Effects of haemodynamically atrio-ventricular optimized His bundle pacing on heart failure symptoms and exercise capacity: the His Optimized Pacing Evaluated for Heart Failure (HOPE-HF) randomized, double-blind, cross-over trial

AIMS

Excessive prolongation of PR interval impairs coupling of atrio-ventricular (AV) contraction, which reduces left ventricular pre-load and stroke volume, and worsens symptoms. His bundle pacing allows AV delay shortening while maintaining normal ventricular activation. HOPE-HF evaluated whether AV optimized His pacing is preferable to no-pacing, in a double-blind cross-over fashion, in patients with heart failure, left ventricular ejection fraction (LVEF) ≤40%, PR interval ≥200 ms and either QRS ≤140 ms or right bundle branch block.

METHODS AND RESULTS

Patients had atrial and His bundle leads implanted (and an implantable cardioverter-defibrillator lead if clinically indicated) and were randomized to 6 months of pacing and 6 months of no-pacing utilizing a cross-over design. The primary outcome was peak oxygen uptake during symptom-limited exercise. Quality of life, LVEF and patients' holistic symptomatic preference between arms were secondary outcomes. Overall, 167 patients were randomized: 90% men, 69 ± 10 years, QRS duration 124 ± 26 ms, PR interval 249 ± 59 ms, LVEF 33 ± 9%. Neither peak oxygen uptake (+0.25 ml/kg/min, 95% confidence interval [CI] -0.23 to +0.73, p = 0.3) nor LVEF (+0.5%, 95% CI -0.7 to 1.6, p = 0.4) changed with pacing but Minnesota Living with Heart Failure quality of life improved significantly (-3.7, 95% CI -7.1 to -0.3, p = 0.03). Seventy-six percent of patients preferred His bundle pacing-on and 24% pacing-off (p < 0.0001).

CONCLUSION

His bundle pacing did not increase peak oxygen uptake but, under double-blind conditions, significantly improved quality of life and was symptomatically preferred by the clear majority of patients. Ventricular pacing delivered via the His bundle did not adversely impact ventricular function during the 6 months.

Right bundle branch pacing: Criteria, characteristics, and outcomes

BACKGROUND

Targets for right-sided conduction system pacing (CSP) include His bundle and right bundle branch. Electrocardiographic patterns, diagnostic criteria, and outcomes of right bundle branch pacing (RBBP) are not known.

OBJECTIVE

Our aims were to delineate electrocardiographic and electrophysiological characteristics of RBBP and to compare outcomes between RBBP and His bundle pacing (HBP).

METHODS

Patients with confirmed right CSP were divided according to the conduction system potential to QRS complex interval at the pacing lead implantation site. Six hypothesized RBBP criteria as well as pacing parameters, echocardiographic outcomes, and all-cause mortality were analyzed.

RESULTS

All analyzed criteria discriminated between HBP and RBBP: double QRS complex transition during the threshold test, selective paced QRS complex different from conducted QRS complex, stimulus to selective-QRS complex > potential-QRS complex, small increase in V₆ R-wave peak time (V₆RWPT) during QRS complex transition, equal capture thresholds of CSP and myocardium, and stimulus-V₆RWPT > potential-V₆RWPT (adopted as the diagnostic standard). According to the last criterion, RBBP was observed in 19.2% of patients (64 of 326) who had been targeted for HBP, present mainly among patients with potential to QRS complex interval <35 ms (90.6% [48 of 53]) and occasionally among the remaining patients (5.6% [16 of 273]). RBBP was characterized by longer QRS complex (by 10.5 ms), longer V₆RWPT (by 11.6 ms), and better sensing (by 2.6 mV) compared with HBP. During a median follow-up duration of 29 months, no differences in capture threshold, echocardiographic outcomes, or mortality were found.

CONCLUSION

RBBP has distinct features that separate it from HBP and is observed in approximately a fifth of patients in whom HBP is intended.

Conduction system pacing learning curve: Left bundle pacing compared to His bundle pacing

Introduction

Conduction system pacing (CSP), consisting of His bundle pacing (HBP) or left bundle branch area pacing (LBBAP) is a rapidly developing field. These pacing techniques result in single lead left ventricular resynchronisation. Understanding of the associated learning curve of the two techniques is an important consideration for new implanters/implanting centres.

Methods

We conducted a review of the first 30 cases of both HBP and LBBAP at The Royal Brompton Hospital. The procedural duration and fluoroscopy time were used as surrogates for the learning curve of each technique.

Results

Patient characteristics were similar in HBP and LBBAP groups; LV ejection fraction (46% vs 54%, p = 0.08), pre-procedural QRS duration (119 ms vs 128 ms, p = 0.32).Mean procedural duration was shorter for LBBAP than for HBP (87 vs 107mins, p = 0.04) and the drop in procedural duration was more marked in LBBAP, plateauing and remaining low at 80mins after the initial 10 cases. Fluoroscopic screening time mirrored procedural duration (8 min vs 16 min, p < 0.01).

Discussion/Conclusion

Our data suggest that the CSP learning curve was shorter for LBBAP than for HBP and appears to plateaux after the first 10 cases, however the HBP learning curve is longer with continued improvement over the first 30 cases. The shorter learning curve of LBBAP in conjunction with the superior electrical parameters and simplified programming mean the establishment of a CSP program is potentially easier with LBBAP compared to with HBP.

Bipolar anodal septal pacing with direct LBB capture preserves physiological ventricular activation better than unipolar left bundle branch pacing

Background

Left bundle branch pacing (LBBP) produces delayed, unphysiological activation of the right ventricle. Using ultra-high-frequency electrocardiography (UHF-ECG), we explored how bipolar anodal septal pacing with direct LBB capture (aLBBP) affects the resultant ventricular depolarization pattern.

Methods

In patients with bradycardia, His bundle pacing (HBP), unipolar nonselective LBBP (nsLBBP), aLBBP, and right ventricular septal pacing (RVSP) were performed. Timing of local ventricular activation, in leads V1-V8, was displayed using UHF-ECG, and electrical dyssynchrony (e-DYS) was calculated as the difference between the first and last activation. Durations of local depolarizations were determined as the width of the UHF-QRS complex at 50% of its amplitude.

Results

aLBBP was feasible in 63 of 75 consecutive patients with successful nsLBBP. aLBBP significantly improved ventricular dyssynchrony (mean -9 ms; 95% CI (-12;-6) vs. -24 ms (-27;-21), ), p < 0.001) and shortened local depolarization durations in V1-V4 (mean differences -7 ms to -5 ms (-11;-1), p < 0.05) compared to nsLBBP. aLBBP resulted in e-DYS -9 ms (-12; -6) vs. e-DYS 10 ms (7;14), p < 0.001 during HBP. Local depolarization durations in V1-V2 during aLBBP were longer than HBP (differences 5-9 ms (1;14), p < 0.05, with local depolarization duration in V1 during aLBBP being the same as during RVSP (difference 2 ms (-2;6), p = 0.52).

Conclusion

Although aLBBP improved ventricular synchrony and depolarization duration of the septum and RV compared to unipolar nsLBBP, the resultant ventricular depolarization was still less physiological than during HBP.

Conduction system pacing: promoting the physiology to prevent heart failure

Cardiac conduction system pacing provides physiological ventricular activation by directly stimulating the conduction system. This review describes the two types of conduction system pacing: His bundle pacing (HBP) and left bundle area pacing (LBAP). The most significant advantage of HB pacing is that it can provide a regular, narrow QRS; however, the disadvantages are challenging implantation and a high risk of re-intervention due to lead dislodgement and the development of high pacing threshold. LBAP provides optimum physiological activation of the left ventricle by engaging the left bundle/fascicular fibers. LBAP is more physiological than traditional RV apical pacing and could be an attractive alternative to conventional cardiac resynchronization therapy (CRT). The advantages of LBAP are a relatively more straightforward implantation technique than HBP, better lead stability and pacing thresholds. HBP and LBAP are more physiological than right ventricular pacing and may be used instead of conventional pacemakers. Both HBP and LBBP are being investigated as alternatives to conventional CRT.

His-Purkinje conduction system pacing and atrioventricular node ablation in treatment of persistent atrial fibrillation refractory to multiple ablation procedures: A case report

In patients with symptomatic atrial fibrillation refractory to optimal medical therapy, atrioventricular node ablation followed by permanent pacemaker implantation is an effective treatment option. A 66-year-old woman with symptomatic persistent atrial fibrillation refractory to multiple ablation procedures was referred to our institution. After optimal drug therapy, the patient still had obvious symptoms. Sequential His-Purkinje conduction system pacing and atrioventricular node ablation were performed. Left bundle branch pacing was used as a backup pacing method if thresholds of His bundle pacing were too high or loss of His bundle capture occurred in the follow-up. At the 6-month follow-up, the European Heart Rhythm Association classification for AF was improved, the score of the Atrial Fibrillation Effect on Quality of Life was enhanced, and the 6-Minute Walk Test was ameliorated. The present case was subjected to His-Purkinje conduction system pacing in combination with atrioventricular node ablation as treatment for a symptomatic persistent atrial fibrillation refractory to multiple ablation procedures, and this procedure alleviated symptoms and improved the quality of life in a short-term follow-up.

Low fluoroscopy permanent His bundle pacing using a new electroanatomic mapping system (KODEX EPD). A multicenter experience

Background

His bundle pacing (HBP) may be a challenging procedure, often involving a long fluoroscopic time (FT) and a long procedural time (PT). We sought to evaluate whether the use of a new nonfluroscopic mapping (NFM) system, the KODEX-EPD, is able to reduce FT and PT when mapping is performed by the pacing catheter rather than an electrophysiological mapping catheter.

Methods and Results

We included 46 consecutive patients (77 ± 8 years; 63% male) who underwent HBP; in 22 a NFM-guided procedure with the KODEX-EPD system was performed (group 1), whereas in 24 a conventional fluoroscopy-guided approach was used (group 2). Pacing indications were sick sinus syndrome in 13, atrioventricular block in 21, and cardiac resynchronization therapy in 12 cases. Both a lumen-less fixed helix lead and a stylet-driven extendable helix lead were used, respectively, in 24% and 76% of patients. HBP was successful in 22 patients (100%) in group 1 and 23 patients (96%) in group 2. The FT was significantly reduced in group 1 (183 ± 117 s vs 464.1 ± 352 s in group 2, p = .012). There were no significant differences between groups in PT and other procedural outcomes.

Conclusions

The KODEX-EPD system may be safely used in HBP procedures. It is effective in reducing ionizing radiation exposure, as evidenced by the significant drop in FT, without increasing PT.

Recruitment of the cardiac conduction system for optimal resynchronization therapy in failing heart

Heart failure (HF) is a leading health burden around the world. Although pharmacological development has dramatically advanced medication therapy in the field, hemodynamic disorders or mechanical desynchrony deteriorated by intra or interventricular conduction abnormalities remains a critical target beyond the scope of pharmacotherapy. In the past 2 decades, nonpharmacologic treatment for heart failure, such as cardiac resynchronization therapy (CRT) via biventricular pacing (BVP), has been playing an important role in improving the prognosis of heart failure. However, the response rate of BVP-CRT is variable, leaving one-third of patients not benefiting from the therapy as expected. Considering the non-physiological activation pattern of BVP-CRT, more efforts have been made to optimize resynchronization. The most extensively investigated approach is by stimulating the native conduction system, e.g., His-Purkinje conduction system pacing (CSP), including His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). These emerging CRT approaches provide an alternative to traditional BVP-CRT, with multiple proof-of-concept studies indicating the safety and efficacy of its utilization in dyssynchronous heart failure. In this review, we summarize the mechanisms of dyssynchronous HF mediated by conduction disturbance, the rationale and acute effect of CSP for CRT, the recent advancement in clinical research, and possible future directions of CSP.

Dyssynchronous Heart Failure: A Clinical Review

PURPOSE OF THE REVIEW

Dyssynchrony occurs when portions of the cardiac chambers contract in an uncoordinated fashion. Ventricular dyssynchrony primarily impacts the left ventricle and may result in heart failure. This entity is recognized as a major contributor to the development and progression of heart failure. A hallmark of dyssynchronous heart failure (HF_d) is left ventricular recovery after dyssynchrony is corrected. This review discusses the current understanding of pathophysiology of HF_d and provides clinical examples and current techniques for treatment.

RECENT FINDINGS

Data show that HF_d responds poorly to medical therapy. Cardiac resynchronization therapy (CRT) in the form of conventional biventricular pacing (BVP) is of proven benefit in HF_d, but is limited by a significant non-responder rate. Recently, conduction system pacing (His bundle or left bundle branch area pacing) has also shown promise in correcting HF_d. HF_d should be recognized as a distinct etiology of heart failure; HF_d responds best to CRT.

New criterion to determine left bundle branch capture on the basis of individualized His bundle or right ventricular septal pacing

BACKGROUND

Left bundle branch pacing (LBBP) is an emerging physiological pacing modality. How to differentiate LBBP from left ventricular septal pacing (LVSP) remains challenging.

OBJECTIVE

We aimed to develop a new personalized intraoperative criterion to confirm left bundle branch (LBB) capture in patients with or without heart failure (HF).

METHODS

Patients were enrolled if 12-lead surface electrocardiograms of LBBP, LVSP, temporary His bundle pacing (HBP), and right ventricular septal pacing (RVSP) were recorded during the procedure, with the leads placed in the basal midseptal region. Left ventricular activation time (LVAT) was measured during different pacing modalities. ΔLVAT1 was defined as the difference in LVAT between HBP and LBBP/LVSP. ΔLVAT2 was estimated by the difference in LVAT between RVSP and LBBP/LVSP. ΔLVAT1% and ΔLVAT2% were calculated as the percent reduction of ΔLVAT1 and ΔLVAT2, respectively.

RESULTS

A total of 105 consecutive patients were included, of whom 80 (76.2%) had normal cardiac function (65 LBBP and 15 LVSP) and 25 had HF. Patients with LBBP showed significantly shorter LVAT than did those with LVSP. In patients with normal cardiac function, a cutoff value of ΔLVAT1 > 12.5 ms showed 73.9% sensitivity and 93.3% specificity to confirm LBB capture. In patients with HF, a cutoff value of ΔLVAT1% > 9.8% exhibited great accuracy for LBB capture (sensitivity 92.0%; specificity 92.3%). The optimal value of ΔLVAT2% for differentiating LBBP from LVSP was 21.2%.

CONCLUSION

Temporary HBP and RVSP can serve as references to confirm LBB capture in an individualized fashion in patients with or without HF.

Atrial-His bundle pacing in fulminant myocarditis with ventricular arrhythmia: a case report

BACKGROUND

Fulminant myocarditis is a clinical syndrome associated with threatening dysrhythmia which temporary pacemaker can be used for life-saving support. As a method of physiological pacing, His bundle pacing (HBP) maintain better cardiac synchronization than traditional right ventricular (RV) pacing.

CASE PRESENTATION

It's a severe case of fulminant myocarditis in a 41-year-old patient who presented for recurrent arrhythmias with hemodynamic instability. Temporary His bundle pacing combined with optimal medical therapy and extracorporeal membrane oxygenators (ECMO) supported him through his critical period of hospitalization.

CONCLUSIONS

During 1-year follow up, the cardiac function recovery was obvious without any pacing related complications. Echocardiography showed better atrioventricular and intra-ventricular synchronization during HBP in DDD mode. This is the first reported case of temporary His-purkinje conduction system pacing used for severe fulminant myocarditis.

Conduction system pacing in everyday clinical practice: EHRA physician survey

With the increasing interest in conduction system pacing (CSP) over the last few years and the inclusion of this treatment modality in the current guidelines, our aim was to provide a snapshot of current practice across Europe. An online questionnaire was sent to physicians participating in the European Heart Rhythm Association research network as well as to national societies and over social media. Data on previous experience with CSP, current indications, preferred tools, unmet needs, and perceptions for the future are reported and discussed.

Conduction System Pacing Versus Conventional Cardiac Resynchronization Therapy in Congenital Heart Disease

BACKGROUND

Dyssynchrony-associated left ventricular systolic dysfunction is a major contributor to heart failure in congenital heart disease (CHD). Although conventional cardiac resynchronization therapy (CRT) has shown benefit, the comparative efficacy of cardiac conduction system pacing (CSP) is unknown.

OBJECTIVES

To compare the clinical outcomes of CSP vs conventional CRT in CHD with biventricular, systemic left ventricular anatomy.

METHODS

Retrospective CSP data from 7 centers were compared with propensity score-matched conventional CRT control subjects. Outcomes were lead performance, change in left ventricular ejection fraction (LVEF), and QRS duration at 12 months.

RESULTS

A total of 65 CSP cases were identified (mean age 37 ± 21 years, 46% men). The most common CHDs were tetralogy of Fallot (n = 12 [19%]) and ventricular septal defect (n = 12 [19%]). CSP was achieved after a mean of 2.5 ± 1.6 attempts per procedure (38 patients with left bundle branch pacing, 17 with HBP, 10 with left ventricular septal myocardial). Left bundle branch area pacing [LBBAP] vs HBP was associated with a smaller increase in pacing threshold (Δ pacing threshold 0.2 V vs 0.8 V; P = 0.05) and similar sensing parameters at follow-up. For 25 CSP cases and control subjects with baseline left ventricular systolic dysfunction, improvement in LVEF was non-inferior (Δ LVEF 9.0% vs 6.0%; P = 0.3; 95% confidence limits: -2.9% to 10.0%) and narrowing of QRS duration was more pronounced for CSP (Δ QRS duration 35 ms vs 14 ms; P = 0.04). Complications were similar (3 [12%] CSP, 4 [16%] conventional CRT; P = 1.00).

CONCLUSIONS

CSP can be reliably achieved in biventricular, systemic left ventricular CHD patients with similar improvement in LVEF and greater QRS narrowing for CSP vs conventional CRT at 1 year. Among CSP patients, pacing electrical parameters were superior for LBBAP vs HBP.

Clinical Outcomes in Conduction System Pacing Compared to Right Ventricular Pacing in Bradycardia

BACKGROUND

Conduction system pacing (CSP) provides more physiological ventricular activation than right ventricular pacing (RVP).

OBJECTIVES

This study evaluated the differences in clinical outcomes in patients receiving CSP and RVP.

METHODS

Consecutive patients with pacemakers implanted for bradycardia from 2016 to 2021 in 2 centers were prospectively followed for the primary composite outcome of heart failure (HF) hospitalizations, upgrade to biventricular pacing, or all-cause mortality, stratified by ventricular pacing burden (Vp) .

RESULTS

Among 860 patients (mean age 74 ± 11 years, 48% female, 48% atrioventricular block), 628 received RVP and 231 received CSP (95 His-bundle pacing, 136 left bundle branch pacing). The primary outcome occurred in 217 (25%) patients, more commonly in patients with RVP than CSP (30% vs 13%, P < 0.001). In multivariable analyses, CSP was independently associated with 47% reduction of the primary outcome (adjusted hazard ratio [AHR]: 0.53; 95% CI: 0.29-0.97; P = 0.04) and HF hospitalization alone (AHR: 0.40; 95% CI: 0.17-0.95; P = 0.04), among only patients with Vp >20%. The incidence of the primary outcome was highest among RVP with Vp >20% and lowest in CSP with Vp >20% (35% vs 10%, P < 0.001). Compared with RVP with Vp >20%, both CSP with Vp >20% (AHR: 0.51; 95% CI: 0.28-0.91; P = 0.02) and all patients with Vp ≤20% (AHR: 0.73; 95% CI: 0.54-0.99; P = 0.04) were independently associated with reduced primary outcome, driven primarily by reductions in HF hospitalizations (P < 0.05). Event-free survival was similar between CSP with Vp >20% and those needing ≤20% Vp.

CONCLUSIONS

CSP significantly reduced adverse clinical outcomes for bradycardic patients requiring ventricular pacing and should be the preferred pacing modality of choice.

Left Bundle Branch Pacing Postatrioventricular Junction Ablation for Atrial Fibrillation: Propensity Score Matching With His Bundle Pacing

BACKGROUND

Left bundle branch pacing (LBBP) has emerged as a promising pacing modality to preserve physiological left ventricular activation; however, prospective data evaluating its long-term safety and efficacy in pacemaker-dependent patients following atrioventricular junction (AVJ) ablation are lacking. This study aimed to examine the feasibility, safety, and efficacy of LBBP in patients with atrial fibrillation and heart failure (HF) after AVJ ablation and compare LBBP with His bundle pacing (HBP) through a propensity score (PS) matching analysis.

METHODS

We prospectively enrolled patients with atrial fibrillation and HF referred for AVJ ablation and LBBP between July 2017 and December 2019. The control group was patients selected from HBP implants performed from 2012 to 2019 using PS matching with a 1:1 ratio.

RESULTS

A total of 99 patients were enrolled in the study. The LBBP implant success rate was 100%. Left ventricular ejection fraction improved from baseline 30.3±4.9 to 1-year 47.3±14.5 in HF patients with reduced ejection fraction and from baseline 56.3±12.1 to 1-year 62.3±9.1 in HF patients with preserved ejection fraction (both P<0.001), and left ventricular ejection fraction in both groups remained stable for up to 3 years of follow-up. A threshold increase >2 V at 0.5 ms occurred in only one patient. Of 176 (81.9%) of 215 patients who received permanent HBP post-AVJ ablation, 86 were matched to the LBBP group by 1:1 PS (propensity score matched His bundle pacing, N=86; propensity score matched left bundle branch pacing, N=86). No significant differences in echocardiographic or clinical outcomes were observed between the 2 groups (P>0.05), whereas lower thresholds, greater sensed R-wave amplitudes, and fewer complications were observed in the propensity score matched left bundle branch pacing group (P<0.05).

CONCLUSIONS

LBBP is feasible, safe, and effective in patients with atrial fibrillation and HF post-AVJ ablation and has similar clinical benefits, a higher implant success rate, better pacing parameters, and fewer complications compared with HBP.

The Effects of His Bundle Pacing Compared to Classic Resynchronization Therapy in Patients with Pacing-Induced Cardiomyopathy

Pacing-induced cardiomyopathy (PICM) is among the most common right ventricular pacing complications. Upgrading to cardiac resynchronization therapy (CRT) is the recommended treatment option. Conduction system pacing with His bundle pacing (HBP) has the potential to restore synchronous ventricular activation and can be an alternative to biventricular pacing (BVP). Patients with PICM scheduled for a system upgrade to CRT were included in the prospective cohort study. Either HBP or BVP was used for CRT. Electrocardiographic, clinical, and echocardiographic measurements were recorded at baseline and six-month follow-up. HBP was successful in 44 of 53 patients (83%). Thirty-nine patients with HBP and 22 with BVP completed a 6-month follow-up. HBP led to a higher reduction in QRS duration than BVP, 118.3 ± 14.20 ms vs. 150.5 ± 18.64 ms, p < 0.0001. The improvement in New York Heart Association (NYHA) class by one or two was more common in patients with HBP than those with BiV (p = 0.04). Left ventricular ejection fraction (LVEF) improved in BVP patients from 32.9 ± 7.93% to 43.9 ± 8.07%, p < 0.0001, and in HBP patients from 34.9 ± 6.45% to 48.6 ± 7.73%, p < 0.0001. The improvement in LVEF was more considerable in HBP patients than in BVP patients, p = 0.019. The improvement in clinical outcomes and left ventricle reverse remodeling was more significant with HBP than BVP. HBP can be a valid alternative to BVP for upgrade procedures in PICM patients.

The usefulness of His bundle pacing in a heterogeneous population of patients with impaired left ventricular systolic function

BACKGROUND

His bundle pacing (HBP) maintains a physiological activation pattern of ventricular activation, and in patients with intraventricular conduction delay (IVCD) it can normalize wide QRS duration.

METHODS

A total of 181 patients from the HBP registry were enrolled into a the study, which was conducted at the Department of Electrocardiology in Katowice, Poland. The patients had left ventricular ejection fraction (LVEF) < 50% and were implanted between November 2015 and April 2019. The HBP indications were as follows: 1) bradycardia and atrioventricular conduction disturbances with expected high pacing burden, 2) IVCD, LVEF ≤ 35%, with an indication for resynchronization therapy, 3) the need to upgrade to resynchronization therapy due to pacing-induced cardiomyopathy. Pacing parameters and echocardiographic and clinical data were assessed for up to 2 years of follow-up (FU).

RESULTS

His bundle pacing was successful in 154 (85.1%) patients. Eighty-two patients completed a 6-month FU. The mean age was 70.6 ± 9.23 years, and 79% were males. At 6 months FU LVEF improved from 35.3 ± 8.22% to 43.1 ± 10.14% (p < 0.0001), and indexed left ventricular end-systolic volume (LVESVi) decreased from 63.1 ± 25.21 mL/m² to 51.9 ± 22.79 mL/m² (p < 0.0001). In 53.1%, the LVESVi reduction was greater than 15%. The improvement in LVEF and LVESVi was also observed after 24 months of FU.

CONCLUSIONS

His bundle pacing in permanently paced patients when LVEF is reduced below 50% is associated with improvement in LVEF and reverse left ventricle remodeling.

Dynamic changes of atrioventricular conduction during Covid-19 infection: Does inflammation matter?

Background

The primary manifestation of COVID-19 infection was pulmonary involvement. However, it can also manifest as a cardiovascular problem.

Methods

We report a case of 82-year-old male COVID-19 patient who experienced atrioventricular (AV) conduction disturbance.

Results

The rhythm was degenerated from sinus rhythm to complete AV block. We observe dynamic AV node dysfunction associated with inflammatory response. His bundle pacing successfully captured distal His region.

Conclusion

The severe inflammatory response during COVID-19 infection might permanently damage cardiac conduction system resulted in a complete AV node block.

Three-dimensional mapping in cardiac implantable electronic device - a feasible and effective alternative to fluoroscopy

BACKGROUND

During the last decade, three-dimensional mapping technology has substantially aided the development of cardiac implanted electronic devices (CIEDs). This article intends to present an outline of the use and benefits of three-dimensional (3D) mapping systems in CIEDs.

RESULT

As an alternative to fluoroscopy, 3D mapping greatly minimizes radiation exposure and eliminates the need for contrast dye during the implantation of CIEDs. Based on the visualization of the pacing lead tip and accurate anatomic reconstruction of the chamber of interest and a specialized mapping technique, 3D mapping technology dramatically improves the efficacy and success of the advanced cardiac implantable devices' placement. Additionally, it provides a superior option for those with complex medical conditions.

CONCLUSION

The use of 3D mapping technology in CIEDs has been proven feasible and effective by accumulating evidence. It is fair to anticipate that it will be widely used in CIED implantation in the future.

His-Purkinje conduction system pacing for pacing-induced cardiomyopathy: a systematic literature review and meta-analysis

BACKGROUND

Upgrading to His-Purkinje conduction system pacing (HPCSP) has been proven to reverse ventricular remodeling and improve cardiac function in patients with pacing-induced cardiomyopathy (PICM). This meta-analysis aimed to assess the efficacy and clinical benefit of upgrading to HPCSP in patients with PICM after chronic right ventricular pacing (RVP).

METHODS

We systematically searched PubMed, Cochrane Library, and Embase for relevant articles from databases' establishment to April 22, 2022. Clinical outcomes and pacing parameters included left ventricular ejection fraction (LVEF) pre-RVP, pre-HPCSP, and during follow-up, New York Heart Association (NYHA) functional class at baseline and follow-up, lead-related complications, heart failure hospitalization (HFH), all-cause mortality, pacing thresholds at implant and during follow-up, and QRS duration (QRSd) pre-RVP, pre-HPCSP, and during follow-up.

RESULTS

A total of 6 articles including 144 patients were enrolled in this meta-analysis. QRSd increased from 127 ± 29 ms at baseline to 175 ± 19 ms (P < 0.001) during RVP and then significantly narrowed to 116 ± 18 ms (P < 0.001) after upgrading to HPCSP. During a mean follow-up of 17.9 ± 10.5 months, LVEF improved from 35 ± 8% pre-HPSCP to 48 ± 12% after upgrading to HPCSP (P < 0.001). The capture thresholds were 1.2 ± 0.9 V at baseline and increased slightly during follow-up. NYHA functional class improved significantly from 2.7 ± 0.8 to 1.9 ± 0.8 during follow-up (P < 0.001).

CONCLUSION

Our meta-analysis indicates that upgrading to HPCSP in patients with PICM is feasible and efficient, as it significantly improves electrical synchrony and cardiac function.

Physiologic Differentiation Between Selective His Bundle, Nonselective His Bundle and Septal Pacing

His bundle (HB) pacing is an increasingly popular method of physiologic ventricular pacing. The electrocardiographic hallmark of physiologic pacing is the preservation or restoration of physiologic activation times in the left ventricle-a principle of paramount diagnostic importance. The current review focuses on the differentiation between 3 possible capture types when the pacing lead is placed in the HB region: selective HB capture when only HB is activated, nonselective HB capture when there is simultaneous activation of the adjacent right ventricular septal (RVS) myocardium, and selective RVS capture when HB is not activated at all but only septal myocardium.