[New pacing strategies for heart failure]. / Neue Pacing-Strategien bei Herzinsuffizienz.

In patients with a reduced left ventricular (LV) systolic function (ejection fraction < 35%) and a left bundle branch block with a QRS duration > 130 ms, cardiac resynchronization therapy (CRT) can contribute to an improvement in the quality of life and a reduction in mortality. The resynchronization is mostly achieved by pacing via an epicardial LV lead in the coronary sinus; however, this approach is often limited by the patient's venous anatomy and an increase in the stimulation threshold over time. In addition, up to 30% of patients do not respond to the intervention. New treatment approaches involve direct stimulation of the conduction system by pacing of the bundle of His or left bundle branch. This enables a more physiological propagation of the stimulus. Pacing of the left bundle branch is achieved by advancing the lead into the right ventricle and screwing it deep into the interventricular septum. Due to the relatively large target area of the left bundle branch the success rate is very high (currently > 90%). Observational studies have shown a greater reduction in the QRS duration, a more pronounced improvement in systolic function and a lower hospitalization rate for heart failure associated with conduction system pacing compared to CRT using a coronary sinus lead. These findings have been confirmed in small randomized trials. Therefore, the use of left bundle branch pacing should be considered not only as a bail out in the case of failed resynchronization using coronary sinus lead placement but increasingly also as an initial pacing strategy. The results of the first large randomized trials are expected to be released in late 2024.

Distal Ventricular Pacing for Drug-Refractory Mid-Cavity Obstructive Hypertrophic Cardiomyopathy: A Randomized, Placebo-Controlled Trial of Personalized Pacing.

BACKGROUND: Patients with refractory, symptomatic left ventricular (LV) mid-cavity obstructive (LVMCO) hypertrophic cardiomyopathy have few therapeutic options. Right ventricular pacing is associated with modest hemodynamic and symptomatic improvement, and LV pacing pilot data suggest therapeutic potential. We hypothesized that site-specific pacing would reduce LVMCO gradients and improve symptoms. METHODS: Patients with symptomatic-drug-refractory LVMCO were recruited for a randomized, blinded trial of personalized prescription of pacing (PPoP). Multiple LV and apical right ventricular pacing sites were assessed during an invasive hemodynamic study of multisite pacing. Patient-specific pacing-site and atrioventricular delays, defining PPoP, were selected on the basis of LVMCO gradient reduction and acceptable pacing parameters. Patients were randomized to 6 months of active PPoP or backup pacing in a crossover design. The primary outcome examined invasive gradient change with best-site pacing. Secondary outcomes assessed quality of life and exercise following randomization to PPoP. RESULTS: A total of 17 patients were recruited; 16 of whom met primary end points. Baseline New York Heart Association was 3±0.6, despite optimal medical therapy. Hemodynamic effects were assessed during pacing at the right ventricular apex and at a mean of 8 LV sites. The gradients in all 16 patients fell with pacing, with maximum gradient reduction achieved via LV pacing in 14 (88%) patients and right ventricular apex in 2. The mean baseline gradient of 80±29 mm Hg fell to 31±21 mm Hg with best-site pacing, a 60% reduction (P<0.0001). One cardiac vein perforation occurred in 1 case, and 15 subjects entered crossover; 2 withdrawals occurred during crossover. Of the 13 completing crossover, 9 (69%) chose active pacing in PPoP configuration as preferred setting. PPoP was associated with improved 6-minute walking test performance (328.5±99.9 versus 285.8±105.5 m; P=0.018); other outcome measures also indicated benefit with PPoP. CONCLUSIONS: In a randomized placebo-controlled trial, PPoP reduces obstruction and improves exercise performance in severely symptomatic patients with LVMCO. REGISTRATION: URL: https://clinicaltrials.gov/study; Unique Identifier: NCT03450252.

Feasibility of epicardial implantation of medtronic 3830 lead in a pediatric patient : case report.

BACKGROUND: High-grade atrioventricular block is the primary reason for epicardial permanent pacemaker implantation during the perioperative period in patients with congenital heart disease. Due to the smaller diameter of venous vessels in children, epicardial permanent pacemaker implantation is usually a preferred choice, we report one pediatric patient who received epicardial permanent pacemaker implantation using a new approach. CASE PRESENTATION: We present the case of a 2-year-old girl who underwent the modified Konno procedure and Pulmonary valvuloplasty surgery and presented after surgery with a High-grade atrioventricular block. At over 20 days after the patient underwent a redo-sternotomy which epicardial permanent pacemaker implantation. Medtronic Model 4965 Capsure Epi ® steroid-eluting unipolar epicardial pacing lead was immobilized on the surface of the right ear. The Medtronic 3830 pacing lead was screwed obliquely and clockwise under direct view from the surface of the right ventricle to the endocardium near the interventricular septum. The patient's recovery was uneventful. CONCLUSION: In this case report, we demonstrate the feasibility and potential benefits of using the Medtronic 3830 lead for epicardial pacing in a pediatric patient with severe cardiac complications following surgery for congenital heart disease. This approach offers a viable alternative to traditional epicardial pacing methods, particularly in complex cases where conventional leads fail to provide stable pacing thresholds.

Conduction System Pacing: Hope, Challenges, and the Journey Forward.

PURPOSE OF THE REVIEW: Cardiac pacing has evolved in recent years currently culminating in the specific stimulation of the cardiac conduction system (conduction system pacing, CSP). This review aims to provide a comprehensive overview of the available literature on CSP, focusing on a critical classification of studies comparing CSP with standard treatment in the two fields of pacing for bradycardia and cardiac resynchronization therapy in patients with heart failure. The article will also elaborate specific benefits and limitations associated with CSP modalities of His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). RECENT FINDINGS: Based on a growing number of observational studies for different indications of pacing therapy, both CSP modalities investigated are advantageous over standard treatment in terms of narrowing the paced QRS complex and preserving or improving left ventricular systolic function. Less consistent evidence exists with regard to the improvement of heart failure-related rehospitalization rates or mortality, and effect sizes vary between HBP and LBBAP. LBBAP is superior over HBP in terms of lead measurements and procedural duration. With regard to all reported outcomes, evidence from large scale randomized controlled clinical trials (RCT) is still scarce. CSP has the potential to sustainably improve patient care in cardiac pacing therapy if patients are appropriately selected and limitations are considered. With this review, we offer not only a summary of existing data, but also an outlook on probable future developments in the field, as well as a detailed summary of upcoming RCTs that provide insights into how the journey of CSP continues.

Recovery of Right Ventricular Apical Pacing-Induced Cardiomyopathy with Left Bundle Branch Pacing.

Right ventricular pacing (RVP) is conventionally preferred in the treatment of patients with atrioventricular block. However, long-term RVP may lead to pacing-induced cardiomyopathy (PICM), characterized by new-onset or worsening ventricular functions due to dyssynchronous ventricular electrical activation, abnormal ventricular remodeling, and increased energy expenditure. Historically, biventricular pacing (BVP) and guideline-directed medical therapy were the only treatment option for PICM. Recently, conduction system pacing, including left bundle branch area pacing (LBBaP), has emerged as a physiological alternative to BVP, showing better results in electro-mechanical ventricular synchronization and hemodynamic parameters compared to BVP. We present a case involving a patient from whom the PICM was successfully recovered shortly after LBBaP.

Early Experience of Left Bundle Branch Pacing with Lumenless Lead in a Single Center: A Case Series.

Left bundle branch pacing (LBBP) has been subject to increasing interest over the last few years due to its capacity for physiological conduction and its advantages compared to His bundle pacing. His bundle pacing has certain limitations, such as a small pacing area for the His bundle, a high threshold that leads to battery depletion, a low R-wave amplitude that may result in atrial or His oversensing, and ventricular signal undersensing. In this case series, four patients (two female and two male) aged 62.2 ± 8.4 years old with symptomatic sick sinus disease and no scar tissue in the interventricular septum underwent LBBP. All LBBPs were done with standard LBBP using a lumenless SelectSecure 3830 lead (Medtronic®, Minneapolis, USA) with a fixed helix. The lead parameters showed a good R-wave amplitudes (13 ± 7.4 mV) and a low threshold  (0.77 ± 0.17 V @ 0.4 ms). All patients were discharged on the next day. During follow-up period of 13.3 ± 12.9 months, all patients were well and no complications were noted. In conclusion, LBBP may be as an alternative of novel conduction pacing techniques and can be done relatively easy and safe, even with limited experience center.

An unusual cause of cardiac arrest in a young infant.

BACKGROUND: Anomalous aortic origin of a coronary artery from the inappropriate sinus of Valsalva (AAOCA) is a rare congenital heart lesion. It is uncommon for patients with AAOCA to present with severe symptoms at a very young age. CASE PRESENTATION: We describe a very rare but critical presentation in a young infant with AAOCA that requires surgical repair and pacemaker placement. A three-month-old infant was referred because of syncope. Cardiac arrest occurred shortly after admission. The electrocardiogram indicated a complete atrioventricular block and a transvenous temporary pacemaker was implanted. A further coronary computed tomographic angiography (CTA) showed the anomalous origin of the right coronary artery from the left sinus of Valsalva. Coronary artery unroofing was performed due to an interarterial course with the intramural component, and a permanent epicardial pacemaker was implanted. The postoperative recovery was uneventful, and this patient was thriving and asymptomatic at the nine-month follow-up. However, the electrocardiogram still indicated a complete pacing rhythm. CONCLUSIONS: By timely diagnosis and treatment, this patient is successfully rescued. Although rare, AAOCA may be fatal even in infants.

Prehospital Cardiac Ultrasound to Confirm Mechanical Capture in Emergency Transcutaneous Pacing: A Case Report.

Point-of-care ultrasound (POCUS) is a safe diagnostic tool that clinicians use to rapidly evaluate critically ill patients.1 POCUS has expanded into the prehospital setting and has been demonstrated to be accurate, feasible, and helpful in guiding clinical decision making.2-4 Additionally, the American College of Emergency Physicians recommends the use of echocardiography to evaluate for ventricular activity in the setting of cardiac arrest.5 There is minimal evidence regarding the use of POCUS to confirm mechanical capture in patients undergoing transcutaneous pacing. This case report highlights the use of POCUS in a patient with bradyasystolic cardiac arrest requiring transcutaneous pacing. Despite electrical capture, the patient had absent central pulses; however, POCUS demonstrated ventricular contractions, indicating mechanical capture. This suggests a role for POCUS for the evaluation of mechanical capture in patients undergoing cardiac pacing.

Closed loop stimulation reduces the incidence of atrial high-rate episodes compared with conventional rate-adaptive pacing in patients with sinus node dysfunctions.

AIMS: Subclinical atrial fibrillation (AF) is associated with increased risk of progression to clinical AF, stroke, and cardiovascular death. We hypothesized that in pacemaker patients requiring dual-chamber rate-adaptive (DDDR) pacing, closed loop stimulation (CLS) integrated into the circulatory control system through intra-cardiac impedance monitoring would reduce the occurrence of atrial high-rate episodes (AHREs) compared with conventional DDDR pacing. METHODS AND RESULTS: Patients with sinus node dysfunctions (SNDs) and an implanted pacemaker or defibrillator were randomly allocated to dual-chamber CLS (n = 612) or accelerometer-based DDDR pacing (n = 598) and followed for 3 years. The primary endpoint was time to the composite endpoint of the first AHRE lasting ≥6 min, stroke, or transient ischaemic attack (TIA). All AHREs were independently adjudicated using intra-cardiac electrograms. The incidence of the primary endpoint was lower in the CLS arm (50.6%) than in the DDDR arm (55.7%), primarily due to the reduction in AHREs lasting between 6 h and 7 days. Unadjusted site-stratified hazard ratio (HR) for CLS vs. DDDR was 0.84 [95% confidence interval (CI), 0.72-0.99; P = 0.035]. After adjusting for CHA2DS2-VASc score, the HR remained 0.84 (95% CI, 0.71-0.99; P = 0.033). In subgroup analyses of AHRE incidence, the incremental benefit of CLS was greatest in patients without atrioventricular block (HR, 0.77; P = 0.008) and in patients without AF history (HR, 0.73; P = 0.009). The contribution of stroke/TIA to the primary endpoint (1.3%) was low and not statistically different between study arms. CONCLUSION: Dual-chamber CLS in patients with SND is associated with a significantly lower AHRE incidence than conventional DDDR pacing.

Robust, stretchable bioelectronic interfaces for cardiac pacing enabled by interfacial transfer of laser-induced graphene via water-response, nonswellable PVA gels.

Implantable cardiac pacemakers are crucial therapeutic tools for managing various cardiac conditions. For effective pacing, electrodes should exhibit flexibility, deformability, biocompatibility, and high conductivity/capacitance. Laser-induced graphene (LIG) shows promise due to its exceptional electrical and electrochemical properties. However, the fragility of LIG and the non-stretchability of polyimide substrates pose challenges when interfacing with the beating heart. Here, we present a simple method for fabricating robust, flexible, and stretchable bioelectronic interfaces by transferring LIG via water-responsive, nonswellable polyvinyl alcohol (PVA) gels. PVA solution penetrates the porous structure of LIG and solidifies into PVA xerogel as the solvent evaporates. The robust PVA xerogel enables the smooth transfer of LIG and prevents stretching of the LIG network during this process, which helps maintain its conductivity. When hydrated, the xerogel becomes a stable, nonswellable hydrogel. This gives the LIG-PVA hydrogel (LIG-PVA-H) composites with excellent conductivity (119.7 ± 4.3Ω sq-1), high stretchability (up to 420%), reliability (cyclic stretch under 15% strain, with ∼ 1-time resistance increase), and good stability in phosphate buffered saline. The LIG-PVA-H composites were used as biointerfaces for electrocardiogram signal recording and electrical pacing on rat hearts ex vivo and in vivo, using commercial setups and a custom-built implantable wireless device. This work expands the application of LIG in bioelectronic interfaces and facilitates the development of electrotherapy for cardiac diseases.

Predictors and 5-Year Clinical Outcomes of Pacemaker After TAVR: Analysis From the PARTNER 2 SAPIEN 3 Registries.

BACKGROUND: Conduction disturbances requiring a permanent pacemaker (PPM) are a frequent complication of transcatheter aortic valve replacement (TAVR) with few reports of rates, predictors, and long-term clinical outcomes following implantation of the third-generation, balloon-expandable SAPIEN 3 (S3) transcatheter heart valve (THV). OBJECTIVES: The aim of this study was to investigate the rates, predictors, and long-term clinical outcomes of PPM implantation following TAVR with the S3 THV. METHODS: The current study included 857 patients in the PARTNER 2 S3 registries with intermediate and high surgical risk without prior PPM, and investigated predictors and 5-year clinical outcomes of new PPM implanted within 30 days of TAVR. RESULTS: Among 857 patients, 107 patients (12.5%) received a new PPM within 30 days after TAVR. By multivariable analysis, predictors of PPM included increased age, pre-existing right bundle branch block, larger THV size, greater THV oversizing, moderate or severe annulus calcification, and implantation depth >6 mm. At 5 years (median follow-up 1,682.0 days [min 2.0 days, max 2,283.0 days]), new PPM was not associated with increased rates of all-cause mortality (Adj HR: 1.20; 95% CI: 0.85-1.70; P = 0.30) or repeat hospitalization (Adj HR: 1.22; 95% CI: 0.67-2.21; P = 0.52). Patients with new PPM had a decline in left ventricular ejection fraction at 1 year that persisted at 5 years (55.1 ± 2.55 vs 60.4 ± 0.65; P = 0.02). CONCLUSIONS: PPM was required in 12.5% of patients without prior PPM who underwent TAVR with a SAPIEN 3 valve in the PARTNER 2 S3 registries and was not associated with worse clinical outcomes, including mortality, at 5 years. Modifiable factors that may reduce the PPM rate include bioprosthetic valve oversizing, prosthesis size, and implantation depth.

Cardiac Remodeling and Ventricular Pacing: From Genes to Mechanics.

Cardiac remodeling and ventricular pacing represent intertwined phenomena with profound implications for cardiovascular health and therapeutic interventions. This review explores the intricate relationship between cardiac remodeling and ventricular pacing, spanning from the molecular underpinnings to biomechanical alterations. Beginning with an examination of genetic predispositions and cellular signaling pathways, we delve into the mechanisms driving myocardial structural changes and electrical remodeling in response to pacing stimuli. Insights into the dynamic interplay between pacing strategies and adaptive or maladaptive remodeling processes are synthesized, shedding light on the clinical implications for patients with various cardiovascular pathologies. By bridging the gap between basic science discoveries and clinical translation, this review aims to provide a comprehensive understanding of cardiac remodeling in the context of ventricular pacing, paving the way for future advancements in cardiovascular care.

Mid-term performance of His bundle pacing and usefulness of backup leads.

Ventricular backup leads may be considered in selected patients with His bundle pacing (HBP), but it remains unknown to what extent this is useful. A total of 184 HBP patients were studied. At last follow-up, 147 (79.9%) patients retained His bundle capture at programmed output. His bundle pacing lead revision was performed in 5/36 (13.9%) patients without a backup lead and in 3/148 (2.0%) patients with a backup lead (P = 0.008). One patient without a backup lead had syncope due to atrial oversensing. Thus, implantation of ventricular backup leads may avoid lead revision and adverse events in selected HBP patients.