Dual-chamber Pacemaker Implantation Research Articles

Dual-chamber pacing confers better myocardial performance and improves clinical outcomes compared to single-chamber pacing

The deleterious effects of long term right ventricular pacing are increasingly being recognized today. Current clinical practice favors the implantation of dual-chamber permanent pacemaker which maintains atrioventricular synchrony and is associated with better quality of life. However, despite the popular belief and common sense surrounding the superiority of dual-chamber pacing over single chamber pacing, the same has never been conclusively verified in clinical trials. Some observational evidence however, does exists which supports the improved cardiac hemodynamics, lower the rate of atrial fibrillation, heart failure and stroke in dual-chamber pacing compared to single-chamber pacing. In the index study by Haque et al , right ventricular pacing, particularly in ventricular paced, ventricular sensed, inhibited response and rate responsive pacemaker adversely impacted the left ventricular functions over 9-months compared to dual pacing, dual sensing, dual responsive and rate responsive pacemaker. Although there are key limitations of this study, these findings does support a growing body of evidence reinstating the superiority of dual chamber pacing compared to single chamber pacing.

Abstract 4138230: Incidence of Worsening Tricuspid Regurgitation Following Implantation of Leadless versus Dual-Chamber Pacemakers

Introduction: Cardiac implantable electronic devices (CIED) may result in or worsen tricuspid regurgitation (TR), which is associated with a higher risk of morbidity and mortality ( Figure 1 ). However, the incidence of TR following implantation of leadless pacemakers versus dual-chamber pacemakers (DC-PPM) is not well described. Hypothesis: Micra leadless pacemakers will have a lower incidence of worsening TR relative to standard DC-PPMs. Aims: To evaluate the incidence of worsening TR after implantation of leadless and DC-PPMs. Methods: We performed a retrospective study of all patients who underwent Micra leadless pacemaker or DC-PPM implantation at the University of California, San Diego from 2/2019-2/2024. The primary outcome was incidence of worsening TR. Results: A total of 476 patients underwent CIED implantation with both pre- and post-echocardiograms completed, of which 26.9% (n=128) had a Micra leadless pacemaker implanted and 73.1% (n=348) had a DC-PPM implanted. The average time to first post-implantation echocardiogram was 359 days in the Micra group and 510 days in the DC-PPM group (p=0.004). Worsening TR post-CIED implantation occurred in 21.9% (n=28) of patients who had a Micra and 25.9% (n=90) of patients who had a DC-PPM (p=0.192). The TR worsened by an average of 0.88 ± 0.32 grades in the Micra group versus 0.98 ± 0.33 grades in the DC-PPM group (p=0.08). Conclusion: In this analysis, leadless pacemaker implantation was associated with a statistically insignificant trend towards less TR. However, the degree of worsening TR following leadless pacemaker or DC-PPM implantation is relatively mild and of unclear clinical significance.

Inadvertent higher rate atrial pacing after dual chamber pacemaker implantation - what is the underlying mechanism?

Unexplained change in parameters, despite good lead positions or odd ECG patterns following implant should lead to suspicion of lead swap, amongst other possibilities. An easy way to confirm this is by paying careful attention to device EGMs and recording the ECG by switching off one channel, and pacing single channel (in either AAI or VVI mode).

Proposal for a pacemaker implant technique with minimum radiation exposure

Objective: To describe a standardized technique for implanting a pacemaker to reduce the time of surgery and radiation exposure and to demonstrate the results in a series of patients. Methods: Through descriptive and cross-sectional statistics, 109 patients undergoing dual-chamber (DDD) and single-chamber (VVI) pacemaker implantation were evaluated, using a standardized technical approach used in the cardiac surgery service of Santa Casa de Misericórdia of Ponta Grossa-PR, Brazil, from November 2016 to November 2019. Clinical aspects, implant indication, implant times, and radiation time were studied. The technique was described, and its most relevant aspects were discussed. Results: 68.81% of the pacemakers were DDD and the surgical time ranged from 11’22’’ to 34’43’’, with a median of 18’15’’. In these cases, the fluoroscopy time ranged from 34’’ to 5’10’’, with a mean of 1’42’’ and a 16.9 mGy median amount of radiation. The time to implant the VVI pacemaker ranged from 12’ to 42’, with a median of 17’12’’. The fluoroscopy time ranged from 26’’ to 6’25’’, with a mean of 1’41’’ and the median amount of radiation was 13.6 mGy. Conclusion: The technique proved to be agile, safe, with low fluoroscopy times and small amount of radiation. There were no postoperative complications. However, few studies were found for comparison.

Study of right atrial and right ventricular function in dual chamber pacemaker patients

Abstract Background Unlike left ventricular function, right ventricular (RV) function in pacemaker patients is less well studied with less studies comparing septal versus apical pacing effects on the RV function and almost none on the right atrial (RA) function. Purpose To assess the effect of RV pacing on the echocardiographic and clinical parameters of the RV and RA function and their correlation with the site of right ventricular lead implantation. Methods The study assessed 59 patients in need of permanent dual chamber pacemaker implantation using clinical and echocardiographic data of the RV and RA size and function using tricuspid annular plane systolic excursion (TAPSE), S wave velocity of the tricuspid annulus and fractional area change (FAC), free wall strain (FWSL), global longitudinal strain (GLS) of the RV, RA strain including reservoir, conduit and contraction phases and 3D ejection fraction of the RV using Epiq 7 Ultrasound machine (Philips Healthcare) by the same echocardiographer before implantation and 6 months after. All programming parameters were recorded postoperative and 6 months later. Results 31 patients had the RV lead in the RV apex whereas 28 had it in the septum and all patients had their RA lead in the right atrial appendage, with no significant difference between both groups regarding baseline demographic, clinical nor echocardiographic data. At 6 months, there was a significant decline of the 3D RVEF from a mean of (58.57% ± 6.35%) to (56.41% ± 6.17%), TAPSE from (2.61 cm ± 0.51) to (2.35 cm ± 0.52) and S wave from (13.73 cm/sec ± 2.84) to (12.64 cm/sec ± 2.61) but none showed a significant difference between septal and apical pacing, on the other hand, the RV strain showed a significant decline 6 months after implantation in both the FWSL from (-31.75% ± 5.39) to (-27.82% ± 5.73) and the GLS from (-25.89% ± 5.17) to (-21.65% ± 4.51) with more decline in the septal group compared to the apical (-20.33% ± 4.70 versus -22.84% ± 4.04 regarding the GLS and -26.11% ± 6.41 versus -29.37% ± 4.62 in the FWSL, respectively). There was no difference in the FAC, tricuspid regurgitation severity, gradient nor the estimated pulmonary artery pressure at 6 months. The RA size showed a significant decline at 6 months but no difference in any of the strain parameters. No clinical RV failure symptoms nor signs were observed. Programming revealed a mean percentage of ventricular pacing of (97.92% ± 2.67%) with a minimum of 91% and atrial pacing of (10.41% ± 12.52%), and the thresholds, impedance and atrial high-rate episodes were comparable postoperatively and 6 months after, with no difference between the septal and apical groups. Conclusion At 6 months follow-up after pacemaker implantation, right ventricular function starts to show decline in both the septal and apical groups with only the right ventricular strain more affected in the septal group compared to the apical.3D right ventricular ejection fraction3D right ventricular strain

Dextrocardia with complete atrioventricular block—the right clinical approach to pace a heart on the right hemithorax: a case report

BackgroundA heart positioned on the right side of the thorax can be more a complex situation than it seems, also the potentially associated congenital cardiopathies are variable. In this regard, patients with dextrocardia presenting with complete atrioventricular block require a thorough anatomical investigation to map the veno-arterial system and potential cardiovascular defects before proceeding with a permanent pacing procedure.Case presentationA 73-year-old Caucasian woman with no significant medical history presented with syncope. Physical examination showed regular heart sounds with an average heart rate of 35–40 beats per minute and no other relevant physical findings. Chest X-rays revealed a heart positioned in the right hemithorax. A standard electrocardiogram revealed complete atrioventricular block with junctional escape rhythm at nearly 35–40 beats per minute. A transthoracic echocardiogram showed a mirror image dextrocardia without any other remarkable abnormalities. Venogram performed using the left peripheral cephalic vein showed normal venous return into the right atrium positioned on the left side. Surgical intervention consisted of permanent dual chamber pacemaker implantation using the left subclavian vein. Discussion is provided based on the relevant medical literature outlining different potential scenarios with associated cardiac and major vessels abnormalities.ConclusionThis case highlights an atypical presentation of atrioventricular block in a patient with dextrocardia and situs inversus, for whom a successful dual-pacemaker implantation procedure was performed.

Impact of atrial high-rate episodes on new onset of atrial fibrillation and all-cause mortality in elderly patients over 90 years old with dual-chamber pacemaker implantation

Objective: To investigate the impacts of atrial high-rate episodes (AHRE) on the risks of new onset of atrial fibrillation and all-cause mortality in elderly patients over 90 years old after cardiac dual-chamber pacemaker implantation. Methods: This study was a retrospective study. Patients aged 90 years and above who were implanted with cardiac dual-chamber pacemakers and followed up in the People's Liberation Army General Hospital from January 2017 to June 2022 were enrolled and divided into AHRE≥6 h group and AHRE<6 h group according to the onset time of AHRE. The primary endpoint was new onset of atrial fibrillation, and the secondary endpoints were all-cause mortality and cardiovascular mortality. Kaplan-Meier survival curve was poltted, and log-rank test was used to compare the differences in the incidence of new onset of atrial fibrillation, all-cause death and cardiovascular death between AHRE≥6 h and AHRE<6 h groups. Multivariate Cox survival analysis was used to investigate the factors affecting new onset of atrial fibrillation, all-cause death and cardiovascular death in elderly patients aged 90 years and above with dual-chamber pacemaker implantation. Results: A total of 169 patients were enrolled, aged (93.95±3.28) years, including 18 females (11%). The median follow-up time was 28.9 months. There were 87 and 82 patients in AHRE≥6 h group and AHRE<6 h group, respectively. Kaplan-Meier survival curve analysis showed that the incidence of new onset of atrial fibrillation (log-rank P<0.001), all-cause death (log-rank P=0.004) and cardiovascular death (log-rank P=0.026) in AHRE≥6 h group was significantly higher than that in AHRE<6 h group.After adjusting for traditional risk factors, multivariate Cox survival analysis showed that AHRE≥6 h was an independent risk factor for new onset of atrial fibrillation (HR=4.046, 95%CI 2.402-6.814, P<0.001) and all-cause mortality (HR=1.668, 95%CI 1.119-2.487, P=0.012) in elderly patients over 90 years old with cardiac dual-chamber pacemaker implantation. However, AHRE≥6 h had no effect on cardiovascular mortality (P>0.05). Anemia (HR=3.098, 95%CI 1.342-7.153, P=0.008) and heart failure with reduced ejection fraction (HR=3.028, 95%CI 1.181-7.763, P=0.021) were both independently associated with cardiovascular mortality. Conclusions: AHRE is common in cardiac dual-chamber pacemakers recipients aged 90 years and above, and AHRE≥6 h can be used as a predictor of new onset of atrial fibrillation or all-cause mortality in these patients.

Implantation techniques for a helix-fixation dual-chamber leadless pacemaker

In a pivotal trial (NCT05252702), the AVEIR DR (Abbott) leadless pacemaker system was found to be safe and effective in delivering DDDR synchronous atrial and ventricular pacing. This dual-chamber system employs 2 leadless pacemakers with implant-to-implant communication. Although implantation of the ventricular device as a single-chamber pacemaker has been well described, there are additional considerations surrounding the dual-chamber implantation procedure. Herein, we review the dual-chamber leadless pacemaker implantation workflow while providing guidance to optimize safe and effective implantation procedures.

Pulmonary Vein Isolation or Pace and Ablate in Elderly Patients With Persistent Atrial Fibrillation (ABLATE Versus PACE)—Rationale, Methods, and Design

Age is a major risk-factor for atrial fibrillation (AF) and associated hospitalisations. With increasing emphasis on rhythm control, pulmonary vein isolation (PVI) is often suggested, even to elderly patients (≥ 75 years of age). Efficacy of PVI aiming at rhythm control is limited in persistent AF. Pacemaker implantation with atrioventricular node (AVN) ablation may represent a reasonable alternative, with the aim of controlling symptoms and improving quality of life in elderly patients. In this investigator-initiated, randomised, multicentre trial, we test the hypothesis that pacemaker implantation and AVN ablation provides superior symptom control over PVI in elderly patients with symptomatic persistent AF, without any increase in adverse event profile. In the ABLATE Versus PACE (NCT 04906668) prospective open-label superiority trial, 196 elderly patients with normal ejection fraction and symptomatic persistent AF despite guideline-indicated medical therapy will be randomised to either cryoballoon PVI (ABLATE) or dual-chamber pacemaker implantation with subsequent AVN ablation (PACE), and followed for a minimum of 12 months. The primary efficacy outcome is a composite end point of rehospitalisation for atrial arrhythmia or cardiac decompensation/heart failure, (outpatient) electrical cardioversion, or upgrade to cardiac resynchronisation therapy owing to worsening of left ventricular ejection fraction to ≤ 35%. Secondary end points include death from any cause, stroke, quality of life, and procedure-related complications. Sample size is designed to achieve 80% power for the primary end point (2-tailed alpha of 5%). ABLATE Versus PACE will determine whether pacemaker implantation and AVN ablation can improve symptom-control in elderly patients with persistent AF over PVI without increasing safety end points.

New-onset atrial high-rate episodes in left bundle branch area pacing versus right ventricular pacing for patients with atrioventricular block.

Left bundle branch area pacing (LBBAP) demonstrated beneficial effects on clinical outcomes. Comparative data on the risk of atrial high-rate episodes (AHREs) between LBBAP and right ventricular pacing (RVP) are lacking. This study aimed to investigate whether LBBAP can reduce the risk of new-onset AHREs compared with RVP in patients with atrioventricular block (AVB). We enrolled 175 consecutive AVB patients with no history of atrial fibrillation undergoing dual-chamber pacemaker implantation (LBBAP or RVP). Propensity score matching for baseline characteristics yielded 43 matched pairs. The primary outcome was new-onset AHREs detected on a scheduled device follow-up. Changes in echocardiographic measurements were also compared between the groups. New-onset AHREs occurred in 42 (24.0%) of all enrolled patients (follow-up 14.1 [7.5] months) and the incidence of new-onset AHREs in the LBBAP group was lower than in the RVP group (19.8% vs. 34.7%; P = 0.04). After propensity score matching, LBBAP still resulted in a lower incidence of new-onset AHREs (11.6% vs. 32.6%; P = 0.02), and a lower hazard ratio for new-onset AHREs compared with RVP (HR, 0.274; 95% CI, 0.113-0.692). At 1 year, LBBAP achieved preserved left ventricular ejection fraction (LVEF) (63.0 [3.2]% to 63.1 [3.1]%; P = 0.56), while RVP resulted in reduced LVEF (63.4 [4.9]% to 60.5 [7.3]%; P = 0.01]). Changes in LVEF were significantly different between the 2 groups (by 2.6% [0.2 to 5.0]%; P = 0.03). LBBAP demonstrated a reduced risk of new-onset AHREs compared with RVP in patients with AVB.

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

In patients undergoing pacemaker implantation with no prior history of heart failure (HF), the presence of left bundle branch block (LBBB) has been identified as an independent predictor of HF-related death or hospitalization, while the prognostic significance of right bundle branch block (RBBB) remains uncertain. We aimed to assess the long-term risk of all-cause mortality in patients with a standard indication for permanent pacing and normal or moderately depressed left ventricular function when RBBB is detected at the time of implantation. We retrospectively enrolled 1348 consecutive patients who had undergone single- or dual-chamber pacemaker implantation at the study center, from January 1990 to December 2022. Patients with a left ventricular ejection fraction ≤35% or a prior diagnosis of HF were excluded. The baseline 12-lead electrocardiogram revealed an RBBB in 241 (18%) and an LBBB in 98 (7%) patients. During a median follow-up of 65 [25th-75th percentile: 32-117] months, 704 (52%) patients died. The combined endpoint of cardiovascular death or HF hospitalization was reached by 173 (13%) patients. On multivariate analysis, RBBB was confirmed as an independent predictor of death [hazard ratio, 1.33; 95% confidence interval (CI), 1.09-1.63; P = 0.005]. However, when considering the combined endpoint of cardiovascular death and HF hospitalization, this endpoint was independently associated with LBBB (hazard ratio, 2.13; 95% CI, 1.38-3.29; P < 0.001), but not with RBBB. In patients with standard pacemaker indications and normal or moderately depressed left ventricular function, the presence of basal RBBB was an independent predictor of mortality. However, it was not associated with the combined endpoint of cardiovascular death and HF hospitalization.

Very early fractures of the stylet-driven Biotronik Solia lead used for left bundle branch area pacing

Abstract Introduction Left bundle branch area pacing (LBBAP) has become increasingly popular due to the relatively simple implantation procedure allowing for conduction system pacing (CSP). Initially, lumen-less leads have been used primarily for CSP. However, several authors have published encouraging results using conventional stylet-driven pacemaker (PM) leads as well and our centers have largely adopted this approach. Methods In our two tertiary referral centers, we assessed all patients, who underwent a LBBAP lead implantation using any lead. We observed several early lead fractures, exhibiting a unique failure mechanism, which we illustrate in this case-series. Results Between January 2022 and November 2023 343/393 patients (87.3%) were implanted with a Solia pacemaker lead, 46/393 (11.7%) received a SelectSecure 3830 lead, and 4/393 (1.0%) another stylet-driven lead. Three patients (0.8%) who initially were implanted with a Solia lead experienced very early intracardiac lead fractures within 1, 11 and 13 months after implantation despite good initial electrical performance values (Table shows initial values and values during the time of failure (bold)). The first case was a 54 year-old woman with permanent 3d degree AV block receiving an LBBAP lead after lead extraction. Four weeks later, she presented with presyncope and exit block at maximum output in uni- and bipolar configuration. The second case was a 72 year-old man with intermittent 3rd degree AV block in the context of an ischemic heart disease. He received a dual-chamber LBBAP PM. 13 months after the implantation, a bipolar impedance &amp;gt; 2’500Ω and exit block were noted. The third case was 65 year-old man suffering from sick sinus syndrome. He initially underwent a dual-chamber PM implantation in 2011 and due to ventricular sensing issues a transvenous lead extraction and implantation of a LBBAP lead in October 2022. During device follow-up after 11 months, a fractured LBBAP lead with bipolar impedance &amp;gt;2’500Ω and exit block during threshold testing was noticed. In all cases, X-rays and macroscopic analysis consistently showed a disintegration of the lead immediately distal to the ring electrode (Figure; site of fracture marked with an arrow). Most likely, this was caused by the repetitive shear stress at the hinge point of the lead where it is entering the septum. Conclusion No dedicated stylet-driven CSP lead is available to date. The implantation site and technique for LBBAP may exert higher mechanical stress on the distal part of the lead, making it more prone to fracture than in a conventional position. Currently, the use of conventional stylet-driven leads is still off-label and the performance of such leads should be monitored closely.TableFigure

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

Abstract Aim In patients undergoing pacemaker implantation with no prior history of heart failure (HF), the presence of left bundle branch block (LBBB) has been identified as an independent predictor of HF-related death or hospitalization, while the prognostic significance of right bundle branch block (RBBB) remains uncertain. We aimed to assess the long-term risk of all-cause mortality in patients with a standard indication for permanent pacing and normal or moderately depressed left ventricular function when RBBB is detected at the time of implantation. Methods We retrospectively enrolled 1348 consecutive patients who had undergone single- or dual-chamber pacemaker implantation at the study center, from January 1990 to December 2022. Patients with a left ventricular ejection fraction ≤35% or a prior diagnosis of HF were excluded. Results The baseline 12-lead electrocardiogram revealed an RBBB in 241 (18%) and an LBBB in 98 (7%) patients. During a median follow-up of 65 [25th-75th percentile: 32-117] months, 704 (52%) patients died. The combined endpoint of cardiovascular death or HF hospitalization was reached by 173 (13%) patients. On multivariate analysis, RBBB was confirmed as independent predictor of death (Hazard Ratio, 1.33; 95% CI, 1.09–1.63; P=0.005). However, when considering the combined endpoint of cardiovascular death and HF hospitalization, this endpoint was independently associated with LBBB (Hazard Ratio, 2.13; 95% CI, 1.38–3.29; P&amp;lt;0.001), but not with RBBB. Conclusions In patients with standard pacemaker indications and normal or moderately depressed LV function the presence of basal RBBB was an independent predictor of mortality. However, it was not associated with the combined endpoint of cardiovascular death and HF hospitalization.Time to event

Left ventricular global longitudinal strain is a long-term predictor of pacemaker-associated cardiomyopathy

Abstract Background Implantation of a permanent pacemaker is an effective treatment for symptomatic bradycardia. However, chronic right ventricular pacing (RVP) may lead to compromised left ventricular (LV) function, atrial fibrillation, heart failure, and increased mortality via pacing induced electrical and mechanical dyssynchrony. A decrease in LV ejection fraction (LVEF) of ≥ 10% with a baseline LVEF &amp;gt; 50% prior to RVP and no alternative explanation for the decline in LVEF is termed pacing-induced cardiomyopathy (PICM). Predictive clinical and imaging-derived measures to identify patients at high risk for pacemaker induced cardiomyopathy (PMIC) are lacking, but essential. Objective The study is a prospective, single center, double-blinded trial evaluating the impact of right ventricular pacing on left ventricular function and clinical outcome. Methods In 105 patients (59 male / 46 female), who underwent a dual-chamber pacemaker implantation at the Charité Campus Virchow Klinikum, RVP burden, LVEF and left ventricular global longitudinal strain (LV-GLS) were obtained. Mean follow-up per patient was 29.6 ±13.9 months. We used a stepwise analytic approach including ROC analysis, univariate testing, binary regression as well as Cox-regression models and Kaplan-Meier analysis to compare low RVP burden (&amp;lt; 30%) and high RVP burden (≥ 30%) cohorts according to change in echocardiographic parameters and clinical outcome (all-cause mortality). Results Mean LVEF was 61 ± 6% and mean LV-GLS was 18 ± 4% at baseline. We identified 7 patients with a LVEF decline in the course of the study. In Pearson’s Chi-squared test, patients with a high RVP burden were more likely to develop LVEF and LV-GLS deterioration (6 patients versus 1 patient for LVEF, p&amp;lt;0.05; 28 versus 16 patients for LV-GLS, p&amp;lt;0.001). In multivariable binary logistic regression, LV-GLS (OR: 1.410, 95% CI: 1.201-1.610, p&amp;lt;0.001) deterioration was significantly associated with a LVEF decline and a high RVP burden ≥ 30% (OR: 1.358, 95% CI: 1.160-1.534, p&amp;lt;0.01). In a log-rank test, time to LVEF decline was significantly shorter in patients with a RVP burden ≥ 30% compared to a RVP burden &amp;lt; 30% (45.2±2.9 versus 55.7±1.0 months, p&amp;lt;0.05). In the Cox-regression analysis, LV-strain decline within 12 months (HR: 7.210, 95% CI: 4.239-9.516, p&amp;lt;0.05) was a significant predictor for a later LVEF decline. In a log-rank test, time to LVEF deterioration was significantly shorter in patients with LV-strain decline within 12 months compared to those without (34.7 ± 4.2 versus 53.7 ± 1.4 months, p&amp;lt;0.001). No significant difference in all-cause mortality between patients with a high RVP burden compared to those with low RVP burden (log-rank test, p=0.2). Conclusion A decline in LV-GLS is a sensitive long-term parameter of subsequent LVEF deterioration in patients with normal preimplant LVEF, who require RVP ≥ 30%. and is associated with a poor clinical outcome.

THROW YOUR LEAD OVER THE OBSTACLE: A CHALLENGING CRT UPGRADING

Abstract High percentage of right ventricular pacing could lead to pacing induced cardiomyopathy in a non–negligible proportion of patients. Cardiac resynchronization therapy upgrading could represent an option to improve ventricular function, reducing heart failure hospitalizations. A 82 yo male was admitted to hospital with symptomatic heart failure. He had history of complete AV block treated with dual chamber pacemaker implantation five years earlier following coronary artery bypass graft surgery, bioprosthetic aortic valve replacement and septal myectomy. He had also history of cardiac arrest occurred in the context of acute coronary syndrome treated with PCI so that ICD implant was not considered at that time, and two more HF hospitalizations in previous years. Progressive LVEF decline was documented since PM impantation until last echo showed severe left ventricular dysfunction (EF 20% from baseline EF 60%). The ECG showed sinus rhythm and wide paced QRS (206 ms) with 100% pacing percentage. A CRT device upgrading was planned. Baseline venography initially showed pervious axillary–subclavian left axis, but unfortunately the guidewire encountered a complete occlusion before entering the superior vena cava. Nevertheless, dye contrast injection documented the presence of a proximal collateral branch (fig A) having a vertical course in the thorax and reaching the lateral wall of the left ventricle with an extrapericardic course then entering the right heart through inferior vena cava. Using a IM 5Fr sheath (usually used by interventional cardiologists to cannulate internal mammary artery) we could reach this branch, inserting a guidewire and finally advancing a quadripolar lead (Fig B–C) which reached the lateral left ventricular wall. LV capture was confirmed when pacing from the three proximal poles, while the distal one caused phrenic nerve capture. The quadripolar lead was connected to the LV port of a three chamber PM along with previous implanted leads thus obtaining biventricular pacing. QRS paced was 50 ms shorter than baseline. No peri–procedural complications occurred. Lead–related venous occlusion might represent an obstacle to CRT upgrade requiring high technical expertise. The presence of a complete venous occlusion might cause procedural failure, particularly in hospitals without surgical facility. In this case, the presence of a collateral branch reaching the lateral wall of the left ventricle allowed to successfully complete the CRT upgrade.

EVALUATION OF EARLY OUTCOMES OF PERMANENT PACEMAKER IMPLANTATION IN HYPERTENSIVE PATIENTS WITH BRADYARRHYTHMIAS

Objective: This study aims to describe the clinical characteristics and the features of bradyarrhythmias on 24-hour Holter monitoring and to evaluate the early outcomes of permanent pacemaker implantation in hypertensive patients with bradyarrhythmias. Subjects and method: This cross-sectional study was conducted on 57 subjects with hypertension and bradyarrhythmias who were indicated for permanent pacemaker implantation. Results: The most common clinical symptoms recorded were fatigue, dizziness, and chest pain, accounting for 47.4%, 45.6%, and 42.1% respectively. The majority of patients had sinus node dysfunction (73.7%) and most underwent dual-chamber permanent pacemaker implantation (87.7%). The 24-hour Holter monitoring results showed that 42.1% had sinus atrial block - sinus pause in the sinus node dysfunction group and 15.8% of patients had third-degree atrioventricular block (AV block) in the AV block group. A good treatment outcome was observed in 72.0% of cases. Age &gt; 70 (OR: 6.1; 95% CI: 1.2-30.1), female gender (OR: 4.2; 95% CI: 1.2-15.4), and single-chamber pacemaker (OR: 8.9; 95% CI: 1.5-52.1) were associated with a higher risk of moderate to poor treatment outcomes. Conclusion: Permanent pacemaker implantation generally tends to have good short-term outcomes. However, it should be noted that older age, female, and single-chamber pacemaker implantation in association with worse outcomes.

Incidence, Risk Factors, and Outcomes of Left Atrial Enlargement in Patients Requiring Right Ventricular Pacing: A Retrospective Study of 461 Cases from 2012 to 2020.

BACKGROUND Long-term right ventricular (RV) pacing has been linked to left atrial enlargement (LAE). The incidence and risk factors associated with significant LAE after RV pacing remain unknown. This retrospective study included 461 patients requiring RV pacing at 2 centers between 2012 and 2020 and aimed to evaluate the incidence, risk factors, outcomes, and complications of LAE. MATERIAL AND METHODS A total of 461 patients with normal-sized pre-implant left atrial dimension and dual-chamber pacing pacemaker implantation for complete atrioventricular block were enrolled. Patients were grouped based on a ≥20% increase from their baseline left atrial dimension by echocardiography, indicating significant LAE, and initial characteristics, echocardiographic data, and outcomes were compared. RESULTS During a mean 7.0±4.9 years follow-up period, 96 patients (20.8%) developed significant LAE, whereas 365 patients did not. In multivariate logistic regression analysis, smaller pre-implant left atrial dimension (OR, 0.776; 95% CI, 0.728-0.828; P<0.001), lower post-implant left ventricular ejection fraction (OR, 0.976; 95% CI, 0.957-0.995; P=0.014), post-implant development of moderate to severe mitral regurgitation (OR, 2.357; 95% CI, 1.172-4.740; P=0.016), and RV pacing duration ≥3.3 years (OR, 1.576; 95% CI, 1.039-2.646; P=0.045) were independent predictors of significant LAE after RV-dependent pacing. There was a significant difference in the incident stroke events between patients without and with significant LAE (9.9% vs 17.7%; log-rank P=0.047). CONCLUSIONS Long-term RV pacing was linked to significant LAE in 20.8% of patients with complete atrioventricular block, with those affected experiencing a higher stroke rate during follow-up.

Prediction of pacemaker-induced cardiomyopathy using a convolutional neural network based on clinical findings prior to pacemaker implantation

Risk factors for pacemaker-induced cardiomyopathy (PICM) have been previously reported, including a high burden of right ventricular pacing, lower left ventricular ejection fraction, a wide QRS duration, and left bundle branch block before pacemaker implantation (PMI). However, predicting the development of PICM remains challenging. This study aimed to use a convolutional neural network (CNN) model, based on clinical findings before PMI, to predict the development of PICM. Out of a total of 561 patients with dual-chamber PMI, 165 (mean age 71.6 years, 89 men [53.9%]) who underwent echocardiography both before and after dual-chamber PMI were enrolled. During a mean follow-up period of 1.7 years, 47 patients developed PICM. A CNN algorithm for prediction of the development of PICM was constructed based on a dataset prior to PMI that included 31 variables such as age, sex, body mass index, left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, severity of mitral regurgitation, severity of tricuspid regurgitation, ischemic heart disease, diabetes mellitus, hypertension, heart failure, New York Heart Association class, atrial fibrillation, the etiology of bradycardia (sick sinus syndrome or atrioventricular block) , right ventricular (RV) lead tip position (apex, septum, left bundle, His bundle, RV outflow tract), left bundle branch block, QRS duration, white blood cell count, haemoglobin, platelet count, serum total protein, albumin, aspartate transaminase, alanine transaminase, estimated glomerular filtration rate, sodium, potassium, C-reactive protein, and brain natriuretic peptide. The accuracy, sensitivity, specificity, and area under the curve of the CNN model were 75.8%, 55.6%, 83.3% and 0.78 respectively. The CNN model could accurately predict the development of PICM using clinical findings before PMI. This model could be useful for screening patients at risk of developing PICM, ensuring timely upgrades to physiological pacing to avoid missing the optimal intervention window.

Atrial Pacing Negatively Affects Left Atrial Morphological and Functional Parameters Similarly to Atrioventricular Dyssynchrony.

Background and Objectives: Atrioventricular (AV) dyssynchrony as well as atrial and ventricular pacing affect left atrial (LA) function. We conducted a study evaluating the effect of atrial and ventricular pacing on LA morphological and functional changes after dual-chamber pacemaker implantation. Materials and Methods: The study prospectively enrolled 121 subjects who had a dual-chamber pacemaker implanted due to sinus node disease (SND) or atrioventricular block (AVB). Subjects were divided into three groups based on indication and pacemaker programming: (1) SND DDDR 60; (2) AVB DDD 60 and (3) AVB DDD 40. Subjects were invited to one- and three-month follow-up visits. Three subsets based on pacing burden were analyzed: (1) high atrial (A) low ventricular (V); (2) high A, high V and (3) low A, high V. LA function was assessed from volumetric parameters and measured strains from echocardiography. Results: The high A, low V group consisted of 38 subjects; while high A, high V had 26 and low A, high V had 23. A significant decrease in reservoir and contractile LA strain parameters were only observed in the high A, low V pacing group after three months (reservoir 25.9 ± 10.3% vs. 21.1 ± 9.9%, p = 0.003, contractile -14.0 ± 9.0% vs. -11.1 ± 7.8, p = 0.018). While the re-established atrioventricular synchrony in the low A, high V group maintained reservoir LA strain at the baseline level after three months (21.4 ± 10.4% vs. 22.5 ± 10.4%, p = 0.975); in the high A, high V group, a further trend to decrease was noted (20.3 ± 8.9% vs. 18.7 ± 8.3%, p = 0.231). Conclusions: High atrial pacing burden independently of atrioventricular dyssynchrony and ventricular pacing impairs LA functional and morphological parameters. Changes appear soon after pacemaker implantation and are maintained.

Long-term outcome of permanent epicardial pacemaker implantation in neonates: Experience from an Indian center.

Permanent pacemaker implantation (PPI) in neonates is challenging with respect to indications, device selection, implantation technique, and long-term outcomes. Complex anatomy, the need for long-term pacing with high rates, and a problematic postoperative period are the major problems. We prospectively followed up 22 newborns who underwent PPI below 28 days of life at our institute. The median age at implantation was 2 days (interquartile range 1-9 days), and 9% were born preterm. The average heart rate before implantation was 46.4 ± 7.2 bpm. Maternal lupus antibodies were positive in 8 (36.4%) neonates, whereas 11 (50.0%) had associated congenital heart disease. Nineteen neonates underwent single chamber (VVI) and three underwent dual chamber (DDD) pacemaker implantation. Over a median follow-up of 46 months (range 2-123 months), the average ventricular pacing percentage was 87.5 ± 24.9%, with a stable pacing threshold. Seven children underwent pulse generator replacement due to battery depletion at a median age of 47 months. Pacing-induced ventricular dysfunction was seen in five children at a median age of 23.6 months, and two underwent upgradation to cardiac resynchronization therapy. Overall mortality was 13.6%, all due to tissue hypoperfusion and lactic acidosis in the postimplantation period. PPI in neonates has a favorable outcome with excellent lead survival. Overall mortality is 13.6%, which is predominantly in the postimplantation period and related to myocardial dysfunction.