Ventricular remodeling during long-term right ventricular pacing following His bundle ablation

Review of Atrioventricular Node Ablation Combined with Permanent His-Purkinje Conduction System Pacing in Patients with Atrial Fibrillation with Heart Failure

With the advancement of pacing technologies, His-Purkinje conduction system pacing (HPCSP) has been increasingly recognized as superior to conventional right ventricular pacing (RVP) and biventricular pacing (BVP). This method is characterized by a series of strategies that either strengthen the native cardiac conduction system or fully preserve physical atrioventricular activation, ensuring optimal clinical outcomes. Treatment with HPCSP is divided into two pacing categories, His bundle pacing (HBP) and left bundle branch pacing (LBBP), and when combined with atrioventricular node ablation (AVNA), can significantly improve left ventricular (LV) function. It effectively prevents tachycardia and regulates ventricular rates, demonstrating its efficacy and safety across different QRS wave complex durations. Therefore, HPCSP combined with AVNA can alleviate symptoms and improve the quality of life in patients with persistent atrial fibrillation (AF) who are unresponsive to multiple radiofrequency ablation, particularly those with concomitant heart failure (HF) who are at risk of further deterioration. As a result, this "pace and ablate" strategy could become a first-line treatment for refractory AF. As a pacing modality, HBP faces challenges in achieving precise localization and tends to increase the pacing threshold. Thus, LBBP has emerged as a novel approach within HPCSP, offering lower thresholds, higher sensing amplitudes, and improved success rates, potentially making it a preferable alternative to HBP. Future large-scale, prospective, and randomized controlled studies are needed to evaluate patient selection and implantation technology, aiming to clarify the differential clinical outcomes between pacing modalities.

The effect of right ventricle septal pacing versus apical pacing in dual-chamber pacemakers on patients' anxiety and depression: a one-year follow-up study

BACKGROUND

Anxiety and depression are potentially harmful outcomes of permanent cardiac pacemakers. Dual-chamber P.P.M. is frequently used to treat life threatening bradycardia. The study aims to estimate the effect of the right ventricular PM lead position on recipients' anxiety and depression before, 6 months, and 1 year after implantation.

RESULTS

A statistically significant correlation was discovered between the studied groups regarding HADS depression score after 6 months (p 0.013) and 1 year (p 0.013). A statistically non-significant difference was found among the studied groups at any point of time regarding baseline (p 0.063), after 6 months (p 0.054), or after 1 year (p 0.099). Significance was found between HADS anxiety score (p 0.015) or depression score after 1 year and the incidence of complications (p 0.001).

CONCLUSIONS

A strong relationship was found between the level of depression and the R.V. site of implantation, as patients with the apical group had higher levels of depression post-implantation. The septal position has less stress and depression on the patient's well-being than the apical one.

Optimizing Patient Selection for Physiological Pacing in Bradyarrhythmia: Factors Associated With High Ventricular Pacing Burden

Background

Right ventricular (RV) pacing is established as the most common ventricular pacing (VP) strategy for patients with symptomatic bradyarrhythmia. Some patients with high VP burden suffer deterioration of left ventricular (LV) function, termed pacing-induced cardiomyopathy (PICM). Patients who pace > 20% of the time from the RV apex are at increased risk of PICM, but independent predictors of increased RV pacing burden have not been elucidated in those who have a permanent pacemaker (PPM) inserted for bradyarrhythmia.

Methods

We aimed to identify factors that are associated with increased VP burden > 20%, hence determining those at risk for resultant PICM. In this retrospective cohort study, we identified the most recent 300 consecutive cardiac implantable electronic device (CIED) implants in our center and collected past medical history, electrocardiogram (ECG), echo, medication and pacemaker check data.

Results

A total of 236 individuals met inclusion criteria. Of the patients, 35% had RV pacing burden < 20%, while 65% had VP burden ≥ 20%; 96.2% of patients with complete heart block (CHB) paced > 20% (P = 0.002). Utilization of DDD or VVI (75.2% and 89.2% of patients, respectively) without mode switch algorithms was associated with VP > 20% (P < 0.001). Male or previous coronary artery bypass grafting (CABG) patients also statistically paced > 20%. Other factors trending towards significance included prolonged PR interval, atrial fibrillation or more advanced age.

Conclusion

High-grade atrioventricular (AV) block was associated with an RV pacing burden > 20% over 3 years but this was not consistent in patients with only transient episodes of high-grade AV block. We found a significant association between high VP% and male sex, previous CABG and the absence of mode switching algorithms.

Incidence, Risk Factors, and Outcomes Associated With Permanent Pacemaker Implantation Following Tricuspid Valve Surgery

BACKGROUND

Data regarding permanent pacemaker (PPM) implantation following tricuspid valve surgery (TVS) are limited. We sought to evaluate its incidence, risk factors, and outcomes.

METHODS AND RESULTS

Medicare beneficiaries who underwent TVS from 2013 to 2020 were identified. Patients who underwent TVS for endocarditis were excluded. The primary exposure of interest was new PPM after TVS. Outcomes included all-cause mortality and readmission with endocarditis or heart failure on follow-up. Among the 13 294 patients who underwent TVS, 2518 (18.9%) required PPM placement. Risk factors included female sex (relative risk [RR], 1.26 [95% CI, 1.17-1.36], P<0.0001), prior sternotomy (RR, 1.12 [95% CI, 1.02-1.23], P=0.02), preoperative second-degree heart block (RR, 2.20 [95% CI, 1.81-2.69], P<0.0001), right bundle-branch block (RR, 1.21 [95% CI, 1.03-1.41], P=0.019), bifascicular block (RR, 1.43 [95% CI, 1.06-1.93], P=0.02), and prior malignancy (RR, 1.23 [95% CI, 1.01-1.49], P=0.04). Tricuspid valve (TV) replacement was associated with a significantly higher risk of PPM implantation when compared with TV repair (RR, 3.20 [95% CI, 2.16-4.75], P<0.0001). After a median follow-up of 3.1 years, mortality was not different in patients who received PPM compared with patients who did not (hazard ratio [HR], 1.02 [95% CI, 0.93-1.12], P=0.7). PPM placement was not associated with a higher risk of endocarditis but was associated with a higher risk of heart failure readmission (HR, 1.28 [95% CI, 1.14-1.43], P<0.001).

CONCLUSIONS

PPM implantation frequently occurs after TVS, notably in female patients and patients undergoing TV replacement. Although mortality is not increased, it is associated with higher rates of heart failure rehospitalization.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Phenogrouping and risk stratification of patients undergoing cardiac resynchronization therapy upgrade using topological data analysis

Choosing the optimal device during cardiac resynchronization therapy (CRT) upgrade can be challenging. Therefore, we sought to provide a solution for identifying patients in whom upgrading to a CRT-defibrillator (CRT-D) is associated with better long-term survival than upgrading to a CRT-pacemaker (CRT-P). To this end, we first applied topological data analysis to create a patient similarity network using 16 clinical features of 326 patients without prior ventricular arrhythmias who underwent CRT upgrade. Then, in the generated circular network, we delineated three phenogroups exhibiting significant differences in clinical characteristics and risk of all-cause mortality. Importantly, only in the high-risk phenogroup was upgrading to a CRT-D associated with better survival than upgrading to a CRT-P (hazard ratio: 0.454 (0.228-0.907), p = 0.025). Finally, we assigned each patient to one of the three phenogroups based on their location in the network and used this labeled data to train multi-class classifiers to enable the risk stratification of new patients. During internal validation, an ensemble of 5 multi-layer perceptrons exhibited the best performance with a balanced accuracy of 0.898 (0.854-0.942) and a micro-averaged area under the receiver operating characteristic curve of 0.983 (0.980-0.986). To allow further validation, we made the proposed model publicly available ( https://github.com/tokmarton/crt-upgrade-risk-stratification ).

Trans-oesophageal echocardiography-guided implantation of a cardiac resynchronization therapy pacemaker and successful ablation of the atrioventricular node after TriClip: case report

Background

Edge-to-edge intervention is the most common trans-catheter procedure performed for isolated severe tricuspid regurgitation in high-surgical-risk patients. However, it creates an obstacle for future right ventricular (RV) procedures such as implantation of cardiac implantable electronic devices (CIEDs). Reports of the management of CIED implantation after tricuspid edge-to-edge therapy are scarce.

Case summary

A 76-year-old woman suffered from severe tricuspid regurgitation with New York Heart Association three symptoms despite optimal medical therapy. After a thorough evaluation, the heart team recommended the TriClip procedure as the treatment of choice. However, 12 months after a successful TriClip procedure, rapid atrial fibrillation needed to be addressed with CIED implantation and atrioventricular (AV) node ablation. Pre-procedural planning included the intended posterior location of the CIED to avoid interference with the implanted clip and future AV node ablation. With an additional left ventricular lead positioned anteriorly to the RV lead, the posterior position of the RV lead was secured. Under peri-procedural trans-oesophageal echocardiography (TEE), the planned procedures were performed successfully.

Discussion

A blind manoeuvring of the RV lead may damage the edge-to-edge tricuspid device. In addition, friction due to an overly close contract between the RV lead and the edge-to-edge device may damage the RV lead. A successful and safe CIED implantation and atrioventricular node ablation can be performed after tricuspid edge-to-edge therapy with careful planning and its precise execution under TEE surveillance.

Left bundle branch pacing preserved left ventricular myocardial work in patients with bradycardia

Background

Left bundle branch pacing (LBBP) is an emerging physiological pacing modality. Left ventricular (LV) myocardial work (MW) incorporates afterload and LV global longitudinal strain to estimate global and segmental myocardial contractility. However, the effect of LBBP on LV MW remains unknown. This study aimed to evaluate the impact of LBBP on LV MW in patients receiving pacemaker for bradyarrhythmia.

Methods

We prospectively enrolled 70 bradycardia patients with normal LV systolic function receiving LBBP (n = 46) and non-selective His-bundle pacing (NS-HBP) (n = 24). For comparative analysis, patients receiving right ventricular pacing (RVP) (n = 16) and control subjects (n = 10) were enrolled. Two-dimensional speckle tracking echocardiography was performed. The LV pressure-strain loop was non-invasively constructed to assess global LV MW.

Results

After 6-month follow-up, LBBP group (with >40% ventricular pacing during 6 months) had shorter peak strain dispersion (PSD) compared with RVP group, and higher LV global longitudinal strain compared with RVP group and NS-HBP group, but had no difference in left intraventricular mechanical dyssynchrony, including septal-to-posterior wall motion delay and PSD, compared with NS-HBP group. During ventricular pacing, LBBP group had higher global MW index (GWI) (2,189 ± 527 vs. 1,493 ± 799 mmHg%, P = 0.002), higher global constructive work (GCW) (2,921 ± 771 vs. 2,203 ± 866 mmHg%, P = 0.009), lower global wasted work (GWW) (211 ± 161 vs. 484 ± 281 mmHg%, P < 0.001) and higher global MW efficiency (GWE) (91.4 ± 5.0 vs. 80.9 ± 8.3%, P < 0.001) compared with RVP group, and had lower GWW (211 ± 161 vs. 406 ± 234 mmHg%, P < 0.001) and higher GWE (91.4 ± 5.0 vs. 86.4 ± 8.1%, P < 0.001) compared with NS-HBP group.

Conclusions

In this study we found that in patients with mid-term (6-month) high ventricular pacing burden (>40%), LBBP preserved more LV MW compared with NS-HBP and RVP. Further studies are warranted to assess the association between LV MW and long-term clinical outcomes in LBBP with high ventricular pacing burden.

Pacing induced cardiomyopathy: recognition and management

Right ventricle (RV) apex continues to remain as the standard pacing site in the ventricle due to ease of implantation, procedural safety and lack of convincing evidence of better clinical outcomes from non-apical pacing sites. Electrical dyssynchrony resulting in abnormal ventricular activation and mechanical dyssynchrony resulting in abnormal ventricular contraction during RV pacing can result in adverse LV remodelling predisposing some patients for recurrent heart failure (HF) hospitalisation, atrial arrhythmias and increased mortality. While there are significant variations in the definition of pacing induced cardiomyopathy (PIC), combining both echocardiographic and clinical features, the most acceptable definition for PIC would be left ventricular ejection fraction (LVEF) of <50%, absolute decline of LVEF by ≥10% and/or new-onset HF symptoms or atrial fibrillation (AF) after pacemaker implantation. Based on the definitions used, the prevalence of PIC varies between 6% and 25% with overall pooled prevalence of 12%. While most patients undergoing RV pacing do not develop PIC, male sex, chronic kidney disease, previous myocardial infarction, pre-existing AF, baseline LVEF, native QRS duration, RV pacing burden, and paced QRS duration are the factors associated with increased risk for PIC. While conduction system pacing (CSP) using His bundle pacing and left bundle branch pacing appear to reduce the risk for PIC compared with RV pacing, both biventricular pacing and CSP may be used to effectively reverse PIC.

miR Profile of Chronic Right Ventricular Pacing: a Pilot Study in Children with Congenital Complete Atrioventricular Block

Chronic ventricular pacing can lead to pacing-induced cardiomyopathy (PICM). Clinical data alone is insufficient to predict who will develop PICM. Our study aimed to evaluate the circulating miR profile associated with chronic right ventricular pacing in children with congenital complete AV block (CCAVB) and to identify candidate miRs for longitudinal monitoring. Clinical data and blood were collected from chronically paced children (N = 9) and compared with non-paced controls (N = 13). miR microarrays from the buffy coat revealed 488 differentially regulated miRs between groups. Pathway analysis predicted both adaptive and maladaptive miR signaling associated with chronic pacing despite preserved ventricular function. Greater profibrotic signaling (miRs-92a, 130, 27, 29) and sodium and calcium channel dysregulation (let-7) were seen in those paced > 10 years with the most dyregulation seen in a patient with sudden death vs. those paced < 10 years. These miRs may help to identify early adverse remodeling in this population.

A Case Report of Pacemaker-Induced Cardiomyopathy in a Patient With Post-atrioventricular Node Ablation for Atrial Fibrillation

Pacemaker-induced cardiomyopathy (PICM) is a rare but well-recognised phenomenon in patients requiring right ventricular (RV) pacing. It can be caused by single-chamber or dual-chamber pacemakers. We present a case of a 64-year-old female patient presenting to the pacemaker clinic with worsening shortness of breath and legs swelling. She was found to have atrial fibrillation and underwent atrioventricular node ablation followed by a dual chamber permanent pacemaker (PPM) implantation as part of a 'pace and ablate' strategy to treat refractory symptomatic atrial tachycardia, and the patient was entirely dependent on RV pacing. In the immediate two months following PPM implantation, the patient was seen in the clinic and reported shortness of breath that was attributed to interstitial lung disease. However, a month later her symptoms worsened, stimulating a referral for echocardiography, which demonstrated a fall in her left ventricular ejection fraction (LVEF) from 60% to 30% in just four months after the device implantation. The patient was diagnosed with PICM. The patient's prognostic heart failure treatment was optimised and her device was upgraded to a cardiac resynchronisation (CRT) device with pacing functionality in an attempt to improve biventricular synchrony. The patient's symptoms have improved significantly since and a repeat echocardiogram 2 months later showed significant improvement in LVEF to 45-50%.

His-Purkinje system pacing reduced tricuspid regurgitation in patients with persistent atrial fibrillation after left-sided valve surgery

Background & objective

Tricuspid regurgitation after left-sided valve surgery was a common and difficult problem. Atrial fibrillation was considered to be an important etiology of tricuspid regurgitation. His-Purkinje system pacing (HPSP) was a physiological pacing method, which could prevent and treat heart failure and might reduce tricuspid regurgitation. Our study aimed to investigate the effect of HPSP on tricuspid regurgitation in patients with persistent atrial fibrillation after left-sided valve surgery.

Methods

This study was a retrospective study. The 3-year patient review focused on those who underwent permanent cardiac pacemaker implantation of HPSP after mitral valve and/or aortic valve replacement from Jan 1st, 2019 to Jan 1st, 2022. HPSP included His bundle pacing (HBP) or left bundle branch pacing (LBBP). Clinical data collected included electrocardiogram, pacing parameters, ultrasonic cardiogram parameters and chest x-ray at implantation and 3-month follow up. Univariate and multivariate linear regression analysis of tricuspid regurgitation velocity were performed.

Results

A total of 44 patients was retrospectively reviewed. Eight patients who had undergone implantation of HPSP after left-sided heart valve replacement were enrolled in the study. All patients had persistent atrial fibrillation. Three of them received HBP and five underwent LBBP. At 3-month follow-up, the tricuspid regurgitation grade was significantly lower than that before implantation (P = 0.007). The tricuspid regurgitation velocity significantly decreased (317 ± 74 cm/s vs. 261 ± 52 cm/s, P = 0.022) and tricuspid valve pressure gradient (PG) reduced (42 ± 21 mmHg vs. 28 ± 10 mmHg, P = 0.040). The cardiothoracic ratio of patients was significantly lower than that before implantation (0.61 ± 0.08 vs. 0.64 ± 0.09, P = 0.017). The NYHA classification of patients also improved (P = 0.013). In multivariate liner regression analysis, the pacing ratio (β = 0.736, P = 0.037) was an independent determinant of tricuspid regurgitation velocity variation.

Conclusion

HPSP might reduce tricuspid regurgitation and improve cardiac function in patients with persistent atrial fibrillation after left-sided valve surgery.

Feasibility of Left Bundle Branch Area Pacing Combined with Atrioventricular Node Ablation in Atrial Fibrillation Patients with Heart Failure

BACKGROUND

Pacemaker implantation combined with atrioventricular node ablation (AVNA) could be a practical choice for atrial fibrillation (AF) patients with heart failure (HF). Left bundle branch area pacing (LBBaP) has been widely reported.

OBJECTIVES

To explore the safety and efficacy of LBBaP combined with AVNA in AF patients with HF.

METHODS AND RESULTS

Fifty-six AF patients with HF attempted LBBaP and AVNA from January 2019 to December 2020. Standard LBBaP was achieved in forty-six patients, and another ten received left ventricular septal pacing (LVSP). The cardiac function indexes and pacemaker parameters were evaluated at baseline, and we conducted a 1-month and 1-year follow-up.

RESULT

At the time of implantation and 1-month and 1-year follow-up, QRS duration of LVSP group was longer than that of LBBaP group. The pacemaker parameters remained stable in both the LBBaP and LVSP groups. At 1-month and 1-year follow-up after LBBaP and AVNA, left ventricular ejection fraction, left ventricular end-diastolic diameter, and NYHA classification continued to improve. Baseline left ventricular ejection fraction and QRS duration change at implantation can predict the magnitude of improvement of left ventricular ejection fraction at 1-year after LBBaP. Baseline right atrial left-right diameter, the degree of tricuspid regurgitation, and interventricular septum thickness may be the factors affecting the success of LBBaP.

CONCLUSION

LBBaP combined with AVNA is safe and effective for patients with AF and HF. Baseline right atrial left-right diameter, the degree of tricuspid regurgitation, and interventricular septum thickness may be the factors affecting the success of LBBaP.

Impact of atrioventricular junction ablation and CRT-D on long-term mortality in patients with left ventricular dysfunction, permanent, refractory atrial fibrillation and narrow QRS: results of a propensity matched analysis

INTRODUCTION

In patients with symptomatic permanent atrial fibrillation (PEAF) and narrow QRS, atrio-ventricular junction ablation (AVJA) plus cardiac resynchronization therapy (CRT) is superior to medical therapy in reducing heart failure (HF) hospitalization and all-cause mortality. To compare the mortality of a population of patients with HF, reduced EF (rEF) and PEAF treated with AVJA plus CRT with that of a contemporary cohort of patients in sinus rhythm (SR) with similar baseline characteristics.

METHODS AND RESULTS

In this prospective, multicentre, observational study, all-cause mortality in a group of consecutive patients undergoing AVJA and implantable cardioverter-defibrillator (ICD) combined with CRT implantation for HFrEF, narrow QRS, and PEAF with uncontrolled ventricular rate was compared with that of a contemporary cohort of patients in SR undergoing ICD implantation (not combined with CRT) for HFrEF and narrow QRS. Individual 1:1 propensity matching of baseline characteristics was performed. A total of 824 patients were enrolled. Propensity matching yielded 107 matched pairs. After a median follow-up of 52 months, all-cause mortality was similar in patients treated with AVJA plus CRT and in the control group (p=0.434). In AVJA plus CRT patients, mortality was significantly lower than in control group patients with a history of paroxysmal/persistent AF (n=45, p=0.020), and similar to that of patients without a history of AF (n=62, p=0.459).

CONCLUSIONS

After adjustment for patient characteristics, the long-term prognosis of patients with HFrEF, narrow QRS and PEAF who underwent AVJA plus CRT was similar to that of a population of patients in SR with similar characteristics. This article is protected by copyright. All rights reserved.

Electrical management of heart failure: from pathophysiology to treatment

Electrical disturbances, such as atrial fibrillation (AF), dyssynchrony, tachycardia, and premature ventricular contractions (PVCs), are present in most patients with heart failure (HF). While these disturbances may be the consequence of HF, increasing evidence suggests that they may also cause or aggravate HF. Animal studies show that longer-lasting left bundle branch block, tachycardia, AF, and PVCs lead to functional derangements at the organ, cellular, and molecular level. Conversely, electrical treatment may reverse or mitigate HF. Clinical studies have shown the superiority of atrial and pulmonary vein ablation for rhythm control and AV nodal ablation for rate control in AF patients when compared with medical treatment. Ablation of PVCs can also improve left ventricular function. Cardiac resynchronization therapy (CRT) is an established adjunct therapy currently undergoing several interesting innovations. The current guideline recommendations reflect the safety and efficacy of these ablation therapies and CRT, but currently, these therapies are heavily underutilized. This review focuses on the electrical treatment of HF with reduced ejection fraction (HFrEF). We believe that the team of specialists treating an HF patient should incorporate an electrophysiologist in order to achieve a more widespread use of electrical therapies in the management of HFrEF and should also include individual conditions of the patient, such as body size and gender in therapy fine-tuning.

Biventricular versus His bundle pacing after atrioventricular node ablation in heart failure patients with narrow QRS

Background: His bundle pacing (HBP) is a physiological alternative to biventricular (BiV) pacing. We compared short-term results of both pacing approaches in symptomatic atrial fibrillation (AF) patients with moderately reduced left ventricular (LV) ejection fraction (EF ≥35% and <50%) and narrow QRS (≤120 ms) who underwent atrioventricular node ablation (AVNA).Methods: Thirty consecutive AF patients who received BiV pacing or HBP in conjunction with AVNA between May 2015 and January 2020 were retrospectively assessed. Electrocardiographic, echocardiographic, and clinical data at baseline and 6 months after the procedure were assessed.Results: Twenty-four patients (age 68.8 ± 6.5 years, 50% female, EF 39.6 ± 4%, QRS 95 ± 10 ms) met the inclusion criteria, 12 received BiV pacing and 12 HBP. Both groups had similar acute procedure-related success and complication rates. HBP was superior to BiV pacing in terms of post-implant QRS duration, implantation fluoroscopy times, reduction of indexed LV volumes (EDVi 63.8 (49.6-81) mL/m² vs. 79.9 (66-100) mL/m², p = 0.055; ESVi 32.7 (25.6-42.6) mL/m² vs. 46.4 (42.9-68.1) mL/m², p = 0.009) and increase in LVEF (46 (41-55) % vs. 38 (35-42) %, p = 0.005). However, the improvement of the NYHA class was similar in both groups.Conclusions: In symptomatic AF patients with moderately reduced EF and narrow QRS undergoing AVNA, HBP could be a conceivable alternative to BiV pacing. Further prospective studies are warranted to address the outcomes between both 'ablate and pace' strategies.

AV junction ablation and cardiac resynchronization for patients with permanent atrial fibrillation and narrow QRS: the APAF-CRT mortality trial

AIMS 

In patients with atrial fibrillation (AF) and heart failure (HF), strict and regular rate control with atrioventricular junction ablation and biventricular pacemaker (Ablation + CRT) has been shown to be superior to pharmacological rate control in reducing HF hospitalizations. However, whether it also improves survival is unknown.

METHODS AND RESULTS 

In this international, open-label, blinded outcome trial, we randomly assigned patients with severely symptomatic permanent AF >6 months, narrow QRS (≤110 ms) and at least one HF hospitalization in the previous year to Ablation + CRT or to pharmacological rate control. We hypothesized that Ablation + CRT is superior in reducing the primary endpoint of all-cause mortality. A total of 133 patients were randomized. The mean age was 73 ± 10 years, and 62 (47%) were females. The trial was stopped for efficacy at interim analysis after a median of 29 months of follow-up per patient. The primary endpoint occurred in 7 patients (11%) in the Ablation + CRT arm and in 20 patients (29%) in the Drug arm [hazard ratio (HR) 0.26, 95% confidence interval (CI) 0.10-0.65; P = 0.004]. The estimated death rates at 2 years were 5% and 21%, respectively; at 4 years, 14% and 41%. The benefit of Ablation + CRT of all-cause mortality was similar in patients with ejection fraction (EF) ≤35% and in those with >35%. The secondary endpoint combining all-cause mortality or HF hospitalization was significantly lower in the Ablation + CRT arm [18 (29%) vs. 36 (51%); HR 0.40, 95% CI 0.22-0.73; P = 0.002].

CONCLUSIONS 

Ablation + CRT was superior to pharmacological therapy in reducing mortality in patients with permanent AF and narrow QRS who were hospitalized for HF, irrespective of their baseline EF.

STUDY REGISTRATION

ClinicalTrials.gov Identifier: NCT02137187.

Brady-arrhythmias in patients with atrial fibrillation and heart failure of reduced ejection fraction: is his-bundle pacing superior to biventricular pacing？

OBJECTIVE

To investigate the efficacy and safety of His-bundle pacing (HBP) compared with the traditional biventricular pacing (BVP) on patients with brady-arrhythmias, who suffer from permanent atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF).

METHODS

All patients with brady-arrhythmias, permanent AF and HFrEF were continuously enrolled from January 2017 to July 2019 and followed up for at least 12 months. The differences in QRS duration (QRSd), New York Heart Association (NYHA) classification, left ventricular ejection fraction (LVEF), tricuspid regurgitation grade, mitral regurgitation grade, left ventricular end-diastolic diameter (LVEDD), and left atrial size were compared.

RESULTS

A total of 52 patients were enrolled: 37 patients were with HBP and 15 patients with BVP. There was no electrode dislodged, perforation, infection or thrombosis during the follow-up of 18.12 ± 4.45 months. The success rate for HBP implantation was 88.10%. The capture threshold of his-bundle and the threshold of the left ventricular lead remained stable during follow-up. LVEF increased to higher than 50% in 11 patients with HBP (29.73%). The NYHA classification (both p < .001), LVEF (both p < .001) and LVEDD improved significantly during the follow-up in both groups. NYHA (p = .030), LVEF (p = .013), and LVEDD (p = .003) improved in patients with HBP compared with BVP.

CONCLUSION

HBP was safe and more effective in improving the cardiac function and remodeling in patients with brady-arrhythmias, permanent AF and HFrEF compared with BVP.

Effectiveness and safety of AV node ablation after His bundle pacing in patients with uncontrolled atrial arrhythmias

INTRODUCTION

In patients with uncontrolled atrial fibrillation, atrioventricular (AV) node ablation after permanent His bundle pacing (p-HBP) could be a therapeutic option for heart rate (HR) control. We aimed to demonstrate the advantages of AV node ablation with p-HBP, and to describe its effectiveness and safety.

METHODS

This descriptive observational study included patients with uncontrolled permanent atrial arrhythmias who were candidates for HR control (January 2019 to July 2020) and underwent p-HBP and AV node ablation.

RESULTS

A total of 39 patients were included. The median left ventricular ejection fraction (LVEF) was 55% (45-60); 46.1% in NYHA class II and 43.6% in NYHA class III. p-HBP was achieved in 92.3% (n = 36), and AV node ablation was successfully performed in all patients. The LVEF improved in patients with reduced LVEF (baseline, 35% [23.8-45.3%]; follow-up, 40% [35-56.5%], p < 0.05); the NYHA class also showed improvement (baseline, 71.4% patients in class III and 7.1% in class II, and at follow-up, 78.6% patients in class II and 14.3% in class I). In patients with previously normal LVEF, LVEF remained stable; nevertheless, a significant NYHA class improvement was observed (baseline, 63.6% class II and 31.8% class III patients; follow-up, 54.5% class I and 45.5% class II patients). The His thresholds and lead parameter values did not significantly change during the follow-up and remained stable.

CONCLUSIONS

In patients with uncontrolled atrial arrhythmias who underwent AV node ablation after p-HBP, the NYHA class improved and the LVEF increased in those with reduced baseline LVEF. The values of pacing parameters were acceptable and remained stable during the follow-up.

Predictors of pacing induced left ventricular dysfunction and cardiomyopathy assessed by three-dimensional echocardiography and speckle tracking strain

Background

Long-term RV pacing leads to ventricular dyssynchrony, in the form of LBBB-like morphology, with subsequent detrimental effects on LV structure and function. Three-dimensional echocardiography allowed early detection of volumetric changes associated with PICMP and provided more accurate assessment of mechanical dyssynchrony. Speckle tracking strain is able to identify LV dysfunction even before any reduction in LVEF. Our aim was to study pacing effects on LV function and hemodynamics using 3D echo and speckle tracking strain.

Results

This was a prospective study of 175 consecutive patients without structural heart disease (LVEF > 50%) presented for permanent pacing. Full-volume 3D echocardiography done before implantation, 1 week, and 6 months together with GLS. Patients were followed for 6 months to detect incidence of PIVD (defined as reduction in LVEF > 10% but still above 50%) and PICMP (defined as decrease in LVEF by 10% from baseline in absence of other known causes of cardiomyopathy resulting in EF< 50%). PIVD and PICMP predictors and risk factors were analyzed. Only 50 patients met study criteria. Twenty-five (50%) patients developed LV systolic dysfunction; of these, 19 (38%) developed PIVD and 6 (12%) developed PICMP. Pre-implantation GLS was significantly lower in the 6 patients who subsequently developed PICMP, compared to those who developed PIVD and the preserved EF group (mean GLS − 15.50 vs. − 21.0, − 20.0 respectively; p = 0.005, 0.033, respectively). At 1 week, GLS was significantly lower in the 25 patients who subsequently developed PIVD, compared to those who did not (GLS − 13.0 vs. − 18.0, respectively; p = 0.002). A reduction of baseline GLS by 15% or more at 1 week was associated with the development of PIVD and PICMP (p = < 0.001). A wider native QRS complex was associated with PIVD and PICMP (p = 0.008, 0.018, respectively). The other predictors were found non-significant.

Conclusion

PICMP may be more common than previously reported and it may occur shortly after implantation. Pre-implantation GLS is a sensitive parameter for PICMP. One-week GLS, pre-implantation QRS complex width are early predictors for PICMP and PIVD before any reduction in EF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43044-021-00136-x.

Long-term outcomes after radiofrequency catheter ablation of the atrioventricular node: The experience of a Portuguese tertiary center

INTRODUCTION

In patients with supraventricular arrhythmias and high ventricular rate, unresponsive to rate and rhythm control therapy or catheter ablation, atrioventricular (AV) node ablation may be performed.

OBJECTIVES

To assess long-term outcomes after AV node ablation and to analyze predictors of adverse events.

METHODS

We performed a detailed retrospective analysis of all patients who underwent AV node ablation between February 1997 and February 2019, in a single Portuguese tertiary center.

RESULTS

A total of 123 patients, mean age 69±9 years and 52% male, underwent AV node ablation. Most of them presented atrial fibrillation at baseline (65%). During a median follow-up of 8.5 years (interquartile range 3.8-11.8), patients improved heart failure (HF) functional class (NYHA class III-IV 46% versus 13%, p=0.001), and there were reductions in hospitalizations due to HF (0.98±1.3 versus 0.28±0.8, p=0.001) and emergency department (ED) visits (1.1±1 versus 0.17±0.7, p=0.0001). There were no device-related complications. Despite permanent pacemaker stimulation, left ventricular ejection fraction did not worsen (47±13% vs. 47%±12, p=0.63). Twenty-eight patients died (23%). The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome (OR 1.8, 95% CI 1.24-2.61, p=0.002).

CONCLUSIONS

Despite pacemaker dependency, the clinical benefit of AV node ablation persisted at long-term follow-up. The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome. AV node ablation should probably be considered earlier in the treatment of patients with supraventricular arrhythmias and HF, especially in cases that are unsuitable for selective ablation of the specific arrhythmia.

Safety and Efficacy Outcomes of Combined Leadless Pacemaker and Atrioventricular Nodal Ablation for Atrial Fibrillation Using a Single Femoral Puncture Approach

BACKGROUND

Atrioventricular nodal (AVN) ablation with permanent pacemaker (PPM) insertion is indicated for rate control in patients with atrial fibrillation (AF) who remain unresponsive to rate or rhythm control strategies. The leadless PPM (Micra Transcatheter Pacing System [TPS], Medtronic, Minneapolis, MN, USA) has the advantage of eliminating transvenous lead and pacemaker pocket-related complications. The aim of this case series was to determine the outcomes of patients who had undergone combined Micra TPS and AVN ablation, performed via a single femoral approach.

METHOD

A retrospective review was undertaken on patients who had undergone concurrent procedures, across two major hospitals in Perth, Western Australia. Procedural details were obtained from a cardiac devices database whilst patient demographics and clinical information were determined from medical records.

RESULTS

Fourteen (14) patients underwent concurrent Micra TPS insertion and AVN ablation for symptomatic AF. The average age was 73±9.2 years, and 43% of them were males. There was no acute procedural/device related complication. Over a median follow-up duration of 9 months (36% completing 12-month follow-up), there was no incidence of device complications, in particular device dislodgement, malfunction or infection. One patient had a resuscitated ventricular fibrillation (VF) arrest event with new onset cardiomyopathy during follow-up and required Micra TPS removal. One patient died at 33 days post procedure from a non-cardiac cause. Device performance was excellent with stable sensing and pacing thresholds during the follow-up period.

CONCLUSION

Our study has shown that combined leadless PPM (Micra TPS) implantation and AVN ablation using a single femoral approach is feasible, with good safety and efficacy profile in the short-medium term. Long-term data involving larger cohorts is needed to confirm the findings of this study and determine the clinical usefulness of this combined approach.

Adverse Consequences of Right Ventricular Apical Pacing and Novel Strategies to Optimize Left Ventricular Systolic and Diastolic Function

Several studies have focused on the deleterious consequences of Right Ventricular Apical (RVA) pacing on Left Ventricular (LV) function, mediated by pacing-induced ventricular dyssyn-chrony. Therapeutic strategies to reduce the detrimental consequences of RVA pacing have been pro-posed, that includes upgrading of RVA pacing to Cardiac Resynchronization Therapy (CRT), alterna-tive Right Ventricular (RV) pacing sites, minimal ventricular pacing strategies, as well as atrial-based pacing. In developing countries, single chamber RV pacing still constitutes a majority of cases of permanent pacing, and assessment of the optimal RV pacing site is of paramount importance. In chronically-paced patients, it is crucial to maintain as close and normal LV physiological function as possible, by minimizing ventricular dyssynchrony, reducing the chances for heart failure and other complications to develop. This review provides an analysis of the deleterious immediate and long-term consequences of RVA pacing, and the most recent available evidence regarding improvements in pacing options and strategies to optimize LV diastolic and systolic function. Furthermore, the place of advanced echocardiography in the identification of patients with pacing-induced LV dysfunction, the potential role of a new predictor of LV dysfunction in RV-paced subjects, and the long- term out-comes of patients with RV septal pacing will be explored

Complications and prognosis of patients undergoing apical or septal right ventricular pacing

Objectives

Optimal right ventricular lead placement remains controversial. Large studies investigating the safety and long-term prognosis of apical and septal right ventricular lead placement have been lacking.

Methods

Consecutive patients undergoing pacemaker insertion for high-degree atrioventricular block at Edinburgh Heart Centre were investigated. Periprocedural 30-day complications were defined (infection/bleeding/pneumothorax/tamponade/lead displacement). Long-term clinical outcomes were obtained from the General Register of Scotland and electronic medical records. The primary endpoint was a composite of all-cause mortality, new heart failure, hospitalisation for a major cardiovascular event, as per the CArdiac REsynchronization in Heart Failure trial. Secondary endpoints were all-cause mortality, new heart failure and their composite.

Results

820 patients were included, 204 (25%) paced from the septum and 616 (75%) from the apex. All baseline variables were similar with the exception of age (septal: 73.2±1.1 vs apical: 76.9±0.5 years, p<0.001). Procedure duration (58±23 vs 55±25 min, p=0.3), complication rates (18 (8.8) vs 46 (7.5)%, p=0.5) and postimplant QRS duration (152 (23) vs 154 (27) ms, p=0.4) were similar. After 1041 days (IQR 564), 278 patients met the primary endpoint, with no difference between the septal and apical groups in unadjusted (HR 0.86 (95% CIs 0.64 to 1.15)) or multivariable analysis correcting for age, gender and comorbidity (HR 0.97 (95% CI 0.72 to 1.30)). Similarly, no differences were observed in the secondary endpoints.

Conclusions

This large real-world cohort of patients undergoing right ventricular lead placement in the septum or apex demonstrated no difference in procedural complications nor long-term clinical outcomes. Both pacing strategies appear reasonable in routine practice.

Altered myocardial characteristics of the preexcited segment in Wolff-Parkinson-White syndrome: A pilot study with cardiac magnetic resonance imaging

Purpose

The preexcited myocardium of Wolff-Parkinson-White (WPW) syndrome would have different characteristics from normal myocardium and these findings might be related to persistent left ventricular systolic dysfunction. We evaluated myocardial tissue characteristics at the preexcited segment in adult WPW syndrome patients and their implicated findings.

Methods

For this prospective study, we enrolled 22 adult WPW syndrome patients (16 male, mean 45.4 ± 17.8 years) with echocardiographic findings of regional wall motion abnormality in our electrophysiology clinic. Of these patients, 14 underwent radiofrequency ablation before cardiac magnetic resonance imaging. All patients underwent cardiac magnetic resonance imaging including cine and late gadolinium enhancement. The ventricular morphology, function and myocardial characteristics of the preexcited segment were analyzed.

Results

A relatively high prevalence of late gadolinium enhancement (9/22, 40.9%) was observed exclusively at the basal septum. The septal accessory pathway was significantly more prevalent in patients with late gadolinium enhancement (P = 0.011). The prevalences of regional myocardial wall thinning and regional akinesia were significantly higher (P = 0.001 for both) and left ventricular function was significantly decreased in patients with late gadolinium enhancement (P < 0.001). In addition, there were no significant relationships between radiofrequency ablation and regional akinesia (P > 0.999), regional myocardial wall thinning (P > 0.999), late gadolinium enhancement (P = 0.662) and low ejection fraction (P > 0.999).

Conclusion

Myocardial fibrosis was observed at the preexcited myocardium of adult WPW syndrome patients with septal accessory pathway, which could accompany regional akinesia and regional myocardial wall thinning and might be related to persistent left ventricular systolic dysfunction even after radiofrequency ablation.

Chronic Right Ventricular Pacing in the Heart Failure Population

Purpose of Review

We review the trials that have demonstrated potentially harmful effects from right ventricular (RV) apical pacing as well as reviewing the evidence of alternative RV pacing sites and cardiac resynchronization therapy (CRT) for patients who have heart failure and atrioventricular (AV) block.

Recent Findings

The role of CRT in patients with AV block and impaired left ventricular function remains an important consideration. The BLOCK HF trial demonstrated better outcomes with CRT pacing over RV pacing in patients with left ventricular systolic dysfunction (LVSD) and AV block who were expected to have a high RV pacing burden, but failed to demonstrate a mortality benefit.

Summary

CRT seems to have a beneficial effect on left ventricular reverse remodeling, systolic function, and clinical outcomes in patients with New York Heart Association (NYHA) functional class I–III heart failure, moderate to severe LVSD, and AV block compared to RV pacing. However, it is less clear whether there is a similar benefit from CRT in patients with a high percentage of RV pacing who have normal or mild LVSD in the treatment of AV block.

Benefits of Permanent His Bundle Pacing Combined With Atrioventricular Node Ablation in Atrial Fibrillation Patients With Heart Failure With Both Preserved and Reduced Left Ventricular Ejection Fraction

BACKGROUND

Clinical benefits from His bundle pacing (HBP) in heart failure patients with preserved and reduced left ventricular ejection fraction are still inconclusive. This study evaluated clinical outcomes of permanent HBP in atrial fibrillation patients with narrow QRS who underwent atrioventricular node ablation for heart failure symptoms despite rate control by medication.

METHODS AND RESULTS

The study enrolled 52 consecutive heart failure patients who underwent attempted atrioventricular node ablation and HBP for symptomatic atrial fibrillation. Echocardiographic left ventricular ejection fraction and left ventricular end-diastolic dimension, New York Heart Association classification and use of diuretics for heart failure were assessed during follow-up visits after permanent HBP. Of 52 patients, 42 patients (80.8%) received permanent HBP and atrioventricular node ablation with a median 20-month follow-up. There was no significant change between native and paced QRS duration (107.1±25.8 versus 105.3±23.9 milliseconds, P=0.07). Left ventricular end-diastolic dimension decreased from the baseline (P<0.001), and left ventricular ejection fraction increased from baseline (P<0.001) in patients with a greater improvement in heart failure with reduced ejection fraction patients (N=20) than in heart failure with preserved ejection fraction patients (N=22). New York Heart Association classification improved from a baseline 2.9±0.6 to 1.4±0.4 after HBP in heart failure with reduced ejection fraction patients and from a baseline 2.7±0.6 to 1.4±0.5 after HBP in heart failure with preserved ejection fraction patients. After 1 year of HBP, the numbers of patients who used diuretics for heart failure decreased significantly (P<0.001) when compared to the baseline diuretics use.

CONCLUSIONS

Permanent HBP post-atrioventricular node ablation significantly improved echocardiographic measurements and New York Heart Association classification and reduced diuretics use for heart failure management in atrial fibrillation patients with narrow QRS who suffered from heart failure with preserved or reduced ejection fraction.

Detecting Regional Myocardial Abnormalities in Patients With Wolff-Parkinson-White Syndrome With the Use of ECG-Gated Cardiac MDCT

OBJECTIVE

Myocardial dyskinesia caused by the accessory pathway and related reversible heart failure have been well documented in echocardiographic studies of pediatric patients with Wolff-Parkinson-White (WPW) syndrome. However, the long-term effects of dyskinesia on the myocardium of adult patients have not been studied in depth. The goal of the present study was to evaluate regional myocardial abnormalities on cardiac CT examinations of adult patients with WPW syndrome.

MATERIALS AND METHODS

Of 74 patients with WPW syndrome who underwent cardiac CT from January 2006 through December 2013, 58 patients (mean [± SD] age, 52.2 ± 12.7 years), 36 (62.1%) of whom were men, were included in the study after the presence of combined cardiac disease was excluded. Two observers blindly evaluated myocardial thickness and attenuation on cardiac CT scans. On the basis of CT findings, patients were classified as having either normal or abnormal findings. We compared the two groups for other clinical findings, including observations from ECG, echocardiography, and electrophysiologic study.

RESULTS

Of the 58 patients studied, 16 patients (27.6%) were found to have myocardial abnormalities (i.e., abnormal wall thinning with or without low attenuation). All abnormal findings corresponded with the location of the accessory pathway. Patients with abnormal findings had statistically significantly decreased left ventricular function, compared with patients with normal findings (p < 0.001). The frequency of regional wall motion abnormality was statistically significantly higher in patients with abnormal findings (p = 0.043). However, echocardiography documented structurally normal hearts in all patients.

CONCLUSION

A relatively high frequency (27.6%) of regional myocardial abnormalities was observed on the cardiac CT examinations of adult patients with WPW syndrome. These abnormal findings might reflect the long-term effects of dyskinesia, suggesting irreversible myocardial injury that ultimately causes left ventricular dysfunction.

The changing landscape of cardiac pacing

A number of trials have shown that irrespective of baseline QRS duration, left ventricular (LV) dysfunction and heart failure are more common in patients with right ventricular (RV) than in those with biventricular (BiV) pacing. By contrast, preliminary results of the BIOPACE trial (follow-up 5.6 years) yielded a disappointing comparison of RV vs. BiV pacing. Pacemaker-induced cardiomyopathy (PIC) may occur in patients with normal and abnormal LV ejection fractions (LVEF) and tends to occur if there is RV pacing more than 40 % of the time. Yet, some pacemaker-dependent patients do not develop LV dysfunction. PIC can be improved in about two thirds of patients by upgrading to a BiV system and the results are comparable to de novo BiV pacing in patients with a wide QRS complex. The findings of the BLOCK HF trial (2013) suggested that patients requiring pacing virtually 100 % of the time might benefit from BiV pacing irrespective of the LVEF (< 50 %), manifestations of heart failure, QRS duration, or functional class. These characteristics would generate many patients for BiV pacing. However, these recommendations should now be weighed against a more conservative approach based on the recently announced results of the BIOPACE trial. Organizational guidelines recommend BiV pacing for bradycardia irrespective of QRS duration for patients with LVEF < 35 %. At this time, BiV pacing for antibradycardia therapy (irrespective of QRS duration) has to be individualized in the setting of a normal or decreased LVEF (> 35 %) and according to the expected percentage of RV pacing. The benefit of BiV pacing should be considered against procedural complications, which are more frequent than with traditional RV pacing.

The role of biventricular pacing in the prevention and therapy of pacemaker-induced cardiomyopathy

Right ventricular (RV) pacing produces well-known long-term deleterious effects not only on already compromised, but also on the normal left ventricle (LV). The activation pattern mimicks that of left bundle branch block, with delayed activation of the LV free wall, and results in electrical and mechanical dyssynchrony. Long-term mandatory (100%) RV pacing, increases LV dimensions and decreases the ejection fraction. Many of these negative effects of pacing can be overcome by biventricular pacing. In this review, we describe the characteristics of pacemaker-induced cardiomyopathy, its incidence, and the use of cardiac resynchronization therapy (CRT) for its therapy and prevention. The gaps in the current organizational guidelines for using CRT in the treatment of bradycardia are identified, and goals for future research are discussed.

Long-term follow-up results of the pacing to avoid cardiac enlargement (PACE) trial

AIMS

We report the results of long-term follow-up of the Pacing to Avoid Cardiac Enlargement (PACE) trial, a prospective, double-blinded, randomized, multicentre study that confirmed the superiority of biventricular (BiV) pacing compared with right ventricular apical (RVA) pacing in prevention of LV adverse remodelling and deterioration of systolic function at 1 and 2 years.

METHODS AND RESULTS

Patients with bradycardia and preserved LVEF were randomized to receive RVA (n = 88) or BiV pacing (n = 89). Co-primary endpoints were LV end-systolic volume (LVESV) and LVEF measured by echocardiography. There were 149 patients who had extended follow-up, with a mean duration of 4.8 ± 1.5 years (2.5-7.8 years). The primary endpoint analyses were performed in 146 patients (74 in the RVA group and 72 in the BiV group). In the RVA pacing group, the LVEF decreased while the LVESV increased progressively at follow-up, but remained unchanged in the BiV pacing group. The differences in LVEF between the RVA and BiV groups were -6.3, -9.2, and -10.7% at 1-year, 2-year, and long-term follow-up, respectively (all P < 0.001). The corresponding differences in LVESV were +7.4, +9.9, and +13.1 mL, respectively (all P < 0.001). The deleterious effects of RVA pacing consistently occurred in all the pre-defined subgroups. Furthermore, patients with RVA pacing had a significantly higher prevalence of heart failure hospitalization than the BiV group (23.9% vs. 14.6%, log-rank χ²  = 7.55, P  = 0.006).

CONCLUSION

Left ventricular adverse remodelling and deterioration of systolic function continued at long-term follow-up in patients with RVA pacing; this deterioration was prevented by the use of BiV pacing. Also, heart failure hospitalization was more prevalent in the RVA pacing group.

Ventricular rate control of atrial fibrillation in heart failure

In the last few years, there has been a major shift in the treatment of atrial fibrillation (AF) in the setting of hear failure (HF), from rhythm to ventricular rate control in most patients with both conditions. In this article, the authors focus on ventricular rate control and discuss the indications; the optimal ventricular rate-control target, including detailed results of the Rate Control Efficacy in Permanent Atrial Fibrillation: a Comparison Between Lenient versus Strict Rate Control II (RACE II) study; and the pharmacologic and nonpharmacologic options to control the ventricular rate during AF in the setting of HF.

Worsening left ventricular apical peak strain early after right ventricular pacing

We aimed to determine the effect of short-term right ventricle pacing (RV) on left ventricle (LV) mechanics using speckle tracking analysis. Conventional echocardiography and two-dimensional strain imaging was studied in 38 patients, mean age 81.6 ± 7.0, that had undergone pacemaker placement and were greater than 90% ventricularly paced. Mean duration of 24 months of RV pacing resulted in a significant decline in: LV apical diastolic rotational velocities (-59.0 ± -38.9 °/s to -28.0 ± -11.5 °/s, p 0.02), peak strain in the LV apical septal wall (-15.6 ± 8.5 to -13.5 ± 7.6, p 0.02), peak strain in LV apical lateral wall (-13.4 ± 8.9 to -11.4 ± 7.3, p 0.02). Thus, with only 24 months of RV pacing, there was a significant decline in peak strain of the LV apex and in apical diastolic rotational velocity that could account for eventual decline in left ventricular function.

Cardiac resynchronization therapy after atrioventricular junction ablation for symptomatic atrial fibrillation: a meta-analysis

AIMS

Atrioventricular junction (AVJ) ablation with permanent pacing improves symptoms in selected patients with atrial fibrillation (AF). The optimal pacing modality after AVJ ablation remains unclear. We performed a meta-analysis of randomized controlled trials to examine whether cardiac resynchronization therapy (CRT) is superior to right ventricular (RV) pacing in this patient population.

METHODS AND RESULTS

We searched the MEDLINE and EMBASE databases for studies evaluating the effect of CRT vs. RV pacing after AVJ ablation for AF. Pooled risk ratios (RRs) and mean differences with 95% confidence intervals (CIs) were calculated for categorical and continuous outcomes, respectively, using a random effects model. Five trials involving 686 patients (413 in CRT and 273 in RV pacing group) were included in the analysis. On the basis of the pooled estimate across the studies, CRT resulted in a non-significant reduction in mortality (RR = 0.75, 95% CI 0.43-1.30; P= 0.30) and a significant reduction in hospitalizations for heart failure (RR = 0.38, 95% CI = 0.17-0.85; P= 0.02) compared with RV pacing. Cardiac resynchronization therapy did not improve 6 min walk distance (mean difference 15.7, 95% CI -7.2 to 38.5 m; P= 0.18) and Minnesota Living with Heart Failure quality-of-life score (mean difference -3.0, 95% CI -8.6 to 2.6; P= 0.30) compared with RV pacing. The change in left ventricular ejection fraction between baseline and 6 months favoured CRT (mean change 2.0%, 95% CI 1.5-2.4%; P< 0.001).

CONCLUSION

Cardiac resynchronization therapy may be superior to RV pacing in patients undergoing AVJ ablation for AF. Further studies, adequately powered to detect clinical outcomes, are required.