Importance of Implantable Cardioverter-Defibrillator Back-Up in Cardiac Resynchronization Therapy Recipients: A Systematic Review and Meta-Analysis

Factors of mortality in patients with cardiac implantable electronic device: 5-year experience

OBJECTIVE

The use of cardiac implantable electronic devices has increased in recent years. It has also brought some issues. Among these, the complications of cardiac implantable electronic devices infection and pocket hematoma are difficult to manage. It can be fatal with the contribution of patient-related risk factors. In this study, we aimed to find mortality rates in patients who developed cardiac implantable electronic devices infection and pocket hematoma over 5 years. We also investigated the risk factors affecting mortality in patients with cardiac implantable electronic devices.

METHODS

A total of 288 cardiac implantable electronic devices patients were evaluated. Demographic details, history, and clinical data of all patients were recorded. Cardiac implantable electronic devices infection was defined according to the modified Duke criteria. The national registry was used to ascertain the mortality status of the patients. The patients were divided into two groups (exitus and survival groups). In addition, the pocket hematoma was defined as significant bleeding at the pocket site after cardiac implantable electronic devices placement.

RESULTS

The cardiac implantable electronic devices infection was similar in both groups (p=0.919), and the pocket hematoma was higher in the exitus group (p=0.019). The exitus group had higher usage of P2Y12 inhibitors (p≤0.001) and novel oral anticoagulants (p=0.031). The Cox regression analysis, including mortality-related factors, revealed that renal failure is the most significant risk factor for mortality. Renal failure was linked to a 2.78-fold higher risk of death.

CONCLUSION

No correlation was observed between cardiac implantable electronic devices infection and mortality, whereas pocket hematoma was associated with mortality. Furthermore, renal failure was the cause of the highest mortality rate in patients with cardiac implantable electronic devices.

Tachycardia Therapy Outcomes of Ischemic Versus Nonischemic Cardiomyopathy on Cardiac Resynchronization Therapy: A Propensity Score-matched Analysis

Objective

This investigation aimed to investigate differences between dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) patients treated with cardiac resynchronization therapy with defibrillator (CRT-D) for tachycardia therapy-related outcomes as well as mortality during follow-up of at least 1 year.

Methods

Seventy-eight patients with DCM (n = 42) and ICM (n = 36) with implantation or upgradation to CRT-D were included in this study and analyzed for incidence of non-sustained ventricular tachycardia (NSVT), non-sustained ventricular fibrillation (NSVF), defibrillator therapies, anti-tachycardia pacing (ATP), and mortality.

Results

DCM was the underlying etiology in 42 (53.84%) and ICM in 36 (46.15%). Time to first therapy was numerically longer in DCM than in ICM (9.5 ± 2.4 vs. 7.1 ± 3.2; P-value = 0.088). DCM patients had significantly higher therapy-free survival and mortality compared with ICM patients (OR (95%CI): 0.238 (0.155-0.424); log-rank P = 0.017) and (OR (95% CI): 0.612 (0.254-0.924); log-rank P = 0.029). ICM (HR (95%CI): 0.529 (0.243-0.925); P-value = 0.014) CAD (HR (95%CI): 0.326 (0.122-0.691): P-value = 0.003), and NSVT (HR (95%CI): 0.703 (0.513-0.849): P-value = 0.005) were demonstrated as independent predictors of the primary endpoint of appropriate therapy in CRT-D and ICM (HR (95%CI): 0.421 (0.321-0.524); P-value = 0.037), chronic kidney disease (CKD; HR (95%CI): 0.289 (0.198-0.380); P-value = 0.013), and CAD (HR (95%CI): 0.786 (0.531-0.967); P-value = 0.003) were predictors of mortality.

Conclusion

The clinical course of ICM and DCM cohorts who were treated with CRT-D differs significantly during follow-up, with increased tachycardia therapy and increased incidence of mortality in ICM patients.

2023 National Heart Center/Saudi Heart Association Focused Update of the 2019 Saudi Heart Association Guidelines for the Management of Heart Failure

Background

The burden of cardiovascular diseases is undeniable in local populations, who have high mortality rates and a young age of disease onset. A systematic review of emerging evidence and update of the Saudi Heart Association (SHA) 2019 heart failure (HF) guidelines was therefore undertaken.

Methodology

A panel of expert cardiologists reviewed recommendations of the 2019 guidelines following the Saudi Heart Association methodology for guideline recommendations. When needed, the panel provided updated and new recommendations endorsed by the national heart council that are appropriate for clinical practice and local resources in Saudi Arabia.

Recommendations and conclusion

The focused update describes the appropriate use of clinical assessment as well as invasive and non-invasive modalities for the classification and diagnosis of HF. The prevention of HF was emphasized by expanding on both primary and secondary prevention approaches. Pharmacological treatment of HF was supplemented with recommendations on newer therapies, such as SGLT-2 inhibitors. Recommendations were also provided on the management of patients with cardiovascular and non-cardiovascular co-morbidities, with a focus on cardio-oncology and pregnancy. Updated clinical algorithms were included in support of HF management in both the acute and chronic settings. The implementation of this focused update on HF management in clinical practice is expected to lead to improved patient outcomes by providing evidence-based comprehensive guidance for practitioners in Saudi Arabia.

Implantable defibrillator therapy and mortality in patients with non-ischaemic dilated cardiomyopathy : An updated meta-analysis and effect on Dutch clinical practice by the Task Force of the Dutch Society of Cardiology

BACKGROUND

Primary prophylactic implantable cardioverter-defibrillators (ICDs) in patients with non-ischaemic cardiomyopathy (NICMP) remains controversial. This study sought to assess the benefit of ICD therapy with or without cardiac resynchronisation therapy (CRT) in patients with NICMP. In addition, data were compared with real-world clinical data to perform a risk/benefit analysis.

METHODS

Relevant randomised clinical trials (RCTs) published in meta-analyses since DANISH, and in PubMed, EMBASE and Cochrane databases from 2016 to 2020 were identified. The benefit of ICD therapy stratified by CRT use was assessed using random effects meta-analysis techniques.

RESULTS

Six RCTs were included in the meta-analysis. Among patients without CRT, ICD use was associated with a 24% reduction in mortality (hazard ratio [HR]: 0.76; 95% confidence interval [CI]: 0.62-0.93; P = 0.008). In contrast, among patients with CRT, a CRT-defibrillator was not associated with reduced mortality (HR: 0.74, 95% CI 0.47-1.16; P = 0.19). For ICD therapy without CRT, absolute risk reduction at 3‑years follow-up was 3.7% yielding a number needed to treat of 27.

CONCLUSION

ICD use significantly improved survival among patients with NICMP who are not eligible for CRT. Considering CRT, the addition of defibrillator therapy was not significantly associated with mortality benefit compared with CRT pacemaker.

Cardiac Resynchronization Therapy With or Without Defibrillation in Patients With Nonischemic Cardiomyopathy: A Systematic Review and Meta-Analysis

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Is there a benefit of ICD treatment in patients with persistent severely reduced systolic left ventricular function after TAVI?

BACKGROUND

In patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) and heart failure with severely reduced ejection fraction, prediction of postprocedural left ventricular ejection fraction (LVEF) improvement is challenging. Decision-making and timing for implantable cardioverter defibrillator (ICD) treatment are difficult and benefit is still unclear in this patient population.

OBJECTIVE

Aims of the study were to analyse long-term overall mortality in TAVI-patients with a preprocedural LVEF ≤ 35% regarding LVEF improvement and effect of ICD therapy.

METHODS AND RESULTS

Retrospective analysis of a high-risk TAVI-population suffering from severe AS and heart failure with a LVEF ≤ 35%. Out of 1485 TAVI-patients treated at this center between January 2013 and April 2018, 120 patients revealed a preprocedural LVEF ≤ 35% and had sufficient follow-up. 36.7% (44/120) of the patients suffered from persistent reduced LVEF without a postprocedural increase above 35% within 1 year after TAVI or before death, respectively. Overall mortality was neither significantly reduced by LVEF recovery above 35% (p = 0.31) nor by additional ICD treatment in patients with persistent LVEF ≤ 35% (p = 0.33).

CONCLUSION

In high-risk TAVI-patients suffering from heart failure with LVEF ≤ 35%, LVEF improvement to more than 35% did not reduce overall mortality. Patients with postprocedural persistent LVEF reduction did not seem to benefit from ICD treatment. Effects of LVEF improvement and ICD treatment on mortality are masked by the competing risk of death from relevant comorbidities.

Sudden cardiac death after implantation of a cardiac resynchronization therapy pacemaker: a case report illustrating that not always less is more

Background

Cardiac resynchronization therapy (CRT) improves symptoms and survival in selected patients with systolic heart failure and ventricular conduction delay. In subjects without prior life-threatening ventricular arrhythmia, clinicians have to select between implanting a CRT pacemaker (CRT-P) or a more complex device with additional defibrillator capability (CRT-D). This individual decision can be challenging in light of the available evidence and the potential risks and benefits.

Case summary

A 76-year-old male with non-ischaemic cardiomyopathy, heart failure New York Heart Association Class III, left bundle branch block (QRS duration 185 ms) and a left ventricular ejection fraction of 30% despite optimal medical therapy was indicated for CRT. In light of the patient characteristics and clinical condition, a CRT-P device was implanted. No complication occurred, and the patient was discharged after an appropriate device function was confirmed. Despite the clinical improvement, he died suddenly without prior symptoms approximately 2 months thereafter. Post-mortem device interrogation provided no evidence for device malfunction and confirmed sudden cardiac death (SCD) due to spontaneous ventricular fibrillation.

Discussion

Patients indicated for CRT often have overlapping internal cardioverter defibrillator indication for the primary prevention of SCD. By weighing individual risks and potential benefits, clinicians have to decide whether to implant a CRT-P (less is more) or a more complex and costly CRT-D device. Despite careful consideration of patient characteristics and clinical conditions, however, SCD can occur in subjects categorized as low risk and implanted with a CRT-P. More data from randomized clinical trials are needed to better support physicians in the often challenging process of selecting the most appropriate device for CRT.

Application of the heart failure meta-score to predict prognosis in patients with cardiac resynchronization defibrillators

BACKGROUND

The Heart Failure (HF) Meta-score may be useful in predicting prognosis in patients with primary prevention cardiac resynchronization defibrillators (CRT-D) considering the competing risk of appropriate defibrillator shock versus mortality.

METHODS

Data from 648 consecutive patients from two centers were used for the evaluation of the performance of the HF Meta-score. The primary endpoint was mortality and the secondary endpoint was time to first appropriate implantable cardioverter-defibrillator (ICD) shock or death without prior appropriate ICD shock. Fine-Gray model was used for competing risk regression analysis.

RESULTS

In the entire cohort, 237 patients died over a median follow-up of 5.2 years. Five-year cumulative incidence of mortality ranged from 12% to 53%, for quintiles 1 through 5 of the HF Meta-score, respectively (log-rank P < 0.001). Compared with the lowest quintile, mortality risk was higher in the highest quintile (HR 6.9; 95%CI 3.7-12.8). The HF Meta-score had excellent calibration, accuracy, and good discrimination in predicting mortality (C-statistic 0.76 at 1-year and 0.71 at 5-year). The risk of death without appropriate ICD shock was higher in risk quintile 5 compared to quintile 1 (sub HR 5.8; 95%CI 3.1-11.0, P < 0.001).

CONCLUSIONS

Our study demonstrated a good ability of the HF Meta-score to predict survival in HF patients treated with CRT-D as primary prevention. The HF Meta-score proved to be useful in identifying a subgroup with a significantly poor prognosis despite a CRT-D.

The benefits of defibrillator in heart failure patients with cardiac resynchronization therapy: A meta-analysis

BACKGROUND

Current guidelines did not provide recommendations on indications of an additional implantable cardioverter-defibrillator (ICD) to patients receiving cardiac resynchronization therapy (CRT), and it still remains controversial due to lack of evidence from randomized controlled trials.

METHOD

PubMed, Embase, and Cochrane CENTRAL from the inception to May 2020 were systematically screened for studies reporting on the comparison of cardiac resynchronization therapy with defibrillator (CRT-D) and cardiac resynchronization therapy with pacemaker (CRT-P), focusing on the adjusted hazard ratio (aHR) of all-cause mortality. We pooled the effects using a random-effect model.

RESULTS

Twenty-one studies encompassing 69,919 patients were included in this meta-analysis. With no restriction to characteristics of including population, CRT-D was associated with a lower all-cause mortality compared with CRT-P significantly (aHR: 0.80, 95% confidence interval [CI]: 0.74-0.87, I²  = 36.8%, p < .001). This mortality benefit was also observed in patients with ischemic cardiomyopathy (aHR: 0.74, 95% CI: 0.64-0.86, I²  = 0%, p < .001). However, there is no significant difference in patients with nonischemic cardiomyopathy (NICM) (aHR: 0.91, 95% CI: 0.82-1.01, I²  = 0%, p = .087), older age (age ≥75 years, aHR: 0.96, 95% CI: 0.83-1.12, I²  = 0%, p = .610). Subgroup analysis was performed and indicated the survival benefit of CRT-D for primary prevention compared with CRT-P (aHR: 0.87, 95% CI: 0.79-0.95, I²  = 0%, p = .003).

CONCLUSION

After adjusted the differences in clinical characteristics, additional ICD therapy was associated with a reduced all-cause mortality in patients receiving CRT. However, our work suggested that additional ICD may not be applied to elderly (≥75 years) or patients with NICM.

Chronic Heart Failure

BACKGROUND

Chronic heart failure (CHF) is the most common reason for hospital admissions in Germany. For the National Disease Management Guideline (NDMG) on CHF, a multidisciplinary expert panel revised the chapters on drug therapy, invasive therapy, and care coordination, following the methods of evidence-based medicine.

METHODS

Recommendations are based on international guideline adaptations or systematic literature search. They were developed by a multidisciplinary expert panel, approved in a formal consensus procedure, and tested in open consultation, as specified by the requirements for S3 guidelines.

RESULTS

The pharmacological treatment is based on ACE inhibitors, beta-blockers and mineralocorticoid receptor antagonists as well as diuretics to treat fluid retention, if present. Sacubitril/Valsartan and ivabradine showed positive effects on mortality in large but methodologically limited RCT. They are recommended if established combination therapy is not sufficient for symptom control, or if drugs are not tolerated/contraindicated. The indications for pacemakers or defibrillators have been confined to patient subgroups in which clinical trials have shown a clear benefit. Moreover, the goals of treatment and the patient's expectations should be aligned with each other. Structured care programs, specialized nurses, remote, or telephone monitoring showed moderate effects on patient related outcomes in RCT.

CONCLUSION

All patients with heart failure are suggested to be enrolled in a structured program (e.g., a disease management program) including coordinated multidisciplinary care and continuous educational interventions. In patients with a poor prognosis, more intensive care is recommended, e.g. specialized nurses, or telephone support.

Improving Cardiac Resynchronisation Therapy

CRT is a cornerstone of therapy for patients with heart failure and reduced ejection fraction. By restoring left ventricular (LV) electrical and mechanical synchrony, CRT can reduce mortality, improve LV function and reduce heart failure symptoms. Since its introduction, many advances have been made that have improved the delivery of and enhanced the response to CRT. Improving CRT outcomes begins with proper patient selection so CRT is delivered to all populations that could benefit from it, and limiting the implantation of CRT in those with a small chance of response. In addition, advancements in LV leads and delivery technologies coupled with multimodality imaging and electrical mapping have enabled operators to place coronary sinus leads in locations that will optimise electrical and mechanical synchrony. Finally, new pacing strategies using LV endocardial pacing or His bundle pacing have allowed for CRT delivery and improved response in patients with poor coronary sinus anatomy or lack of response to traditional CRT.

Saudi Heart Association (SHA) guidelines for the management of heart failure

Heart failure (HF) is the leading cause of morbidity and mortality worldwide and negatively impacts quality of life, healthcare costs, and longevity. Although data on HF in the Arab population are scarce, recently developed regional registries are a step forward to evaluating the quality of current patient care and providing an overview of the clinical picture. Despite the burden of HF in Saudi Arabia, there are currently no standardized protocols or guidelines for the management of patients with acute or chronic heart failure. Therefore, the Heart Failure Expert Committee, comprising 13 local specialists representing both public and private sectors, has developed guidelines to address the needs and challenges for the diagnosis and treatment of HF in Saudi Arabia. The ultimate aim of these guidelines is to assist healthcare professionals in delivering optimal care and standardized clinical practice across Saudi Arabia.

Increased mortality and ICD therapies in ischemic versus non-ischemic dilated cardiomyopathy patients with cardiac resynchronization having survived until first device replacement

INTRODUCTION

Cardiac resynchronization therapy combined with an implantable cardioverter defibrillator (CRT-D) is widely applied in heart failure patients. Sufficient data on arrhythmia and defibrillator therapies during long-term follow-up of more than 4 years are lacking and data on mortality are conflicting. We aimed to characterize the occurrence of ventricular arrhythmia, respective defibrillator therapies and mortality for several years following CRT-D implantation or upgrade.

MATERIAL AND METHODS

Eighty-eight patients with ischemic (ICM) or non-ischemic dilated cardiomyopathy (DCM) and at least one CRT-D replacement were included in this study and analyzed for incidence of non-sustained ventricular tachycardia (NSVT), defibrillator shocks, anti-tachycardia pacing (ATP) and mortality.

RESULTS

ICM was the underlying disease in 59%, DCM in 41% of patients. During a mean follow-up of 76.4 ±24.8 months the incidence of appropriate defibrillator therapies (shock or ATP) was 46.6% and was elevated in ICM compared to DCM patients (57.7% vs. 30.6%, respectively; p = 0.017). Kaplan-Meier analysis revealed significantly higher ICD therapy-free survival rates in DCM patients (p = 0.031). Left ventricular ejection fraction, NSVT per year and ICM (vs. DCM) were independent predictors of device intervention. The ICM patients showed increased mortality compared to DCM patients, with cumulative all-cause mortality at 9 years of follow-up of 45.4% and 10.6%, respectively. Chronic renal failure, peripheral artery disease and chronic obstructive pulmonary disease were independent predictors of mortality.

CONCLUSIONS

The clinical course of patients with ICM and DCM treated with CRT-D differs significantly during long-term follow-up, with increased mortality and incidence of ICD therapies in ICM patients.

Clinical outcomes of cardiac resynchronization therapy with and without a defibrillator in elderly patients with heart failure

BACKGROUND

Evidence regarding the incremental benefit of cardiac resynchronization therapy (CRT) with a defibrillator (CRT-D) versus without (CRT-P) in elderly patients with heart failure is limited. We compared mortality and cardiac hospitalisation between CRT-D and CRT-P in the elderly.

METHODS

A retrospective chart review identified all consecutive patients with age ≥75 with CRT implantation over the last 10 years at a Canadian tertiary care cardiac centre. Kaplan-Meier survival analyses and cumulative incidence curves were used to compare mortality and time to first cardiac hospitalisation, respectively, with CRT-D versus CRT-P over a 3 year period. Analyses were also repeated with propensity score matching based on age, sex, primary versus secondary prevention, date of implant, and Charlson Comorbidity Index.

RESULTS

One hundred and seventy CRT patients were identified. A total of 128 received CRT-D while 42 received CRT-P. Median age was 79 (IQR 77-81), and the majority were male (83%). CRT-P patients had a higher burden of comorbidities (Charlson score 7, IQR 6-8) than CRT-D patients (Charlson score 5, IQR 5-7; P < 0.001). There was no significant difference in survival between the two groups in an unmatched comparison (P = 0.69) and with a propensity score-matched cohort (P = 0.91). Secondary prevention CRT-D patients had a higher risk of hospitalisation compared to primary prevention CRT-D patients; however, there was no significant difference in hospitalisation between the CRT-D and CRT-P groups.

CONCLUSION

This study suggests there is no significant difference in mortality or cardiac hospitalisation between CRT-D and CRT-P in elderly patients with heart failure.

Cardiac resynchronization therapy in the ageing population - With or without an implantable defibrillator?

BACKGROUND

Cardiac resynchronization therapy (CRT) is an effective treatment option for systolic heart failure, but the benefit of an additional implantable cardioverter-defibrillator (ICD) in elderly patients is not well established. The aim of our study was to evaluate the impact of an additional ICD on survival in elderly CRT recipients.

METHODS

Patients aged ≥75 years with an indication for CRT and primary preventive ICD therapy, which underwent implantation of either a CRT-pacemaker (CRT-P) or CRT-defibrillator (CRT-D) were included in the study. Patient characteristics, procedural and follow-up data, and subsequent all-cause mortality were analyzed.

RESULTS

A total of 775 consecutive patients underwent CRT implantation, whereof 177 patients fulfilled the inclusion criteria. Of these, 80 patients with CRT-P and 97 with CRT-D formed the two study groups. Patients in the CRT-P group were significantly older (82.6 ± 4.5 vs. 77.8 ± 1.9 years, p < 0.001) and more often female (44 vs. 25%; p < 0.001), had a better left ventricular ejection fraction (29.5 ± 5.7 vs. 27.4 ± 6.0%; p = 0.019) and narrower QRS-complex (150 ± 19 vs. 158 ± 18 ms; p = 0.025). During a mean follow-up of 26 ± 19 months, 62 (35%) study patients died, 28 (35%) in the CRT-P and 34 (35%) in the CRT-D group (p = 0.994). The Kaplan-Meier analysis of survival probability showed no significant difference between the two groups (p = 0.562).

CONCLUSION

In our study, an additional ICD had no impact on survival in elderly patients undergoing implantation of a CRT device. Randomized controlled trials have to confirm this finding.

Cardiac resynchronization therapy: a comprehensive review

Despite improved understanding of heart failure (HF) and advances in medical treatments, its prevalence continues to rise, and the role of implantable devices continues to evolve. While cardiac resynchronization therapy (CRT) is an accepted form of treatment for many suffering from HF, there is an ever-evolving body of evidence examining novel indications, optimization of lead placement and device programming, with several competing technologies now also on the horizon. This review aims to take a clinical perspective on the major trials, current indications, controversies and emerging aspects of CRT in the treatment of HF.

Device complications with addition of defibrillation to cardiac resynchronisation therapy for primary prevention

OBJECTIVE

In patients indicated for cardiac resynchronisation therapy (CRT), the choice between a CRT-pacemaker (CRT-P) versus defibrillator (CRT-D) remains controversial and indications in this setting have not been well delineated. Apart from inappropriate therapies, which are inherent to the presence of a defibrillator, whether adding defibrillator to CRT in the primary prevention setting impacts risk of other acute and late device-related complications has not been well studied and may bear relevance for device selection.

METHODS

Observational multicentre European cohort study of 3008 consecutive patients with ischaemic or non-ischaemic dilated cardiomyopathy and no history of sustained ventricular arrhythmias, undergoing CRT implantation with (CRT-D, n=1785) or without (CRT-P, n=1223) defibrillator. Using propensity score and competing risk analyses, we assessed the risk of significant device-related complications requiring surgical reintervention. Inappropriate shocks were not considered except those due to lead malfunction requiring lead revision.

RESULTS

Acute complications occurred in 148 patients (4.9%), without significant difference between groups, even after considering potential confounders (OR=1.20, 95% CI 0.72 to 2.00, p=0.47). During a mean follow-up of 41.4±29 months, late complications occurred in 475 patients, giving an annual incidence rate of 26 (95% CI 9 to 43) and 15 (95% CI 6 to 24) per 1000 patient-years in CRT-D and CRT-P patients, respectively. CRT-D was independently associated with increased occurrence of late complications (HR=1.68, 95% CI 1.27 to 2.23, p=0.001). In particular, when compared with CRT-P, CRT-D was associated with an increased risk of device-related infection (HR 2.10, 95% CI 1.18 to 3.45, p=0.004). Acute complications did not predict overall late complications, but predicted device-related infection (HR 2.85, 95% CI 1.71 to 4.56, p<0.001).

CONCLUSIONS

Compared with CRT-P, CRT-D is associated with a similar risk of periprocedural complications but increased risk of long-term complications, mainly infection. This needs to be considered in the decision of implanting CRT with or without a defibrillator.

Narrowing filtered QRS duration on signal-averaged electrocardiogram predicts outcomes in cardiac resynchronization therapy patients with nonischemic heart failure

BACKGROUND

To evaluate the impact of changes in the filtered QRS duration (fQRS) on signal-averaged electrocardiograms (SAECGs) from pre- to postimplantation on the clinical outcomes in nonischemic heart failure (HF) patients under cardiac resynchronization therapy (CRT).

METHODS

We studied 103 patients with nonischemic HF and sinus rhythm who underwent CRT implantation. SAECGs were obtained within 1 week before and 1 week after implantation and narrowing fQRS was defined as a decrease in fQRS from pre- to postimplantation. Echocardiography was performed before and 6 months after CRT implantation. The primary outcome was death from any cause. The secondary outcomes were hospitalization due to worsened HF and occurrence of ventricular tachyarrhythmias.

RESULTS

Of the 103 CRT patients, 53 (51%) showed narrowing fQRS. Left ventricular end-diastolic volume and end-systolic volume were significantly reduced (both p < .001), and the left ventricular ejection fraction was significantly increased (p < .001) after CRT in patients with narrowing fQRS, but not in patients with nonnarrowing fQRS. During a median follow-up period of 33 months, patients with narrowing fQRS exhibited better survival than patients with nonnarrowing fQRS (p = .007). A lower incidence of hospitalization due to worsened HF (p < .001) and a lower occurrence of ventricular tachyarrhythmias (p = .071) were obtained in patients with narrowing fQRS. After adjusting for confounding variables, narrowing fQRS was associated with a low risk of mortality (HR 0.27, p = .006).

CONCLUSION

Our results suggested that narrowing fQRS on SAECG after CRT implantation predicts LV reverse remodeling and long-term outcomes in nonischemic HF patients.

Survival and Heart Failure Hospitalization in Patients With Cardiac Resynchronization Therapy With or Without a Defibrillator for Primary Prevention in Japan - Analysis of the Japan Cardiac Device Treatment Registry Database

BACKGROUND

Randomized control trials comparing the effectiveness of cardiac resynchronization therapy devices, with (CRT-D) or without (CRT-P) a defibrillator, are scarce in heart failure patients with no prior sustained ventricular tachyarrhythmias.

METHODS AND RESULTS

The Japan Cardiac Device Treatment Registry (JCDTR) has data for 2714 CRT-D and 555 CRT-P recipients for primary prevention with an implantation date between January 2011 and August 2015. Of these patients, follow-up data were available for 717. Over the mean follow-up period of 21 months, Kaplan-Meier curves of survival free of combined events for all-cause death or heart failure hospitalization (whichever came first) diverged between the CRT-D (n=620) and CRT-P (n=97) groups with a rate of 22% vs. 42%, respectively, at 24 months (P=0.0011). However, this apparent benefit of CRT-D over CRT-P was no longer significant after adjustment for covariates. With regard to mortality, including heart failure death or sudden cardiac death, there was no significant difference between the 2 groups.

CONCLUSIONS

In patients without sustained ventricular tachyarrhythmias enrolled in the JCDTR, there was no significant difference in mortality between the CRT-D and CRT-P groups, despite a lower trend in CRT-D recipients. This study was limited by large clinical and demographic differences between the 2 groups.

Implantable cardioverter defibrillator in non-ischemic cardiomyopathy: a meta-analysis of randomized controlled trials

BACKGROUND

Sudden cardiac death (SCD) is a significant cause of mortality in patients with non-ischemic cardiomyopathy (NICM). Implantable cardioverter defibrillators (ICDs) are currently indicated for the primary prevention of SCD in these patients. Conflicting results from published randomized controlled trials (RCTs) have recently questioned the protective role of ICD in NICM patients to perform an updated meta-analysis of the effect of ICDs on outcomes of NICM patients.

METHODS

We performed a search of PubMed, EMBASE, and Cochrane databases for RCTs comparing ICD to medical therapy in patients with NICM. Outcomes were all-cause mortality, SCD, and cardiac mortality. Mantel-Haenszel (MH) risk ratios (RR) were calculated using random-effects meta-analysis for the outcomes mentioned. Heterogeneity was assessed using I² statistics and Q-statistic.

RESULTS

A total of five RCTs met the inclusion criteria, with a total of 1,503 patients in the ICD group and 1,364 patients in the medical therapy. Compared to medical therapy, ICD use resulted in a 24% relative risk reduction (RRR) of all-cause mortality (RR 0.76, 95% CI 0.64-0.91, P=0.002), and 60% RRR of SCD (RR 0.40, 95% CI 0.18-0.90, P=0.03), but was not associated with a statistically significant benefit in the prevention of cardiac mortality (RR 0.75, 95% CI 0.39-1.44, P=0.39). Limiting the analysis to patients who received an ICD only without cardiac resynchronization therapy (CRT) pacemakers (4 trials, 1,825 patients) showed similar all-cause mortality results with 24% RRR in ICD group (RR 0.76, 95% CI 0.61-0.94, P=0.01).

CONCLUSIONS

ICD therapy reduces all-cause mortality and SCD in patients with NICM.

Cardiac resynchronization therapy in ischemic and non-ischemic cardiomyopathy

Cardiac resynchronization therapy (CRT) using a biventricular pacing system has been an effective therapeutic strategy in patients with symptomatic heart failure with a reduced left ventricular ejection fraction (LVEF) of 35% or less and a QRS duration of 130 ms or more. The etiology of heart failure can be classified as either ischemic or non-ischemic cardiomyopathy. Ischemic etiology of patients receiving CRT is prevalent predominantly in North America, moderately in Europe, and less so in Japan. CRT reduces mortality similarly in both ischemic and non-ischemic cardiomyopathy, whereas reverse structural left ventricular remodeling occurs more favorably in non-ischemic cardiomyopathy. Because the substrate for ventricular arrhythmias appears to be more severe in cases of ischemic as compared with non-ischemic cardiomyopathy, the use of an implantable cardioverter-defibrillator (ICD) backup method could prolong the long-term survival, especially of patients with ischemic cardiomyopathy, even in the presence of CRT. The aim of this review article is to summarize the effects of CRT on outcomes and the role of ICD backup in ischemic and non-ischemic cardiomyopathy.

Trends and determinant factors in the use of cardiac resynchronization therapy devices in Japan: Analysis of the Japan cardiac device treatment registry database

Background

The choice of cardiac resynchronization therapy device, with (CRT-D) or without (CRT-P) a defibrillator, in patients with heart failure largely depends on the physician׳s discretion, because it has not been established which subjects benefit most from a defibrillator.

Methods

We examined the annual trend of CRT device implantations between 2006 and 2014, and evaluated the factors related to the device selection (CRT-D or CRT-P) for primary prevention of sudden cardiac death in patients with heart failure by analyzing the Japan Cardiac Device Treatment Registry (JCDTR) database from January 2011 and August 2015 (CRT-D, n=2714; CRT-P, n=555).

Results

The proportion of CRT-D implantations for primary prevention among all the CRT-D recipients was more than 70% during the study period. The number of CRT-D implantations for primary prevention reached a maximum in 2011 and decreased gradually between 2011 and 2014, whereas CRT-P implantations increased year by year until 2011 and remained unchanged in recent years. Multivariate analysis identified age (odds ratio [OR] 0.92, 95% confidence interval [CI] 0.90–0.95, P<0.0001), male sex (OR 1.99, 95% CI 1.28–3.11, P<0.005), reduced left ventricular ejection fraction (LVEF) (OR 0.96, 95% CI 0.94–0.98, P<0.0001), and non-sustained ventricular tachycardia (NSVT) (OR 2.85, 95% CI 1.87–4.35, P<0.0001) as independent factors favoring the choice of CRT-D.

Conclusions

Younger age, male sex, reduced LVEF, and a history of NSVT were independently associated with the choice of CRT-D for primary prevention of sudden cardiac death in patients with heart failure in Japan.