Cardiac resynchronization therapy pacemaker or cardiac resynchronization therapy defibrillator: what determines the choice?-findings from the ESC CRT Survey II

Is conduction system pacing a panacea for pacemaker therapy?

INTRODUCTION

While supported by robust evidence and decades of clinical experience, right ventricular apical pacing for bradycardia is associated with a risk of progressive left ventricular dysfunction. Cardiac resynchronization therapy for heart failure with reduced ejection fraction can result in limited electrical resynchronization due to anatomical constraints and epicardial stimulation. In both settings, directly stimulating the conduction system below the atrio-ventricular node (either the bundle of His or the left bundle branch area) has potential to overcome these limitations. Conduction system pacing has met with considerable enthusiasm in view of the more physiological electrical conduction pattern, is rapidly becoming the preferred option of pacing for bradycardia, and is gaining momentum as an alternative to conventional biventricular pacing.

AREAS COVERED

This article provides a review of the current efficacy and safety data for both people requiring treatment for bradycardia and the management of heart failure with conduction delay and discusses the possible future roles for conduction system pacing in routine clinical practice.

EXPERT OPINION

Conduction system pacing might be the holy grail of pacemaker therapy without the disadvantages of current approaches. However, hypothesis and enthusiasm are no match for robust data, demonstrating at least equivalent efficacy and safety to standard approaches.

What determines who gets cardiac resynchronization therapy in Europe? A comparison between ESC-HF-LT registry, SwedeHF registry, and ESC-CRT Survey II

AIMS

Cardiac resynchronization therapy (CRT) is effective in heart failure with reduced ejection fraction (HFrEF) and dyssynchrony but is underutilized. In a cohort study, we identified clinical, organizational, and level of care factors linked to CRT implantation.

METHODS AND RESULTS

We included HFrEF patients fulfilling study criteria in the ESC-HF-Long Term Registry (ESC-HF-LT, n = 1031), the Swedish Heart Failure Registry (SwedeHF) (n = 5008), and the ESC-CRT Survey II (n = 11 088). In ESC-HF-LT, 36% had a CRT indication of which 47% had CRT, 53% had indication but no CRT, and the remaining 54% had no indication and no CRT. In SwedeHF, these percentages were 30, 25, 75, and 70%. Median age of patients with CRT indication and CRT present vs. absent was 68 vs. 65 years with 24% vs. 22% women in ESC-HF-LT, 76 vs. 74 years with 26% vs. 26% women in SwedeHF, and 70 years with 24% women in CRT Survey II (all had CRT). For ESC-HF-LT, independent predictors of having CRT were guideline-directed medical therapy (GDMT), atrial fibrillation (AF), prior HF hospitalization, and NYHA class. For SwedeHF, they were GDMT, age, AF, previous myocardial infarction, lower NYHA class, enrolment at university hospital, and follow-up at HF centre/Hospital. In SwedeHF, above median income and higher education level were also independently associated with having CRT. In the ESC-CRT Survey II (n = 11 088), all patients received CRT but with differences in the clinical characteristics between countries.

CONCLUSION

CRT was used in a minority of eligible patients and more used in ESC-HF-LT than in SwedeHF.

Mapping the research trends and hot topics of ventricular arrhythmia: A bibliometric analysis from 2001 to 2020

BACKGROUND

Studies of ventricular arrhythmia (VA) have drawn much scholarly attention over the past two decades. Our study aimed to assess the current situation and detect the changing research trends of VA quantitatively and qualitatively.

MATERIALS AND METHODS

All the information used in our statistical and bibliometric analysis were collected and summarized from papers retrieved from the Web of Science Core Collection (WoSCC) database on December 22, 2021 using certain criteria. Visual analytics were realized using CiteSpace, VOSviewer, the bibliometrix R package, and the bibliometric online analysis platform.

RESULTS

A total of 6,897 papers (6,711 original articles, 182 proceedings papers, three book chapters, and one data paper) were published in 796 journals that concentrated on the research areas of cardiovascular and critical care medicine. The most productive country and influential institution was the USA and the Mayo Clinic, respectively. Heart Rhythm (551 articles and 8,342 local citations) published the most manuscripts. The keyword co-occurrence and co-citation network of references analyses revealed that the most popular terms were ventricular tachycardia, ventricular fibrillation, catheter ablation, implantable cardioverter defibrillator (ICD), and sudden cardiac death (SCD). Further, the burst detection analysis demonstrated that topics strongly associated with clinical prognosis, such as meta-analysis, long-term outcomes, and impact, were new concerns.

CONCLUSION

Our study offers a comprehensive picture of VA research and provides profound insights into the current research status. Moreover, we show that new topics within the VA research field have focused more on prognosis and evidence-based clinical guidelines.

Survival of patients undergoing cardiac resynchronization therapy with or without defibrillator: the RESET-CRT project

AIMS

Cardiac resynchronization therapy (CRT) is an established treatment for heart failure. There is contradictory evidence whether defibrillator capability improves prognosis in patients receiving CRT. We compared the survival of patients undergoing de novo implantation of a CRT with defibrillator (CRT-D) option and CRT with pacemaker (CRT-P) in a large health claims database.

METHODS AND RESULTS

Using health claims data of a major German statutory health insurance, we analysed patients with de novo CRT implantation from 2014 to 2019 without indication for defibrillator implantation for secondary prevention of sudden cardiac death. We performed age-adjusted Cox proportional hazard regression and entropy balancing to calculate weights to control for baseline imbalances. The analysis comprised 847 CRT-P and 2722 CRT-D patients. Overall, 714 deaths were recorded during a median follow-up of 2.35 years. A higher cumulative incidence of all-cause death was observed in the initial unadjusted Kaplan-Meier time-to-event analysis [hazard ratio (HR): 1.63, 95% confidence interval (CI): 1.38-1.92]. After adjustment for age, HR was 1.13 (95% CI: 0.95-1.35) and after entropy balancing 0.99 (95% CI: 0.81-1.20). No survival differences were found in different age groups. The results were robust in sensitivity analyses.

CONCLUSION

In a large health claims database of CRT implantations performed in a contemporary setting, CRT-P treatment was not associated with inferior survival compared with CRT-D. Age differences accounted for the greatest part of the survival difference that was observed in the initial unadjusted analysis.

Cardiac resynchronization therapy with or without defibrillation: a long-standing debate

Cardiac resynchronization therapy (CRT) was shown to improve cardiac function, reduce heart failure hospitalizations, improve quality of life and prolong survival in patients with severe left ventricular dysfunction and intraventricular conduction disturbances, mainly left bundle branch block, on optimal medical therapy with ACE-inhibitors, β-blockers and mineralocorticoid receptor antagonists up-titrated to maximum tolerated evidence-based doses. CRT can be achieved by means of pacemaker systems (CRT-P) or devices with defibrillation capabilities (CRT-D). CRT-Ds offer an undoubted advantage in the prevention of arrhythmic death, but such an advantage may be of lesser degree in non-ischemic heart failure aetiologies. Moreover, the higher CRT-D hardware complexity compared to CRT-P may predispose to device/lead malfunctions and the higher current drainage may cause a shorter battery duration with consequent premature replacements and the well-known incremental complications. In a period of financial constraints, also device costs should be carefully evaluated, with recent reports suggesting that CRT-Ps may be favoured over CRT-Ds in patients with non-ischemic cardiomyopathy and no prior history of cardiac arrhythmias from a cost-effectiveness point of view. The choice between a CRT-P or a CRT-D device should be patient-tailored whenever straightforward defibrillator indications are not present. The Goldenberg score may facilitate this decision-making process in ambiguous settings. Age, comorbidities, kidney disease, atrial fibrillation, advanced functional class, inappropriate therapy risk, implantable device infections and malfunctions are factors potentially reducing the expected benefit from defibrillating capabilities. Future prospective, randomized controlled trials are warranted to directly compare the efficacy and safety of CRT-Ps and CRT-Ds.

Cardiac Resynchronization and Defibrillator Therapy (CRT-D) or CRT Alone (CRT-P) in patients with dilated cardiomyopathy and heart failure without late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMRI) high-risk markers - CRT-REALITY study - Study design and rationale

BACKGROUND

Primary preventive implantation of implantable defibrillator (ICD) is according to current guidelines indicated in patients with heart failure NYHA (New York Heart Association) class II/III and LVEF <35%. Thanks to advances in heart failure pharmacotherapy, a decrease in mortality could render a benefit of ICD insufficient to justify its implantation in some patients.

METHODS

Study design: multicenter, prospective, randomized, controlled trial evaluating the benefit of implantation of Cardiac Resynchronization and Defibrillator Therapy (CRT-D) or CRT Alone (CRT-P) in non-ischemic patients with reduced left ventricle ejection fraction (LVEF) and optimal pharmacotherapy without significant mid-wall myocardial fibrosis detected by cardiac magnetic resonance (CMR). The primary end-point: Re-hospitalization for heart failure, ventricular tachycardia, major adverse cardiac events (MACE). The secondary end-points: Sudden cardiac death, cardiovascular death, resuscitated cardiac arrest or sustained ventricular tachycardia, device-related complications, and change in quality of life. Course of the study: After a pharmacotherapy is optimized and significant mid-wall myocardial fibrosis excluded, patients will be randomized 1:1 to CRT-P or CRT-D implantation.

DISCUSSION

If our hypothesis is confirmed, this could provide evidence for the management of these patients with a significant impact on common daily praxis and health care expenditures.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04139460.

Extrahepatic bile duct reconstruction in pigs with heterogenous animal-derived artificial bile ducts: A preliminary experience

BACKGROUND

Extrahepatic biliary duct injury (BDI) remains a complicated issue for surgeons. Although several approaches have been explored to address this problem, the high incidence of complications affects postoperative recovery. As a nonimmunogenic scaffold, an animal-derived artificial bile duct (ada-BD) could replace the defect, providing good physiological conditions for the regeneration of autologous bile duct structures without changing the original anatomical and physiologic conditions.

AIM

To evaluate the long-term feasibility of a novel heterogenous ada-BD for treating extrahepatic BDI in pigs.

METHODS

Eight pigs were randomly divided into two groups in the study. The animal injury model was developed with an approximately 2 cm segmental defect of various parts of the common bile duct (CBD) for all pigs. A 2 cm long novel heterogenous animal-derived bile duct was used to repair this segmental defect (group A, ada-BD-to-duodenum anastomosis to repair the distal CBD defect; group B, ada-BD-to-CBD anastomosis to repair the intermedial CBD defect). The endpoint for observation was 6 mo (group A) and 12 mo (group B) after the operation. Liver function was regularly tested. Animals were euthanized at the above endpoints. Histological analysis was carried out to assess the efficacy of the repair.

RESULTS

The median operative time was 2.45 h (2-3 h), with a median anastomosis time of 60.5 min (55-73 min). All experimental animals survived until the endpoints for observation. The liver function was almost regular. Histologic analysis indicated a marked biliary epithelial layer covering the neo-bile duct and regeneration of the submucosal connective tissue and smooth muscle without significant signs of immune rejection. In comparison, the submucosal connective tissue was more regular and thicker in group B than in group A, and there was superior integrity of the regeneration of the biliary epithelial layer. Despite the advantages of the regeneration of the bile duct smooth muscle observed in group A, the effect on the patency of the ada-BD grafts in group B was not confirmed by macroscopic assessment and cholangiography.

CONCLUSION

This approach appears to be feasible for repairing a CBD defect with an ada-BD. A large sample study is needed to confirm the durability and safety of these preliminary results.

Sex Disparities in the Choice of Cardiac Resynchronization Therapy Device: An Analysis of Trends, Predictors, and Outcomes

BACKGROUND

There is limited evidence on the influence of sex on the decision to implant a cardiac resynchronization therapy device with pacemaker (CRT-P) or defibrillator (CRT-D) and the existence of sex-dependent differences in complications that may affect this decision.

METHODS

All patients undergoing de novo CRT implantation (2004-2014) in the United States National Inpatient Sample were included and stratified by device type (CRT-P and CRT-D). Multivariable logistic regression models were conducted to assess the association of female sex with receipt of CRT-D and periprocedural complications.

RESULTS

Out of 400,823 weighted CRT procedural records, the overall percentages of women undergoing CRT-P and CRT-D implantations were 41.5% and 27.8%, respectively, and these percentages increased compared with men over the study period. Women were less likely to receive CRT-D (odds ratio 0.66, 95% confidence interval 0.64-0.67), and this trend remained stable throughout the study period (P = 0.06). Furthermore, compared with men, women were associated with increased odds of procedure-related complications (bleeding, thoracic, and cardiac) in the CRT-D group but not in the CRT-P group. Factors such as atrial fibrillation, malignancies, renal failure, advanced age (> 60 years), and admission to nonurban/small hospitals favoured the receipt of CRT-P over CRT-D, whereas history of ischemic heart disease, cardiac arrest ,or ventricular arrhythmias favoured the receipt of CRT-D over CRT-P.

CONCLUSIONS

Women were associated with persistently reduced odds of receipt of CRT-D compared with men over an 11-year period. This study identifies important factors that predict the choice of CRT device offered to patients in the United States.