Johannes B. van Rees

Inappropriate implantable cardioverter-defibrillator shocks: incidence, predictors, and impact on mortality.

OBJECTIVES The purpose of this study was to assess the incidence, predictors, and outcome of inappropriate shocks in implantable cardioverter-defibrillator (ICD) patients. BACKGROUND Despite the benefits of ICD therapy, inappropriate defibrillator shocks continue to be a significant drawback. The prognostic importance of inappropriate shocks outside the setting of a clinical trial remains unclear. METHODS From 1996 to 2006, all recipients of defibrillator devices equipped with intracardiac electrogram storage were included in the current analysis and clinically assessed at implantation. During follow-up, the occurrence of inappropriate ICD shocks and all-cause mortality was noted. RESULTS A total of 1,544 ICD patients (79% male, age 61 ± 13 years) were included in the analysis. During the follow-up period of 41 ± 18 months, 13% experienced ≥1 inappropriate shocks. The cumulative incidence steadily increased to 18% at 5-year follow-up. Independent predictors of the occurrence of inappropriate shocks included a history of atrial fibrillation (hazard ratio [HR]: 2.0, p < 0.01) and age younger than 70 years (HR: 1.8, p = 0.01). Experiencing a single inappropriate shock resulted in an increased risk of all-cause mortality (HR: 1.6, p = 0.01). Mortality risk increased with every subsequent shock, up to an HR of 3.7 after 5 inappropriate shocks. CONCLUSIONS In a large cohort of ICD patients, inappropriate shocks were common. The most important finding is the association between inappropriate shocks and mortality, independent of interim appropriate shocks.

Implantation-Related Complications of Implantable Cardioverter-Defibrillators and Cardiac Resynchronization Therapy Devices: A Systematic Review of Randomized Clinical Trials

The number of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy (CRT) implantations is increasing drastically worldwide, and hence, the number of implanting centers is also increasing. Despite abundant data on the beneficial effect of these devices, little is known regarding safety and complication rates. Eleven ICD and 7 CRT trials were systematically reviewed to provide data on the frequency of in-hospital mortality and complications related to the implantation. Average in-hospital mortality was 2.7% in trials using both thoracotomy and nonthoracotomy ICDs, 0.2% in trials using nonthoracotomy ICDs, and 0.3% in CRT trials. The pneumothorax rate was similar between the nonthoracotomy ICD and CRT trials (0.9%) Coronary sinus complications occurred in 2.0% of patients undergoing CRT. Lead dislodgement rates were higher in CRT trials (5.7%) than in nonthoracotomy ICD trials (1.8%).

Long-term follow-up of primary and secondary prevention implantable cardioverter defibrillator patients

AIMS The beneficial effects of implantable cardioverter defibrillators (ICDs) in primary and secondary prevention patients are well established. However, data on potential differences between both groups in mortality and ICD therapy rates during long-term follow-up are scarce. The aim of the study was to assess differences in mortality and ICD therapy between secondary and primary prevention ICD recipients. METHODS AND RESULTS With the exception of patients with congenital monogenetic cardiac disease, all patients treated with an ICD, regardless of the underlying cardiac pathology, from 1996 to 2008 at the Leiden University Medical Center were included in the current analysis. The study population was grouped by the type of prevention (secondary or primary) for sudden cardiac death. The primary endpoint was all-cause mortality. The secondary endpoint was the occurrence of device therapy (appropriate or inappropriate). A total of 2134 (80% men, mean age 63 ± 12 years) ICD recipients were included. Of these, 1302 (61%) patients received an ICD for primary prevention of sudden cardiac death and 832 (39%) patients for secondary prevention. During a mean follow-up of 3.4 ± 2.8 years, 423 (20%) patients died. The 5-year cumulative incidence of mortality was 25% [95% confidence intervals (CI): 21-29%] for primary prevention patients and 23% (95% CI: 20-26%) for secondary prevention patients. Secondary prevention patients exhibited a 74% increased risk for appropriate therapy when compared with primary prevention patients [hazard ratios (HR): 1.7; P< 0.001]. A comparable risk for inappropriate shocks was observed (HR: 1.0; P= 0.9). CONCLUSION During long-term follow-up, primary prevention patients exhibited a lower risk of appropriate therapy, but comparable mortality rates were observed between both groups. Both groups showed similar occurrence of inappropriate shocks.

Implantable cardioverter-defibrillator longevity under clinical circumstances: An analysis according to device type, generation, and manufacturer

BACKGROUND One of the major drawbacks of implantable cardioverter-defibrillator (ICD) treatment is the limited device service life. Thus far, data concerning ICD longevity under clinical circumstances are scarce. In this study, the ICD service life was assessed in a large cohort of ICD recipients. OBJECTIVE To assess the battery longevity of ICDs under clinical circumstances. METHODS All patients receiving an ICD in the Leiden University Medical Center were included in the analysis. During prospectively recorded follow-up visits, reasons for ICD replacement were assessed and categorized as battery depletion and non-battery depletion. Device longevity and battery longevity were calculated. The impact of device type, generation, manufacturer, the percentage of pacing, the pacing output, and the number of shocks on the battery longevity was assessed. RESULTS Since 1996, 4673 ICDs were implanted, of which 1479 ICDs (33%) were replaced. Mean device longevity was 5.0 ± 0.1 years. A total of 1072 (72%) ICDs were replaced because of battery depletion. Mean battery longevity of an ICD was 5.5 ± 0.1 years. When divided into different types, mean battery longevity was 5.5 ± 0.2 years for single-chamber ICDs, 5.8 ± 0.1 for dual-chamber ICDs, and 4.7 ± 0.1 years for cardiac resynchronization therapy-defibrillators (P <.001). Devices implanted after 2002 had a significantly better battery longevity as compared with devices implanted before 2002 (5.6 ± 0.1 years vs 4.9 ± 0.2 years; P <.001). In addition, large differences in battery longevity between manufacturers were noted (overall log-rank test, P <.001). CONCLUSIONS The majority of ICDs were replaced because of battery depletion. Large differences in longevity exist between different ICD types and manufacturers. Modern ICD generations demonstrated improved longevity.

Prognostic Importance of Atrial Fibrillation in Implantable Cardioverter-Defibrillator Patients

OBJECTIVES This study aimed to assess the prevalence of different types of atrial fibrillation (AF) and their prognostic importance in implantable cardioverter-defibrillator (ICD) patients. BACKGROUND The prevalence of AF has taken epidemic proportions in the population with cardiovascular disease. The prognostic importance of different types of AF in ICD patients remains unclear. METHODS Data on 913 consecutive patients (79% men, mean age 62 + or - 13 years) receiving an ICD at the Leiden University Medical Center were prospectively collected. Among other characteristics, the existence and type of AF (paroxysmal, persistent, or permanent) were assessed at implantation. During follow-up, the occurrence of appropriate or inappropriate device therapy as well as mortality was noted. RESULTS At implantation, 73% of patients had no history of AF, 9% had a history of paroxysmal AF, 7% had a history of persistent AF, and 11% had permanent AF. During 833 + or - 394 days of follow-up, 117 (13%) patients died, 228 (25%) patients experienced appropriate device discharge, and 139 (15%) patients received inappropriate shocks. Patients with permanent AF exhibited more than double the risk of mortality, ventricular arrhythmias triggering device discharge, and inappropriate device therapy. Patients with paroxysmal or persistent AF did not show a significant increased risk of mortality or appropriate device therapy but demonstrated almost 3 times the risk of inappropriate device therapy. CONCLUSIONS In the population currently receiving ICD treatment outside the setting of clinical trials, a large portion has either a history of AF or permanent AF. Both types of AF have prognostic implications for mortality and appropriate as well as inappropriate device discharge.

Clinical prediction model for death prior to appropriate therapy in primary prevention implantable cardioverter defibrillator patients with ischaemic heart disease: the FADES risk score.

Objectives To construct a risk score out of baseline variables to estimate the risk of death without prior implantable cardioverter defibrillator (ICD) in primary prevention ICD patients with ischaemic heart disease. Design Retrospective cohort study. Setting Tertiary care facility in The Netherlands. Patients All patients with ischaemic heart disease who received an ICD for primary prevention of sudden cardiac death at the Leiden University Medical Center, Leiden, The Netherlands in the period 1996–2009. Main outcome measure All-cause mortality without prior appropriate ICD therapy (anti-tachycardia pacing or shock). Results 900 patients (87% men, mean age 64±10 years) were included in the analysis. During a median follow-up of 669 days (IQR 363–1322 days), 150 patients (17%) died and 191 (21%) patients received appropriate device therapy. 114 (13%) patients died without prior appropriate therapy. Stratification of the risk for death without prior appropriate therapy resulted in risk categorisation of patients as low, intermediate or high risk. NYHA ≥III, advanced age, diabetes mellitus, left ventricular ejection fraction ≤25% and a history of smoking were significant independent predictors of death without appropriate ICD therapy. 5-year cumulative incidence for death without prior appropriate therapy ranged from 10% (95% CI 6% to 16%) in low-risk patients to 41% (95% CI 33% to 51%) in high-risk patients. Conclusions The risk of death without prior appropriate ICD therapy can be predicted in primary prevention ICD patients with ischaemic heart disease, which facilitates patient-tailored risk estimation.

Cardiac device infections are associated with a significant mortality risk.

BACKGROUND Cardiac device infections (CDIs) are a serious complication associated with the implantation of cardiac rhythm devices. However, the effect of CDI on the subsequent risk of mortality is unknown. OBJECTIVE To assess the prognostic importance of CDI in recipients of implantable cardioverter-defibrillator and cardiac resynchronization therapy - defibrillator. METHODS All patients who received their initial implantable cardioverter-defibrillator/cardiac resynchronization therapy - defibrillator between January 2000 and September 2009 were included. During follow-up, the occurrence of CDI and all-cause mortality were noted. The prognostic importance of the first CDI on mortality was assessed by modeling CDI as a time-dependent covariate in the Cox proportional hazards model. RESULTS A total of 2476 patients (79% men; mean age 62 ± 13 years) were included in this analysis. During follow-up, CDI occurred in 64 (2.6%) patients. The 1-year mortality following first CDI was 16.9% (95% confidence interval 6.7%-27.1%). Experiencing the first CDI was associated with a 1.9-fold (hazard ratio 1.87; 95% confidence interval 1.07-3.26) increased risk of mortality compared to patients who did not experience CDI. After controlling for possible confounders, this increased to a 2.4-fold (hazard ratio 2.40; 95% confidence interval 1.35-4.28) increased risk of mortality. CONCLUSIONS In a large cohort of patients who receive implantable cardioverter-defibrillator/cardiac resynchronization therapy - defibrillator after their initial implant, the 3-year incidence of CDI was 2.6%. The occurrence of CDI was associated with substantial 1-year mortality, and patients experiencing CDI had a more than 2-fold increased risk of mortality compared with patients who remained free from CDI.

Implantable cardioverter-defibrillator patients who are upgraded and respond to cardiac resynchronization therapy have less ventricular arrhythmias compared with nonresponders.

OBJECTIVES The purpose of this study was to evaluate the impact of upgrading implantable cardioverter-defibrillator (ICD) therapy to cardiac resynchronization therapy (CRT) combined with defibrillator (CRT-D) on the occurrence of ventricular arrhythmia (VA) and appropriate ICD therapies. BACKGROUND CRT has been shown to improve left ventricular (LV) systolic function and induce reverse LV remodeling. In addition, it has been hypothesized that CRT may reduce the incidence of VA. METHODS Heart failure patients receiving an upgrade from ICD to CRT-D were evaluated. Patients were considered responders to CRT if LV end-systolic volume reduced ≥15% at 6 months of follow-up. Episodes of VA, triggering device therapy (anti-tachycardia pacing and shocks) were recorded before and after upgrade for the overall population. In addition, these outcomes were compared between CRT responders and nonresponders during the follow-up period after CRT response was assessed. RESULTS One hundred fifteen patients (93 males [81%], age 65 ± 12 years) were evaluated during a mean follow-up of 54 ± 34 months before CRT-D upgrade and 37 ± 27 months after upgrade. In CRT responders (n = 70), the frequency of VA requiring appropriate device therapy demonstrated a trend toward a decrease from 0.51 ± 0.79 to 0.30 ± 0.59 per patient per year after CRT-D upgrade (p = 0.052). In CRT nonresponders (n = 45), the frequency of VA requiring appropriate device therapy significantly increased from 0.40 ± 0.69 to 1.21 ± 2.53 per patient per year after CRT-D upgrade (p = 0.014). CONCLUSIONS After upgrade from ICD to CRT-D, nonresponders to CRT showed a significant increase in VA burden requiring appropriate device therapy.

The clinical course of patients with implantable cardioverter-defibrillators: Extended experience on clinical outcome, device replacements, and device-related complications

BACKGROUND Large randomized trials demonstrated the beneficial effect of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) treatments in selected patients. Data on long-term follow-up of patients outside the setting of clinical trials are scarce. OBJECTIVE The aim of this study was to evaluate the long-term outcome of ICD and CRT-D recipients. METHODS All patients who underwent ICD (n = 1729 [57%]) or CRT-D (n = 1326 [43%]) implantation at the Leiden University Medical Center since 1996 were evaluated. Follow-up visits were performed every 3-6 months, and events were registered. Cumulative incidence curves of device therapy and device-related complications were adjusted for the competing risk of all-cause mortality. RESULTS After a median follow-up of 5.1 years (25th-75th percentile 3.1-7.8 years), 842 patients (28%) died. The cumulative incidence of all-cause mortality was 49% (95% confidence interval [CI] 45%-54%) in ICD recipients after 12 years of follow-up and 55% (95% CI 52%-58%) in CRT-D recipients after 8 years of follow-up. A total of 1081 patients (35%) received appropriate defibrillator therapy. The cumulative incidence of appropriate therapy in ICD patients was 58% (95% CI 54%-62%) after 12 years of follow-up and 39% (95% CI 35%-43%) in CRT-D patients after 8 years of follow-up. Twelve-year cumulative incidences of adverse events were 20% (95% CI 18%-22%) for inappropriate shock, 6% (95% CI 5%-8%) for device-related infection, and 17% (95% CI 14%-21%) for lead failure. CONCLUSION After long-term follow-up of ICD (12 years) and CRT-D (8 years) recipients, 49% of ICD recipients and 55% of CRT-D recipients had died. Appropriate ICD therapy was received by the majority (58%) of ICD recipients and by almost 40% of CRT-D recipients.

Primary prevention implantable cardioverter defibrillator recipients: the need for defibrillator back-up after an event-free first battery service-life.

ICD Replacement After a Therapy‐Free First Service‐Life. Introduction: In primary prevention implantable cardioverter defibrillator (ICD) patients, the relatively low incidence of ventricular arrhythmias (VA) combined with the limited battery service‐life potentially results in a large group of patients who have had no benefit of the ICD during first service‐life. Data on the occurrence of VA after device replacement remain scarce. The purpose of this study was to give clinicians better insight in the dilemma whether or not to replace an ICD after an event‐free first battery service‐life.