/VF was more common in the 60 patients with LV hypertrophy versus the 67 with normal LV mass (40% vs 13%; P = .001) and in the 61 patients with LV enlargement versus the 66 with a normal chamber size (34% vs 18%; P = .04). When LV chamber size, wall mass, and geometry were assessed in a combinatorial fashion, a Kaplan-Meier analysis indicated that the occurrence of VT/VF was highest in the patients with eccentric hypertrophy (43%), intermediate in those with concentric remodeling/hypertrophy (30%), and lowest (12%) in those with normal geometry (all P < .02). The EFs were similar (P = ns) in these 3 groups of distinctly different patterns of remodeling.

CONCLUSIONS

Life-threatening ventricular arrhythmias in patients with a low EF are related to the pattern of LV remodeling, not the degree of LV dysfunction. Risk stratification of such patients might be improved by a consideration of the pattern of LV remodeling.

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

BACKGROUND

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

OBJECTIVE

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

METHODOLOGY

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

RESULTS

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

CONCLUSION

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