Update on small-diameter implantable cardioverter-defibrillator leads performance.

BACKGROUND: The performance of small diameter implantable cardioverter defibrillator (ICD) leads is questionable. However, data on performance during long-term follow-up are scarce. The aim of this study is to provide an update for the lead failure and cardiac perforation rate of Medtronic's Sprint Fidelis ICD lead (Medtronic Inc., Minneapolis, MN, USA) and St. Jude Medical's Riata ICD lead (St. Jude Medical Inc., St. Paul, MN, USA). METHODS: Since 1996, all ICD system implantations at the Leiden University Medical Center, the Netherlands, are registered. For this study, data up to February 2011 on 396 Sprint Fidelis leads (follow-up 3.4 ± 1.5 years), 165 8-French (F) Riata leads (follow-up 4.6 ± 2.6 years), and 30 7-F Riata leads (follow-up 2.9 ± 1.3 years) were compared with a benchmark cohort of 1,602 ICD leads (follow-up 3.4 ± 2.7 years) and assessed for the occurrence of lead failure and cardiac perforation. RESULTS: During follow-up, the yearly lead failure rate of the Sprint Fidelis lead, 7-F Riata lead, 8-F Riata lead, and the benchmark cohort was 3.54%, 2.28%, 0.78%, and 1.14%, respectively. In comparison to the benchmark cohort, the adjusted hazard ratio of lead failure was 3.7 (95% confidence interval [CI] 2.4-5.7, P < 0.001) for the Sprint Fidelis lead and 4.2 (95% CI 1.0-18.0, P < 0.05) for the 7-F Riata lead. One cardiac perforation was observed (3.3%) in the 7-F Riata group versus none in the 8-F Riata and Sprint Fidelis lead population. CONCLUSION: The current update demonstrates that the risk of lead failure during long-term follow-up is significantly increased for both the Sprint Fidelis and the 7-F Riata lead in comparison to the benchmark cohort. Only one cardiac perforation occurred.

Primary prevention implantable cardioverter defibrillator recipients: the need for defibrillator back-up after an event-free first battery 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. METHODS AND RESULTS: All patients treated with an ICD for primary prevention who had a replacement because of battery depletion and who did not receive appropriate therapy before device replacement were included in this analysis. Of 154 primary prevention ICD patients needing replacement because of battery depletion, 114 (74%) patients (mean age 61 ± 11 years, 80% male) had not received appropriate ICD therapy for VA. Follow-up was 71 ± 24 months after the initial implantation and 25 ± 21 months after device replacement. Following replacement, 3-year cumulative incidence of appropriate therapy in response to ventricular tachycardia or ventricular fibrillation was 14% (95% CI 5-22%). CONCLUSION: The majority of primary prevention ICD patients do not experience VA during first battery service-life. However, a substantial part of these patients does experience appropriate ICD therapy after replacement.

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.

Mortality risk score in primary prevention implantable cardioverter defibrillator recipients with non-ischaemic or ischaemic heart disease.

AIMS: To assess survival and to construct a baseline mortality risk score in primary prevention implantable cardioverter defibrillator (ICD) patients with non-ischaemic or ischaemic heart disease. METHODS AND RESULTS: Since 1996, data of all consecutive patients who received an ICD system in the Leiden University Medical Center were collected and assessed at implantation. For the current study, all 1036 patients [age 63 (SD 11) years, 81% male] with a primary indication for defibrillator implantation were evaluated and followed for 873 (SD 677) days. During follow-up, 138 patients (13%) died. Non-ischaemic and ischaemic patients demonstrated similar survival but exhibited different factors that influence risk for mortality. A risk score, consisting of simple baseline variables could stratify patients in low, intermediate, and high risk for mortality. In non-ischaemic patients, annual mortality was 0.4% (95% CI 0.0-2.2%) in low risk and 9.4% (95% CI 6.6-13.1%) in high risk patients. In ischaemic patients, mortality was 1.0% (95% CI 0.2-3.0%) in low risk and 17.8% (95% CI 13.6-22.9%) in high risk patients. CONCLUSION: Utilization of an easily applicable baseline risk score can create an individual patient-tailored estimation on mortality risk to aid clinicians in daily practice.

Recurrent implantable cardioverter-defibrillator replacement is associated with an increasing risk of pocket-related complications.

BACKGROUND: Despite beneficial effects of implantable cardioverter-defibrillator (ICD) therapy, limited service life results in replacement within the majority of patients. Data concerning the effect of replacement procedures on the occurrence of pocket-related adverse events are scarce. In this study, the requirement for pocket-related surgical re-interventions following ICD treatment and the effect of device replacement were evaluated. METHODS: From 1992 to 2008, 2,415 patients receiving an ICD at the Leiden University Medical Center were analyzed. Pocket-related complications requiring surgical re-intervention following ICD implantation or replacement were noted. Elective device replacement, lead failure, and device malfunction were not considered pocket-related complications. RESULTS: A total of 3,161 ICDs were included in the analysis. In total, 145 surgical re-interventions were required in 122 (3.9%) ICDs implanted in 114 (4.7%) unique patients. Three-year cumulative incidence for first surgical re-intervention in all ICDs was 4.7% (95% confidence interval [CI] 3.9-5.5%). Replacement ICDs exhibited a doubled requirement for surgical re-intervention (rate ratio 2.2, 95% CI 1.5-3.0). Compared to first implanted ICDs, the occurrence of surgical re-intervention in replacements was 2.5 (95% CI 1.6-3.7) times higher for infectious and 1.7 (95% CI 0.9-3.0) for noninfectious causes. Subdivision by the number of ICD replacements showed an increase in the annual risk for surgical re-intervention, ranging from 1.5% (95% CI 1.2-1.9%) for the first, to 8.1% (95% CI 1.7-18.3%) for the fourth implanted ICD. CONCLUSIONS: ICD replacement is associated with a doubled risk for pocket-related surgical re-interventions. Furthermore, the need for re-intervention increases with every consecutive replacement.

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.

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.

Predicting ventricular arrhythmias in patients with ischemic heart disease: clinical application of the ECG-derived QRS-T angle.

BACKGROUND: In patients with primary prevention implantable cardioverter-defibrillators (ICDs), the incidence of life-threatening ventricular arrhythmias resulting in ICD therapy is relatively low, prompting for better risk stratification. The aim of this study was to assess the value of the QRS-T angle for prediction of ICD therapy and mortality in primary prevention patients with ischemic heart disease. METHODS AND RESULTS: ICD patients (n=412, 361 men; age, 63+/-11 years) with ischemic heart disease and a left ventricular ejection fraction < or = 40% were included. After device implantation, the occurrence of appropriate ICD therapy and mortality was noted. A survival analysis was performed comparing patients with a planar QRS-T angle < or = 90 degrees (n=124, 30%) with patients with a planar QRS-T angle >90 degrees before device implantation. Furthermore, patients with a spatial QRS-T angle < or = 100 degrees (n=56, 14%) were compared with patients with a spatial QRS-T angle >100 degrees , before implantation. For patients with a planar QRS-T angle >90 degrees as compared with < or = 90 degrees , the adjusted hazard ratio for the occurrence of appropriate device therapy was 2.4 (95% CI, 1.1 to 5.2); a spatial QRS-T angle >100 degrees was associated with an adjusted hazard ratio of 7.3 (95% CI, 1.0 to 53.8). Furthermore, a spatial QRS-T angle < or = 100 degrees exhibited a positive predictive value of 98% (95% CI, 95 to 100) for the prediction of an appropriate therapy-free follow-up. CONCLUSIONS: A wide QRS-T angle is a strong predictor of appropriate device therapy in primary prevention ICD recipients with ischemic heart disease. Furthermore, a spatial QRS-T angle < or = 100 degrees might be of value in the identification of patients in whom, although currently indicated, ICD treatment should be reconsidered.