Mortality and cardiac resynchronization therapy with or without defibrillation in primary prevention

Cardiac resynchronization therapy-defibrillator implantation with shock lead placement in the left bundle branch area: a case report

Background

Cardiac resynchronization therapy (CRT) with biventricular pacing is a well-established therapy. Left bundle branch area pacing (LBBAP) is a safe technique providing physiological pacing, and LBBAP-optimized CRT (LOT-CRT) has been shown to provide better electrical resynchronization than traditional CRT. However, there are few reports on shock lead placement in the left bundle branch area (LBBA) during CRT-defibrillator (CRT-D) implantation.

Case summary

A 76-year-old woman with heart failure from dilated cardiomyopathy presented with left bundle branch block pattern (QRS duration, 160 ms). Left ventricular ejection fraction was 21%. Cardiac resynchronization therapy-defibrillator implantation was performed due to worsening symptoms. By reshaping the Agilis HisPro catheter and adding a septal curve, the shock lead was placed deep into the ventricular septum, narrowing QRS duration to 114 ms. Left ventricular activation time was 84 ms. A defibrillation threshold test confirmed successful treatment without adverse events. At 6-month follow-up, left ventricular ejection fraction improved from 21 to 63%, with the patient's condition improving from New York Heart Association class III to class I.

Discussion

It was reported that QRS narrowing in CRT was related to long-term mortality, and LOT-CRT further decreased QRS duration as compared with LBBP only or biventricular pacing and increased the response rate. Combining LBBAP with coronary sinus pacing can potentially achieve superior electrical resynchronization. Lack of a suitable tool for direct shock lead placement in LBBA necessitated additional LBBAP lead in conventional LOT-CRT. Our successful LOT-CRT-D procedure with minimal number of leads through Agilis HisPro catheter reshaping enabled direct LBBA shock lead placement.

Time-trend treatment effect of cardiac resynchronization therapy with or without defibrillator on mortality: a systematic review and meta-analysis

AIMS

This study aimed to investigate the impact of cardiac resynchronization therapy with a defibrillator (CRT-D) on mortality, comparing it with CRT with a pacemaker (CRT-P). Additionally, the study sought to identify subgroups, evaluate the time trend in treatment effects, and analyze patient characteristics, considering the changing indications over the past decades.

METHODS AND RESULTS

PubMed, CENTRAL, and Embase up to October 2021 were screened for studies comparing CRT-P and CRT-D, focusing on mortality. Altogether 26 observational studies were selected comprising 128 030 CRT patients, including 55 469 with CRT-P and 72 561 with CRT-D device. Cardiac resynchronization therapy with defibrillator was able to reduce all-cause mortality by almost 20% over CRT-P [adjusted hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.76-0.94; P < 0.01] even in propensity-matched studies (HR: 0.83; 95% CI: 0.80-0.87; P < 0.001) but not in those with non-ischaemic aetiology (HR: 0.95; 95% CI: 0.79-1.15; P = 0.19) or over 75 years (HR: 1.08; 95% CI 0.96-1.21; P = 0.17). When treatment effect on mortality was investigated by the median year of inclusion, there was a difference between studies released before 2015 and those thereafter. Time-trend effects could be also observed in patients' characteristics: CRT-P candidates were getting older and the prevalence of ischaemic aetiology was increasing over time.

CONCLUSION

The results of this systematic review of observational studies, mostly retrospective with meta-analysis, suggest that patients with CRT-D had a lower risk of mortality compared with CRT-P. However, subgroups could be identified, where CRT-D was not superior such as non-ischaemic and older patients. An improved treatment effect of CRT-D on mortality could be observed between the early and late studies partly related to the changed characteristics of CRT candidates.

Optimizing patient selection for primary prevention implantable cardioverter-defibrillator implantation: utilizing multimodal machine learning to assess risk of implantable cardioverter-defibrillator non-benefit

AIMS

Left ventricular ejection fraction (LVEF) is suboptimal as a sole marker for predicting sudden cardiac death (SCD). Machine learning (ML) provides new opportunities for personalized predictions using complex, multimodal data. This study aimed to determine if risk stratification for implantable cardioverter-defibrillator (ICD) implantation can be improved by ML models that combine clinical variables with 12-lead electrocardiograms (ECG) time-series features.

METHODS AND RESULTS

A multicentre study of 1010 patients (64.9 ± 10.8 years, 26.8% female) with ischaemic, dilated, or non-ischaemic cardiomyopathy, and LVEF ≤ 35% implanted with an ICD between 2007 and 2021 for primary prevention of SCD in two academic hospitals was performed. For each patient, a raw 12-lead, 10-s ECG was obtained within 90 days before ICD implantation, and clinical details were collected. Supervised ML models were trained and validated on a development cohort (n = 550) from Hospital A to predict ICD non-arrhythmic mortality at three-year follow-up (i.e. mortality without prior appropriate ICD-therapy). Model performance was evaluated on an external patient cohort from Hospital B (n = 460). At three-year follow-up, 16.0% of patients had died, with 72.8% meeting criteria for non-arrhythmic mortality. Extreme gradient boosting models identified patients with non-arrhythmic mortality with an area under the receiver operating characteristic curve (AUROC) of 0.90 [95% confidence intervals (CI) 0.80-1.00] during internal validation. In the external cohort, the AUROC was 0.79 (95% CI 0.75-0.84).

CONCLUSIONS

ML models combining ECG time-series features and clinical variables were able to predict non-arrhythmic mortality within three years after device implantation in a primary prevention population, with robust performance in an independent cohort.

Effectiveness of adding a defibrillator with cardiac resynchronization therapy in heart failure according to the modified Model for End-stage Liver Disease-Albumin score

Current guidelines lack clear recommendations between the implantation of cardiac resynchronization therapy (CRT) with defibrillator (CRT-D) and CRT with pacemaker (CRT-P). We hypothesized that modified model for end-stage liver disease score including albumin (MELD-Albumin score), could be used to select patients who may not benefit from CRT-D. We consecutively included patients with CRT-P or CRT-D implantation between 2010 and 2022. The primary endpoint was the composite of all-cause mortality or worsening heart failure. We performed multivariable-adjusted Cox proportional hazard regression. We assessed the interaction between the MELD-Albumin score and the effect of adding a defibrillator with CRT.A total of 752 patients were included in this study, with 291 implanted CRT-P. During a median follow-up of 880 days, 205 patients reached the primary endpoint. MELD-Albumin score was significantly associated with the primary endpoint in the CRT-D group [HR 1.16 (1.09-1.24); P < 0.001] but not in the CRT-P group [HR 1.03 (0.95-1.12); P = 0.49]. There was a significant interaction between the MELD-Albumin score and the effect of CRTD (P = 0.013). The optimal cut-off value of the MELD-Albumin score was 12. For patients with MELD-Albumin ≥ 12, CRT-D was associated with a higher occurrence of the primary endpoint [HR 1.99 (1.10-3.58); P = 0.02], whereas not in patients with MELD-Albumin < 12 [HR 1.19 (0.83-1.70); P = 0.35). Our findings suggest that CRT-D is associated with an excess risk of composite clinical endpoints in HF patients with higher MELD-Albumin score.

An updated meta-analysis of cardiac resynchronization therapy with or without defibrillation in patients with nonischemic cardiomyopathy

Background

Cardiac resynchronization therapy (CRT) is a major device therapy used to treat patients suffering from heart failure (HF) and electrical asynchrony. It can improve HF symptoms, reduce HF hospitalization time, and improve long-term survival in HF with and without implantable cardioverter (ICD) therapy. However, the benefit of defibrillator therapy in CRT-eligible patients with nonischemic cardiomyopathy (NICM) remains unknown. As a result, we conducted a systematic review and meta-analysis to compare clinical outcomes in patients with NICM and HF who were treated with implantable CRT defibrillators (CRT-D) vs. a CRT pacemaker (CRT-P) alone.

Methods

We searched the electronic databases PubMed, Embase, and Cochrane for all studies comparing CRT-D vs. CRT-P treatment in patients with NICM. The time frame was from 1990 to September 2022. All-cause mortality and cardiovascular mortality were the primary clinical outcomes of interest to us. To pool adjusted hazard ratios (HRs) and 95% confidence intervals (CIs), a random-effects model with inverse variance was used.

Results

A pooled meta-analysis included two randomized controlled trials (RCTs), each with 1,200 CRT-eligible patients with NICM (592 with CRT-D and 608 with CRT-P) and nine cohort studies representing 27,568 CRT-eligible patients with NICM (16,196 with CRT-D and 11,372 with CRT-P). The adjusted HR for all-cause mortality for CRT-D vs. CRT-P was 0.90 (95% CI, 0.81-0.99). In a subgroup analysis of two RCTs and nine cohort studies, the adjusted HR for all-cause mortality was 0.72 (95% CI, 0.43-1.19) and HR 0.92 (95% CI, 0.83-1.03) for CRT-D vs. CRT-P, respectively.

Conclusion

With the addition of defibrillation leads, we found a significantly lower risk of all-cause mortality in patients with NICM, but this association was not found in subgroup analyses of RCTs and observational studies.

The Challenges of Cardiac Resynchronization Therapy in Patients with Dilated Cardiomyopathy and Persistent Left Superior Vena Cava: A Case Report and Concise Literature Review

Heart failure with reduced ejection fraction (HFrEF) is a chronic and debilitating disease, which requires extensive diagnostic and treatment resources in order to achieve an acceptable quality of life for the patient. While optimal medical treatment remains at the core of the disease's management, interventional cardiology also plays a very important role. However, in very rare situations, interventionists might find cases especially challenging due to the presence of venous anomalies, such as persistent left superior vena cava (PLSVC), anomalies that may go undiscovered during the patient's lifetime until venous cannulation is necessary. While these types of malformations also pose challenges in regards to standard pacemaker implantation, cardiac resynchronization (CRT) devices pose several additional challenges due to the complexity of the device and the necessity of finding an optimal position for the coronary sinus (CS) lead. We present the case of a 55-year-old male patient with advanced heart failure due to dilated cardiomyopathy (DCM) and LBBB who was a candidate for CRT-D therapy, describing the investigations that led to the discovery of the PLSVC as well as the technique and results of the intervention, while comparing our case to similar cases found in recent literature.

Is CRT-D superior to CRT-P in patients with nonischemic cardiomyopathy?

Background

Recent studies have questioned the role of implanted cardiac defibrillators (ICDs) in nonischemic cardiomyopathy (NICM). Cardiac resynchronization therapy (CRT) can be delivered by a pacemaker (CRT-P) or an ICD (CRT-D). This meta-analysis assessed the effect of CRT-P versus CRT-D on mortality in patients with NICM.

Methods

Databases were searched for studies reporting the effect of CRT on all-cause mortality in patients with nonischemic cardiomyopathy (Ovid MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar, and EBSCO CINAHL). The primary endpoint was all-cause mortality. The minimum duration of follow-up required for inclusion was one year. The search was not restricted to time or publication status.

Results

The literature search identified 955 candidate studies, 15 studies and 22,763 patients were included. Mean follow-up was 53 months (17–100 months). CRT-D in NICM was associated with lower all-cause mortality (log HR − 0.169, SE 0.055; p = 0.002) compared to CRT-P. Heterogeneity: df = 15 (P 0.03), I2 = 43; test for overall effect: Z = − 3.043 (P = 0.002).

Conclusion

CRT-D in NICM was associated with lower all-cause mortality than CRT-P.

Primary prevention implantable cardioverter-defibrillator use in non-ischemic dilated cardiomyopathy based on arrhythmic risk stratification and left ventricular reverse remodeling prediction

Sudden cardiac death (SCD) and significant ventricular arrhythmias in patients with dilated cardiomyopathy (DCM) have been markedly reduced over the last couple of decades as a result of the advances in pharmacological and non-pharmacological treatment. Primary prevention implantable cardioverter-defibrillator (ICD) plays an important role in the treatment of patients at risk of SCD caused by ventricular arrhythmias. However, the arrhythmic risk stratification in patients with DCM remains extremely challenging, and the decision for primary prevention ICD implantation based on left ventricular ejection fraction (LVEF) solely appears to be insufficient. This review provides an update on current evidence for primary prevention ICD implantation, arrhythmic risk stratification, and left ventricular reverse remodeling (LVRR) prediction in patients with DCM in addition to most recent guideline recommendations for primary prevention ICD implantation in DCM patients and a proposed multiparametric algorithm based on arrhythmic risk stratification and left ventricular reverse remodeling (LVRR) prediction to better identify patients who are likely to benefit from primary prevention ICD.

Predicting outcome after cardiac resynchronisation therapy defibrillator implantation: the CRT-D Futility score

BACKGROUND

Risk-benefit for cardiac resynchronisation therapy (CRT) defibrillator (CRT-D) over CRT pacemaker remains a matter of debate. We aimed to identify patients with a poor outcome within 1 year of CRT-D implantation, and to develop a CRT-D Futility score.

METHODS

Based on an administrative hospital-discharge database, all consecutive patients treated with prophylactic CRT-D implantation in France (2010-2019) were included. A prediction model was derived and validated for 1-year all-cause death after CRT-D implantation (considered as futility) by using split-sample validation.

RESULTS

Among 23 029 patients (mean age 68±10 years; 4873 (21.2%) women), 7016 deaths were recorded (yearly incidence rate 7.2%), of which 1604 (22.8%) occurred within 1 year of CRT-D implantation. In the derivation cohort (n=11 514), the final logistic regression model included-as main predictors of futility-older age, diabetes, mitral regurgitation, aortic stenosis, history of hospitalisation with heart failure, history of pulmonary oedema, atrial fibrillation, renal disease, liver disease, undernutrition and anaemia. Area under the curve for the CRT-D Futility score was 0.716 (95% CI: 0.698 to 0.734) in the derivation cohort and 0.692 (0.673 to 0.710) in the validation cohort. The Hosmer-Lemeshow test had a p-value of 0.57 suggesting accurate calibration. The CRT-D Futility score outperformed the Goldenberg and EAARN scores for identifying futility. Based on the CRT-D Futility score, 15.9% of these patients were categorised at high risk (predicted futility of 16.6%).

CONCLUSIONS

The CRT-D Futility score, established from a large nationwide cohort of patients treated with CRT-D, may be a relevant tool for optimising healthcare decision-making.

Heart Failure in Older Adults: Medical Management and Advanced Therapies

As the population ages and the prevalence of heart failure increases, cardiologists and geriatricians can expect to see more elderly patients with heart failure in their everyday practice. With the advancement of medical care and technology, the options for heart failure management have expanded, though current guidelines are based on studies of younger populations, and the evidence in older populations is not as robust. Pharmacologic therapy remains the cornerstone of heart failure management and has improved long-term mortality. Prevention of sudden cardiac death with implantable devices is being more readily utilized in older patients. Advanced therapies have provided more options for end-stage heart failure, though its use is still limited in older patients. In this review, we discuss the current guidelines for medical management of heart failure in older adults, as well as the expanding literature on advanced therapies, such as heart transplantation in older patients with end-stage heart failure. We also discuss the importance of a multidisciplinary care approach including consideration of non-medical co-morbidities such as frailty and cognitive decline.

Timely and individualized heart failure management: need for implementation into the new guidelines

Due to remarkable improvements in heart failure (HF) management over the last 30 years, a significant reduction in mortality and hospitalization rates in HF patients with reduced ejection fraction (HFrEF) has been observed. Currently, the optimization of guideline-directed chronic HF therapy remains the mainstay to further improve outcomes for patients with HFrEF to reduce mortality and HF hospitalization. This includes established device therapies, such as implantable defibrillators and cardiac resynchronization therapies, which improved patients' symptoms and prognosis. Over the last 10 years, new HF drugs have merged targeting various pathways, such as those that simultaneously suppress the renin-angiotensin-aldosterone system and the breakdown of endogenous natriuretic peptides (e.g., sacubitril/valsartan), and those that inhibit the If channel and, thus, reduce heart rate (e.g., ivabradine). Furthermore, the treatment of patient comorbidities (e.g., iron deficiency) has shown to improve functional capacity and to reduce hospitalization rates, when added to standard therapy. More recently, other potential treatment mechanisms have been explored, such as the sodium/glucose co-transporter inhibitors, the guanylate cyclase stimulators and the cardiac myosin activators. In this review, we summarize the novel developments in HFrEF pharmacological and device therapy and discuss their implementation strategies into practice to further improve outcomes.

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.