Mortality, morbidity, and complications in 3344 patients with implantable cardioverter defibrillators: results fron the German ICD Registry EURID

Can Frailty Be a Predictor of ICD Shock after the Implantation of a Cardioverter Defibrillator in Elderly Patients?

INTRODUCTION

The aim of the study was to assess the prevalence of frailty among elderly patients who had an implanted cardioverter defibrillator, as well as the influence of frailty on the main endpoints during the follow-up.

METHODS

The study included 103 patients > 60 years of age (85M, aged 71.56-8.17 years). All of the patients had an implanted single or dual-chamber cardioverter-defibrillator. In the research, there was a 12-month follow-up. The occurrence of frailty syndrome was assessed using the Tilburg Frailty Indicator scale (TFI).

RESULTS

Frailty syndrome was diagnosed in 75.73% of the patients that were included in the study. The mean values of the TFI were 6.55 ± 2.67, in the physical domain 4.06 ± 1.79, in the psychological domain 2.06 ± 1.10, and in the social domain 0.44 ± 0.55. During the follow-up period, 27.2% of patients had a defibrillator cardioverter electric shock, which occurred statistically more often in patients with diagnosed frailty syndrome (34.6%) compared to the robust patients (4%); p = 0.0062. In the logistic regression, frailty (OR: 1.203, 95% CI:1.0126-1.4298; p < 0.030) was an independent predictor of a defibrillator cardioverter electric shock. Similarly, in the logistic regression, frailty (OR: 1.3623, 95% CI:1.0290-1.8035; p = 0.019) was also an independent predictor for inadequate electric shocks.

CONCLUSION

About three-quarters of the elderly patients that had qualified for ICD implantation were affected by frailty syndrome. In the frailty subgroup, adequate and inadequate shocks occurred more often compared to the robust patients.

Relationship of LVEF and Myocardial Scar to Long-Term Mortality Risk and Mode of Death in Patients With Nonischemic Cardiomyopathy

BACKGROUND

Nonischemic cardiomyopathy is a leading cause of reduced left ventricular ejection fraction (LVEF) and is associated with high mortality risk from progressive heart failure and arrhythmias. Myocardial scar on cardiovascular magnetic resonance imaging is increasingly recognized as a risk marker for adverse outcomes; however, left ventricular dysfunction remains the basis for determining a patient's eligibility for primary prophylaxis with implantable cardioverter-defibrillator. We investigated the relationship of LVEF and scar with long-term mortality and mode of death in a large cohort of patients with nonischemic cardiomyopathy.

METHODS

This study is a prospective, longitudinal outcomes registry of 1020 consecutive patients with nonischemic cardiomyopathy who underwent clinical cardiovascular magnetic resonance imaging for the assessment of LVEF and scar at 3 centers.

RESULTS

During a median follow-up of 5.2 (interquartile range, 3.8, 6.6) years, 277 (27%) patients died. On survival analysis, LVEF ≤35% and scar were strongly associated with all-cause (log-rank test P=0.002 and P<0.001, respectively) and cardiac death (P=0.001 and P<0.001, respectively). Whereas scar was strongly related to sudden cardiac death (SCD; P=0.001), there was no significant association between LVEF ≤35% and SCD risk (P=0.57). On multivariable analysis including established clinical factors, LVEF and scar are independent risk markers of all-cause and cardiac death. The addition of LVEF provided incremental prognostic value but insignificant discrimination improvement by C-statistic for all-cause and cardiac death, but no incremental prognostic value for SCD. Conversely, scar extent demonstrated significant incremental prognostic value and discrimination improvement for all 3 end points. On net reclassification analysis, the addition of LVEF resulted in no significant improvement for all-cause death (11.0%; 95% CI, -6.2% to 25.9%), cardiac death (9.8%; 95% CI, -5.7% to 29.3%), or SCD (7.5%; 95% CI, -41.2% to 42.9%). Conversely, the addition of scar extent resulted in significant reclassification improvement of 25.5% (95% CI, 11.7% to 41.0%) for all-cause death, 27.0% (95% CI, 11.6% to 45.2%) for cardiac death, and 40.6% (95% CI, 10.5% to 71.8%) for SCD.

CONCLUSIONS

Myocardial scar and LVEF are both risk markers for all-cause and cardiac death in patients with nonischemic cardiomyopathy. However, whereas myocardial scar has strong and incremental prognostic value for SCD risk stratification, LVEF has no incremental prognostic value over clinical measures. Scar assessment should be incorporated into patient selection criteria for primary prevention implantable cardioverter-defibrillator placement.

Reduction in depressive symptoms in primary prevention ICD scheduled patients - One year prospective study

OBJECTIVE

Implantable Cardioverter Defibrillators (ICDs), have previously been associated with the onset of depression and anxiety. The aim of this one-year prospective study was to evaluate the rate of new onset psychopathological symptoms after elective ICD implantation.

METHODS

A total of 158 consecutive outpatients who were scheduled for an elective ICD implantation were diagnosed and screened based on the Mini International Neuropsychiatric Interview (MINI). Depression and anxiety were evaluated using the Hamilton Rating Scales for Depression (HAM-D) and Anxiety (HAM-A). Patient's attitude toward the ICD device was evaluated using a Visual Analog Scale (VAS).

RESULTS

Patients' mean age was 64±12.4years; 134 (85%) were men, with the majority of patients performing the procedure for reasons of 'primary prevention'. According to the MINI diagnosis at baseline, three (2%) patients suffered from major depressive disorder and ten (6%) from dysthymia. Significant improvement in HAM-D mean scores was found between baseline, three months and one year after implantation (6.50±6.4; 4.10±5.3 and 2.7±4.6, respectively F(2100)=16.42; p<0.001). There was a significantly more positive attitude toward the device over time based on the VAS score [F(2122)=53.31, p<0.001].

CONCLUSIONS

ICD implantation significantly contributes to the reduction of depressive symptoms, while the overall mindset toward the ICD device was positive and improved during the one-year follow-up.

Long-term complications, reoperations and survival following cardioverter-defibrillator implant

OBJECTIVE

Implantable cardioverter-defibrillators (ICDs) reduce risk of death in select populations, but are also associated with harms. We aimed to characterise long-term complications and reoperation rate.

METHODS

We assessed the rate, cumulative incidence and predictors of long-term reoperation and survival using a prospective, multicentre registry serving British Columbia in Canada, a universal single payer healthcare system with 4.5 million residents. 3410 patients (mean 63.3 years, 81.7% male) with new primary (n=1854) or secondary prevention (n=1556) ICD implant from 2003 to 2012 were followed for a median of 34 months (single chamber n=1069, dual chamber n=1905, biventricular n=436). Independent predictors of adverse outcomes were defined using Cox regression models.

RESULTS

The overall reoperation rate was 12.0% per patient-year, and less for single vs dual vs biventricular ICDs (9.1% vs 12.5% vs 17.8% per patient-year, respectively). The Kaplan-Meier complication estimates (excluding generator end of life) at 1, 3 and 5 years were respectively: single chamber 10.2%, 16.2% and 21.6%; dual 11.7%, 19.1% and 27.4% and biventricular 15.9%, 22.2% and 24.7%. Cardiac resynchronisation therapy had the highest rate of early lead complications, but lower long-term need for upgrade. Device complexity, age and atrial fibrillation were key determinants of complications. Overall mortality at 1, 3 and 5 years was 5.4%, 17.4% and 32.7%, respectively. In younger patients, observed 5-year survival approached the expected survival in the general population (relative survival ratio=0.96 (0.90-0.98)). With increasing age, observed survival steadily declined relative to expected.

CONCLUSIONS

In a prospective registry capturing all procedures, complication and reoperation rates following de novo ICD implantation were high. Shared decision making must carefully consider these factors.

Results of a curtailed randomized controlled trial, evaluating the efficacy and safety of azimilide in patients with implantable cardioverter-defibrillators: The SHIELD-2 trial

BACKGROUND

Frequent hospital attendances in patients with implantable cardioverter-defibrillators (ICDs) result in significant morbidity and health care costs. Current drugs to reduce ICD shocks and hospital visits have limited efficacy and considerable toxicity. We evaluated the efficacy and safety of azimilide, a novel oral class III antiarrhythmic, for use in ICD patients.

METHODS

A total of 240 patients were enrolled in a prospective, randomized, double-blind, placebo-controlled trial to evaluate the effect of oral azimilide 75 mg daily in ICD patients with previously documented ventricular tachycardia or ventricular fibrillation, and a left ventricular ejection fraction ≤40%. The primary outcome metric was the adjudicated time-to-first unplanned cardiovascular (CV) hospitalization, or CV emergency department (ED) visit, or CV death. The trial was prematurely discontinued due to withdrawal of study sponsorship.

RESULTS

Azimilide demonstrated numerical but statistically nonsignificant reductions in the primary composite outcome (odds ratio [OR] 0.79, 95% CI 0.44-1.44), unplanned CV hospitalizations (OR 0.75, 95% CI 0.41-1.38), ED visits (OR 0.68, 95% CI 0.35-1.31), and all-cause shocks (OR 0.58, 95% CI 0.32-1.05). The incidence of adverse events was lower in the azimilide group. Neutropenia was not observed (absolute neutrophil count <1000 μ/L), and there was one possible torsade de pointes case that led to a successful ICD discharge.

CONCLUSION

The SHIELD-2 trial was statistically underpowered due to early trial termination and did not meet its primary objective. Despite this limitation, azimilide showed promise as a safe and effective drug in reducing all-cause shocks, unplanned hospitalizations, and ED visits in ICD patients.

Implantable Cardioverter Defibrillator Therapy and the Need for Concomitant Antiarrhythmic Drugs

Implantable cardioverter defibrillators (ICDs) are increasingly used for the prevention of sudden cardiac death in patients with life-threatening ventricular arrhythmias (VAs); however, there is a potential for severe and debilitating anxiety caused by symptoms associated with ICD therapy and anticipation of shocks. Anxiety is a psycho-logic stressor, including physiologic components that may lead to adrenergic excitation triggering new arrhythmias and ICD therapies. This often requires concomitant antiarrhythmic medication to reduce the frequency of shocks and symptomatic arrhythmias treated by anti-tachycardia pacing. Although published studies have documented the efficacy of currently available antiarrhythmics, they have limitations in patients with heart failure, may affect the defibrillation threshold, and/or have been associated with major side-effects. In conclusion, for the patient with an ICD experiencing symptomatic ventricular tachycardia (VTs) episodes or ICD shocks, there is a need for pharmacologic therapy to reduce the incidence of such events without affecting the performance of the ICD or causing major side-effects.

A Subclavian Arteriovenous Fistula Associated with Implantable Cardioverter-Defibrillator Implantation

Subclavian arteriovenous fistulas (AVFs) should be considered in the differential diagnosis of a patient presenting with worsening CHF symptoms or unilateral edema immediately after device implantation. A palpable thrill may be present or a bruit may be auscultated in the region of the fistula. Ultrasonography has limitations in the subclavian region and definitive diagnosis is only made by angiogram. Percutaneous occlusion of the AVF is preferred as surgical repair is associated with significant morbidity and mortality.

Cardiac sympathetic innervation assessed with (123)I-MIBG retains prognostic utility in diabetic patients with severe left ventricular dysfunction evaluated for primary prevention implantable cardioverter-defibrillator

BACKGROUND

Scintigraphy with iodine-123-metaiodobenzylguanidine ((123)I-MIBG) is a non-invasive tool for the assessment of cardiac sympathetic innervation (CSI) that has proven to be an independent predictor of survival. Recent studies have shown that diabetic patients with heart failure (HF) have a higher deterioration in CSI. It is unknown if (123)I-MIBG has the same predictive value for diabetic and non-diabetic patients with advanced HF. An analysis is performed to determine whether CSI with (123)I-MIBG retains prognostic utility in diabetic patients with HF, evaluated for a primary prevention implantable cardioverter-defibrillator (ICD).

MATERIAL AND METHODS

Seventy-eight consecutive HF patients (48 diabetic) evaluated for primary prevention ICD implantation were prospectively enrolled and underwent (123)I-MIBG to assess CSI (heart-to-mediastinum ratio - HMR). A Cox proportional hazards multivariate analysis was used to determine the influence of (123)I-MIBG images for prediction of cardiac events in both diabetic and non-diabetic patients. The primary end-point was a composite of arrhythmic event, cardiac death, or admission due to HF.

RESULTS

During a mean follow-up of 19.5 [9.3-29.3] months, the primary end-point occurred in 24 (31%) patients. Late HMR was significantly lower in diabetic patients (1.30 vs. 1.41, p=0.014). Late HMR≤1.30 was an independent predictor of cardiac events in diabetic (hazard ratio 4.53; p=0.012) and non-diabetic patients (hazard ratio 12.31; p=0.023).

CONCLUSIONS

Diabetic patients with HF evaluated for primary prevention ICD show a higher deterioration in CSI than non-diabetics; nevertheless (123)I-MIBG imaging retained prognostic utility for both diabetic and non-diabetic patients.

Rates of and Factors Associated With Infection in 200 909 Medicare Implantable Cardioverter-Defibrillator Implants

Background—

The rate of implantable cardioverter-defibrillator (ICD) infections has been increasing faster than that of implantation. We sought to determine the rate and predictors of ICD infection in a large cohort of Medicare patients.

Methods and Results—

Cases submitted to the ICD Registry from 2006 to 2009 were matched to Medicare fee-for-service claims data using indirect patient identifiers. ICD infections occurring within 6 months of hospital discharge after implantation were identified by ICD-9 codes. Logistic regression was used to examine factors associated with risk of ICD infection. Of 200 909 implants, 3390 patients (1.7%) developed an ICD infection. The infection rate was 1.4%, 1.5%, and 2.0% for single, dual, and biventricular ICDs, respectively ( P <0.001). Generator replacement had a higher rate compared with initial implant (1.9% versus 1.6%, P <0.001). The factors associated with infection were adverse event during implant requiring reintervention (odds ratio [OR], 2.692; 95% confidence interval [CI], 2.304–3.145), previous valvular surgery (OR, 1.525; 95% CI, 1.375–1.692), reimplantation for device upgrade, malfunction, or manufacturer advisory (OR, 1.354; 95% CI, 1.196–1.533), renal failure on dialysis (OR, 1.342; 95% CI, 1.123–1.604), chronic lung disease (OR, 1.215; 95% CI, 1.125–1.312), cerebrovascular disease (OR, 1.172; 95% CI, 1.076–1.276), and warfarin (OR, 1.155; 95% CI, 1.060–1.257).

Conclusions—

Patients who developed an ICD infection were more likely to have had peri-ICD implant complications requiring early reintervention, previous valve surgery, device replacement for reasons other than battery depletion, and increased comorbidity burden. Efforts should be made to carefully consider when to reenter the pocket at any time other than battery replacement.

Follow-up of implantable cardioverter-defibrillator therapy: comparison of coronary artery disease and dilated cardiomyopathy

PURPOSE

Since several large trials have proven the effectiveness of implantable cardioverter-defibrillators (ICDs) in patients with left ventricular dysfunction, disadvantages have become more apparent. As the prognosis of patients with cardiovascular diseases is improving, assessment of ICD patients and re-evaluation of the current guidelines is mandatory. We aimed to evaluate differences in mortality and occurrence of (in)appropriate shocks in ICD patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM).

METHODS

In a large teaching hospital, all consecutive patients with systolic dysfunction due to CAD or DCM who received an ICD with and without resynchronisation therapy, were collected in a database.

RESULTS

A total of 320 consecutive patients (age 67 ± 10 years) were classified as CAD patients and 178 (63 ± 11 years) as DCM patients. Median follow-up was 40 months (interquartile range [IQR] 23─57 months). All-cause mortality was 14 % (CAD 15 % vs DCM 13 %). Appropriate shocks occurred in 13 % of all patients (CAD 15 % vs DCM 11 %, p = 0.12) and inappropriate shocks occurred in 10 % (CAD 8 % vs DCM 12 %, p = 0.27). Multivariate analysis demonstrated impaired left ventricular ejection fraction, QRS >120, age ≥75 years and low estimated glomerular filtration rate as predictors for all-cause mortality. Predictors for inappropriate shocks were permanent and paroxysmal atrial fibrillation.

CONCLUSION

Mortality rates were similar in patients with CAD and DCM who received an ICD. Furthermore, no differences were found in the occurrence of appropriate and inappropriate ICD interventions between these patient groups.

Reduction of the inappropriate ICD therapies by implementing a new fuzzy logic-based diagnostic algorithm

AIMS

The aim of the study was to analyze the value of a completely new fuzzy logic-based detection algorithm (FA) in comparison with arrhythmia classification algorithms used in existing ICDs in order to demonstrate whether the rate of inappropriate therapies can be reduced.

METHODS

On the basis of the RR intervals database containing arrhythmia events and controls recordings from the ICD memory a diagnostic algorithm was developed and tested by a computer program. This algorithm uses the same input signals as existing ICDs: RR interval as the primary input variable and two variables derived from it, onset and stability. However, it uses 15 fuzzy rules instead of fixed thresholds used in existing devices. The algorithm considers 6 diagnostic categories: (1) VF (ventricular fibrillation), (2) VT (ventricular tachycardia), (3) ST (sinus tachycardia), (4) DAI (artifacts and heart rhythm irregularities including extrasystoles and T-wave oversensing-TWOS), (5) ATF (atrial and supraventricular tachycardia or fibrillation), and 96) NT (sinus rhythm). This algorithm was tested on 172 RR recordings from different ICDs in the follow-up of 135 patients.

RESULTS

All diagnostic categories of the algorithm were present in the analyzed recordings: VF (n = 35), VT (n = 48), ST (n = 14), DAI (n = 32), ATF (n = 18), NT (n = 25). Thirty-eight patients (31.4%) in the studied group received inappropriate ICD therapies. In all these cases the final diagnosis of the algorithm was correct (19 cases of artifacts, 11 of atrial fibrillation and 8 of ST) and fuzzy rules algorithm implementation would have withheld unnecessary therapies. Incidence of inappropriate therapies: 3 vs. 38 (the proposed algorithm vs. ICD diagnosis, respectively) differed significantly (p < 0.05). VT/VF were detected correctly in both groups. Sensitivity and specificity were calculated: 100%, 97.8%, and 100%, 72.9% respectively for FA and tested ICDs recordings (p < 0.05).

CONCLUSIONS

Diagnostic performance of the proposed fuzzy logic based algorithm seems to be promising and its implementation could diminish ICDs inappropriate therapies. We found FA usefulness in correct diagnosis of sinus tachycardia, atrial fibrillation and artifacts in comparison with tested ICDs.

Intraoperative defibrillation threshold testing and postoperative long-term efficacy of cardioverter-defibrillator implantation

The aim of this study was to determine the defibrillation threshold (DFT) of implantable cardioverter-defibrillators (ICDs) and outcomes of treatment. Sixty-four patients received cardioverter-defibrillator implantation. During implantation, the DFT was determined by the defibrillation safety margin (DSM). All patients were followed up for 12–48 months after the implantation. The overall DFT was 14.27±2.56 J and the DSM was 18.40±1.89 J. Malignant ventricular arrhythmias occurred in 42 patients following cardioverter-defibrillator implantation including 500 episodes of non-sustained ventricular tachycardia (VT) and 289 episodes of persistent VT. VT was treated using antitachycardia pacing (ATP); 265 episodes were treated successfully by a single ATP treatment (91.69%) and 12 episodes were treated successfully by two ATP treatments (4.15%). Twelve episodes were converted by low-energy electrical cardioversion (4.15%). A total of 175 ventricular fibrillation (VF) episodes were identified, of which 18 episodes automatically terminated prior to treatment. In total, 146 episodes were converted by a single cardioversion with a defibrillation energy of 13.21±2.58 J and 11 episodes were converted by two cardioversions with a defibrillation energy of 16.19±2.48 J. It is safe and feasible to determine the DFT by DSM measurement during cardioverterdefibrillator implantation.

Assessment of myocardial scarring improves risk stratification in patients evaluated for cardiac defibrillator implantation

OBJECTIVES

We tested whether an assessment of myocardial scarring by cardiac magnetic resonance imaging (MRI) would improve risk stratification in patients evaluated for implantable cardioverter-defibrillator (ICD) implantation.

BACKGROUND

Current sudden cardiac death risk stratification emphasizes left ventricular ejection fraction (LVEF); however, most patients suffering sudden cardiac death have a preserved LVEF, and many with poor LVEF do not benefit from ICD prophylaxis.

METHODS

One hundred thirty-seven patients undergoing evaluation for possible ICD placement were prospectively enrolled and underwent cardiac MRI assessment of LVEF and scar. The pre-specified primary endpoint was death or appropriate ICD discharge for sustained ventricular tachyarrhythmia.

RESULTS

During a median follow-up of 24 months the primary endpoint occurred in 39 patients. Whereas the rate of adverse events steadily increased with decreasing LVEF, a sharp step-up was observed for scar size >5% of left ventricular mass (hazard ratio [HR]: 5.2; 95% confidence interval [CI]: 2.0 to 13.3). On multivariable Cox proportional hazards analysis, including LVEF and electrophysiological-study results, scar size (as a continuous variable or dichotomized at 5%) was an independent predictor of adverse outcome. Among patients with LVEF >30%, those with significant scarring (>5%) had higher risk than those with minimal or no (≤5%) scarring (HR: 6.3; 95% CI: 1.4 to 28.0). Those with LVEF >30% and significant scarring had risk similar to patients with LVEF ≤30% (p = 0.56). Among patients with LVEF ≤30%, those with significant scarring again had higher risk than those with minimal or no scarring (HR: 3.9; 95% CI: 1.2 to 13.1). Those with LVEF ≤30% and minimal scarring had risk similar to patients with LVEF >30% (p = 0.71).

CONCLUSIONS

Myocardial scarring detected by cardiac MRI is an independent predictor of adverse outcome in patients being considered for ICD placement. In patients with LVEF >30%, significant scarring (>5% LV) identifies a high-risk cohort similar in risk to those with LVEF ≤30%. Conversely, in patients with LVEF ≤30%, minimal or no scarring identifies a low-risk cohort similar to those with LVEF >30%.

Sudden cardiac arrest and sudden cardiac death on dialysis: Epidemiology, evaluation, treatment, and prevention

Sudden cardiac death is the most common cause of death in dialysis patients and is usually preceded by sudden cardiac arrest due to ventricular tachycardia or ventricular fibrillation. A variety of risk factors have been identified that predispose the sudden cardiac arrest and sudden cardiac death in dialysis patients. Primary prevention of sudden cardiac arrest in dialysis patients may be accomplished by avoiding the use of low potassium dialysate. Pharmacotherapy with beta-blockers angiotensin converting enzyme inhibitors and angiotensin receptor blockers and use of implantable cardioverter defibrillators (ICDs) may also prevent sudden cardiac arrest and sudden cardiac death in high-risk dialysis patients. Secondary prevention of sudden cardiac death may be accomplished by similar pharmacotherapy and by the use of ICDs. Indications for ICD use in dialysis patients are similar to those for nondialysis patients; however, survival rates following ICD implantation in dialysis patients are substantially lower than in non-dialysis patients.

Managing anticoagulation in patients receiving implantable cardiac devices

A substantial proportion of patients who undergo cardiac rhythm device implantation receive anticoagulation to prevent thromboembolism. Many patients have coexisting cardiovascular diseases treated with antiplatelet therapy. Anticoagulation may increase the risk of hemorrhagic complication, while withdrawal of anticoagulation may increase thromboembolic risk. In this article, we review and describe the available evidence, in order to inform best practice .

Health care utilisation after defibrillator implantation for primary prevention according to the guidelines in 2 Dutch academic medical centres

Background

The benefit of implantable defibrillators (ICDs) for primary prevention remains debated. We analysed the implications of prophylactic ICD implantation according to the guidelines in 2 tertiary hospitals, and made a healthcare utilisation inventory.

Methods

The cohort consisted of all consecutive patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM) receiving a primary prophylactic ICD in a contemporary setting (2004–2008). Follow-up was obtained from hospital databases, and mortality checked at the civil registry. Additional data came from questionnaires sent to general practitioners.

Results

There were no demographic differences between the 2 centres; one had proportionally more CAD patients and more resynchronisation therapy (CRT-D). The 587 patients were followed over a median of 28 months, and 50 (8.5%) patients died. Appropriate ICD intervention occurred in 123 patients (21%). There was a small difference in intervention-free survival between the 2 centres. The questionnaires revealed 338 hospital admissions in 52% of the responders. Device-related admissions happened on 68 occasions, in 49/276 responders. The most frequently reported ICD-related admission was due to shocks (20/49 patients); for other cardiac problems it was mainly heart failure (52/99). Additional outpatient visits occurred in 19%.

Conclusion

Over a median follow-up of 2 years, one fifth of prophylactic ICD patients receive appropriate interventions. A substantial group undergoes readmission and additional visits. The high number of admissions points to a very ill population. Overall mortality was 8.5%. The 2 centres employed a similar procedure with respect to patient selection. One centre used more CRT-D, and observed more appropriate ICD interventions.

Long-term follow-up of prophylactic implantable cardioverter-defibrillator-only therapy: comparison of ischemic and nonischemic heart disease

BACKGROUND

The benefits of primary prophylactic implantable cardioverter-defibrillators (ICDs) are actually debated, as some drawbacks become more apparent and as the natural history of cardiac disease seems to improve. Therefore, contemporary follow-up data of non-trial populations treated according to current guidelines remain necessary. The aim of this study was to evaluate mortality and the occurrence of ICD interventions in patients with coronary artery disease (CAD) and dilated cardiomyopathy (DCM) who received in the recent era a primary prophylactic ICD without resynchronization therapy.

HYPOTHESIS

Survival and event-free rates from appropriate ICD therapy are different between ischemic and nonischemic ICD patients.

METHODS

Prospective cohort study of 427 consecutive primary prevention ICD patients with ischemic or nonischemic heart disease, excluding patients with resynchronization.

RESULTS

Ischemic heart disease was present in 290 patients (68%), nonischemic heart disease in 137 patients (32%). During a median follow-up of 31 months (interquartile range [IQR] 15-45 months), 30 patients (7%) died. Mortality was not different in both disease categories. The incidence of appropriate ICD interventions was similar in CAD and DCM (23% vs 21%). Appropriate ICD intervention occurred more frequently in patients with atrial fibrillation (29% vs 19%). Inappropriate ICD intervention occurred in 11% of patients.

CONCLUSIONS

The clinical course of ischemic and nonischemic heart disease patients treated with a primary prophylactic ICD is similar with respect to mortality and to appropriate and inappropriate ICD interventions, in spite of a younger age at baseline of the DCM patients.

Characterization and financial impact of implantable cardioverter-defibrillator patients without interventions 5 years after implantation

BACKGROUND

Implantable cardioverter defibrillators (ICD's) are increasingly used for primary and secondary prevention of sudden cardiac death. However, data on how many ICD patients indeed receive appropriate ICD therapy during long-term follow-up is scarce.

AIM

The aim of our study was to determine the number of patients without appropriate ICD therapy 5 years after ICD implantation, to identify predicting factors, to assess the occurrence of late first ICD therapy and to quantify the financial impact of ICD therapy in a real-world setting.

DESIGN

Prospective observational study.

METHODS

We prospectively enrolled 322 consecutive ICD patients. Baseline data were collected at implantation and patients were followed for a median of 7.3 years (IQR 5.8-9.2 years). Time to first appropriate ICD therapy (either antitachycardia pacing or cardioversion) was documented.

RESULTS

Five years after implantation, 139 patients (43%) had not received appropriate ICD therapy. In multivariable analysis, a primary prevention indication and negative electrophysiological studies prior to ICD implantation were independent predictors of freedom from ICD therapy. Of the patients without ICD therapy, 5 years after implantation, 25% had experienced inappropriate ICD shocks. Two hundred and seven devices (1.5 devices per patient) were needed for the 139 patients without ICD intervention within 5 years, accounting for € 31,784 per patient. During an additional follow-up of 3 years, 12% of the patients with unused ICD received a late first appropriate ICD therapy.

CONCLUSION

About half of the ICD patients receive appropriate ICD therapy within 5 years after implantation. Furthermore, there is a significant proportion of patients receiving late first shocks after five initially uneventful years.

Predictors of short-term complications after implantable cardioverter-defibrillator replacement: results from the Ontario ICD Database

BACKGROUND

Complications after implantable cardioverter-defibrillator (ICD) replacement are often clinically devastating, particularly when infection or reoperation occurs. Identifying factors contributing to complications may permit identification of high-risk individuals that warrant incremental monitoring and therapy to attenuate risk. In addition, replacement may be a discretionary decision in the context of an advisory or borderline device performance and patient, device, and implanter factors that predict adverse outcome may assist in clinical decision-making.

METHODS AND RESULTS

In a prospective, multicenter, population-based registry of all ICD patients at 18 centers in Ontario, Canada, we examined 45-day complication and all-cause mortality rates from February 2007 to August 2009 in patients undergoing ICD generator replacement. Complications were determined longitudinally and were categorized as major or minor. ICD replacement was performed in 1081 of 5176 patients (20.8%) undergoing ICD implantation (age, 64.3±12.7 years; 78.5% men). In patients undergoing ICD replacement, 47 patients (4.3%) had a complication within 45 days, with 47 major complications in 28 patients (2.6%), most commonly infection (n=23), lead revision (n=35), electrical storm (n=14), and pulmonary edema (n=13). Minor complications occurred in 2.3% of patients, most commonly incisional infection (n=10) and pocket hematoma (n=10). On multivariable analysis, risk factors associated with major complications were Canadian Cardiovascular Society angina class (adjusted hazard ratio [HR], 3.70 for class 2 to 4 versus 0 to 1; P=0.027) and multiple previous procedures on the pocket (adjusted HR, 3.35 for >1 versus 1; P=0.058). Risk factors associated with any complication were the use of antiarrhythmic therapy (adjusted HR, 6.29; P=0.001), implanter volume (adjusted HR 10.4 for <60/y versus >120/y, P=0.026), and Canadian Cardiovascular Society angina class (adjusted HR, 3.00 for class 2 to 4 versus 0 to 1; P=0.031). In a Cox model with a time-dependent variable of major complication within 45 days after replacement, major complications after ICD replacement were associated with an increased risk of mortality at 45, 90, and 180 days (adjusted HR, 9.61, 12.69, and 6.41, respectively; P=0.002 to 0.039).

CONCLUSIONS

Risk factors associated with complications after ICD replacement include the presence of angina, antiarrhythmic therapy, increased number of previous procedures, and low implanter volume. Major complications may be associated with increased risk of subsequent mortality.

Acute Antiarrhythmic Therapy of Ventricular Tachycardia and Ventricular Fibrillation

Ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation) are often associated with underlying structural heart disease and require prompt assessment and treatment. Acute treatment involves initial hemodynamic stabilization of the patient followed by suppressive treatment with pharmacologic and nonpharmacologic approaches for reducing the risk of recurrence of ventricular arrhythmias and potential development of sudden cardiac death. This article reviews acute antiarrhythmic drug therapy for ventricular arrhythmias based on the clinical presentation.

Chronic Suppression of Ventricular Tachyarrhythmias in Patients with ICDs

In this review, we examine the data evaluating the role of adjuvant therapy with antiarrthymic drugs (AADs) in chronic suppression of ventricular tachyarrhythmias in the patient with an ICD. It must be noted that all uses of AADs for this indication represent "off-label" prescription. No AAD is approved by the Food and Drug Administration (FDA) specifically as a therapy to reduce ICD shocks.

Predictors of appropriate therapy in patients with implantable cardioverter-defibrillator for primary prevention of sudden cardiac death

The purpose of this study was to evaluate predictors of appropriate therapy in patients with implantable cardioverter-defibrillators (ICD) for primary prevention of sudden cardiac death. A retrospective cohort of 321 patients with systolic heart failure undergoing ICD placement for primary prevention of sudden cardiac death was queried with a mean follow-up period of 2.6 years. Appropriate ICD therapy was defined as therapy delivered for termination of a ventricular tachyarrhythmia. Appropriate ICD therapy was delivered in 142 (44%) of the patients. In a multivariate model, body mass index ≥28.8 kg/m², chronic kidney disease, left ventricular ejection fraction ≤20% and metabolic syndrome were found to be independent predictors of appropriate ICD therapy. Appropriate ICD therapy was associated with higher cardiovascular mortality. These findings show the importance of identification of risk factors, especially metabolic syndrome, in patients following ICD implantation as aggressive treatment of these co-morbidities may decrease appropriate ICD therapy and cardiovascular mortality.

Predictors for short-term progressive heart failure death in New York Heart Association II patients implanted with a cardioverter defibrillator--the EVADEF study

BACKGROUND

Sudden cardiac death (SCD) is the predominant cause of mortality in patients with mild heart failure (HF). This 2-year follow-up, multicenter, cohort study aimed to assess the extent to which implantable cardioverter defibrillators (ICDs), by reducing SCD, lead to predominant progressive HF death in mildly symptomatic HF patients at baseline in daily medical practice.

METHODS

Between June 2001 and June 2003, 1,030 New York Heart Association II patients received an ICD in 22 French centers. Sudden cardiac death and progressive HF mortality rates were assessed using competing risk methodology, and predictors for progressive HF at baseline were tested in a multivariate regression model.

RESULTS

During a mean follow-up of 22 +/- 6 months, 114 deaths occurred: 12 (10.5%) due to SCD and 52 (45.6%) due to progressive HF (24-month cause-specific mortality rates of 1.2% [95% CI 0.6-1.9] and 5.4% [95% CI 4.0-6.8], respectively). Diuretics use (hazard ratio [HR] 2.8, 95% CI 1.5-5.5, P = .002), history of atrial fibrillation (HR 2.09, 95% CI 1.2-3.65, P = .01), and low ejection fraction (HR 2.7, 95% CI 1.4-4.8, P = .0008) were independent predictors for progressive HF death, whereas beta-blocker therapy was a protector (HR 0.6, 95% CI 0.3-0.9, P = .04). Half of the patients (48%) who died from progressive HF within 2 years of ICD implant initially presented with enlarged QRS (> or =120 milliseconds).

CONCLUSIONS

Because of ICD efficiency, progressive HF is the main cause of death within 2 years of implant, although these patients are only mildly symptomatic at implantation. In addition to optimal pharmacologic therapy, these results raise the question of systematically implanting ICDs with cardiac resynchronization therapy in patients with electrical asynchronism at baseline.

Evaluation of early complications related to De Novo cardioverter defibrillator implantation insights from the Ontario ICD database

OBJECTIVES

This study examined the predictors of early complications after defibrillator implantation.

BACKGROUND

Although implantable cardioverter-defibrillators are widely used, predictors of procedural complications and the consequences of these events have not been determined.

METHODS

In a prospective, multicenter, population-based clinical outcomes registry of all newly implanted defibrillator patients at 18 centers in Ontario, Canada, we examined 45-day complications and all-cause mortality from February 2007 to May 2009. Complications were determined longitudinally and were categorized as direct implant-related or indirect events.

RESULTS

Among 3,340 patients (mean age 63.8 +/- 12.5 years, 78.5% men), major complications occurred in 4.1% of de novo procedures. Compared with those undergoing a single-chamber device, implantation of a cardiac resynchronization defibrillator (adjusted hazard ratio [HR]: 2.17, 95% confidence interval [CI]: 1.38 to 3.43, p < 0.001) or dual-chamber device (adjusted HR: 1.82, 95% CI: 1.19 to 2.79, p = 0.006) was associated with increased risk of major complications. Major complications were increased in women (adjusted HR: 1.49, 95% CI: 1.02 to 2.16, p = 0.037) and when left ventricular end-systolic dimension exceeded 45 mm (adjusted HR: 1.54, 95% CI: 1.08 to 2.20, p = 0.018). Major complications (excluding death) occurring early after defibrillator implantation were associated with increased adjusted risk of subsequent death up to 180 days after defibrillator implant (adjusted HR: 3.70, 95% CI: 1.64 to 8.33, p = 0.002). Direct implant-related complications were associated with increased risk of early death (adjusted HR: 24.89, p = 0.01), whereas indirect clinical complications conferred increased risk of near-term death (adjusted HR: 12.35, p < 0.001) after defibrillator implantation.

CONCLUSIONS

Complications after de novo defibrillator implantation were strongly associated with device type. Major complications were associated with increased risk of mortality.

Inappropriate Implantable Cardioverter-Defibrillator Therapy

Although improvements in implantable cardioverter-defibrillator (ICD) therapy have taken place, many challenges do remain. Inappropriate delivery of therapy is a big problem that impacts the quality of life of ICD recipients. Although there is now a clear understanding that atrial arrhythmias are the main cause of inappropriate ICD therapies, physicians have not been very successful in preventing them. Additionally, although many tachycardia detection discriminators have been shown to be helpful, it is not clear that there is a particular combination that is ideal for all patients. Until such an algorithm is developed (which may not be possible), a detailed knowledge and use of all available programming options, guided by special characteristics of each unique patient, are the only foreseeable solutions. Finally, one must face the prospect that this problem cannot be vanquished, but only ameliorated.

Predictors of implantable cardioverter defibrillator shocks during the first year

The purpose of this study was to predict implantable cardioverter defibrillator (ICD) shocks using demographic and clinical characteristics in the first year after implantation for secondary prevention of cardiac arrest. A prospective design was used to follow 168 first-time ICD recipients over 12 months. Demographic and clinical data were obtained from medical records at the time of ICD insertion. Implantable cardioverter defibrillator shock data were obtained from ICD interrogation reports at hospital discharge, 3, 6, and 12 months. Logistic regression was used to predict ever receiving an ICD shock using background characteristics. Patients received an ICD for secondary prevention of sudden cardiac arrest, they were 64.1 years old, 89% were white, 77% were male, with a mean (SD) ejection fraction of 33.7% (14.1%). The cumulative percentage of ever receiving an ICD shock was 33.3% over 1 year. Three variables predicted shocks in the first year: history of chronic obstructive pulmonary disease (COPD) (odds ratio [OR], 4.42; 95% confidence interval [CI], 1.2-16.4; P = .03), history of congestive heart failure (OR, 3.55; 95% CI, 1.4-9.3; P = .01), and documented ventricular tachycardia (VT) at the time of ICD implant (OR, 10.05; 95% Cl, 1.8-55.4; P = .01). High levels of anxiety approached significance (OR = 2.82; P = .09). The presence of COPD, congestive heart failure, or VT at ICD implant was a significant predictor of receiving an ICD shock in the first year after ICD implantation. Because ICD shocks are distressing, painful, and associated with greater mortality, healthcare providers should focus attention on prevention of shocks by controlling VT, careful management of HF symptoms, reduction of the use of short acting beta agonist medications in COPD, and perhaps recognizing and treating high levels of anxiety.

Competing risk analysis of cause-specific mortality in patients with an implantable cardioverter-defibrillator: The EVADEF cohort study

BACKGROUND

Although implantable cardioverter-defibrillator (ICD) therapy has been evaluated in randomized controlled trials, enrolling highly selected patients, mortality events in ICD patients have received little attention in routine medical care. We sought to assess the 24-month total and cause-specific mortality rates and their predictors in "real life" patients with an ICD.

METHODS

The Evaluation Médico-Economique du Défibrillateur Automatique Implantable study was a French multicenter, prospective, observational cohort study of ICD patients with a 2-year follow-up. Cause-specific mortality rates and predictors at implantation of sudden cardiac death (SCD) or progressive heart failure (HF) death were assessed using competing risk methodology.

RESULTS

From June 2001 to June 2003, 2,296 unselected patients were implanted and followed until June 2005. During a mean follow-up of 20.5 +/- 6.7 months, 274 deaths occurred: 29 (10.6%) were SCD and 146 (53.3%) were HF deaths, corresponding to 24-month cause-specific mortality rates of 1.4% (95% confidence interval 0.9%-1.9%) and 6.9% (95% confidence interval 5.8%-8.0%), respectively. Among the characteristics at implantation, ejection fraction (EF) <30% and history of atrial fibrillation were independently associated with SCD; age, high New York Heart Association class, systemic hypertension, prior atrial fibrillation, QRS duration, EF <30%, and lack of beta-blocker therapy were independently associated with HF death.

CONCLUSIONS

In this large cohort of "daily" patients, the 2-year incidence of SCD (1.4%) was comparable with the event rate observed in randomized controlled trials; HF remained the predominant mode of death. An EF <30% at implantation appears to be the most important predictor of ICD-unresponsive SCD.

Fatal complications of pacemaker and implantable cardioverter-defibrillator implantation: medical malpractice?

OBJECTIVES

Pacemaker implantation has become a routine procedure in modern cardiology, and implantable cardioverter-defibrillators are implanted with rising frequency. Although fatal complications are relatively rare, they may give rise to malpractice lawsuits against medical personnel. The objective was to identify fatal complications after pacemaker and implantable cardioverter-defibrillators implantation and to evaluate the legal consequences in alleged malpractice cases.

METHODS

Retrospective analysis of all 27,730 autopsy cases performed at the Institute of Legal Medicine, Hamburg, Germany, between January 1983 and June 2007. Study cases were identified using the keywords 'cardiac death', 'malpractice', 'complications', 'pacemaker' and 'implantable cardioverter-defibrillator'.

RESULTS

Eleven pacemaker-related and four implantable cardioverter-defibrillator-related fatalities where lawsuits had been filed were identified. A causal connection between the procedure and fatal outcome was confirmed by autopsy in six cases. Malpractice or violation of the rules of good medical practice could be excluded in all cases. All inquiries were abandoned.

CONCLUSION

Fatal complications after pacemaker and implantable cardioverter-defibrillator implantation attributable to medical malpractice are extremely rare. The study illustrates the importance of a medico-legal autopsy in alleged fatal malpractice cases.

Prevention of inappropriate therapy in implantable defibrillators: A meta-analysis of clinical trials comparing single-chamber and dual-chamber arrhythmia discrimination algorithms

INTRODUCTION

A proposed benefit of dual-chamber arrhythmia discrimination is a reduction in inappropriate therapy in implantable cardioverter-defibrillators (ICDs). The aim of this meta-analysis was to establish whether dual-chamber arrhythmia discrimination algorithms reduce inappropriate device therapy.

METHODS AND RESULTS

Public domain databases, MEDLINE, EMBASE, and Cochrane Register of Controlled Trials, were searched from 1996 to 2006. Two investigators abstracted data independently. Pooled estimates were calculated using both fixed-effects and random-effects models. We retrieved 5 prospective studies comparing dual-chamber with single-chamber arrhythmia discrimination, accumulating data on 748 patients. Pooled per-patient based analysis demonstrated that the number of patients receiving inappropriate ICD therapy was not different between single- and dual-chamber devices (odds ratio [OR] 1.23; 95% CI, 0.83 to 1.81; p=0.31). Per-episode based analysis demonstrated a favoring benefit for dual-chamber arrhythmia discrimination (OR 0.64; 95% CI, 0.52 to 0.78; p<0.001). A mean reduction of 1.1 inappropriately treated atrial episodes per patient was observed with dual-chamber arrhythmia discrimination (p<0.001).

CONCLUSIONS

Dual-chamber arrhythmia discrimination is associated with a reduction in the number of inappropriate treated episodes. The number of patients who experience inappropriate therapy is not reduced by dual-chamber discrimination.