Predicting long-term survival after de novo cardioverter-defibrillator implantation for primary prevention: A population based study

Background

Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death in patients with left ventricular dysfunction. While short-term mortality benefit of ICD insertion has been established in landmark randomized controlled trials, little is known about the long-term outcomes of patients with ICDs in clinical practice. In this paper, we describe the long-term survival of patients following de novo ICD implantation for primary prevention in clinical practice and determine the factors which help predict survival after ICD implant.

Methods

Retrospective population-based study of all patients receiving a de novo ICD for primary prevention in Ontario, Canada from 2007 to 2011 using the Ontario ICD Database housed within ICES. Simple random selection was used to split the population into a derivation and internal validation cohort in a ratio of 2:1. Cox proportional hazards regression was used to determine predictors of interest and predict 10-year survival, model performance was assessed using calibration and validation.

Results

In the derivation cohort (n = 3399), mean age was 65.3 years (standard deviation [SD] = 11.0), 664 patients were female (19.5 %) and 2344 patients (69.0 %) had ischemic cardiomyopathy. Ten year survival was 45.7 % (95 % confidence interval [CI] 44.0 %-47.4 %). The final prediction model included age, sex, disease factors (ischemic vs nonischemic cardiomyopathy, left ventricular ejection fraction) and patient factors (symptoms, comorbidities), and biomarkers at the time of ICD assessment. This model had good discrimination and calibration in derivation (0.79, 95 % CI 0.77, 0.81) and validation samples (0.78, 95 % CI 0.76, 0.79).

Conclusions

A combination of demographic and clinical factors determined at baseline can be used to predict 10-year survival in patients with implantable cardioverter-defibrillators with good accuracy. Our findings help to identify individuals at risk of long-term mortality and may be useful in targeting future prevention strategies to enhance longevity in this high-risk population.

Comparison and predictors of implantable cardioverter-defibrillator therapy for primary and secondary prevention

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) are effective in detecting and treating ventricular arrhythmias. Studies on ICD therapy for different indications (primary and secondary prevention) and possible predictors of ICD therapy are limited. In this study, the incidence and type of ICD therapy were related to the indication and the underlying cardiac pathology.

METHODS

A single-centre, retrospective and observational study was performed of 482 patients who underwent ICD implantation for primary (53.3%) or secondary prevention (46.7%) between 2015 and 2020 at the Radboud University Medical Centre.

RESULTS

During a median follow-up of 2.4 years (interquartile range 0.2-3.9), the occurrence of appropriate ICD therapy for primary versus secondary prevention was 9.7% and 27.6%, respectively (p < 0.001). Time to appropriate ICD therapy was significantly shorter in the secondary prevention group (p < 0.001). No difference in ICD therapy was seen for different underlying aetiologies. In the majority of cases (70%) ICD therapy was given for ventricular tachycardia (VT). The occurrence of adverse events (16.3% vs 17.3%, p = 0.772), hospitalisation for cardiovascular reasons (29.2% vs 35.1%, p = 0.559) and all-cause mortality (12.5% vs 11.6%, p = 0.763) were similar in both groups. Male gender (3.53, 95% confidence interval (CI) (1.003, 12.403), p = 0.049) and secondary prevention indication (4.90, 95% CI (1.495, 16.066), p = 0.009) were predictors of appropriate ICD therapy.

CONCLUSION

The risk associated with appropriate ICD therapy is higher in secondary prevention patients, who have their first therapy within a shorter time frame after device implantation. Rates of complications, hospitalisation and all-cause mortality are comparable. Future treatment options should target the prevention of ICD therapy, mainly by preventing the recurrence of VT.

CRT-D replacement strategy: results of the BioCONTINUE study

BACKGROUND

In patients with cardiac resynchronization therapy defibrillators (CRT-Ds), the need for implantable cardioverter-defibrillator (ICD) back-up may be questionable at time of CRT-D replacement (REP) if ICD implant criteria are no longer met due to an improved left ventricular ejection fraction (LVEF) and if no major ventricular arrhythmic event (VAE) occurred during the CRT-D lifetime. The aim of our study was to assess the relevance of ICD back-up and predictors of VAE after REP in primary prevention CRT-D patients.

METHODS

The prospective, observational, international BioCONTINUE study investigated the rate of patients with at least 1 sustained VAE (sVAE) post-REP and searched for predictive factors of sVAE.

RESULTS

Two hundred seventy-six patients (70 ± 10 years, 77% men, mean LVEF 40.6 ± 12.6%) were followed for 28.4 ± 10.2 months. The rate of patients with sVAE was 8.3%, 10.3%, and 21.2% at 1, 2, and 4 years post-REP. Patients without persistent ICD indication at REP still had a sVAE rate of 5.7% (95% CI 2.3-11.5%) at 2 years. In multivariate analysis, predictive factors of subsequent sVAE were (i) persistent ICD indication (hazard ratio (HR) 3.6; 95% CI 1.6-8.3; p = 0.003); (ii) 64-72 years of age as compared to ≥ 79 years (HR 3.7; 95% CI 1.4-9.7; p = 0.008); and (iii) ischemic heart disease (HR 4.4; 95% CI 2.1-9.3; p < 0.0001).

CONCLUSIONS

The risk of sVAE (21.2% at 4 years post-REP) depends on age, ischemic heart disease, and ICD indication at the time of REP. A non-trivial risk of sVAE remains in patients without persistent ICD indication.

CLINICAL TRIAL REGISTRATION

NCT02323503.

Appropriate Implantable Cardioverter-Defibrillator Therapy in Patients with Ventricular Arrhythmia of Unclear Cause in Secondary Prevention of Sudden Cardiac Death

In this study, we sought to investigate the occurrence of appropriate implantable cardioverter-defibrillator (ICD) therapies and inappropriate shocks in secondary prevention ICD recipients with ventricular arrhythmia of unclear cause and ventricular arrhythmia in the context of underlying heart disease. In this retrospective study, consecutive patients with an ICD implanted for secondary prevention in the University Medical Center Groningen (UMCG), the Netherlands between 1 January 2012 and 31 December 2018 were included. Patients were classified as having ventricular arrhythmia of unclear cause if no clear cause was found which could explain the index ventricular arrhythmia. The primary outcome was appropriate ICD therapy. The study population consisted of 257 patients. In 220 patients, an underlying heart disease could be identified as the cause of ventricular arrhythmia, while 37 patients had an unclear cause of ventricular arrhythmia. The median age was 64 years (interquartile range (IQR) 53-72 years). Forty-five (18%) patients were women. During a median duration of follow-up of 6.2 years (IQR 4.8-7.8 years), appropriate ICD therapy occurred in 95 (37%) patients. This number was 90 (41%) in the group with a clear etiology and 5 (14%) in the group with an unclear etiology. In multivariable analysis, index ventricular arrhythmia of unclear cause was associated with fewer appropriate ICD therapies (HR 0.37 [95% CI 0.14-0.99]; p = 0.048), as well as an increased risk of inappropriate ICD shocks (HR 3.71 [95% CI 1.17-11.80]; p = 0.026). Index ventricular arrhythmia of unclear cause was significantly associated with fewer appropriate ICD therapies.

Use of Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death in Asia

The effectiveness of primary prevention implantable cardioverter-defibrillators (ICDs) is well established. However, there are several unsolved problems related to ICD use for primary prevention in Asia, including ICD underuse, population differences in underlying heart disease, and the rate of appropriate ICD therapy compared with Western countries. Although the prevalence of ischemic cardiomyopathy in Asia is lower than in Europe and the United States, the mortality rate of Asian patients with ischemic heart disease has been increasing recently. As for the use of ICDs for primary prevention, there have been no randomized clinical trials, and limited data are available in Asia. This review focuses on the unmet needs related to ICD use for primary prevention in Asia.

Impact of the timing of first appropriate shock on outcomes in patients with an implantable cardioverter-defibrillator: Early versus late

BACKGROUND

Appropriate implantable cardioverter-defibrillator (ICD) shocks are associated with an increased risk of mortality and heart failure (HF) events. The first appropriate shock may occur late after implantation. However, whether the timing of the first appropriate shock influences prognosis is unknown. This study aimed to evaluate the clinical significance of the timing of the first appropriate shock in patients with ICD.

METHODS

This retrospective and observational study enrolled 565 consecutive ICD patients. Patients who received an appropriate shock were divided into the early group (first appropriate shock <1 year after ICD implantation) and late group (first appropriate shock ≥1 year after ICD implantation). All-cause mortality was compared between the two groups.

RESULTS

Over a median follow-up of 5.6 years, 112 (19.8%) patients received an appropriate shock, including 32 patients (28.6%) in the early group and 80 patients (71.4%) in the late group. Comparisons of baseline characteristics at ICD implantation revealed that the late group was more likely to receive cardiac resynchronization therapy (66.3% vs. 31.3%, p < 0.001), ICD for primary prevention (60.0% vs. 31.3%, p = 0.001), and angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker treatment (88.8% vs. 71.9%, p = 0.028). Survival after shock was significantly worse in the late group than in the early group (p = 0.027). In multivariable Cox proportional hazards analysis, the late group had an increased risk of all-cause mortality compared with the early group (HR: 2.22; 95% CI 1.01-4.53; p = 0.029). In both groups, the most common cause of death was HF.

CONCLUSIONS

Late occurrence of the first appropriate ICD shock was associated with a worse prognosis compared with early occurrence of the first appropriate shock. Cardiac death was the most common cause of death in patients who experienced late occurrence of the first appropriate ICD shock, resulting from HF in most cases.

Atrioventricular 2:1-conduction via an accessory pathway during left atrial flutter unmasking WPW syndrome: a case report

Background

Implantable cardioverter defibrillators (ICDs) are most effective in treating sudden cardiac death. However, accurate diagnostic workup of broad complex tachycardia is crucial to ensure correct indication for ICD treatment and to avoid unnecessary invasive treatment and device-associated morbidity.

Case summary

We present a case of atypical atrial flutter with 2:1 atrioventricular (AV) conduction via a left-posterior accessory pathway (AP), leading to the diagnosis of Wolff-Parkinson-White (WPW) syndrome. Upon admission, the 72-year-old patient showed a regular broad complex tachycardia with superior axis and positive concordance in precordial leads, suggestive of either ventricular tachycardia (VT), antidromic AV re-entrant tachycardia (AVRT), or supraventricular tachycardia with antegrade conduction via a left-posterior AP. Interrogation of the two-chamber ICD, which was very likely implanted unjustified in a peripheral clinic before, revealed atrial flutter with 2:1 AV conduction. Remarkably, after the restoration of sinus rhythm, no classic echocardiogram (ECG) criteria for preexcitation syndrome were detected. An invasive electrophysiological study proved the diagnosis of a bidirectionally conducting, left-posterior AP, which was successfully ablated.

Discussion

Differential diagnosis of broad complex tachycardia with superior axis and positive concordance of chest leads consists of i) VT with a left ventricular exit at the posterior mitral annulus, ii) antidromic AVRT involving a left-posterior AP, and iii) supraventricular tachycardia predominantly conducted via a left-posterior AP. The absence of classic ECG criteria for preexcitation syndrome does not rule out AP sufficiently, highlighting the importance of minimal surface-ECG preexcitation criteria. In the case of detection of minimal surface-ECG preexcitation criteria, administration of adenosine rules out or proves the existence of an AP noninvasively and cost-effectively.

Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator? Results From the Multicenter Randomized PARTITA Trial

BACKGROUND

Optimal timing for catheter ablation of ventricular tachycardia is an important unresolved issue. There are no randomized trials evaluating the benefit of ablation after the first implantable cardioverter defibrillator (ICD) shock.

METHODS

We conducted a 2-phase, prospective, multicenter, randomized clinical trial. Patients with ischemic or nonischemic dilated cardiomyopathy and primary or secondary prevention indication for ICD were enrolled in an initial observational phase until first appropriate shock (phase A). After reconsenting, patients were randomly assigned 1:1 in phase B to immediate ablation (within 2 months from shock delivery) or continuation of standard therapy. The primary end point was a composite of death from any cause or hospitalization for worsening heart failure. Amiodarone intake was not allowed except for documented atrial tachyarrhythmias. On July 23, 2021, phase B of the trial was interrupted as a result of the first interim analysis on the basis of the Bayesian adaptive design.

RESULTS

Of the 517 patients enrolled in phase A, 154 (30%) had ventricular tachycardia, 56 (11%) received an appropriate shock over a median follow-up of 2.4 years (interquartile range, 1.4-4.4), and 47 of 56 (84%) agreed to participate in phase B. After 24.2 (8.5-24.4) months, the primary end point occurred in 1 of 23 (4%) patients in the ablation group and 10 of 24 (42%) patients in the control group (hazard ratio, 0.11 [95% CI, 0.01-0.85]; P=0.034). The results met the prespecified termination criterion of >99% Bayesian posterior probability of superiority of treatment over standard therapy. No deaths were observed in the ablation group versus 8 deaths (33%) in the control group (P=0.004); there was 1 worsening heart failure hospitalization in the ablation group (4%) versus 4 in the control group (17%; P=0.159). ICD shocks were less frequent in the ablation group (9%) than in the control group (42%; P=0.039).

CONCLUSIONS

Ventricular tachycardia ablation after first appropriate shock was associated with a reduced risk of the combined death or worsening heart failure hospitalization end point, lower mortality, and fewer ICD shocks. These findings provide support for considering ventricular tachycardia ablation after the first ICD shock.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01547208.

Pharmacologic Management for Ventricular Arrhythmias: Overview of Anti-Arrhythmic Drugs

Ventricular arrhythmias (Vas) are a life-threatening condition and preventable cause of sudden cardiac death (SCD). With the increased utilization of implantable cardiac defibrillators (ICD), the focus of VA management has shifted toward reduction of morbidity from VAs and ICD therapies. Anti-arrhythmic drugs (AADs) can be an important adjunct therapy in the treatment of recurrent VAs. In the treatment of VAs secondary to structural heart disease, amiodarone remains the most well studied and current guideline-directed pharmacologic therapy. Beta blockers also serve as an important adjunct and are a largely underutilized medication with strong evidentiary support. In patients with defined syndromes in structurally normal hearts, AADs can offer tailored therapies in prevention of SCD and improvement in quality of life. Further clinical trials are warranted to investigate the role of newer therapeutic options and for the direct comparison of established AADs.

Rationale and design of the SafeHeart study: Development and testing of a mHealth tool for the prediction of arrhythmic events and implantable cardioverter-defibrillator therapy

Background

Patients with an implantable cardioverter-defibrillator (ICD) are at a high risk of malignant ventricular arrhythmias. The use of remote ICD monitoring, wearable devices, and patient-reported outcomes generate large volumes of potential valuable data. Artificial intelligence–based methods can be used to develop personalized prediction models and improve early-warning systems.

Objective

The purpose of this study was to develop an integrated web-based personalized prediction engine for ICD therapy.

Methods

This international, multicenter, prospective, observational study consists of 2 phases: (1) a development study and (2) a feasibility study. We plan to enroll 400 participants with an ICD (with or without cardiac resynchronization therapy) on remote monitoring: 300 participants in the development study and 100 in the feasibility study. During 12-month follow-up, electronic health record data, remote monitoring data, accelerometry-assessed physical behavior data, and patient-reported data are collected. By using machine- and deep-learning approaches, a prediction engine is developed to assess the risk probability of ICD therapy (shock and antitachycardia pacing). The feasibility of the prediction engine as a clinical tool, the SafeHeart Platform, is assessed during the feasibility study.

Results

Development study recruitment commenced in 2021. The feasibility study starts in 2022.

Conclusion

SafeHeart is the first study to prospectively collect a multimodal data set to construct a personalized prediction engine for ICD therapy. Moreover, SafeHeart explores the integration and added value of detailed objective accelerometer data in the prediction of clinical events. The translation of the SafeHeart Platform to clinical practice is examined during the feasibility study.

Prognostic role of left atrial enlargement in patients with implantable cardioverter defibrillators for primary prevention

PURPOSE

Left atrial volume index (LAVI) is a predictor of heart failure and adverse events, irrespective of left ventricular systolic function. The role of LAVI in the prediction of appropriate implantable cardioverter-defibrillator (ICD) therapies is currently unclear and was the focus of this study.

METHODS

Consecutive heart failure patients with ischaemic (ICM) or idiopathic (DCM) aetiology receiving ICD for primary prevention were included. The primary endpoint was the occurrence of appropriate ICD therapies (ATs): shocks or antitachycardia pacing (ATP). Inappropriate ICD shocks were also assessed as secondary endpoint.

RESULTS

Among 198 included patients, severe left atrial dilatation (SLAE = LAVI ≥ 60 ml/m²) was present in 54 (27%). SLAE patients had a higher prevalence of NYHA class ≥ III, severe mitral regurgitation and atrial fibrillation history. During a median follow-up of 45 months (IQR 25-68), ATs occurred more frequently in SLAE group (33% vs. 15%, p = .007) as well as appropriate shocks (24% vs. 10%, p = .014). At multivariate analysis SLAE was an independent predictor of ATs (OR 3.19, 95% CI 1.38-7.38, p = .007). Inappropriate shocks were associated with AF during implantation (p = .03), but not with SLAE (p = .009).

CONCLUSION

In DCM or ICM patients candidate to receive an ICD for primary prevention, a severely enlarged left atrium is a predictive factor for ATs (shocks or ATP). The risk of inappropriate shocks was increased in patients with atrial fibrillation, rather than SLAE.

Nomogram predicting death and heart transplantation before appropriate ICD shock in dilated cardiomyopathy

Aims

This study aimed to develop and validate a competing risk nomogram for predicting all‐cause mortality and heart transplantation (HT) before first appropriate shock in non‐ischaemic dilated cardiomyopathy (DCM) patients receiving implantable cardioverter‐defibrillators (ICD).

Methods and results

A total of 218 consecutive DCM patients implanted with ICD between 2010 and 2019 at our institution were retrospectively enrolled. Cox proportional hazards model was primarily built to identify variables associated with death and HT. Then, a Fine–Gray model, accounting for the appropriate shock as a competing risk, was constructed using these selected variables along with implantation indication (primary vs. secondary). Finally, a nomogram based on the Fine–Gray model was established to predict 1‐, 3‐, and 5‐year probabilities of all‐cause mortality and HT before first appropriate shock. The area under the receiver operating characteristic (ROC) curve (AUC), Harrell's C‐index, and calibration curves were used to evaluate and internally validate the performance of this model. The decision curve analysis was applied to assess its clinical utility. The 1‐, 3‐, and 5‐year cumulative incidence of all‐cause mortality and HT without former appropriate shock were 5.3% [95% confidence interval (CI) 2.9–9.9%], 16.6% (95% CI 11–25.0%), and 25.3% (95% CI 17.2–37.1%), respectively. Five variables including implantation indication, left ventricular end‐diastolic diameter, N‐terminal pro‐brain natriuretic peptide, angiotensin‐converting enzyme inhibitor/angiotensin receptor blocker, and amiodarone treatment were independently associated with it (all P < 0.05) and were used for constructing the nomogram. The 1‐, 3‐, and 5‐year AUC of the nomogram were 0.83 (95% CI 0.73–0.94, P < 0.001), 0.84 (95% CI 0.75–0.93, P < 0.001), and 0.85 (95% CI 0.77–0.94, P < 0.001), respectively. The Harrell's C‐index was 0.788 (95% CI 0.697–0.877, P < 0.001; 0.762 for the optimism‐corrected C‐index), showing the good discriminative ability of the model. The calibration was acceptable (optimism‐corrected slope 0.896). Decision curve analysis identified our model was clinically useful within the entire range of potential treatment thresholds for ICD implantation. Three risk groups stratified by scores were significantly different between cumulative incidence curves (P < 0.001). The identified high‐risk group composed 17.9% of our population and did not derive long‐term benefit from ICD.

Conclusions

The proposed nomogram is a simple, useful risk stratification tool for selecting potential ICD recipients in DCM patients. It might facilitate the shared decision‐making between patients and clinicians.

Long-term outcome of myocardial scarring and deformation with cardiovascular magnetic resonance in out of hospital cardiac arrest survivors

AIMS

Cardiovascular magnetic resonance (CMR) is increasingly recognized as a diagnostic and prognostic tool in out of hospital cardiac arrest (OHCA) survivors. After assessing CMR findings early after ventricular fibrillation (VF) OHCA, we sought to explore the long-term outcome of myocardial scarring and deformation.

METHODS AND RESULTS

We included 121 consecutive VF OHCA survivors (82% male, median 62 years) undergoing CMR within 2 weeks from cardiac arrest. Late gadolinium-enhancement (LGE) was quantified using the full width at half maximum method and tissue tracking analysis software was used to assess myocardial deformation. LGE was found in 71% of patients (median LGE mass 6.2% of the left ventricle, LV), mainly with an ischaemic pattern. Myocardial deformation was overall impaired and showed a significant correlation with LGE presence and extent (P < 0.001). A composite end-point of all-cause mortality and appropriate ICD discharge/anti-tachycardia pacing was met in 24% of patients. Patients meeting the end-point had significantly greater LGE extent (8.6% of LV myocardium vs. 4.1%, P = 0.02), while there was no difference with regards to myocardial deformation. Survival rate was significantly lower in patients with LGE (P = 0.05) and LGE mass >4.4% of the LV identified a group of patients at higher risk of adverse events (P = 0.005).

CONCLUSIONS

We found a high prevalence of LGE, early after OHCA, and an overall impaired myocardial deformation. On long-term follow-up both LGE presence and extent showed a significant association with recurrent adverse events, while LV ejection fraction and myocardial deformation did not identify patients with an unfavourable outcome.

Multimodality imaging predictors of sudden cardiac death

Sudden cardiac death (SCD) is the worst clinical event occurring in the clinical context of cardiomyopathies. Current guidelines recommend using LV ejection fraction as the only imaging-derived parameter to identify patients who may benefit from ICD implantation in cardiomyopathies with reduced ejection fraction; however, a relevant proportion of high-risk population is left with unmet therapeutic goal. In case of dilated, hypertrophic, or arrhythmogenic cardiomyopathies, there is still a room for more sensitive and specific risk markers for identifying a cluster at higher risk of SCD. In this paper, we reviewed the evidence supporting the use of advanced echocardiography, CMR, and nuclear cardiology for SCD stratification in patients with the most common cardiomyopathies. The added value of these modalities may be explained on the basis of tissue characterization, especially scar detection, a central player in the pathogenesis of arrhythmias. Therefore, integration of these modalities to our everyday clinical practice may help in dealing with the gray zones where current guidelines are still ineffective for patient selection.

Prognosis of Japanese Patients With Coronary Artery Disease Who Underwent Implantable Cardioverter Defibrillator Implantation - The JID-CAD Study

Background: There has been no large multicenter clinical trial on the prognosis of implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy with a defibrillator (CRT-D) in Japanese patients with coronary artery disease (CAD). The aim of the present study was to compare differences in the prognoses of Japanese patients with CAD between primary and secondary prevention, and to identify potential predictors of prognosis.

Methods and Results: We investigated 392 CAD patients (median age 69 years, 90% male) treated with ICD/CRT-D enrolled in the Japan Implantable Devices in CAD (JID-CAD) Registry. The primary endpoint was all-cause death, and the secondary endpoint was appropriate ICD therapies. Endpoints were assessed by dividing patients into primary prevention (n=165) and secondary prevention (n=227) groups. The mean (±SD) follow-up period was 2.1±0.9 years. The primary endpoint was similar in the 2 groups (P=0.350).

Conclusions: The mortality rate in Japanese patients with CAD who underwent ICD/CRT-D implantation as primary prevention was not lower than that of patients who underwent ICD/CRT-D implantation as secondary prevention, despite the lower cardiac function in the patients undergoing ICD/CRT-D implantation as primary prevention.

Comparison of second appropriate defibrillator therapy occurrence in patients implanted for primary prevention and secondary prevention - Sub-analysis of the Nippon Storm Study

Background

Patients with implantable cardioverter defibrillator (ICD) use for primary prevention (primary prevention patients) of sudden cardiac death have lower incidence of appropriate ICD therapy (app-Tx) compared with those with ICD use for secondary prevention (secondary prevention patients). However, detail analysis of a second app-Tx after a first app-Tx is still lacking.

Objective

This study aimed to compare the incidence of a second app-Tx in primary vs secondary prevention patients.

Methods

We conducted sub-analysis of the Nippon Storm Study, which was a prospective, observational study involving 985 patients with structural heart disease (left ventricular ejection fraction ≤ 50%). Of these, we selected 251 patients (62 ± 14 years old, 82% men) who experienced at least one appropriate ICD therapy, and compared occurrence of a second app-Tx between primary (n = 116) and secondary (n = 135) prevention patients.

Results

There was no significant difference in the incidence of a second app-Tx between primary and secondary prevention patients (the cumulative incidence for a second app-Tx was 59% at 1 year and 79% at 3 years in primary prevention patients vs the cumulative incidence for the second app-Tx was 59% at 1 year and 75% at 3 years in secondary prevention patients).

Additionally, we evaluated the incidence of a second app-Tx according to basal structural disease (ischemic and non-ischemic cardiomyopathy) and found no significant difference between primary and secondary prevention patients.

Conclusion

Once app-Tx occurs, primary prevention patients acquire the high risk of subsequent ventricular arrhythmias because there is a comparable incidence of a second app-Tx in secondary prevention patients.

Long-Term Outcomes Among a Nationwide Cohort of Patients Using an Implantable Cardioverter-Defibrillator: UMBRELLA Study Final Results

Background

Large‐scale studies describing modern populations using an implantable cardioverter‐defibrillator (ICD) are lacking. We aimed to analyze the incidence of arrhythmia, device interventions, and mortality in a broad spectrum of real‐world ICD patients with different heart disorders.

Methods and Results

The UMBRELLA study is a prospective, multicenter, nationwide study of contemporary patients using an ICD followed up by remote monitoring, with a blinded review of arrhythmic episodes. From November 2005 to November 2017, 4296 patients were followed up. After 46.6±27.3 months, 16 067 episodes of sustained ventricular arrhythmia occurred in 1344 patients (31.3%). Appropriate ICD therapy occurred in 27.3% of study population. Patients with ischemic cardiomyopathy (hazard ratio [HR], 1.51; 95% CI, 1.29–1.78), dilated cardiomyopathy (HR, 1.28; 95% CI, 1.07–1.53), and valvular heart disease (HR, 1.94; 95% CI, 1.43–2.62) exhibited a higher risk of appropriate ICD therapies, whereas patients with hypertrophic cardiomyopathy (HR, 0.72; 95% CI, 0.54–0.96) and Brugada syndrome (HR, 0.25; 95% CI, 0.14–0.45) showed a lower risk. All‐cause death was 13.4% at follow‐up. Ischemic cardiomyopathy (HR, 3.09; 95% CI, 2.58–5.90), dilated cardiomyopathy (HR, 3.33; 95% CI, 2.18–5.10), and valvular heart disease (HR, 3.97; 95% CI, 2.25–6.99) had the worst prognoses. Delayed high‐rate detection was enabled in 39.7% of patients, and single‐zone programming occurred in 52.6% of primary prevention patients. Both parameters correlated with lower risk of first appropriate ICD therapy, with no excess risk of mortality. The rate of inappropriate shocks at follow‐up was low (6%) and did not differ among type of ICD but was lower in SmartShock‐capable devices.

Conclusions

Irrespective of the cause, contemporary ICD patients with heart failure–related disorders had a similar risk of ICD life‐saving interventions and death. Current ICD programming recommendations still need to be implemented.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NTC01561144.

Coronary Angiography After Cardiac Arrest Without ST Segment Elevation: One-Year Outcomes of the COACT Randomized Clinical Trial

Importance

Ischemic heart disease is a common cause of cardiac arrest. However, randomized data on long-term clinical outcomes of immediate coronary angiography and percutaneous coronary intervention (PCI) in patients successfully resuscitated from cardiac arrest in the absence of ST segment elevation myocardial infarction (STEMI) are lacking.

Objective

To determine whether immediate coronary angiography improves clinical outcomes at 1 year in patients after cardiac arrest without signs of STEMI, compared with a delayed coronary angiography strategy.

Design, Setting, and Participants

A prespecified analysis of a multicenter, open-label, randomized clinical trial evaluated 552 patients who were enrolled in 19 Dutch centers between January 8, 2015, and July 17, 2018. The study included patients who experienced out-of-hospital cardiac arrest with a shockable rhythm who were successfully resuscitated without signs of STEMI. Follow-up was performed at 1 year. Data were analyzed, using the intention-to-treat principle, between August 29 and October 10, 2019.

Interventions

Immediate coronary angiography and PCI if indicated or coronary angiography and PCI if indicated, delayed until after neurologic recovery.

Main Outcomes and Measures

Survival, myocardial infarction, revascularization, implantable cardiac defibrillator shock, quality of life, hospitalization for heart failure, and the composite of death or myocardial infarction or revascularization after 1 year.

Results

At 1 year, data on 522 of 552 patients (94.6%) were available for analysis. Of these patients, 413 were men (79.1%); mean (SD) age was 65.4 (12.3) years. A total of 162 of 264 patients (61.4%) in the immediate angiography group and 165 of 258 patients (64.0%) in the delayed angiography group were alive (odds ratio, 0.90; 95% CI, 0.63-1.28). The composite end point of death, myocardial infarction, or repeated revascularization since the index hospitalization was met in 112 patients (42.9%) in the immediate group and 104 patients (40.6%) in the delayed group (odds ratio, 1.10; 95% CI, 0.77-1.56). No significant differences between the groups were observed for the other outcomes at 1-year follow-up. For example, the rate of ICD shocks was 20.4% in the immediate group and 16.2% in the delayed group (odds ratio, 1.32; 95% CI, 0.66-2.64).

Conclusions and Relevance

In this trial of patients successfully resuscitated after out-of-hospital cardiac arrest and without signs of STEMI, a strategy of immediate angiography was not found to be superior to a strategy of delayed angiography with respect to clinical outcomes at 1 year. Coronary angiography in this patient group can therefore be delayed until after neurologic recovery without affecting outcomes.

Trial Registration

trialregister.nl Identifier: NTR4973.

Cause-specific death and risk factors of one-year mortality after implantable cardioverter-defibrillator implantation: a nationwide study

AIMS

Current treatment guidelines recommend implantable cardioverter-defibrillators (ICDs) in eligible patients with an estimated survival beyond one year. There is still an unmet need to identify patients who are unlikely to benefit from an ICD.We determined cause-specific one-year mortality after ICD implantation and identified associated risk factors.

METHODS AND RESULTS

Using Danish nationwide registries (2000-2017), we identified 14,516 patients undergoing first-time ICD implantation for primary or secondary prevention. Risk factors associated with one-year mortality were evaluated using multivariable logistic regression. The median age was 66 years, 81.3% were male, and 50.3% received an ICD for secondary prevention. The one-year mortality rate was 4.8% (694/14,516). ICD recipients who died within one year were older and more comorbid compared to those who survived (72 vs. 66 years, p < 0.001). Risk factors associated with increased one-year mortality included dialysis (OR:3.26, CI:2.37-4.49), chronic renal disease (OR:2.14, CI:1.66-2.76), cancer (OR:1.51, CI:1.15-1.99), age 70-79 years (OR:1.65, CI:1.36-2.01), and age ≥80 years (OR:2.84, CI:2.15-3.77). The one-year mortality rates for the specific risk factors were: dialysis (13.8%), chronic renal disease (13.1%), cancer (8.5%), age 70-79 years (6.9%), and age ≥80 years (11.0%). Overall, the most common causes of mortality were related to cardiovascular diseases (62.5%), cancer (10.1%), and endocrine disorders (5.0%). However, the most common cause of death among patients with cancer was cancer-related (45.7%).

CONCLUSION

Among ICD recipients, mortality rates were low and could be indicative of relevant patient selection. Important risk factors of increased one-year mortality included dialysis, chronic renal disease, cancer, and advanced age.

Social cognitive intervention following an initial implantable cardioverter defibrillator: Better treatment response for secondary versus primary prevention

BACKGROUND

The patient + partner (P+P) is a patient/partner-focused social cognitive intervention with demonstrated efficacy to improve outcomes following an initial implantable cardioverter defibrillator (ICD). Little is known about how the patient response may differ by ICD implant indication. The aim of this study was to examine the response to intervention for patients with an initial ICD by reasons for primary versus secondary ICD indication.

METHOD

A longitudinal secondary analysis of data from a randomized clinical trial testing the P+P intervention examined patient health outcomes over 12 months, stratified by the indication for the ICD: primary prevention without cardiac resynchronization therapy (CRT) (1o No CRT, n = 100), primary prevention with CRT (1o CRT, n = 78), secondary prevention after cardiac arrest (2° Cardiac Arrest, n = 66), and secondary prevention for other arrhythmias (2o Other, n = 57). Outcomes included physical and mental health status (Short-Form-36 Physical Component Summary and Mental Component Summary), physical symptoms (Patient Concerns Assessment), depression (Patient-Health-Questionniare-9), and anxiety (State-Trait Anxiety Inventory).

RESULTS

Participants (n = 301) were on average 64 years old, primarily male (73.7%) and Caucasian (91%) with reduced ejection fraction (34%). There were no baseline differences between ICD groups for all outcomes (P > .05). Patients in the 2° Cardiac Arrest group showed greater improvement from baseline to 3 months in physical and mental health outcomes. The 2° Cardiac Arrest group had better physical (F = 11.48, P = .004) and mental health (F = 4.34, P = .038) and less severe physical (z = 2.24, P = 0.013) and depressive symptoms (z = 2.71, P = .003) at 12 months compared to the 1o No CRT group.

CONCLUSION

The P+P intervention was more effective for promoting physical and psychological health outcomes for individuals receiving an ICD for 2o prevention after cardiac arrest.

Predictors of Subcutaneous Implantable Cardioverter-Defibrillator Shocks and Prognostic Impact in Patients With Structural Heart Disease

BACKGROUND

In this study we aimed to assess long-term outcomes in subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients with structural heart disease by focussing especially on shock incidence, predictors, and associated prognoses.

METHODS

In this multicenter registry‒based study, we retrospectively included all patients who underwent S-ICD implantation at 3 tertiary centers. The prognostic impact of S-ICD shock was assessed with a composite outcome that included all-cause death and hospitalisation for heart failure.

RESULTS

A total of 351 patients with underlying cardiomyopathy were included in the investigation. Using multivariable Fine and Gray regression models, secondary prevention, left ventricular ejection fraction (LVEF), conditional shock threshold, and QRS duration appeared to be independent predictors of appropriate S-ICD shock occurrence. In the multivariate Cox regression model adjusted for age, baseline LVEF, underlying cardiomyopathy subtype, New York Heart Association class, and appropriate shocks were significantly associated with increased composite prognostic outcome risk (hazard ratio [HR], 2.61; 95% confidence interval [CI], 1.21-5.65; P = 0.014), whereas inappropriate shocks were not (HR, 1.35; 95% CI, 0.75-4.48; P = 0.18). The analysis of each component of the composite prognostic outcome highlighted that the occurrence of appropriate shocks was associated with an increased risk of hospitalisation for heart failure (HR, 3.10; 95% CI, 1.26-7.58; P = 0.013) and a trend for mortality (HR, 2.19; 95% CI, 0.78-6.16; P = 0.14).

CONCLUSIONS

Appropriate S-ICD shocks were associated with a 3-fold increase in acute heart failure admission, whereas inappropriate shocks were not. Conditional shock threshold programming is an independent predictor of S-ICD shock, and its prognostic impact should be investigated further in patients with structural heart disease.

High Risk of Sustained Ventricular Arrhythmia Recurrence After Acute Myocarditis

Acute myocarditis is associated with cardiac arrhythmia in 25% of cases; a third of these arrhythmias are ventricular tachycardia (VT) or ventricular fibrillation (VF). The implantation of a cardiac defibrillator (ICD) following sustained ventricular arrhythmia remains controversial in these patients. We sought to assess the risk of major arrhythmic ventricular events (MAEs) over time in patients implanted with an ICD following sustained VT/VF in the acute phase of myocarditis compared to those implanted for VT/VF occurring on myocarditis sequelae. Our retrospective observational study included patients implanted with an ICD following VT/VF during acute myocarditis or VT/VF on myocarditis sequelae, from 2007 to 2017, in 15 French university hospitals. Over a median follow-up period of 3 years, MAE occurred in 11 (39%) patients of the acute myocarditis group and 24 (60%) patients of the myocarditis sequelae group. Kaplan–Meier MAE rate estimates at one and three years of follow-up were 19% and 45% in the acute group, and 43% and 64% in the sequelae group. Patients who experienced sustained ventricular arrhythmias during acute myocarditis had a very high risk of VT/VF recurrence during follow-up. These results show that the risk of MAE recurrence remains high after resolution of the acute episode.

ICD implantation for secondary prevention in patients with ventricular arrhythmia in the setting of acute cardiac ischemia and a history of myocardial infarction

INTRODUCTION

In patients with a prior myocardial infarction (MI) but preserved left ventricular (LV) function, sustained ventricular arrhythmias (VAs) may arise in the setting of an acute coronary syndrome (ACS). It is unknown whether an implantable cardioverter-defibrillator (ICD) is mandatory in these patients as VA might be triggered by a reversible cause. The purpose of this study is to analyze the benefit of ICD therapy in this patient population.

METHODS

We conducted a retrospective observational study in ICD recipients implanted from 2008 to 2011. The study group consisted of patients with sustained VA in the setting of an ACS, with a history of MI, but with left ventricular ejection fraction (LVEF) greater than 35 (group A). The two control groups consisted of patients admitted with VA with a history of MI, but without ACS at presentation, either with LVEF greater than 35% (group B) or ≤35% (group C). The primary endpoint was the number of patients with appropriate ICD therapy (antitachycardia pacing or shock).

RESULTS

A total of 291 patients were included with a mean follow-up of 5.3 years. Appropriate ICD therapy occurred in 45.6% of the patients in group A vs 51.6% and 60.4% in groups B and C (P = .11). In group A, 31.1% received an appropriate ICD shock vs 34.7% and 44.3% in control groups B and C (P = .12).

CONCLUSION

On the basis of these data, ICD implantation seems warranted in patients with history of MI presenting with VA in the setting of an ACS, despite preserved LV function and adequate revascularization. Further trials, preferably randomizes, should be performed to address these findings.

Risk of subsequent ventricular arrhythmia is higher in primary prevention patients with implantable cardioverter defibrillator than in secondary prevention patients

BACKGROUND

Because of previous ventricular arrhythmia (VA) episodes, patients with implantable cardioverter-defibrillator (ICD) for secondary prevention (SP) are generally considered to have a higher burden of VAs than primary prevention (PP) patients. However, when PP patients experienced VA, the difference in the prognosis of these two patient groups was unknown.

METHODS

The clinical characteristics and follow-up data of 835 ICD patients (364 SP patients and 471 PP patients) with home monitoring feature were retrospectively analysed. The incidence rate and risk of subsequent VA and all-cause mortality were compared between PP patients after the first appropriate ICD therapy and SP patients.

RESULTS

During a mean follow-up of 44.72 ± 20.87 months, 210 (44.59%) PP patients underwent appropriate ICD therapy. In the Kaplan-Meier survival analysis, the PP patients after appropriate ICD therapy were more prone to VA recurrence and all-cause mortality than SP patients (P<0.001 for both endpoints). The rate of appropriate ICD therapy and all-cause mortality in PP patients after the first appropriate ICD therapy was significantly higher than that in SP patients (for device therapy, 59.46 vs 20.64 patients per 100 patient-years; incidence rate ratio [IRR] 2.880, 95% confidence interval [CI]: 2.305-3.599; P<0.001; for all-cause mortality, 14.08 vs 5.40 deaths per 100 patient-years; IRR 2.607, 95% CI: 1.884-3.606; P<0.001). After propensity score matching for baseline characteristics, the risk of VA recurrence in PP patients with appropriate ICD therapy was still higher than that in SP patients (41.80 vs 19.10 patients per 100 patient-years; IRR 2.491, 95% CI: 1.889-3.287; P<0.001), but all-cause mortality rates were similar between the two groups (12.61 vs 9.33 deaths per 100 patient-years; IRR 1.352, 95% CI: 0.927-1.972; P = 0.117).

CONCLUSIONS

Once PP patients undergo appropriate ICD therapy, they will be more prone to VA recurrence and death than SP patients.

Outcomes of patients with heart failure after primary prevention ICD unit generator replacement

OBJECTIVE

Data describing outcomes after implantable cardioverter-defibrillator (ICD) unit generator replacement in patients with heart failure (HF) with primary prevention devices are limited.

METHOD

Data on patients with HF who underwent primary prevention ICD/cardiac resynchronisation therapy-defibrillator (CRT-D) implantation from 2007 until mid-2015 who subsequently received unit generator replacement were analysed. Outcomes assessed were mortality, appropriate ICD therapy and shock, and procedural complications.

RESULTS

61 of 385 patients with HF with primary prevention ICD/CRT-D undergoing unit generator replacement were identified. Follow-up period was 1.8±1.5 years after replacement. 43 (70.5%) patients had not received prior appropriate ICD therapy prior to unit replacement. The cumulative risks of appropriate ICD therapy at 1, 3 and 5 years after unit replacement in those without prior ICD therapy were 0%, 6.2% and 50% compared with 6.2%, 59.8% and 86.6%, respectively (p=0.005) in those with prior ICD therapies. No predictive factors associated with appropriate ICD therapy after replacement could be identified. 41 (32.8%) patients no longer met guideline indications at the time of unit replacement but risks of subsequent appropriate ICD interventions were not different compared with those who continued to meet primary prevention ICD indications.The 5-year mortality risk after unit replacement was 18.4% and there were high procedural complication rates (9.8%).

CONCLUSION

No predictive marker successfully stratified patients no longer needing ICD support prospectively. Finding such a marker is important in decision-making about device replacement particularly given the concerns about the complication rates. These factors should be considered at the time of ICD unit replacement.

Predictors of appropriate ICD therapy in Japanese patients with structural heart diseases: A major role of prior sustained ventricular tachycardia in secondary prevention

BACKGROUND

Implantable cardioverter defibrillator (ICD) and cardiac resynchronization with a defibrillator (CRT-D) are established therapies for secondary prevention of sudden cardiac death (SCD) in patients with structural heart disease (SHD), but the rates of subsequent ICD/CRT-D therapy widely differ among patients with SHD. The aim of this study was to determine clinical factors associated with appropriate therapy for preventing SCD in patients with SHD.

METHODS

We enrolled 147 patients with SHD (mean age, 59 ± 15 years; mean ejection fraction [EF], 45 ± 15%) who underwent ICD/CRT-D implantation for secondary prevention of SCD (ischemic heart disease, n = 50; nonischemic heart disease, n = 97). ICD/CRT-D was implanted for aborted cardiopulmonary arrest (CPA, n = 65) or sustained ventricular tachycardia (VT, n = 82).

RESULTS

During a follow-up period of 3.2 ± 3.6 years, 79 of the 147 patients had appropriate ICD/CRT-D therapies. A Kaplan-Meier survival curve showed that the rate of appropriate therapy was 54% at 5-year follow-up. Prior sustained VT, lower EF, and use of a class I antiarrhythmic drug were significantly more frequent in patients with appropriate therapy. In multivariate analysis, prior sustained VT (hazard ratio, 2.8; 95% CI, 1.60-4.46; P = .001) was the only independent predictor for appropriate ICD/CRT-D therapy. Kaplan-Meier survival curves showed that rates of appropriate therapy during a 5-year follow-up period were 70% and 34% in patients with sustained VT and those with CPA, respectively (P = .001).

CONCLUSIONS

In SHD patients implanted with an ICD/CRT-D, prior sustained VT as an indication of ICD/CRT-D implantation, but not EF or an antiarrhythmic drug, predicts a high rate of appropriate therapy.

Cost Saving Potential of an Early Detection of Atrial Fibrillation in Patients after ICD Implantation

Atrial fibrillation (AF) is a relevant comorbidity in recipients of implantable cardioverter-defibrillators (ICD). Latest generation single-chamber ICD allow the additional sensing of atrial tachyarrhythmias and, therefore, contribute to the early detection and treatment of AF, potentially preventing AF-related stroke. The present study aimed to measure the impact on patient-related costs of this new ICD compared to conventional ICD. A Markov model was developed to simulate the long-term incidence of stroke in patients treated with a single-chamber ICD with or without atrial sensing capabilities. The median annual cost per patient and its difference, the number of strokes avoided, and the cost per stroke avoided were estimated. During a 9-year horizon, the costs for the ICD and stroke treatment were €570 per patient-year for an ICD with atrial sensing capabilities and €491 per patient-year for a conventional ICD. Per 1,000 patients, 4.6 strokes per year are assumed to be avoided by the new device. Higher CHA2DS2-VASc scores are associated with higher numbers of avoided strokes and larger potential for cost savings. Apart from clinical advantages, the use of ICD with atrial sensing capabilities may reduce the incidence of stroke and, in high-risk patients, may also contribute to reduce overall health care costs.

The Value of the Tei Index in Predicting Implantable Cardioverter Defibrillator Shocks

Objectives:

An implantable cardioverter defibrillator (ICD) decreases the risk of sudden death in the appropriate patients. However, a relationship between ICD shocks and increased mortality and morbidity has been suspected. This report is an investigation of an association between ICD shocks and the Tei index, an echocardiographic parameter now commonly used to predict cardiovascular events.

Methods:

The basic characteristics of 250 patients with chronic heart failure who had an ICD implanted and 2 years of follow-up device recordings were retrospectively analyzed. Patients who received shock therapy during follow-up were compared with those who did not, based on demographic and other characteristics and the Tei index.

Results:

The mean Tei index value of ICD shock recipients was significantly higher than the score of non-recipients of ICD shock (0.70±0.10 vs 0.56±0.10; p<0.001). The percentage of patients for whom it was primary prevention who received either appropriate or inappropriate ICD shocks was 28.9%, whereas in those who received an ICD for secondary prevention, the percentage was 71.1% (p<0.001). ICD shock recipient patients were older, and had a greater rate of hypertension and smoking pack-years compared with those to whom an ICD shock was not delivered (p<0.001).

Conclusion:

The results of this study demonstrated a relationship between the Tei index and ICD shocks, either appropriate or inappropriate. The Tei index is a simple method to predict ICD shocks.

Spectrum and Outcome of Patients Who Have Undergone Implantation of an Implantable Cardioverter Defibrillator After Aborted-Sudden Cardiac Arrest

Most of implantable cardioverter defibrillator (ICD) secondary prevention studies have been published 2 decades ago. We aimed to describe a contemporary cohort of patients who have undergone implantation of an ICD after an aborted-sudden cardiac arrest (SCA). We retrospectively evaluated consecutive patients referred to our centers between 2005 and 2013. Predictors of overall mortality or heart transplant were analyzed using Cox proportional hazards models. A total of 250 patients (76.4% male, 48.7 ± 16.7 years) were included (mean follow-up = 49.6 ± 35 months). The presence of a structural heart disease (SHD) was considered as the primary cause of the aborted-SCA in 160 patients (64%). In 90 patients (36%), no SHD was observed, with patients much younger (40.9 ± 16.2 years vs 53.0 ± 15.5 years in the SHD group, p < 0.0001). The 5-year estimated rates of death or heart transplant were 14.3% and 5.2% in the group with and without SHD, respectively (hazard ratio = 4.65, 95% confidence interval 1.40 to 15.6, p = 0.014). The 5-year estimated rates of appropriate ICD therapy in the ventricular fibrillation zone were 16.7% and 25.1% in patients without and with SHD (p = 0.24), respectively. Only left ventricular ejection fraction remained independently associated with mortality or heart transplant (hazard ratio = 0.94, 95% confidence interval 0.90 to 0.97, p = 0.0004). Overall, 69 patients (27.6%) experienced at least 1 ICD-related complication. In conclusion, compared with secondary prevention pivotal studies, the current patients who have undergone implantation of an ICD after aborted-SCA are younger, with a high proportion of structurally normal hearts. Compared with patients without SHD, who depicted a relatively favorable outcome, patients with SHD present a fourfold higher risk of death during follow-up. Reduced left ventricular ejection fraction remains the major influencing factor.

Predictors of mortality and ICD shock therapy in primary prophylactic ICD patients-A systematic review and meta-analysis

Background

There is evidence that the benefit of a primary prophylactic ICD therapy is not equal in all patients.

Purpose

To evaluate risk factors of appropriate shocks and all- cause mortality in patients with a primary prophylactic ICD regarding contemporary studies.

Data source

PubMed, LIVIVO, Cochrane CENTRAL between 2010 and 2016.

Study selection

Studies were eligible if at least one of the endpoints of interest were reported.

Data extraction

All abstracts were independently reviewed by at least two authors. The full text of all selected studies was then analysed in detail.

Data synthesis

Our search strategy retrieved 608 abstracts. After exclusion of unsuitable studies, 36 papers with a total patient number of 47282 were included in our analysis. All-cause mortality was significantly associated with increasing age (HR 1.41, CI 1.29–1.53), left ventricular function (LVEF; HR 1.21, CI 1.14–1.29), ischemic cardiomyopathy (ICM; HR 1.37, CI 1.14–1.66) and co-morbidities such as impaired renal function (HR 2.30, CI 1.97–2.69). Although, younger age (HR 0.96, CI 0.85–1.09), impaired LVEF (HR 1.26, CI 0.89–1.78) and ischemic cardiomyopathy (HR 2.22, CI 0.83–5.93) were associated with a higher risk of appropriate shocks, none of these factors reached statistical significance.

Limitations

Individual patient data were not available for most studies.

Conclusion

In this meta-analysis of contemporary clinical studies, all-cause mortality is predicted by a variety of clinical characteristics including LVEF. On the other hand, the risk of appropriate shocks might be associated with impaired LVEF and ischemic cardiomyopathy. Further prospective studies are required to verify risk factors for appropriate shocks other than LVEF to help select appropriate patients for primary prophylactic ICD-therapy.

Mortality Implications of Appropriate Implantable Cardioverter Defibrillator Therapy in Secondary Prevention Patients: Contrasting Mortality in Primary Prevention Patients From a Prospective Population-Based Registry

Background

We sought to examine the mortality impact of appropriate implantable cardioverter defibrillator (ICD) therapy between patients who received ICD for primary versus secondary prevention purposes.

Methods and Results

From a prospective, population‐based registry, we identified 7020 patients who underwent de novo ICD implantation between February 2007 and May 2012 in Ontario, Canada. The primary outcome was all‐cause mortality. We used multivariable Cox proportional hazard modeling to adjust for differences in baseline characteristics and analyzed the mortality impact of first appropriate ICD therapy (shock and antitachycardia pacing [ATP]) as a time‐varying covariate. There were 1929 (27.5%) patients who received ICDs for secondary prevention purposes. The median follow‐up period was 5.02 years. Compared with those with secondary prevention ICDs, patients with primary prevention ICDs had more medical comorbidities, and lower ejection fraction. Patients who experienced appropriate ICD shock or ATP had greater risk of death compared with those who did not, irrespective of implant indication. In the primary prevention group, the adjusted hazard ratios of death for appropriate shock and ATP were 2.00 (95% CI: 1.72–2.33) and 1.73 (95% CI: 1.52–1.97), respectively. In the secondary prevention group, the adjusted hazard ratios of death for appropriate ICD shock and ATP were 1.46 (95% CI: 1.20–1.77) and 1.38 (95% CI: 1.16–1.64), respectively.

Conclusions

Despite having a more favorable clinical profile, occurrence of appropriate ICD shock or ATP in patients with secondary prevention ICDs was associated with similar magnitudes of mortality risk as those with primary prevention ICDs. A heightened degree of care is warranted for all patients who experience appropriate ICD shock or ATP therapy.

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.

Effect of Sleep-Disordered Breathing on Appropriate Implantable Cardioverter-Defibrillator Therapy in Patients With Heart Failure: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with heart failure and reduced ejection fraction are at increased risk of malignant ventricular arrhythmias. Implantable cardioverter-defibrillator (ICD) is recommended to prevent sudden cardiac death in some of these patients. Sleep-disordered breathing (SDB) is highly prevalent in this population and may impact arrhythmogenicity. We performed a systematic review and meta-analysis of prospective studies that assessed the impact of SDB on ICD therapy.

METHODS AND RESULTS

Relevant prospective studies were identified in the Ovid MEDLINE, EMBASE, and Google Scholar databases. Weighted risk ratios of the association between SDB and appropriate ICD therapies were estimated using random effects meta-analysis. Nine prospective cohort studies (n=1274) were included in this analysis. SDB was present in 52% of the participants. SDB was associated with a 55% higher risk of appropriate ICD therapies (45% versus 28%; risk ratio, 1.55; 95% confidence interval, 1.32-1.83). In a subgroup analysis based on the subtypes of SDB, the risk was higher in both central (risk ratio, 1.50; 95% confidence interval, 1.11-2.02) and obstructive (risk ratio, 1.43; 95% confidence interval, 1.01-2.03) sleep apnea.

CONCLUSIONS

SDB is associated with an increased risk of appropriate ICD therapy in patients with heart failure and reduced ejection fraction.

[3-D mapping and ablation of recurrent ventricular tachycardia in patients with ischemic cardiomyopathy]

Catheter ablation of ventricular tachycardia (VT) is an established therapy for patients with ischemic cardiomyopathy to reduce implantable cardioverter-defibrillator (ICD) interventions and is a class I recommendation in international guidelines. Numerous publications confirm its value. Use of three-dimensional mapping systems with or without image integration is standard for ablation of complex arrhythmias. In patients with history of myocardial infarction they help to understand activation of reentrant circuits and are prerequisite for substrate mapping. While a combination of activation and substrate mapping is performed in many patients based on clinical presentation, substrate-based ablation appears to be superior to clinical VT ablation alone.

Association of air pollution with increased incidence of ventricular tachyarrhythmias recorded by implantable cardioverter defibrillators: Vulnerable patients to air pollution

BACKGROUND

This study investigated the acute effects of exposure to air pollution on ventricular tachyarrhythmias (VTAs) in an East Asian population. The association between air pollution and VTA has not yet been studied in an East Asian country affected by the Asian dust phenomenon, which worsens air quality.

METHODS

The study cohort consisted of 160patients with implantable cardioverter defibrillator (ICD) devices in the Seoul metropolitan area who were followed for 5.5±3.8years. We used ICD records of VTAs and matched these with hourly measurements of air pollutant concentrations and meteorological data. Fine particle mass and gaseous air pollution plus temperature and relative humidity were measured hourly during the study period.

RESULTS

During the study period, 1064 VTA events including 204 instances of ventricular fibrillation (VF) were observed. We found a statistically significant association between overall VTA events and SO₂ (lag 24h; OR 1.49, 95%CI 1.16-1.92, p=0.002), PM₁₀ (lag 2h; OR 2.56, 95%CI 2.03-3.23, p<0.001), NO₂ (lag 24h; OR 1.25, 95%CI 1.19-1.31, p<0.001) and CO (lag 24h; OR 1.05, 95%CI 1.02-1.08, p=0.003). Sustained ventricular tachycardia or VF was also independently associated with SO₂, PM₁₀, NO₂ and CO (all p<0.01). Exposures to SO₂, PM₁₀, NO₂, and CO (all p<0.01) were significantly related to overall VTAs, especially in patients with structural heart disease (SHD).

CONCLUSIONS

Associations between air pollution and VTA were observed in a metropolitan area of an East Asian country. Exposures to SO₂, PM₁₀, NO₂, and CO were significantly associated with VTAs in ICD patients with SHD.

Application and comparison of the FADES, MADIT, and SHFM-D risk models for risk stratification of prophylactic implantable cardioverter-defibrillator treatment

AIMS

Implantable cardioverter-defibrillator (ICD) treatment is beneficial in selected patients. However, it remains difficult to accurately predict which patients benefit most from ICD implantation. For this purpose, different risk models have been developed. The aim was to validate and compare the FADES, MADIT, and SHFM-D models.

METHODS AND RESULTS

All patients receiving a prophylactic ICD at the Leiden University Medical Center were evaluated. Individual model performance was evaluated by C-statistics. Model performances were compared using net reclassification improvement (NRI) and integrated differentiation improvement (IDI). The primary endpoint was non-benefit of ICD treatment, defined as mortality without prior ventricular arrhythmias requiring ICD intervention. A total of 1969 patients were included (age 63 ± 11 years; 79% male). During a median follow-up of 4.5 ± 3.9 years, 318 (16%) patients died without prior ICD intervention. All three risk models were predictive for event-free mortality (all: P < 0.001). The C-statistics were 0.66, 0.69, and 0.75, respectively, for FADES, MADIT, and SHFM-D (all: P < 0.001). Application of the SHFM-D resulted in an improved IDI of 4% and NRI of 26% compared with MADIT; IDI improved 11% with the use of SHFM-D instead of FADES (all: P < 0.001), but NRI remained unchanged (P = 0.71). Patients in the highest-risk category of the MADIT and SHFM-D models had 1.7 times higher risk to experience ICD non-benefit than receive appropriate ICD interventions [MADIT: mean difference (MD) 20% (95% CI: 7-33%), P = 0.001; SHFM-D: MD 16% (95% CI: 5-27%), P = 0.005]. Patients in the highest-risk category of FADES were as likely to experience ICD intervention as ICD non-benefit [MD 3% (95% CI: -8 to 14%), P = 0.60].

CONCLUSION

The predictive and discriminatory value of SHFM-D to predict non-benefit of ICD treatment is superior to FADES and MADIT in patients receiving prophylactic ICD treatment.

Usefulness of Atrial Fibrillation as a Marker for Adverse Cardiovascular Outcomes in Both Primary and Secondary Prevention in Patients With Implantable Cardioverter-Defibrillators

Whether the risk factors for cardiovascular (CV) outcomes are different in primary versus secondary prevention implantable cardioverter-defibrillator (ICD) patients is unclear. We sought to identify predictors of CV outcomes in ICD recipients for primary (G1) versus secondary prevention (G2). Consecutive patients who had ICD implanted during August 2005 to December 2009 were included. The primary outcome was a composite of appropriate shock, acute coronary syndrome, ischemic stroke, coronary revascularization, heart failure exacerbation, CV hospitalization, or all-cause death. We used Cox proportional hazards model and a stepwise selection method to fit the most parsimonious model to predict the primary outcome in all patients and separately for G1 and G2 patients. We followed 223 (184 G1 and 39 G2, mean age 61 years) patients through December 31, 2012; 141 (63.2%) developed the primary outcome. In all patients, atrial fibrillation (AF; hazard ratio 6.72, 95% CI 4.20 to 10.75; p <0.001), use of antiarrhythmic drug (1.55, 1.02 to 2.36; p = 0.04), and lower estimated glomerular filtration rate (0.99, 0.98 to 0.997; p = 0.01) were associated with increased risk of the primary outcome; the attributable risks were 21.6%, 16.0%, and 15.9%, respectively. In G1, AF, hypertension, and lower estimated glomerular filtration rate were associated with increased risk, whereas in G2, AF, use of antiarrhythmic drug, and nonischemic cardiomyopathy were associated with increased risk. In conclusion, although risk factors are different for primary and secondary prevention patients, AF is a strong and consistent risk factor for adverse outcomes in both populations.

Survival After Secondary Prevention Implantable Cardioverter-Defibrillator Placement: An Analysis From the NCDR ICD Registry

OBJECTIVES

This study sought to define the characteristics and risks of death of patients receiving a physician-designated secondary prevention implantable cardioverter-defibrillator (ICD) in contemporary clinical practice.

BACKGROUND

Data on utilization and outcomes of ICDs for the secondary prevention of sudden cardiac death (SCD) are limited.

METHODS

Patients enrolled in the National Cardiovascular Data Registry's (NCDR) ICD Registry from 2006 to 2009 with a physician-designated secondary prevention indication for ICD implantation were identified and linked to the Social Security Death Master File. Those patients with a history either of tachycardic arrest or sustained ventricular tachycardia (SCD/VT) or of syncope without SCD/VT were included. Kaplan-Meier survival analysis was used to assess mortality. Cox proportional hazards survival modeling was used to assess the risk of death in these groups, adjusting for patient characteristics.

RESULTS

In the study cohort of 46,685 patients (mean age 66 ± 14 years, 73.5% male, 85% white), 78% had SCD/VT and 22% had syncope. Overall mortality was 10.4% at 1 year and 16.4% at 2 years. Compared with patients having SCD/VT, the adjusted hazard of death at 1 year was lower in the patients having syncope (hazard ratio: 0.89; 95% confidence interval: 0.83 to 0.96) but was not significantly different by 2 years (hazard ratio: 0.96; 95% confidence interval: 0.90 to 1.01).

CONCLUSIONS

Nearly 9 of 10 patients receiving a secondary prevention ICD in clinical practice are alive 1 year after implantation. The risk of death varies by indication and is highest among patients who survive SCD or sustained VT in the first year after device implantation.