Implantable Defibrillator Patients Research Articles

Outcome of Subcutaneous Implantable Cardioverter Defibrillator Implantation in Patients with End-Stage Renal Disease on Dialysis.

Although the subcutaneous ICD (S-ICD®) is an attractive alternative in patients with end-stage renal disease (ESRD), data on S-ICD outcomes in dialysis patients are lacking. Patients with cardiomyopathy undergoing S-ICD implantation in our center were stratified by need for chronic dialysis at the time of implant. The primary endpoint was incidence of death, heart failure hospitalization or appropriate S-ICD shocks, and secondary endpoints were incidence of inappropriate shocks or implant related complications requiring surgical re-intervention. Mean follow-up was longer in the nondialysis cohort (514 ± 495 vs. 227 ± 233 days, P = 0.006), so all endpoints were analyzed using time-dependent comparisons and reported as annual event rates. Out of 79 S-ICD implants included in this analysis, 27 patients were on dialysis. Dialysis patients were older and more likely to be diabetic. Mean ejection fraction across the entire cohort was 26.9% without significant difference between dialysis and nondialysis groups. Although not significant, the incidence of the primary endpoint was higher in the dialysis cohort (23.8%/year vs. 10.9%/year, P = 0.317), driven primarily by a higher rate of appropriate shocks. The rate of inappropriate shocks was similar between groups (dialysis 6.0%/year vs. nondialysis 6.8%/year, P = 0.509). No patients in the dialysis cohort had complications requiring surgical re-intervention versus 6 patients in the nondialysis cohort (P = 0.086). Our data suggest that S-ICD implantation in dialysis patients is not associated with an excess risk of implant related complications or inappropriate shocks.

Information provision, satisfaction and emotional distress in patients with an implantable cardioverter-defibrillator

The implantable cardioverter-defibrillator (ICD) is the treatment of choice for primary and secondary prevention of sudden cardiac death due to ventricular arrhythmias [ 1 Moss A. Hall W. Cannom D. et al. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. N Engl J Med. 1996; 335: 1933-1940 Crossref PubMed Scopus (3569) Google Scholar , 2 Bardy G.H. Lee K.L. Mark D.B. et al. Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med. 2005; 352: 225-237 Crossref PubMed Scopus (5302) Google Scholar , 3 The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators A comparison of antiarrhythmic-drug therapy with implantable defibrillators in patients resuscitated from near-fatal ventricular arrhythmias. N Engl J Med. 1997; 337: 1576-1584 Crossref PubMed Scopus (3004) Google Scholar ]. Although the majority of patients adapts well to living with an ICD, 1 in 4 patients report anxiety and depression [ [4] Sears S.F. Conti J.B. Quality of life and psychological functioning of ICD patients. Heart. 2002; 87: 488-493 Crossref PubMed Google Scholar ]. Sufficient understanding of the reasons for ICD implantation, its benefits, side effects, and impact on daily life plays a major role in adaptation. Adequate information provision and psycho-education may facilitate adaptation and reduce emotional distress [ 5 Vazquez L.D. Conti J.B. Sears S.F. Female-specific education, management, and lifestyle enhancement for implantable cardioverter defibrillator patients: the FEMALE-ICD study. Pacing Clin Electrophysiol. 2010; 33: 1131-1140 Crossref PubMed Scopus (38) Google Scholar , 6 Dunbar S.B. Dougherty C.M. Sears S.F. et al. Educational and psychological interventions to improve outcomes for recipients of implantable cardioverter defibrillators and their families: a scientific statement from the American Heart Association. Circulation. 2012; 126: 2146-2172 Crossref PubMed Scopus (158) Google Scholar , 7 Dunbar S.B. Langberg J.J. Reilly C.M. et al. Effect of a psychoeducational intervention on depression, anxiety, and health resource use in implantable cardioverter defibrillator patients. Pacing Clin Electrophysiol. 2009; 32: 1259-1271 Crossref PubMed Scopus (81) Google Scholar , 8 Eads A.S. Sears S.F.J. Sotile W.M. Conti J.B. Supportive communication with implantable cardioverter defibrillator patients: seven principles to facilitate psychosocial adjustment. J Cardiopulm Rehabil Prev. 2000; 20: 109-114 Crossref Scopus (22) Google Scholar ]. Paradoxically, recent surveys indicate that many patients have insufficient knowledge about their ICD and associated challenges [ 9 Cinar F.I. Tosun N. Kose S. Evaluation of an education and follow-up programme for implantable cardioverter defibrillator-implanted patients. J Clin Nurs. 2013; 22: 2474-2486 Crossref PubMed Scopus (15) Google Scholar , 10 Groarke J. Beirne A. Buckley U.N.A. et al. Deficiencies in patients' comprehension of implantable cardioverter defibrillator therapy. Pacing Clin Electrophysiol. 2012; 35: 1097-1102 Crossref PubMed Scopus (23) Google Scholar ].

Clinical outcome of implantable cardioverter defibrillator implantation in patients with long-QT syndrome

Clinical outcome of implantable cardioverter defibrillator implantation in patients with long-QT syndrome

Ventricular tachycardia/fibrillation early after defibrillator implantation in patients with hypertrophic cardiomyopathy is explained by a high-risk subgroup of patients

Implantable cardioverter-defibrillator (ICD) studies in patients with coronary artery disease report higher risk of ventricular tachycardia/fibrillation (VT/VF) early post-implant, potentially related to local proarrhythmic effects of ICD leads. To characterize early and long-term risk of ICD discharge for VT/VF in a large hypertrophic cardiomyopathy (HCM) cohort. By using HCM multicenter registry data, we compared long-term risk of VT/VF subsequent to an early post-implant period (a priori defined as within 3 months of implant) between patients with or without VT/VF within 3 months after ICD implantation. Over a median follow-up of 4.3 years, 109 of 506 (22%) patients with HCM who received ICDs received at least 1 ICD discharge for VT/VF. Risk of first ICD discharge for VT/VF was highest in the first year post-implant (10.8% per person-year; 95% confidence interval 7.9-13.8) and particularly in the first 3 months (17.0% per person-year; 95% confidence interval 9.8-24.3). Patients with early VT/VF (≤3 months post-implant) were older, and more commonly had secondary prevention ICDs following cardiac arrest or systolic dysfunction (end-stage HCM with ejection fraction<50%). Only 2 of 247 (0.7%) patients with primary prevention ICDs and preserved systolic function had early VT/VF. Patients with VT/VF early post-implant (≤3 months) had more than 5-fold higher risk for future VT/VF during long-term follow-up compared with patients without early VT/VF (adjusted hazard ratio 5.4; 95% confidence interval 2.3-12.6). High-risk patients with HCM and VT/VF early after ICD implantation are particularly prone to subsequent VT/VF throughout follow-up. Early ICD interventions for VT/VF are largely confined to patients with prior cardiac arrest or systolic dysfunction and therefore more likely driven by higher arrhythmic risk rather than lead-related proarrhythmia.

Contemporary and future trends in cardiac resynchronization therapy to enhance response

The rationale for cardiac resynchronization therapy (CRT), expectations in terms of patient benefit, patient selection for CRT, selection of a CRT pacemaker (CRT-P) vs CRT plus implantable cardioverter-defibrillator (CRT-D) platform, and studies evaluating device programming to enhance benefit from CRT are reviewed. The notion of an "optimal" left ventricular (LV) pacing site, the rationale for identifying and avoiding LV pacing in regions of scar, the use of anatomic, hemodynamic, and electrical parameters to identify an optimal LV pacing site, and the potential utility of multisite LV pacing to enhance benefit from CRT are discussed. Finally, the advantages and disadvantages of the various methods for LV lead delivery are reviewed.

Use of remote monitoring in the management of system-related complications in implantable defibrillator patients

Remote monitoring of implantable defibrillators (ICDs) is designed to minimise regular follow-up visits and to facilitate early detection of adverse events. With the increased rate of ICD implantations in today's clinical setting and multiple device advisories, which pose management challenges, this approach becomes very attractive. The aim of this article is to present the role of remote monitoring in the detection of system-related complications, its potential benefits and its barriers in the outpatient management of ICD patients.

Rhetorical Strategies Used in the Reporting of Implantable Defibrillator Primary Prevention Trials

Previous studies have suggest that the authors of randomized trial reports frequently use rhetorical strategies, such as framing, the use of ratios rather than absolute values to report results, and underreporting of complications, to convince readers of treatment efficacy. The objective of this study was to determine if such rhetorical strategies were used in the publication of implantable-cardioverter defibrillator (ICD) primary prevention trials. Medline and the Cochrane Central Register of Controlled Trials were searched for all publications that described ICD primary prevention trials and that involved >100 subjects. Each publication was analyzed for evidence of message framing, the exclusive use of ratios to report outcomes, underreporting of ICD complications, and interpretation bias favoring ICD therapy. Ten publications were identified. Introductory remarks in 8 of the 10 publications cited the evaluation of ICD benefits as the sole objective and mentioned only background studies that supported ICD efficacy, suggesting message framing in support of ICD efficacy. Five publications provided no specific information about the frequency of unsuccessful ICD implantations, and 8 publications provided incomplete or no information about implantation and postimplantation complications. ICD complications were not mentioned in the discussion sections of 9 publications, and none of the publications included a comprehensive comparison of ICD benefits versus risks, consistent with interpretation bias. Ratios and statistically insignificant data were not used to emphasize ICD benefits. In conclusion, message framing, underreporting of ICD complications, and interpretation bias were used to emphasize ICD efficacy in the reporting of ICD primary prevention trials.

The prognosis of implantable defibrillator patients treated with cardiac resynchronization therapy: comorbidity burden as predictor of mortality

AimsComorbidity, such as myocardial infarction, diabetes, and renal failure, plays a pivotal role in the prognosis of a patient with arrhythmias. However, data on the prognostic impact of comorbiditiy in heart failure patients with cardiac resynchronization therapy and defibrillation (CRT-D) are scarce. The purpose of this study was to determine the impact of comorbidity on survival in CRT-D patients.Methods and resultsThe study population consisted of 463 heart failure patients who received a CRT-D between 1999 and 2008 in Rotterdam and Basel. The Charlson comorbidity index (CCI) is often used as an adjusting variable in prognostic models. The Cox proportional hazards analysis was performed to determine the independent effect of comorbidity on survival. During a median follow-up of 30.5 months, 85 patients died. Mortality rates at 1 and 7 years were 6.3 and 32.3%. Cumulative incidence of implantable cardioverter defibrillator (ICD) therapy at 7 years was 50%, and death without ICD therapy was observed in 9% of patients. At least three comorbid conditions were observed in 81% of patients. Patients who died had a higher CCI score compared with those who survived (3.9 ± 1.5 vs. 2.9 ± 1.5; P < 0.001). An age-adjusted CCI score ≥5 was a predictor of mortality (hazard ratio 3.69, 95% CI 2.06–6.60; P < 0.001) independent from indication for ICD therapy, and from ICD interventions during the clinical course.ConclusionComorbidity is often present in heart failure patients, and a high comorbidity burden was a significant predictor of mortality in CRT-D recipients. Comorbidity cannot predict appropriate ICD therapy. Death without prior ICD therapy occurs in a minor proportion of patients.

Analysis of large databases in vascular surgery

Large databases can be a rich source of clinical and administrative information on broad populations. These datasets are characterized by demographic and clinical data for over 1000 patients from multiple institutions. Since they are often collected and funded for other purposes, their use for secondary analysis increases their utility at relatively low costs. Advantages of large databases as a source include the very large numbers of available patients and their related medical information. Disadvantages include lack of detailed clinical information and absence of causal descriptions. Researchers working with large databases should also be mindful of data structure design and inherent limitations to large databases, such as treatment bias and systemic sampling errors. Withstanding these limitations, several important studies have been published in vascular care using large databases. They represent timely, "real-world" analyses of questions that may be too difficult or costly to address using prospective randomized methods. Large databases will be an increasingly important analytical resource as we focus on improving national health care efficacy in the setting of limited resources.

Selection Bias in a Study of Implantable Defibrillator Patients: The Role of Type D Personality

BackgroundSelection bias constitutes a major issue in research using volunteers as study participants.PurposeWe examined whether research in partners may affect participation rates of implantable cardioverter-defibrillator (ICD) patients with a Type D personality (joint presence of negative affectivity and social inhibition).MethodPatients who underwent ICD implantation between May 2003 and November 2007, and who had a partner, were included (n = 440). In September 2005, a substudy on partners of ICD patients was added (n = 276 patients).ResultsThe proportion Type D patients after the start of the partner substudy was significantly lower as compared to the proportion before this substudy (17.5% versus 28.8%; p = 0.006). Patients who participated following the start of the partner substudy were less likely to have a Type D personality (OR = 0.44; p = 0.002), adjusting for possible confounders. In the partner substudy, nonparticipation was more prevalent among partners of Type D patients as compared to partners of non-Type D patients (20.4% versus 10.1%; p = 0.044). Partner nonparticipation was marginally significantly associated with Type D personality of the patient (OR = 2.13; p = 0.083), adjusting for confounders.ConclusionsThe addition of a partner substudy may be related to a decreased proportion of participants with a Type D personality. Nonparticipation was more prevalent among partners of Type D patients. These observations may influence results of studies, as Type Ds tend to be less healthy.

Catheter ablation of stable ventricular tachycardia before defibrillator implantation in patients with coronary heart disease (VTACH): a multicentre randomised controlled trial

Catheter ablation of stable ventricular tachycardia before defibrillator implantation in patients with coronary heart disease (VTACH): a multicentre randomised controlled trial

Catheter ablation of stable ventricular tachycardia before defibrillator implantation in patients with coronary heart disease (VTACH): a multicentre randomised controlled trial

In patients with ventricular tachycardia (VT) and a history of myocardial infarction, intervention with an implantable cardioverter defibrillator (ICD) can prevent sudden cardiac death and thereby reduce total mortality. However, ICD shocks are painful and do not provide complete protection against sudden cardiac death. We assessed the potential benefit of catheter ablation before implantation of a cardioverter defibrillator. The Ventricular Tachycardia Ablation in Coronary Heart Disease (VTACH) study was a prospective, open, randomised controlled trial, undertaken in 16 centres in four European countries. Patients aged 18-80 years were eligible for enrolment if they had stable VT, previous myocardial infarction, and reduced left-ventricular ejection fraction (LVEF; <or=50%). 110 patients were randomly allocated in a 1:1 ratio to receive catheter ablation and an ICD (ablation group, n=54) or ICD alone (control group, n=56). Randomisation was done by computer-generated randomly permuted blocks and stratified by centre and LVEF (<or=30% or >30%). Patients were followed up for at least 1 year. The primary endpoint was the time to first recurrence of VT or ventricular fibrillation (VF). Analysis was by intention to treat (ITT). This study is registered with ClinicalTrials.gov, number NCT00919373. 107 patients were included in the ITT population (ablation group, n=52; control group, n=55). Two patients (one in each group) withdrew consent immediately after randomisation without any follow-up data and one patient (ablation group) was excluded because of a protocol violaton. Mean follow-up was 22.5 months (SD 9.0). Time to recurrence of VT or VF was longer in the ablation group (median 18.6 months [lower quartile 2.4, upper quartile not determinable]) than in the control group (5.9 months [IQR 0.8-26.7]). At 2 years, estimates for survival free from VT or VF were 47% in the ablation group and 29% in the control group (hazard ratio 0.61; 95% CI 0.37-0.99; p=0.045). Complications related to the ablation procedure occurred in two patients; no deaths occurred within 30 days after ablation. 15 device-related complications requiring surgical intervention occurred in 13 patients (ablation group, four; control group, nine). Nine patients died during the study (ablation group, five; control group, four). Prophylactic VT ablation before defibrillator implantation seemed to prolong time to recurrence of VT in patients with stable VT, previous myocardial infarction, and reduced LVEF. Prophylactic catheter ablation should therefore be considered before implantation of a cardioverter defibrillator in such patients. St Jude Medical.

Axillary subpectoral approach for pacemaker or defibrillator implantation in patients with ipsilateral prepectoral infection and limited venous access

The prepectoral approach is the procedure of choice for pacemaker or defibrillator (device) implantation. Epicardial or transiliac approaches are reserved for patients in whom the pectoral approach is not feasible. We studied the viability of the axillary subpectoral approach for implanting devices in patients in whom the standard prepectoral approach was not feasible. Devices and leads were extracted from 16 patients with infected devices in the prepectoral position. The contralateral site was unsuitable for reimplantation because of infection or inadequate venous access. On the side ipsilateral to that with prior prepectoral device infection, we made an incision on the anterior axillary line along the border of the pectoralis major; dissection was continued below the muscle to create a pocket for generator implantation. Axillary venous puncture was performed from the axillary incision and beneath the pectoralis major muscle using a long 14-gauge needle. Long guidewires and peel-away sheaths were used for positioning the lead. The generator was placed in the subpectoral pocket; the wound was closed with absorbable sutures. One patient developed a pocket hematoma; one developed a pneumothorax; no other surgical complication, lead malfunction, or recurrence of infection was observed. The axillary subpectoral approach is an acceptable, technically feasible method for reimplantation for patients with pectoral device infection and limited venous access options. It offers the advantage of a new sterile fascial plane ipsilateral to the site of prepectoral device infection.

Risk of chronic anxiety in implantable defibrillator patients: A multi-center study

Little is known about the prevalence of chronic anxiety in patients with an implantable cardioverter defibrillator (ICD). In a multi-center, prospective study, we examined 1) the prevalence of chronic anxiety (i.e., patients anxious at implantation and 12 months), and 2) predictors of chronic anxiety. ICD patients (N=284; 21.1% women) anxious (cut-off ≥ 40 on the State Trait Anxiety Inventory (STAI)) at the time of implantation qualified for inclusion in the current study. Patients completed the Type D Scale at baseline and the STAI (state measure) at baseline and 12 months. Of 284 patients anxious at baseline, 53.9% (153/284) remained anxious at 12-month follow-up. Diabetes (OR:2.49; 95%CI:1.16-5.36), cardiac resynchronization therapy (CRT) (OR:2.03; 95%CI:1.02-4.05), and Type D personality (OR:1.87; 95%CI:1.09-3.19) were independent predictors of 12-month anxiety, adjusting for demographic and clinical variables including ICD therapy during follow-up. Shocks (both appropriate and inappropriate during follow-up) were not associated with chronic anxiety at 12 months (OR:0.94; 95%CI:0.42-2.12). The prevalence of chronic anxiety in the 96 patients with no risk factors was 34.4% and 63.8% in the 120 patients with either diabetes, CRT, or Type D personality. More than 50% of ICD patients anxious at the time of implantation were still anxious at 12 months, indicating a high level of chronicity. Diabetes, CRT, and Type D personality were independent predictors of chronic anxiety. ICD patients anxious at implantation should be closely monitored and offered adjunctive psychosocial intervention if symptoms do not remit spontaneously in order to prevent adverse health outcomes.

Defibrillation testing in patients with atrial fibrillation

Implantable cardioverter defibrillator implantation in patients with atrial fibrillation (AF) is complicated by the need for anticoagulation during defibrillation testing. In this retrospective study, we evaluated the factors associated with successful cardioversion of AF during ventricular defibrillation testing and the safety of our local anticoagulation protocol.

Invited Commentary

Invited Commentary

Optimizing the clinical use of implantable defibrillators in patients with Brugada syndrome

Our review highlights the difficulties we face when treating patients with Brugada syndrome (BS) by an implantable cardioverter defibrillator (ICD). Higher defibrillation thresholds, high inappropriate shock rates because of sinus tachycardia and supraventricular tachycardias, T wave oversensing, and high lead failure rates should be expected. Psychosocial adjustment problems also occur frequently in this patient population. These high complications rates are because of specific characteristics of the BS patient population, consisting of young, active patients with a primary electrical disease. The management strategies include prevention and early recognition of the expected complications. Additionally, individualized careful programming of the ICD is essential to ensure maximal safety and minimal complication rates in patients with BS.

Assessment, Significance and Mechanism of Ventricular Electrical Instability after Myocardial Infarction

The mechanism of reentrant tachycardia was established nearly a century ago, but the relationships between myocardial infarction and predisposition to sudden death were not unravelled until much later. In the latter half of the twentieth century many studies sought to ascertain what variables were predictive of death following myocardial infarction. Approximately one half of all deaths during the year following myocardial infarction are sudden and due to ventricular tachycardia (VT) or ventricular fibrillation (VF). We aimed to utilise non-invasive signal-averaging, along with programmed electrical stimulation of the heart, to determine whether one could predict spontaneous ventricular tachycardia and sudden death late after myocardial infarction. The sensitivity of ventricular electrical instablility (inducible ventricular tachycardia or fibrillation) as a predictor of instantaneous death or spontaneous VT was 86%, and the specificity was 83%. When other variables (delayed ventricular activation at signal-averaging, ejection fraction at gated heart pool scan, ventricular ectopic activity at ambulatory monitoring and exercise testing) were taken into account, inducible VT at electrophysiological study was the single best predictor of spontaneous VT and sudden cardiac death after myocardial infarction. The Westmead studies of Uther et al. in the decade or so from 1980 established programmed stimulation as the best predictor of sudden death after myocardial infarction. Subsequent studies by others have demonstrated a survival advantage of defibrillator implantation in patients with low ejection fraction (and inducible ventricular tachycardia) after myocardial infarction.

Sudden death secondary to cardiac arrhythmias: mechanisms and treatment strategies

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

Review Article

Review Article