Implantable cardioverter defibrillators and cardiac resynchronization therapy in patients with left ventricular dysfunction: randomized trial evidence through 2004

Long-term follow-up of normal and structural heart ventricular tachycardia catheter ablation: real-world experience from a UK tertiary centre

Background

Ventricular tachycardia (VT) is associated with increased morbidity and mortality. There is growing evidence for the effectiveness of catheter ablation in improving outcomes in patients with recurrent VT. Consequently the threshold for referral for VT ablation has fallen over recent years, resulting in increased number of procedures.

Objective

To evaluate the effectiveness and safety of VT ablation in a real-world tertiary centre setting.

Methods

This is a prospective analysis of all VT ablation cases performed at University Hospital Coventry. Follow-up data were obtained from review of electronic medical records and patient interview. The primary endpoint for normal heart VT was death, cardiovascular hospitalisation and VT recurrence, and for structural heart VT was arrhythmic death, VT storm (>3 episodes within 24 hours) or appropriate shock.

Results

Forty-seven patients underwent 53 procedures from January 2012 to January 2018. The mean age ±SD was 57±15 years, 68% were male, 81% were Caucasian and 66% were elective cases. The aetiology of VT included normal heart (49%), ischaemic cardiomyopathy (ICM, 36%), dilated cardiomyopathy (9%), hypertrophic cardiomyopathy (4%) and valvular heart disease (2%). Procedural success occurred in 83%, with six major complications. After a median follow-up of 231 days (lower quartile 133, upper quartile 631), the primary outcome occurred in 28% of patients. There were two non-arrhythmic deaths (4%). At a median follow-up of 193 days (129–468), the primary outcome occurred in 19% of patients with ICM, while VT storm/appropriate shocks occurred in three patients (17%).

Conclusions

Our real-world registry confirms that VT ablation is safe, and is associated with high acute procedural success and long-term outcomes comparable with randomised controlled studies.

New York Heart Association class and the survival benefit from primary prevention implantable cardioverter defibrillators: A pooled analysis of 4 randomized controlled trials

BACKGROUND

Primary prevention implantable cardioverter defibrillator (ICD) reduce all-cause mortality by reducing sudden cardiac death. There are conflicting data regarding whether patients with more advanced heart failure derive ICD benefit owing to the competing risk of nonsudden death.

METHODS

We performed a patient-level meta-analysis of New York Heart Association (NYHA) class II/III heart failure patients (left ventricular ejection fraction ≤35%) from 4 primary prevention ICD trials (MADIT-I, MADIT-II, DEFINITE, SCD-HeFT). Bayesian-Weibull survival regression models were used to assess the impact of NYHA class on the relationship between ICD use and mortality.

RESULTS

Of the 2,763 patients who met study criteria, 68% (n=1,867) were NYHA II and 52% (n=1,435) were randomized to an ICD. In a multivariable model including all study patients, the ICD reduced mortality (hazard ratio [HR] 0.65, 95% posterior credibility interval [PCI]) 0.40-0.99). The interaction between NYHA class and the ICD on mortality was significant (posterior probability of no interaction=.036). In models including an interaction term for the NYHA class and ICD, the ICD reduced mortality among NYHA class II patients (HR 0.55, PCI 0.35-0.85), and the point estimate suggested reduced mortality in NYHA class III patients (HR 0.76, PCI 0.48-1.24), although this was not statistically significant.

CONCLUSIONS

Primary prevention ICDs reduce mortality in NYHA class II patients and trend toward reducing mortality in the heterogeneous group of NYHA class III patients. Improved risk stratification tools are required to guide patient selection and shared decision making among NYHA class III primary prevention ICD candidates.

Regulation of medicines and medical devices: contrasts and similarities

In recent times, there has been an unprecedented level of public interest and active debate regarding the regulation of medical devices. This is in light of the topical, rather dissimilar, incidents involving poly-implant-prothèse (PIP) breast and metal-on-metal hip implants. Although medicines and devices are regulated under European Union (EU) law, the regulatory regimes are very different and some have argued that features of the pharmaceutical regime should be applied to medical devices in the current review of the medical devices directives. Both medicines and certain devices need to have an assessment of their risks and benefits before being used in patients, and undergo subsequent monitoring for adverse events. However, there are significant differences between these two groups in terms of the number of products, the pattern of innovation and development, and the types of adverse events that arise from their use. This review will summarise the key issues through a comparison of how both are regulated and monitored.

Cost-effectiveness of implantable cardioverter-defibrillator in today's world

The implantable cardioverter-defibrillator (ICD) is an example of an effective intervention with high up-front costs and delayed benefits. It has become a proven and well-accepted therapy not only for secondary but also for primary prevention of sudden cardiac death in patients with ischemic and non-ischemic heart disease. In recent years, the international guidelines have extended the indications to the prophylactic ICD, increasing the number of eligible patients and, together, the financial challenges of a widespread implementation. In this article, we review the available economic tools that can help address the ICD cost issue. We think that the awareness of such knowledge may facilitate dialogues between physicians, administrators and policy-makers, and help foster rational decision making.

Risk stratification for sudden cardiac death: current approaches and predictive value

Sudden cardiac death (SCD) is a serious public health problem; the annual incidence of out-of-hospital cardiac arrest in North America is approximately 166,200. Identifying patients at risk is a difficult proposition. At the present time, left ventricular ejection fraction (LVEF) remains the single most important marker for risk stratification. According to current guidelines, most patients with LVEF <35% could benefit from prophylactic ICD implantation, particularly in the setting of symptomatic heart failure. Current risk stratification strategies fail to identify patients at risk of SCD in larger population groups encompassing a greater number of potential SCD victims. However, the best approach to identifying patients and the value of various risk stratification tools is not entirely clear. The goal of this review is to discuss the problem of SCD and the value of the different risk stratification markers and their potential clinical use either alone or in combination with other risk stratification markers.

Effectiveness of prophylactic implantation of cardioverter-defibrillators without cardiac resynchronization therapy in patients with ischaemic or non-ischaemic heart disease: a systematic review and meta-analysis

Aims

Much controversy exists concerning the efficacy of primary prophylactic implantable cardioverter-defibrillators (ICDs) in patients with low ejection fraction due to coronary artery disease (CAD) or dilated cardiomyopathy (DCM). This is also related to the bias created by function improving interventions added to ICD therapy, e.g. resynchronization therapy. The aim was to investigate the efficacy of ICD-only therapy in primary prevention in patients with CAD or DCM.

Methods and results

Public domain databases, MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials, were searched from 1980 to 2009 for randomized clinical trials of ICD vs. conventional therapy. Two investigators independently abstracted the data. Pooled estimates were calculated using both fixed-effects and random-effects models. Eight trials were included in the final analysis (5343 patients). Implantable cardioverter-defibrillators significantly reduced the arrhythmic mortality [relative risk (RR): 0.40; 95% confidence interval (CI): 0.27–0.67] and all-cause mortality (RR: 0.73; 95% CI: 0.64–0.82). Regardless of aetiology of heart disease, ICD benefit was similar for CAD (RR: 0.67; 95% CI: 0.51–0.88) vs. DCM (RR: 0.74; 95% CI: 0.59–0.93).

Conclusions

The results of this meta-analysis provide strong evidence for the beneficial effect of ICD-only therapy on the survival of patients with ischaemic or non-ischaemic heart disease, with a left ventricular ejection fraction ≤35%, if they are 40 days from myocardial infarction and ≥3 months from a coronary revascularization procedure.

Cost-effectiveness of implantable cardioverter-defibrillators in Brazil: primary prevention analysis in the public sector

BACKGROUND

Several studies have demonstrated the effectiveness and cost-effectiveness of implantable cardioverter-defibrillators (ICDs) in chronic heart failure (CHF) patients. Despite its widespread use in developing countries, limited data exist on its cost-effectiveness in these settings.

OBJECTIVE

To evaluate the cost-effectiveness of ICD in CHF patients under the perspective of the Brazilian Public Healthcare System (PHS).

METHODS

We developed a Markov model to evaluate the incremental cost-effectiveness ratio (ICER) of ICD compared with conventional therapy in patients with CHF and New York Heart Association class II and III. Effectiveness was evaluated in quality-adjusted life years (QALYs) and time horizon was 20 years. We searched MEDLINE for clinical trials and cohort studies to estimate data from effectiveness, complications, mortality, and utilities. Costs from the PHS were retrieved from national administrative databases. The model's robustness was assessed through Monte Carlo simulation and one-way sensitivity analysis. Costs were expressed as international dollars, applying the purchasing power parity conversion rate (PPP US$).

RESULTS

ICD therapy was more costly and more effective, with incremental cost-effectiveness estimates of PPP US$ 50,345/QALY. Results were more sensitive to costs related to the device, generator replacement frequency and ICD effectiveness. In a simulation resembling the MADIT-I population survival and ICD benefit, the ICER was PPP US$ 17,494/QALY and PPP US$ 15,394/life years.

CONCLUSIONS

In a Brazilian scenario, where ICD cost is proportionally more elevated than in developed countries, ICD therapy was associated with a high cost-effectiveness ratio. The results were more favorable for a patient subgroup at increased risk of sudden death.

Rationale and design for the Defibrillators to Reduce Risk by Magnetic Resonance Imaging Evaluation (DETERMINE) trial

BACKGROUND

Cardiac magnetic resonance imaging (CMR) can accurately determine infarct size. Prior studies using indirect methods and CMR to assess infarct size have shown that patients with larger myocardial infarctions have worse prognoses. Implantable cardioverter defibrillators (ICD) have been shown to improve survival among patients with severe left ventricular (LV) dysfunction. However, the majority of cardiac arrests occur in patients with higher ejection fractions.

METHODS

The Defibrillators To Reduce Risk By Magnetic Resonance Imaging Evaluation study (DETERMINE) is a prospective, multicenter, randomized, clinical trial in patients with coronary artery disease (CAD) and mild-to-moderate LV dysfunction. The purpose of this trial is to test the hypothesis that patients with an infarct size > or = 10% of LV mass, randomized to ICD plus appropriate medical therapy will have improved survival compared with patients randomized to medical therapy alone. Cine and myocardial delayed contrast CMR will be performed in patients with CAD. The primary endpoint will be death from any cause. At least 10,000 patients with CAD will undergo CMR. The target enrollment is 1,550 patients with an estimated 36-month enrollment period. The patients will be followed up for 24 months after the last patient randomization. During the follow-up period, 330 deaths are estimated to occur. This study is powered to detect a 28% reduction in mortality by ICD therapy.

CONCLUSION

The DETERMINE trial will assess the efficacy of ICD therapy to improve survival among patients with CAD, mild-to-moderate LV dysfunction, and infarct size > or = 10% of LV mass as measured by CMR.

Are there long-term benefits in following stable heart failure patients in a heart failure clinic?

OBJECTIVES AND DESIGN

This study describes the long-term outcome of 163 patients with stable mild to moderate heart failure (NYHA II-III), who already were enrolled in a heart failure clinic and now were randomized to continued follow-up in the heart failure (HF) clinic or else to usual care (UC). The primary outcome was unplanned hospitalisations and death, the secondary endpoints were pharmacological therapy, NYHA class, six-minute-walking distances and NT-pro BNP level.

RESULTS

At the end of follow-up we found no significant differences in total number of hospitalisation (p = 0.2) or mortality (16% vs. 16%) between the two groups. Patients in the HF clinic cohort achieved a significantly better NYHA score (p < 0.01), significantly longer walking-distances (p = 0.04) and received a significantly higher dose of angiotensin-converting enzyme inhibitors (p < 0.001) and beta-blockers (p < 0.001). No significant difference was found on the level of NT-pro BNP (p = 0.4).

CONCLUSIONS

Patients with mild to moderate HF may benefit from long-term follow-up in a HF clinic in terms of pharmacological therapy and functional status, but we found no significant impact on unplanned hospitalisations or death.

Expenditure and value for money: the challenge of implantable cardioverter defibrillators

Many technology-driven interventions entail considerable financial cost, raising affordability issues. The implantable cardioverter defibrillator (ICD) is a case of an effective primary prevention intervention with high initial costs that is capable of delivering long-term population benefits. At first glance, such interventions may provoke diffidence, if not active resistance, due to the financial burdens which inevitably accompany their widespread adoption. In this article, we review the available economic tools that can help address the ICD cost issue. We think awareness of such knowledge may facilitate dialogues between physicians, administrators and policymakers, and help foster rational decision-making.

Choosing pacemakers appropriately

The range of implantable cardiac pacing devices has expanded, with the advances in available technology. Indications for cardiac pacing devices, that is pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy devices (CRTs), have expanded for the treatment, diagnosis and monitoring of bradycardia, tachycardia and heart failure. While the need for pacemakers is increasing, not all patients who require pacemakers are receiving them, especially in the Asia-Pacific region. There is a need to be more critical in advising the use of more expensive devices like ICDs and CRT/CRT-D devices, since most patients in the Asia-Pacific region pay out of pocket for these therapies. The AHA-ACC guidelines need not be blindly followed, since they are too wide-sweeping and are often based on the intention-to-treat basis of trials rather than on the parameters of the patients actually enrolled.

Unresolved issues in implantable cardioverter-defibrillator therapy

Over the last 15 years, a series of well-designed randomized clinical trials has clearly demonstrated that implantable cardioverter-defibrillator (ICD) therapy reduces mortality in select high-risk populations. Despite the widespread acceptance of ICD therapy, many questions related to its optimal use remain. This article discusses several key issues now confronting clinicians.

Inflammatory biomarkers are not predictive of intermediate-term risk of ventricular tachyarrhythmias in stable CHF patients

BACKGROUND

Elevated levels of inflammatory biomarkers and brain natriuretic peptide (BNP) are associated with increased mortality in patients with heart failure (HF).

HYPOTHESIS

: The aim of the current study was to assess the correlation between circulating biomarkers and ventricular tachyarrhythmias among patients with HF.

METHODS

Blood samples from 50 stable ambulatory HF patients with moderate to severe systolic left ventricular (LV) dysfunction and an implantable cardioverter defibrillator (ICD) were analyzed for interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), high-sensitivity C-reactive protein (hsCRP) and BNP. Thereafter, the patients were followed for a mean period of 152 +/- 44 days, during which ventricular tachyarrhythmias were recorded by the ICDs.

RESULTS

Follow-up data were obtained from 47 patients. Of them, 45 (96%) had ischemic cardiomyopathy, 38 (81%) had New York Heart Association class I-II, 43 (91%) were males, and the mean age was 68.6 +/- 11.1 years. During follow-up, 5 patients (11%) had nonsustained ventricular tachycardia (NSVT), 6 patients (13%) had sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and 36 patients (76%) had no events. The circulating biomarkers' levels upon enrollment were not significantly different between patients who subsequently had NSVT or VT/VF and patients who were free of events.

CONCLUSIONS

No correlation was found between plasma levels of IL-6, TNF-alpha, hsCRP and BNP and ventricular arrhythmic events among stable HF patients during an intermediate term follow-up of 5.1 months. Further studies are still required to assess the association between these biomarkers and long-term risk of ventricular tachyarrhythmia.

Resource allocation among cardiovascular specialists and trainees: a pilot survey

OBJECTIVE

To assess the relative importance that cardiovascular specialists assign to new technologies.

METHODS

A pilot survey of practising cardiologists in one tertiary hospital and cardiology trainees from two university programs. Respondents were asked to distribute a hypothetical budget among several new technologies.

RESULTS

A total of 28 responses (response rate of 62%) were analyzed. In the hypothetical situation described, doctors appeared willing to spend approximately equal amounts on implantable cardiac defibrillators (median 25%, interquartile range 5% to 30%) and bare metal coronary stents (median 28%, interquartile range 20% to 40%). Physicians were more restrained in their allocation for refinements of these two technologies, including drug-eluting stents and biventricular pacing. Wide individual variations in technology use were noted.

CONCLUSIONS

There is considerable uncertainty among cardiovascular specialists regarding the relative value of new technologies. Further work is required to better quantify this uncertainty and its determinants.

I-123-mIBG myocardial imaging for assessment of risk for a major cardiac event in heart failure patients: insights from a retrospective European multicenter study

PURPOSE

Single-center experiences have shown that myocardial meta-iodobenzylguanidine (mIBG) uptake has prognostic value in heart failure (HF) patients. To verify these observations using a rigorous clinical trial methodology, a retrospective review and prospective quantitative reanalysis was performed on a series of cardiac (123)I-mIBG scans acquired during a 10-year period at six centers in Europe.

METHODS

(123)I-mIBG scans obtained on 290 HF patients [(262 with left ventricular ejection fraction (LVEF) < 50%)] from 1993 to 2002 were reanalyzed using a standardized methodology to determine the heart-to-mediastinum ratio (H/M) on delayed planar images. All image results were verified by three independent reviewers. Major cardiac events [MCEs; cardiac death, cardiac transplant, potentially fatal arrhythmia (including implantable cardioverter-defibrillator discharge)] during 24-month follow-up were confirmed by an adjudication committee.

RESULTS

MCEs occurred in 67 patients (26%): mean H/M ratio was 1.51 +/- 0.30 for the MCE group and 1.97 +/- 0.54 for the non-MCE group (p < 0.001). Two-year event-free survival using an optimum H/M ratio threshold of 1.75 was 62% for H/M ratio less than 1.75, 95% for H/M ratio greater than or equal to 1.75 (p < 0.0001). Logistic regression showed H/M ratio and LVEF as the only significant predictors of MCE. Using the lower and upper H/M quartiles of 1.45 and 2.17 as high- and very low-risk thresholds, 2-year event-free survival rates were 52% and 98%, respectively. Among patients with LVEF < or = 35% and H/M > or = 1.75 (n = 73), there were nine MCEs because of progressive HF and only one because of an arrhythmia.

CONCLUSION

Application of a clinical trial methodology via the retrospective reanalysis of (123)I-mIBG images confirms the previously reported prognostic value of this method in HF patients, including potential identification of a quantitative threshold for low risk for cardiac mortality and potentially fatal ventricular arrhythmias.

Preventing tomorrow's sudden cardiac death today: part II: Translating sudden cardiac death risk assessment strategies into practice and policy

Although current evidence supporting a more precise strategy for identifying patients at highest risk for sudden cardiac death (SCD) is sparse, strategies for translating existing and future evidence into clinical practice and policy are needed today. A great many unanswered questions exist. Examples include the following: At what level of risk for SCD should we pursue further testing or therapy? How should clinical strategies ethically and economically balance alternative outcomes? How can we best translate optimal strategies into clinical practice so as to prevent tomorrow's SCDs? On July 20 and 21, 2006, a group of individuals with expertise in clinical cardiovascular medicine, biostatistics, economics, and health policy was joined by government (Food and Drug Administration; Centers for Medicare and Medicaid Services; National Heart, Lung, and Blood Institute; Agency for Healthcare Research and Quality), professional societies (Heart Rhythm Society), and industry to discuss strategies for risk assessment and prevention of SCD. The meeting was organized by the Duke Center for the Prevention of Sudden Cardiac Death and the Duke Clinical Research Institute. This article, the second of 2 documents, summarizes the policy discussions of that meeting, discusses an analytic framework for evaluating the risks and benefits associated with SCD prevention and risk stratification, and addresses the translation of SCD risk assessment strategies into practice and policy.

Preventing tomorrow's sudden cardiac death today: part I: Current data on risk stratification for sudden cardiac death

Accurate and timely prediction of sudden cardiac death (SCD) is a necessary prerequisite for effective prevention and therapy. Although the largest number of SCD events occurs in patients without overt heart disease, there are currently no tests that are of proven predictive value in this population. Efforts in risk stratification for SCD have focused primarily on predicting SCD in patients with known structural heart disease. Despite the ubiquity of tests that have been purported to predict SCD vulnerability in such patients, there is little consensus on which test, in addition to the left ventricular ejection fraction, should be used to determine which patients will benefit from an implantable cardioverter defibrillator. On July 20 and 21, 2006, a group of experts representing clinical cardiology, cardiac electrophysiology, biostatistics, economics, and health policy were joined by representatives of the US Food and Drug administration, Centers for Medicare Services, Agency for Health Research and Quality, the Heart Rhythm Society, and the device and pharmaceutical industry for a round table meeting to review current data on strategies of risk stratification for SCD, to explore methods to translate these strategies into practice and policy, and to identify areas that need to be addressed by future research studies. The meeting was organized by the Duke Center for the Prevention of SCD at the Duke Clinical Research Institute and was funded by industry participants. This article summarizes the presentations and discussions that occurred at that meeting.

Primary Prevention of Sudden Cardiac Death: Can We Afford the Cost of Cardioverter-Defibrillators? Data from the Search-MI Registry-Italian Sub-study

BACKGROUND

Large randomized trials show that in appropriately selected patients with left ventricular dysfunction, implantable cardioverter-defibrillators (ICDs) can improve overall survival at 2-5 years. Since direct implementation of the criteria used in the MADIT II and SCD-HeFT will lead to a marked rise in ICD implants, there is a growing fear that increased use of ICDs may cause a dramatic burden to health care systems. The ICD has traditionally been seen as an expensive form of treatment, which is difficult to accept at the first look. This is mainly due to the nonlinear character of the ICD investment, characterized by high initial expenditure, followed by a deferred pay-off in terms of clinical benefits. Cost-effectiveness analysis may help provide a different perspective on the problem of ICD cost, as may estimation of the daily cost of ICD treatment, assuming a time horizon of 5-7 years--a particularly interesting subject for further registry studies.

METHODS AND RESULTS

Based on real expenditure data from 2002 to 2005, as recorded in the Search-MI Registry-Italian Sub-study of patients implanted on MADIT II indications, we estimated the daily costs associated with the device and leads. Over a 5-7 year time horizon, the average daily cost was estimated to be euro 4.60-euro 6.70. Translation of these figures into U.S. market conditions suggests a daily cost of around $7.90-$11.40.

CONCLUSIONS

These findings appear useful to help evaluate the affordability of ICD in comparison with other therapeutic options in a context of limited available economic resources.

Extending the horizon in chronic heart failure: effects of multidisciplinary, home-based intervention relative to usual care

BACKGROUND

The long-term impact of chronic heart failure management programs over the typical life span of affected individuals is unknown.

METHODS AND RESULTS

The effects of a nurse-led, multidisciplinary, home-based intervention (HBI) in a typically elderly cohort of patients with chronic heart failure initially randomized to either HBI (n=149) or usual postdischarge care (UC) (n=148) after a short-term hospitalization were studied for up to 10 years of follow-up (minimum 7.5 years of follow-up). Study end points were all-cause mortality, event-free survival (event was defined as death or unplanned hospitalization), recurrent hospital stay, and cost per life-year gained. Median survival in the HBI cohort was almost twice that of UC (40 versus 22 months; P<0.001), with fewer deaths overall (HBI, 77% versus 89%; adjusted relative risk, 0.74; 95% CI, 0.53 to 0.80; P<0.001). HBI was associated with prolonged event-free survival (median, 7 versus 4 months; P<0.01). HBI patients had more unplanned readmissions (560 versus 550) but took 7 years to overtake UC; the rates of readmission (2.04+/-3.23 versus 3.66+/-7.62 admissions; P<0.05) and related hospital stay (14.8+/-23.0 versus 28.4+/-53.4 days per patient per year; P<0.05) were significantly lower in the HBI group. HBI was associated with 120 more life-years per 100 patients treated compared with UC (405 versus 285 years) at a cost of 1729 dollars per additional life-year gained when we accounted for healthcare costs including the HBI.

CONCLUSIONS

In altering the natural history of chronic heart failure relative to UC (via prolonged survival and reduced frequency of recurrent hospitalization), HBI is a remarkably cost- and time-effective strategy over the longer term.

Prevalence of arrhythmias and their risk factors mid- and long-term after the arterial switch operation

Early results of the arterial switch operation (ASO) for transposition of the great arteries (TGA) are good, but there are few mid- and long-term data on postoperative arrhythmias, especially in Japan. In this study, clinical data on 624 1-year survivors who had an ASO between 1976 and 1995 were collected from six institutes in Japan up to October 2002. Sixty (9.6%) 1-year survivors had significant arrhythmias. Bradycardia occurred in 22 patients, including complete atrioventricular block (CAVB) in 12, sick sinus syndrome (SSS) in 6, and second-degree atrioventricular block in 4. Syncope developed in 2 with CAVB and 2 with SSS. Ten patients with bradycardia underwent permanent pacemaker implantation. Supraveutricular tachycardia (SVT) was seen in 25 patients, including paroxysmal supraventricular tachycardia in 16, atrial flutter in 7, and atrial fibrillation in 2. Six patients with SVT received antiarrhythmic medication. SVT was transient in 20 and persistent in 5. Ventricular arrhythmias occurred in 13 patients, including nonsustained ventricular tachycardia in 5, paroxysmal ventricular contractions with couplets in 5, ventricular flutter in 2, and sustained ventricular tachycardia in 1. Four patients with ventricular arrhythmias received antiarrhythmic medication. Of the study patients, 8 died 1 year or more after ASO. Death was directly related to arrhythmia in 1 patient and was due to nonsustained ventricular tachycardia with severe congestive heart failure. The presence of a ventricular septal defect (VSD) was a risk factor for postoperative arrhythmia. Patients with TGA and VSD had more arrhythmias than those with TGA and an intact ventricular septum (13.7 vs 8.7%, p < 0.05), and this was especially true for CAVB (3.9% vs 1.0%, p < 0.05). In 36 patients clearly documented time onset of postoperative arrhythmia arrhythmia developed in 18 (50%) after less than 1 year and in 15 (42%) after more than 5 years. In summary serious arrhythmias after ASO were uncommon, but postoperative arrhythmias, such as unpaced CAVB, SSS, and VT, were related to morbidity and mortality. VSD was a risk factor for postoperative arrhythmia, especially CAVB. Approximately half of the arrhythmias developed late. Lifelong monitoring with respect to arrhythmia is needed for patients after ASO.

Universal access -- but when? Treating the right patient at the right time: access to electrophysiology services in Canada

The Canadian Cardiovascular Society Access to Care Working Group has published a series of commentaries on access to cardiovascular care in Canada. The present article reviews the evidence for timely access to electrophysiology services. Using the best available evidence along with expert consensus by the Canadian Heart Rhythm Society, the panel proposed a series of benchmarks for access to the full scope of electrophysiology services, from initial consultation through to operative procedures. The proposed benchmarks are presented herein.

Sudden death secondary to cardiac arrhythmias: mechanisms and treatment strategies

PURPOSE OF REVIEW

This article reviews mechanisms and available therapeutic options for arrhythmias leading to sudden cardiac death in patients with coronary artery disease.

RECENT FINDINGS

Intensive efforts have led to a better understanding of the pathophysiology and various treatments of sudden cardiac death. Antiarrhythmic medications have not demonstrated a survival benefit. Beta-adrenergic blocking agents have been revalidated in recent studies to improve survival and reduce risk of sudden cardiac death in patients with myocardial infarction. Angiotensin-converting enzyme inhibitors and aldosterone antagonists should also be used in these patients. Data from randomized trials demonstrate significant survival benefit with an implantable cardioverter-defibrillator and indications have expanded. Patients with established ischemic cardiomyopathy do not require electrophysiologic studies for induction of tachyarrhythmias based on these trials. One recent trial did not demonstrate mortality reduction with implantable defibrillators in patients with recent myocardial infarction. Devices may not provide survival benefit in patients with advanced New York Heart Association class IV heart failure.

SUMMARY

The incidence of arrhythmia-related sudden death in the general population remains relatively high. Better risk stratification tools are needed to identify high-risk patients in the general population and in those with known coronary disease and to exclude low-risk patients.

Evaluation of diagnostic imaging technologies and therapeutics devices: better information for better decisions: proceedings of a multidisciplinary workshop

We are entering an era in which the success of biomedical science and the increasing understanding of the value of evidence for practice are in a state of tension. This tension is especially notable in the device arena, in which the short life cycles and iterative nature of development are at odds with current design constructs of the types of clinical trials that provide evidence for medical decision making. The financial pressure arising from strained budgets and expanding costs from the aging of the population and the continued development of new technology heightens the need for a focus on new approaches. Given this background, a group of experts representing constituencies with different perspectives were convened for a day and a half to discuss key issues and their potential solutions. Because of the complex and heterogeneous nature of the environments in which devices are used, the meeting focused on 3 broad, general uses of devices: imaging, risk stratification, and therapeutics. The goal of the meeting was to develop a preliminary list of ideas that could be framed as researchable questions or constructs for consideration by policy makers that ultimately might lead to improvements in the current system. Across diagnostic imaging, risk stratification devices, and therapeutic devices, the crosscutting issues can be identified: We need better methods of collaborative funding and priority setting, improved and more flexible methods, and new approaches to the integration of federal agencies in overseeing the system.

Patients with recently diagnosed nonischemic cardiomyopathy benefit from implantable cardioverter-defibrillators

OBJECTIVES

This study sought to determine whether the time from diagnosis to randomization was related to outcome in a clinical trial of implantable cardioverter-defibrillator (ICD) insertion in nonischemic cardiomyopathy.

BACKGROUND

Whether the duration of nonischemic cardiomyopathy is related to arrhythmic risk and the possible benefit of ICD insertion is unknown.

METHODS

The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial randomized 458 patients with nonischemic dilated cardiomyopathy and a left ventricular ejection fraction <36% to receive standard medical therapy with or without an ICD. Patients were randomized regardless of the duration of known cardiomyopathy as long as a reversible cause of left ventricular dysfunction was not present. Patients were divided into recently and remotely diagnosed nonischemic cardiomyopathy groups based on the time from diagnosis of cardiomyopathy to randomization. To categorize patients, cut points of three and nine months were used.

RESULTS

Patients with recently diagnosed cardiomyopathy who received an ICD had better survival than those treated with standard therapy at both cut points. This difference in survival was significant at three months (p < 0.05) and was borderline significant at nine months (p = 0.058). Patients with remotely diagnosed cardiomyopathy did not have a significant survival benefit with ICD insertion, but there were no significant differences between ICD benefit in the recent and remote diagnosis groups (p = 0.17 and 0.25).

CONCLUSIONS

Patients who have a recent cardiomyopathy diagnosis do not have any less ICD benefit than those with a remote diagnosis. Thus, ICD therapy should be considered in such patients as soon as they are identified as long as a reversible cause of left ventricular dysfunction is excluded.

Sudden Cardiac Death Unresponsive to Implantable Defibrillator Therapy: An Urgent Target for Clinicians, Industry and Government

A major expansion in utilization of implantable cardioverter-defibrillators (ICDs) is anticipated based on the results of randomized clinical trials (RCT) that demonstrate increased survival in a sizable population of patients with reduced left ventricular function. However, if RCT accurately reflect clinical practice, then a substantial proportion of patients will die suddenly despite ICD implantation. ICD-unresponsive sudden cardiac death (SCD) has been recognized since the initial ICD experience. Yet, despite 25 years of technical advances, the frequency of ICD-unresponsive SCD has not declined. Pooled analysis of RCT indicates a crude rate of ICD-unresponsive SCD of 5%. This may not cause alarm in an average practice, but it comprises about 30% of cardiac deaths. Meta-analyses of RCT show that ICD therapy is associated with a relative risk reduction of SCD of approximately 60%, far less than the greater than 90% efficacy that many expect. The suboptimal performance of ICD therapy accounts for the failure of some RCT to achieve statistically significant effects on survival. The number of patients with ICD-unresponsive SCD is highly correlated with the number of cardiac deaths among control patients as well as ICD recipients. Otherwise, no definite patterns have emerged that clearly distinguish this mode of demise from other modes of cardiac death. Retrospective post-hoc analyses have not revealed distinguishing characteristics of patients with ICD-unresponsive SCD with respect to clinical variables, pre-terminal symptoms or to the setting of the terminal event. Despite advanced storage capabilities of implanted devices, almost no information has become available from RCT regarding the terminal rhythm or the response of the ICD. These observations have implications for clinical management and research. Candidates for ICD implantation based on RCT should be accurately informed about the residual risk of SCD. Investigators seeking to identify populations likely to benefit from ICD therapy based on SCD incidence should recognize that a significant fraction may not respond to ICD therapy. Reducing the incidence of ICD-unresponsive SCD would substantially improve survival and cost-effectiveness related to ICD therapy. Close cooperation between clinicians, investigators and representatives of industry and government is urgently needed to develop strategies to identify patients prone to ICD-unresponsive SCD, to determine its mechanisms and to develop methods of prevention and treatment.

Cost-effectiveness of implantable cardioverter-defibrillators

BACKGROUND

Eight randomized trials have evaluated whether the prophylactic use of an implantable cardioverter-defibrillator (ICD) improves survival among patients who are at risk for sudden death due to left ventricular systolic dysfunction but who have not had a life-threatening ventricular arrhythmia. We assessed the cost-effectiveness of the ICD in the populations represented in these primary-prevention trials.

METHODS

We developed a Markov model of the cost, quality of life, survival, and incremental cost-effectiveness of the prophylactic implantation of an ICD, as compared with control therapy, among patients with survival and mortality rates similar to those in each of the clinical trials. We modeled the efficacy of the ICD as a reduction in the relative risk of death on the basis of the hazard ratios reported in the individual clinical trials.

RESULTS

Use of the ICD increased lifetime costs in every trial. Two trials--the Coronary Artery Bypass Graft (CABG) Patch Trial and the Defibrillator in Acute Myocardial Infarction Trial (DINAMIT)--found that the prophylactic implantation of an ICD did not reduce the risk of death and thus was both more expensive and less effective than control therapy. For the other six trials--the Multicenter Automatic Defibrillator Implantation Trial (MADIT) I, MADIT II, the Multicenter Unsustained Tachycardia Trial (MUSTT), the Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial, the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) trial, and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)--the use of an ICD was projected to add between 1.01 and 2.99 quality-adjusted life-years (QALY) and between 68,300 dollars and 101,500 dollars in cost. Using base-case assumptions, we found that the cost-effectiveness of the ICD as compared with control therapy in these six populations ranged from 34,000 dollars to 70,200 dollars per QALY gained. Sensitivity analyses showed that this cost-effectiveness ratio would remain below 100,000 dollars per QALY as long as the ICD reduced mortality for seven or more years.

CONCLUSIONS

Prophylactic implantation of an ICD has a cost-effectiveness ratio below 100,000 dollars per QALY gained in populations in which a significant device-related reduction in mortality has been demonstrated.