The evolving state of cardiac resynchronization therapy and conduction system pacing: 25 years of research at EP Europace journal

Cardiac rhythm devices in heart failure with reduced ejection fraction - role, timing, and optimal use in contemporary practice. European Journal of Heart Failure expert consensus document

Guidelines for management of heart failure with reduced ejection fraction (HFrEF) emphasize personalized care, patient engagement, and shared decision-making. Medications and cardiac rhythm management (CRM) devices are recommended with a high level of evidence. However, there are significant disparities: patients who could benefit from devices are frequently referred too late or not at all. Misconceptions about device therapy and the notion that the needs of patients (especially the prevention of sudden cardiac death) can now be met by expanding drug therapies may play a role in these disparities. This state-of-the-art review is produced by members of the DIRECT HF initiative, a patient-centred, expert-led educational programme that aims to advance guideline-directed use of CRM devices in patients with HFrEF. This review discusses the latest evidence on the role of CRM devices in reducing HFrEF mortality and morbidity, and provides practical guidance on patient referral, device selection, implant timing and patient-centred follow-up.

The Outcomes of Physiological Ventricular Rhythm Resetting With AV Node Ablation and Left Bundle Branch Pacing in Patients With AF-Induced Cardiomyopathy: A Prospective Cohort Study

The mechanism of AF-induced cardiomyopathy (AF-CM) is still unclear. Expect for heart rate, atrial contraction lost and ventricular rhythm irregularity are believed as possible contributors to AF-CM. This study aimed to investigate ventricular rhythm irregularity effects on AF-CM. The AF-CM patients underwent the physiological ventricular rhythm resetting (PVRR) with atrioventricular node ablation combined with left bundle branch pacing or pharmacological therapy. To avoid heart rate effects, the heart rate (HR) setting according to preoperative Holter averages heart rate for each patient in the PVRR group. The primary endpoint was the echocardiographic response rate, defined as an absolute increase of left ventricular ejection fraction (LVEF) > 5%. Secondary endpoints included heart failure (HF) rehospitalization and worsening HF. Finally, 71 patients (mean age 65 ± 11 years, 36 PVRR and 35 no-PVRR group) were enrolled this study. Compared with no-PVRR group, the PVRR without changed pre-and postprocedure HR significantly enhance echocardiographic response rate (86.1% vs 31.4%, p <0.001), improve LVEF (12.0% ± 6.6% vs 4.0% ± 8.1%, p <0.001), and shorten left ventricular end-diastolic diameter, and left ventricular end-systolic diameter (-4.6 ± 4.1 mm vs -1.7 ± 5.5 mm, p <0.05; -6.8 ± 3.8 mm vs -2.4 ± 6.3 mm, p <0.01, respectively) in 13.1 ± 6.6 months follow-up. Furthermore, HF rehospitalization and worsening HF rates were significantly lower in the PVRR group (5.6% vs 31.4%, p <0.01). In conclusion, the ventricular rhythm irregularity is an important reversible contributor for AF-CM. The PVRR significantly enhances cardiac function, lowers HF rehospitalization and worsening HF rates. The PVRR could become a promising therapeutic strategy for AF-CM patients.

Probabilistic learning of the Purkinje network from the electrocardiogram

The identification of the Purkinje conduction system in the heart is a challenging task, yet essential for a correct definition of cardiac digital twins for precision cardiology. Here, we propose a probabilistic approach for identifying the Purkinje network from non-invasive clinical data such as the standard electrocardiogram (ECG). We use cardiac imaging to build an anatomically accurate model of the ventricles; we algorithmically generate a rule-based Purkinje network tailored to the anatomy; we simulate physiological electrocardiograms with a fast model; we identify the geometrical and electrical parameters of the Purkinje-ECG model with Bayesian optimization and approximate Bayesian computation. The proposed approach is inherently probabilistic and generates a population of plausible Purkinje networks, all fitting the ECG within a given tolerance. In this way, we can estimate the uncertainty of the parameters, thus providing reliable predictions. We test our methodology in physiological and pathological scenarios, showing that we are able to accurately recover the ECG with our model. We propagate the uncertainty in the Purkinje network parameters in a simulation of conduction system pacing therapy. Our methodology is a step forward in creation of digital twins from non-invasive data in precision medicine. An open source implementation can be found at http://github.com/fsahli/purkinje-learning.

Tissue characterization using cardiac magnetic resonance imaging and response to cardiac resynchronization therapy

AIMS

Cardiac magnetic resonance (CMR) imaging for tissue characterization offers valuable insights for risk stratification among patients with cardiomyopathy. This study aimed to assess the prognostic value of CMR-based tissue characterization in predicting response to cardiac resynchronization therapy (CRT) in patients with non-ischaemic cardiomyopathy (NICM).

METHODS AND RESULTS

Retrospective analysis was performed on CMR data from NICM patients before CRT implantation. Various CMR parameters, including the late gadolinium enhancement (LGE), native T1, T2, and extracellular volume (ECV), were analysed. Among the 101 patients (mean age: 66 years, male: 52.5%), 72 (71.3%) were CRT responders. The CRT responders had lower LGE burden (13.1 vs. 35.3%, P < 0.001), native T1 (1334.5 vs. 1371.6 ms, P = 0.012), T2 (42.2 vs. 45.7 ms, P < 0.001), and ECV (30.8 vs. 36.8%, P < 0.001) compared with CRT non-responders. After adjusting for other risk factors, LGE burden ≤ 20% [odds ratio (OR): 22.61, 95% confidence interval (CI): 4.73-176.68, P < 0.001], ECV ≤ 34% (OR: 15.93, 95% CI: 3.01-115.13, P = 0.002), and T2 ≤ 45 ms (OR: 8.10, 95% CI: 1.82-43.75, P = 0.008) were identified as predictors of good CRT response and favourable clinical outcomes (log-rank P < 0.001).

CONCLUSION

Cardiac magnetic resonance-based tissue parameters effectively predict CRT response and clinical outcomes in patients with NICM, independently of conventional predictors.

Impact of myocardial phenotype on optimal atrioventricular delay settings during biventricular and left bundle branch pacing at rest and during exercise: insights from a virtual patient study

AIMS

Previous studies have not examined the role of non-electrical myocardial disease substrates in determining the optimal atrio-ventricular delay (AVD) settings. We conducted virtual patient simulations to evaluate whether myocardial disease substrates influence the acute response to AVD optimization at rest and during exercise.

METHODS AND RESULTS

The CircAdapt cardiovascular model was used to simulate various left ventricular (LV) remodelling found in cardiac resynchronization therapy candidates. We simulated electrical dyssynchrony, LV dilatation with preserved and reduced contractility, and increased LV passive stiffness. We simulated cardiac resynchronization following biventricular (BiVP) and non-selective LBB pacing (nsLBBP). The paced-AVD ranged from 220 to 40 ms. Cardiac output and heart rate were increased to simulate different levels of exercise. The optimal AVD was the one leading to the highest stroke volume (SV) and the lowest mean left atrial pressure (mLAP). At rest, in simulations with healthy myocardium the gain in SV by AVD optimization was larger compared to those with reduced contractility and stiff myocardium. However, mLAP was comparably decreased by AVD optimization in both healthy and diseased myocardium. During exercise, the optimal AVD shifted to shorter values, and mLAP was more sensitive to AVD, particularly in the presence of hypo-contractile and stiff myocardium.

CONCLUSION

Simulations show that hypocontractility and stiffness reduce the effect of AVD optimization on SV but enhance its benefit in lowering mLAP. Notably, virtual patients with stiff ventricles experience greater benefits from AVD optimization during exercise compared to resting conditions. Furthermore, nsLBBP provides more favourable improvements in mLAP than BiVP.

Biventricular vs. right ventricular pacing devices in patients anticipated to require frequent ventricular pacing (BioPace)

AIMS

Right ventricular (RV) pacing may promote left ventricular (LV) dysfunction. Particularly in patients with preserved LV ejection fraction (LVEF), narrow QRS, and anticipated high ventricular pacing burden (HVPB), evidence is missing that biventricular (BiV) pacing can improve clinical outcome. We therefore evaluated whether implantation of a BiV pacing device (BiVPD) compared with a RV pacing device (RVPD) may improve clinical outcome in predominantly this kind of patients.

METHODS AND RESULTS

In the Biventricular Pacing for atrioventricular Block to Prevent Cardiac Desynchronization (BioPace) trial [multicentre, single-blinded (patients), randomized, parallel group], patients were equally allocated to either receive a BiVPD or a RVPD. Co-primary endpoints were (i) the composite of time to death or first heart failure hospitalization and (ii) survival time. We analysed 1810 randomized patients (median age: 73.5 years; female sex: 31.7%; mean LVEF 55.4%; mean QRS 118.4 ms), 902 to BiV and 908 to RV pacing. During mean follow-up of 68.8 months, the difference in the primary composite endpoint between both groups [346 vs. 363 events, hazard ratio (HR) 0.878; 95% confidence interval (CI) 0.756-1.020; P = 0.0882) or in mortality (305 vs. 307 deaths, HR 0.926; 95% CI 0.789-1.088; P = 0.3492) was smaller than 20%.

CONCLUSION

In patients, predominantly with preserved LVEF, narrow QRS, and HVPB, superiority of implanting BiVPDs compared with RVPDs could not be proven. Right ventricular pacing may be less harmful for this kind of patients than often suggested and primary BiV pacing does not clearly improve their clinical outcome.

CLINICAL TRIAL REGISTRATION

Registered in ClinicalTrials.gov, number NCT00187278 (https://clinicaltrials.gov/ct2/show/study/NCT00187278).

Presence of Ineffective Cardiac Resynchronization Therapy Pacing Provides Insights Into Hidden Causes and Therapeutic Targets of Nonresponder

INTRODUCTION

An effective cardiac resynchronization therapy (CRT) algorithm classifies each left ventricular (LV) pace as effective or ineffective based on electrogram morphology. Loss of capture, latency, pseudo-fusion during sinus rhythm, and rapid ventricular responses due to atrial fibrillation (AF) and premature ventricular conductions (PVCs) are potential causes of ineffective CRT pacing. However, little is known about the relationship between percentage of ineffective CRT pacing (%i-CRT) and CRT response.

METHODS AND RESULTS

Among 136 consecutive CRT recipients, we evaluated 44 patients with an effective CRT algorithm. The primary outcome was the prevalence of CRT responders, defined as a reduction in the LV end-systolic volume by ≥ 10% 6 months after implantation. The median values of percent ventricular pacing and %i-CRT were 97.5% (interquartile range [IQR]: 96.4%-98.3%) and 0.3% (IQR: 0.1%-1.0%), respectively. Patients in the highest quartile of %i-CRT (%i-CRT ≥ 1%) showed a significantly lower prevalence of CRT responders (4 [36.4%] vs. 28 [84.8%], p = 0.004) than the remaining quartiles. The univariate analysis showed that %i-CRT ≥ 1% was negatively associated with the CRT response (odds ratio: 0.10, 95% confidence interval: 0.02-0.48). The most frequent cause of ineffective pacing was rapid ventricular responses due to AF and/or PVCs, whereas the cause of the highest %i-CRT in this cohort was latency. A total of three nonresponders with a high %i-CRT showed favorable responses after therapeutic interventions for their hidden causes.

CONCLUSION

High %i-CRT could be associated with an unfavorable CRT response and provide insights into hidden causes and therapeutic targets.

Multipoint pacing is associated with improved prognosis and cardiac resynchronization therapy response: MORE-CRT MPP randomized study secondary analyses

AIMS

Cardiac resynchronization therapy (CRT) via biventricular (BIV) pacing is indicated in patients with heart failure (HF), reduced ejection fraction, and prolonged QRS duration. Quadripolar leads and multipoint pacing (MPP) allow multiple left ventricle (LV) sites pacing. We aimed to assess the clinical benefit of MPP in patients who do not respond to standard BIV pacing.

METHODS AND RESULTS

Overall, 3724 patients were treated with standard BIV pacing. After 6 months, 1639 patients were considered as CRT non-responders (echo-measured relative reduction in LV end-systolic volume (LVESV) < 15%) and randomized to MPP or BIV. We analysed 593 randomized patients (291 MPP, 302 BIV), who had BIV pacing >97% of the time before randomization and complete 12 months of clinical and echocardiographic data. The endpoint composed of freedom from cardiac death and HF hospitalizations and by LVESV relative reduction ≥15% between randomization and 12 months occurred more frequently in MPP [96/291 (33.0%)] vs. BIV [71/302 (23.5%), P = 0.0103], which was also confirmed at multivariate analysis (hazard ratio = 1.55, 95% confidence interval = 1.02-2.34, P = 0.0402 vs. BIV). HF hospitalizations occurred less frequently in MPP [14/291 (4.81%)] vs. BIV [29/302 (9.60%), incidence rate ratio = 50%, P = 0.0245]. Selecting patients with a large (>30 ms) dispersion of interventricular electrical delay among the four LV lead dipoles, reverse remodelling was more frequent in MPP [18/51 (35.3%)] vs. BIV [11/62 (17.7%), P = 0.0335].

CONCLUSION

In patients who do not respond to standard CRT despite the high BIV pacing percentage, MPP is associated with lower occurrence of HF hospitalizations and higher probability of reverse LV remodelling compared with BIV pacing.

Cardiac resynchronization therapy for patients with mild to moderately reduced ejection fraction and left bundle branch block

BACKGROUND

It is unknown whether cardiac resynchronization therapy (CRT) would improve or halt the progression of heart failure (HF) in patients with mild to moderately reduced ejection fraction (HFmmrEF) and left bundle branch block (LBBB).

OBJECTIVE

This study aimed to investigate the outcomes of CRT in patients with HFmmrEF and left ventricular conduction delay.

METHODS

A prospective, randomized clinical trial sponsored by the National Heart, Lung, and Blood Institute included 76 patients who met the study inclusion criteria (left ventricular ejection fraction [LVEF] of 36%-50% and LBBB). Patients received CRT-pacemaker and were randomized to CRT-OFF (right ventricular pacing 40 beats/min) or CRT-ON (biventricular pacing 60-150 beats/min). At a 6-month follow-up, pacing programming was changed to the opposite settings. New York Heart Association class, N-terminal pro-brain natriuretic peptide levels, and echocardiographic variables were collected at baseline, 6 months, and 12 months. The primary study end point was the left ventricular end-systolic volume (LVESV) change from baseline, and the primary randomized comparison was the comparison of 6-month to 12-month changes between randomized groups.

RESULTS

The mean age of the patients was 68.4 ± 9.8 years (male, 71%). Baseline characteristics were similar between the 2 randomized groups (all P > .05). In patients randomized to CRT-OFF first, then CRT-ON, LVESV was reduced from baseline only after CRT-ON (baseline, 116.1 ± 36.5 mL; CRT-ON, 87.6 ± 26.0 mL; P < .0001). The randomized analysis of LVEF showed a significantly better change from 6 to 12 months in the OFF-ON group (P = .003). LVEF was improved by CRT (baseline, 41.3% ±.7%; CRT-ON, 46.0% ± 8.0%; P = .002). In patients randomized to CRT-ON first, then CRT-OFF, LVESV was reduced after both CRT-ON and CRT-OFF (baseline, 109.8 ± 23.5 mL; CRT-ON, 91.7 ± 30.5 mL [P < .0001]; CRT-OFF, 99.3 ± 28.9 mL [P = .012]). However, the LVESV reduction effect became smaller between CRT-ON and CRT-OFF (P = .027). LVEF improved after both CRT-ON and CRT-OFF (baseline, 42.7% ± 4.3%; CRT-ON, 48.5% ± 8.6% [P < .001]; CRT-OFF, 45.9% ± 7.7% [P = .025]).

CONCLUSION

CRT for patients with HFmmrEF significantly improves LVEF and ventricular remodeling after 6 months of CRT. The study provides novel evidence that early CRT benefits patients with HFmmrEF with LBBB.

2024 updated European Heart Rhythm Association core curriculum for physicians and allied professionals: a statement of the European Heart Rhythm Association of the European Society of Cardiology

Heart rhythm management is a continuously evolving sub-speciality of cardiology. Every year, many physicians and allied professionals (APs) start and complete their training in cardiac implantable electronic devices (CIEDs) or electrophysiology (EP) across the European Heart Rhythm Association (EHRA) member countries. While this training ideally ends with an EHRA certification, the description of the learning pathway (what, how, when, and where) through an EHRA core curriculum is also a prerequisite for a successful training. The first EHRA core curriculum for physicians was published in 2009. Due to the huge developments in the field of EP and device therapy, this document needed updating. In addition, a certification process for APs has been introduced, as well as a recertification process and accreditation of EHRA recognized training centres. Learning pathways are more individualized now, with Objective Structured Assessment of Technical Skills (OSATS) to monitor learning progression of trainees. The 2024 updated EHRA core curriculum for physicians and APs describes, for both CIED and EP, the syllabus, OSATS, training programme and certification, and recertification for physicians and APs and stresses the importance of continued medical education after certification. In addition, requirements for accreditation of training centres and trainers are given. Finally, suggested reading lists for CIED and EP are attached as online supplements.

LV cathode position in CRT recipients: How can we benefit from CMR?

BACKGROUND

Left ventricular lead positioning represents a key step in CRT optimization. However, evidence for its guidance based on specific topographical factors and related imaging techniques is sparse.

OBJECTIVE

To analyze reverse remodeling (RR) and clinical events in CRT recipients based on LV cathode (LVC) position relative to latest mechanical activation (LMA) and scar as determined by cardiac magnetic resonance (CMR).

METHODS

This is a retrospective single-center study of 68 consecutive Q-LV-guided CRT-D and CRT-P recipients. Through CMR-based 3D reconstructions overlayed on fluoroscopy images, LVCs were stratified as concordant, adjacent, or discordant to LMA (3 segments with latest and greatest radial strain) and scar (segments with >50% scar transmurality). The primary endpoint of RR (expressed as percentage ESV change) and secondary composite endpoint of HF hospitalizations, LVAD/heart transplant, or cardiovascular death were compared across categories.

RESULTS

LVC proximity to LMA was associated with a progressive increase in RR (percentage ESV change: concordant -47.0 ± 5.9%, adjacent -31.4 ± 3.1%, discordant +0.4 ± 3.7%), while proximity to scar was associated with sharply decreasing RR (concordant +10.7 ± 12.9%, adjacent +0.3 ± 5.3%, discordant -31.3 ± 4.4%, no scar -35.4 ± 4.8%). 4 integrated classes of LVC position demonstrated a significant positive RR gradient the more optimal the category (class I -47.0 ± 5.9%, class II -34.9 ± 2.8%, class III -5.5 ± 4.3%, class IV + 3.4 ± 5.2%). Freedom from composite secondary endpoint of HF hospitalization, LVAD/heart transplant, or cardiovascular death confirmed these trends demonstrating significant differences across both integrated as well as individual LMA and scar categories.

CONCLUSION

Integrated CMR-determined LVC position relative to LMA and scar stratifies response to CRT.

Machine learning-based prediction of 1-year all-cause mortality in patients undergoing CRT implantation: validation of the SEMMELWEIS-CRT score in the European CRT Survey I dataset

Aims

We aimed to externally validate the SEMMELWEIS-CRT score for predicting 1-year all-cause mortality in the European Cardiac Resynchronization Therapy (CRT) Survey I dataset-a large multi-centre cohort of patients undergoing CRT implantation.

Methods and results

The SEMMELWEIS-CRT score is a machine learning-based tool trained for predicting all-cause mortality in patients undergoing CRT implantation. This tool demonstrated impressive performance during internal validation but has not yet been validated externally. To this end, we applied it to the data of 1367 patients from the European CRT Survey I dataset. The SEMMELWEIS-CRT predicted 1-year mortality with an area under the receiver operating characteristic curve (AUC) of 0.729 (0.682-0.776), which concurred with the performance measured during internal validation [AUC: 0.768 (0.674-0.861), P = 0.466]. Moreover, the SEMMELWEIS-CRT score outperformed multiple conventional statistics-based risk scores, and we demonstrated that a higher predicted probability is not only associated with a higher risk of death [odds ratio (OR): 1.081 (1.061-1.101), P < 0.001] but also with an increased risk of hospitalizations for any cause [OR: 1.013 (1.002-1.025), P = 0.020] or for heart failure [OR: 1.033 (1.015-1.052), P < 0.001], a less than 5% improvement in left ventricular ejection fraction [OR: 1.033 (1.021-1.047), P < 0.001], and lack of improvement in New York Heart Association functional class compared with baseline [OR: 1.018 (1.006-1.029), P = 0.003].

Conclusion

In the European CRT Survey I dataset, the SEMMELWEIS-CRT score predicted 1-year all-cause mortality with good discriminatory power, which confirms the generalizability and demonstrates the potential clinical utility of this machine learning-based risk stratification tool.

Selection of candidates for cardiac resynchronization therapy and implantation management: an Italian survey promoted by the Italian Association of Arrhythmology and Cardiac Pacing

BACKGROUND

Cardiac resynchronization therapy (CRT) represents an effective heart failure treatment, associated with reduction in mortality and heart failure hospitalizations. This Italian survey aimed to address relevant CRT issues.

METHODS

An online survey was administered to AIAC members.

RESULTS

One hundred and five electrophysiologists participated, with a median of 40 (23-70) CRT implantations/year (33% in high-volume centres). Forty-five percent of respondents (especially working in high-volume centres) reported an increase in CRT implantations in the last 2 years, in 16% a decrease, and in 38% CRT remained stable. Seventy-five percent of respondents implanted CRT only in patients with European Heart Rhythm Association (EHRA) class I indications. All operators collected ECG and echocardiography before implantation. Eighty-five percent of respondents selected coronary sinus target vein empirically, whereas 10% used mechanical and/or electrical delay techniques. Physicians working in high-volume centres reported a lower failure rate compared with others (16 vs. 34%; P = 0.03). If the coronary sinus lead could not be positioned in the target branch, 80% placed it in another vein, whereas 16% opted for a surgical approach or for conduction system pacing (CSP). Eighty percent accomplished CRT optimization in all patients, 17% only in nonresponders. Regarding anticoagulation, high agreement with EHRA guidelines emerged.

CONCLUSION

CRT represents a valid therapeutic option in heart failure treatment. Nowadays, CRT implantations remain stable and are mainly performed in patients with class I indications. ECG remains the preferred tool for patient selection, whereas imaging is increasingly used to determine the left pacing target area. In most patients, the left ventricular lead can be successfully positioned in the target vein, but in some cases, the result can be unsatisfactory; however, the decision to explore alternative resynchronization approaches is rarely pursued.

Clinical significance and prognostic value of right bundle branch block in permanent pacemaker patients

AIMS

In patients undergoing pacemaker implantation with no prior history of heart failure (HF), the presence of left bundle branch block (LBBB) has been identified as an independent predictor of HF-related death or hospitalization, while the prognostic significance of right bundle branch block (RBBB) remains uncertain. We aimed to assess the long-term risk of all-cause mortality in patients with a standard indication for permanent pacing and normal or moderately depressed left ventricular function when RBBB is detected at the time of implantation.

METHODS

We retrospectively enrolled 1348 consecutive patients who had undergone single- or dual-chamber pacemaker implantation at the study center, from January 1990 to December 2022. Patients with a left ventricular ejection fraction ≤35% or a prior diagnosis of HF were excluded.

RESULTS

The baseline 12-lead electrocardiogram revealed an RBBB in 241 (18%) and an LBBB in 98 (7%) patients. During a median follow-up of 65 [25th-75th percentile: 32-117] months, 704 (52%) patients died. The combined endpoint of cardiovascular death or HF hospitalization was reached by 173 (13%) patients. On multivariate analysis, RBBB was confirmed as an independent predictor of death [hazard ratio, 1.33; 95% confidence interval (CI), 1.09-1.63; P  = 0.005]. However, when considering the combined endpoint of cardiovascular death and HF hospitalization, this endpoint was independently associated with LBBB (hazard ratio, 2.13; 95% CI, 1.38-3.29; P  < 0.001), but not with RBBB.

CONCLUSION

In patients with standard pacemaker indications and normal or moderately depressed left ventricular function, the presence of basal RBBB was an independent predictor of mortality. However, it was not associated with the combined endpoint of cardiovascular death and HF hospitalization.

[Treatment with cardiac electronic implantable devices]

Cardiac device therapy provides not only treatment options for bradyarrhythmia but also advanced treatment for heart failure and preventive measures against sudden cardiac death. In heart failure treatment it enables synergistic reverse remodelling and reduces pharmacological side effects. Cardiac resynchronization therapy (CRT) has revolutionized the treatment of reduced left ventricular ejection fraction (LVEF) and left bundle branch block by decreasing the mortality and morbidity with improvement of the quality of life and resilience. Conduction system pacing (CSP) as an alternative method of physiological stimulation can improve heart function and reduce the risk of pacemaker-induced cardiomyopathy. Leadless pacers and subcutaneous/extravascular defibrillators offer less invasive options with lower complication rates. The prevention of infections through preoperative and postoperative strategies enhances the safety of these therapies.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy

AIMS

Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP.

METHODS AND RESULTS

Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05).

CONCLUSION

Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

Length of hospital stay for elective electrophysiological procedures: a survey from the European Heart Rhythm Association

AIMS

Electrophysiological (EP) operations that have traditionally involved long hospital lengths of stay (LOS) are now being undertaken as day case procedures. The coronavirus disease-19 pandemic served as an impetus for many centres to shorten LOS for EP procedures. This survey explores LOS for elective EP procedures in the modern era.

METHODS AND RESULTS

An online survey consisting of 27 multiple-choice questions was completed by 245 respondents from 35 countries. With respect to de novo cardiac implantable electronic device (CIED) implantations, day case procedures were reported for 79.5% of implantable loop recorders, 13.3% of pacemakers (PMs), 10.4% of implantable cardioverter defibrillators (ICDs), and 10.2% of cardiac resynchronization therapy (CRT) devices. With respect to CIED generator replacements, day case procedures were reported for 61.7% of PMs, 49.2% of ICDs, and 48.2% of CRT devices. With regard to ablations, day case procedures were reported for 5.7% of atrial fibrillation (AF) ablations, 10.7% of left-sided ablations, and 17.5% of right-sided ablations. A LOS ≥ 2 days for CIED implantation was reported for 47.7% of PM, 54.5% of ICDs, and 56.9% of CRT devices and for 54.5% of AF ablations, 42.2% of right-sided ablations, and 46.1% of left-sided ablations. Reimbursement (43-56%) and bed availability (20-47%) were reported to have no consistent impact on the organization of elective procedures.

CONCLUSION

There is a wide variation in the LOS for elective EP procedures. The LOS for some procedures appears disproportionate to their complexity. Neither reimbursement nor bed availability consistently influenced LOS.