The effects of right ventricular apical pacing on ventricular function and dyssynchrony implications for therapy

Incremental Prognostic Value of Echocardiography Measures of Right Ventricular Systolic Function in Patients With Chronic Heart Failure

BACKGROUND

Tricuspid annular plane systolic excursion (TAPSE), Doppler tissue imaging-derived tricuspid lateral annular systolic wave velocity (S'), and right ventricular fractional area change (RV-FAC) are the most widely used echocardiographic measures of right ventricular systolic function. This study aimed to compare the prognostic value of TAPSE, S', and RV-FAC in a large cohort of patients with chronic heart failure.

METHODS

Consecutive outpatients with heart failure and left ventricular ejection fraction <50% on guideline-recommended therapies undergoing echocardiography were followed up for the end point of cardiac and all-cause death.

RESULTS

Among 1590 patients (71±12 years, 77% men, left ventricular ejection fraction 34%±9%), 202 (13%) died from cardiac causes during a median follow-up of 28 (interquartile range, 14-40) months. According to the recommended cut points for TAPSE (<17 mm), S' (<9.5 cm/s), or RV-FAC (<35%), right ventricular systolic dysfunction was found in 37%, 40%, and 35% of patients, respectively, with 21%, 31%, and 33% of discordant cases comparing TAPSE versus S', TAPSE versus RV-FAC, and S' versus RV-FAC. Both TAPSE <17 mm and RV-FAC <35% were more accurate than S' <9.5 cm/s in predicting the risk of cardiac death (P<0.001), and their combination showed incremental prognostic power (P<0.001). Adding S' to the combination of TAPSE and RV-FAC did not provide further incremental value (P=0.145). Similar findings were obtained when all-cause death was considered as the end point.

CONCLUSIONS

In patients with chronic heart failure and left ventricular ejection fraction <50%, TAPSE, and RV-FAC are more accurate than S' in predicting the risk of cardiac and all-cause death. Considering both RV-FAC and TAPSE provides incremental prognostic value.

Conduction system pacing associated with reduced heart failure hospitalizations and all-cause mortality compared with traditional right ventricular pacing in the Medicare population

BACKGROUND

Conduction system pacing (CSP) has emerged as an alternative therapy to traditional right ventricular (RV) pacing. However, most CSP studies reflect small cohorts or single-center experience.

OBJECTIVE

This analysis compared CSP with dual-chamber (DC) RV pacing in a large, population-based cohort using data from the Micra Coverage with Evidence Development study.

METHODS

Medicare administrative claims data were used to identify patients implanted with a DC RV pacemaker. Lead placement data from Medtronic's device registration system identified patients treated with CSP (n = 6197) using a 3830 catheter-delivered lead or DC RV (non-3830 lead, non-CSP placement; n = 16,989) at the same centers. CSP patients were stratified into left bundle branch area pacing (LBBAP; n = 4738) and His bundle pacing (HBP; n = 1459). Incident heart failure hospitalizations, all-cause mortality, complication rates, and reinterventions at 6 months were analyzed.

RESULTS

CSP patients with a 3830 catheter-delivered lead experienced significantly lower rates of incident heart failure hospitalization (hazard ratio [HR], 0.70; P = .02) and all-cause mortality at 6 months compared with DC RV patients (HR, 0.66; P < .0001). There was no difference in chronic complications (HR, 0.97; P = .62) or need for reintervention (HR, 0.95; P = .63) with CSP compared with DC RV, although LBBAP patients experienced significantly lower rates of complications (HR, 0.71; P = .001) compared with HBP.

CONCLUSION

DC pacemaker patients treated with CSP using a 3830 catheter-delivered lead experienced significant all-cause mortality and heart failure hospitalization benefits compared with DC RV pacing. LBBAP had lower complications compared with HBP. These real-world results align with findings in small clinical studies demonstrating the benefits of CSP.

Prevalence and predictors of permanent pacemaker implantation in patients with aortic stenosis undergoing transcatheter aortic valve implantation: a prospective cohort study

OBJECTIVES

The primary objectives were to identify the predictors of new permanent pacemaker implantation in patients with aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI). The secondary objectives were to investigate the temporal changes in permanent pacemaker implantation following TAVI and its impact on long-term prognosis.

DESIGN

Prospective observational cohort study of patients with AS undergoing TAVI.

SETTING

Single-centre study conducted at a tertiary hospital in Western Norway between 2012 and 2019.

PARTICIPANTS

Among 600 consecutive patients with severe AS who were treated with TAVI, 52 patients with permanent pacemaker prior to TAVI were excluded. The remaining 548 patients were included in the present study.

BASELINE MEASURES

An evaluation of baseline risk factors, 12-lead ECG and echocardiography.

PRIMARY OUTCOME MEASURES

The need for a new pacemaker implantation ≤30 days following TAVI and all-cause death.

RESULTS

The mean age was 80.6±6.7 years, and 50% were males. Among the 548 eligible patients, 173 (31.6%) underwent pacemaker implantation ≤30 days following TAVI, evenly distributed between females and males (29.6% vs 33.6%, p=0.317), with higher implant rates at low-volume phase (2012-2015) and lower implant rates at high-volume phase (2016-2019) (45.8% vs 23.9%, p<0.001). On multivariable analysis, an abnormal electrocardiogram (OR 1.73; 95% CI 1.14 to 2.63, p=0.010), right bundle branch block (OR 2.23; 95% CI 1.09 to 4.59, p=0.028) and atrial fibrillation (OR 1.89; 95% CI 1.24 to 2.88, p=0.003) at baseline were strong predictors of pacemaker implantation. The type of bioprosthesis, but not size, was associated with permanent pacemaker implantation (mechanically expandable valves OR 3.48, 95% CI 2.16 to 5.59; balloon-expandable valves OR 0.07, 95% CI 0.02 to 0.29, both p<0.001)-irrespective of age and sex. During a median follow-up of 60.4 months (range 3-131 months), permanent pacemaker implantation following TAVI was not associated with all-cause mortality (HR 0.89; 95% CI 0.69 to 1.16, p=0.403).

CONCLUSIONS

In the current study, the rates of permanent pacemaker implantation following TAVI decreased substantially from the early low-volume phase to the late high-volume phase. An abnormal baseline ECG, right bundle branch block, atrial fibrillation and bioprosthesis selection remained important predictors of permanent pacemaker implantation. Permanent pacemaker implantation following TAVI had no impact on short or long-term survival.

ETHICS AND DISSEMINATION

The Regional Committees for Medical and Health Research Ethics (approval number: REK vest 33814/2019) and the Institutional Data Protection Services approved the study protocol. The dissemination of study findings was through peer-reviewed publication, presentation at national and international scientific meetings and conferences.

TRIAL REGISTRATION NUMBER

NCT04417829.

Atrioventricular Block Treatment: Pacing Site, AV Synchrony, or Both?

Background/Objectives: Right ventricular pacing (RVP), leadless pacing (LL), and conduction system pacing (CSP) are treatment options for atrioventricular block (AVB), each with distinct characteristics. However, the long-term outcomes of these pacing strategies remain insufficiently compared. This study evaluates clinical and echocardiographic outcomes of patients with AVB treated with dual chamber RVP, His bundle pacing (HBP), or LL. Methods: This single-center observational registry study included 22 consecutive patients receiving LL with atrioventricular resynchronization functionality (October 2020 to October 2022), matched with 66 control patients receiving either RVP (33 patients) or HBP (33 patients) using propensity score matching (2:3:3 ratio). Primary and secondary endpoints included all-cause mortality, cardiovascular mortality, heart failure, and echocardiographic outcomes. Atrioventricular synchrony in the LL group was assessed. Results: At two years, all-cause mortality was significantly higher in the LL group compared to RVP (36.4% vs. 6.1%, p = 0.002) and HBP (36.4% vs. 12.1%, p = 0.03), but LL had a more severe clinical profile. Cardiovascular mortality and heart failure incidence showed no significant differences. Patients receiving RVP showed a significant decrease in left ventricular ejection fraction and an increase in ventricular volumes. In contrast, HBP patients exhibited favorable cardiac remodeling. Stratification based on atrial sensing showed that LL patients with >66% AV synchrony had a lower mortality (p = 0.02). Conclusions: CSP offers superior results compared to other pacing methods in terms of ventricular function owing to a physiological ventricular activation and maintenance of AV synchrony. However, LL may be a viable alternative for frail and high-risk patients, as the suboptimal AV synchrony is traded off with lesser ventricular dyssynchrony.

The Impact of Permanent Pacemaker Implantation After TAVI on Mortality and Quality of Life: A POPular TAVI Substudy

BACKGROUND

Conduction disturbances are common after transcatheter aortic valve implantation (TAVI) and frequently require permanent pacemaker implantation (PPI). Data regarding its impact on mortality and morbidity are conflicting. This study aims to assess the impact of PPI before or within 30 days after TAVI on mortality and health-related Quality of Life (QoL) during the first year after TAVI.

METHODS

In this POPular TAVI substudy, 978 patients were included and categorized into three groups: Neither PPI before or within 30 days after TAVI (no PPI, n = 779), PPI before TAVI (PPI pre-TAVI, n = 102), PPI within 30 days after TAVI (PPI post-TAVI, n = 97). All-cause death and cardiac death were evaluated at 1 year. QoL was assessed using the SF-12 and EQ-5D-5L questionnaires at baseline and 3, 6, and 12 months.

RESULTS

At 1-year, all-cause death was seen in 6.9% (PPI pre-TAVI, p = 0.53) and 10.3% (PPI post-TAVI, p = 0.66) of the patients compared to 8.7% of the patients (no PPI). Cardiac death was observed in 4.9% (PPI pre-TAVI, p = 0.58) and 6.2% (PPI post-TAVI, p = 0.94) of the patients compared to 6.2% of patients (no PPI). Regarding QoL, the PPI pre-TAVI group showed lower PCS-12 over time compared to the no PPI group (p = 0.04), while MCS-12, EQ-5D Index and EQ-5D VAS scores were equal. No significant differences in QoL were seen between the PPI post-TAVI group and the no PPI group.

CONCLUSION

PPI before or within 30 days after TAVI was not associated with increased mortality within 1 year. PPI pre-TAVI was associated with lower physical QoL.

Post-Implant Global Longitudinal Strain as a Predictor of Pacing-Induced Cardiomyopathy in Patients with Preserved Ejection Fraction Undergoing Pacemaker Placement

Background

Right ventricular (RV) pacing exacerbates heart failure and increases cardiac mortality in patients with reduced ejection fraction (EF). However, its impact on left ventricular dysfunction in patients with preserved EF remains inconclusive. This study investigates the relationship between RV pacing, global longitudinal strain (GLS), and EF in patients with preserved EF.

Methods

This prospective registry study included patients with preserved EF (≥50%) undergoing de novo permanent pacemaker (PPM) implantation for atrioventricular block at Chosun University Hospital, South Korea, from 2018 to 2022. Echocardiographic evaluations were performed pre-implant, post-implant, and at 12 months, with follow-up visits every 3-6 months. Composite outcomes included cardiac death, heart failure hospitalization, pacing-induced cardiomyopathy (PICM), and biventricular pacing (BVP) upgrade.

Results

A total of 71 patients (28 males, mean age 73.1 years) were included. Following PPM implantation, significant declines in both EF and GLS were noted, especially in those with PICM. Over three years, 2 patients died, 6 were hospitalized, 7 developed PICM, and 3 underwent a BVP upgrade. Reduced post-implant GLS was an independent predictor of PICM (hazard ratios (HR) 1.715, 95% CI 1.174-2.504; p = 0.005). Receiver operating characteristic (ROC) analysis showed an area under curve (AUC) of 0.92 for GLS, with a GLS <-15.0 having 100% sensitivity and 80.9% specificity for predicting PICM.

Conclusions

Post-implant GLS is a reliable predictor of PICM in patients with preserved EF. Regular GLS monitoring can guide timely interventions, including guideline-directed medical therapy or BVP upgrades, to prevent deterioration and improve outcomes.

Spatial ventricular gradient is associated with pacing-induced cardiomyopathy

BACKGROUND

Pacing-induced cardiomyopathy (PICM) is a frequent complication of right ventricular pacing that often requires reoperation for biventricular or conduction system pacing. Better methods for predicting PICM may inform initial pacing strategy and follow-up monitoring.

OBJECTIVE

The purpose of this study was to determine whether the spatial ventricular gradient (SVG), a vectorcardiographic marker of ventricular electrical and mechanical heterogeneity, is associated with the subsequent development of PICM.

METHODS

This was a retrospective study of patients with pacemakers implanted between 2003 and 2012 at the Hospital of the University of Pennsylvania. Baseline demographic, echocardiographic, and electrocardiographic parameters, including SVG magnitude, elevation, and azimuth, were measured from standard 12-lead electrocardiograms. Adjusted Cox proportional hazards modeling was used to assess the associations between the SVG and the risk of PICM over follow-up.

RESULTS

Of the 203 patients with a median age of 74 years (p25-p75 64-79), 110 (54%) male, and median baseline left ventricular ejection fraction 65% (p25-p75 57-70), 44 (22%) developed PICM during follow-up. In unadjusted Cox regression, male sex, native QRS duration in patients without bundle branch block, and both native and paced mean adjusted SVG azimuth predicted future PICM. After multivariable adjustment, higher tertile (tertile 3 vs tertiles 1-2) of the mean adjusted SVG azimuth before (adjusted hazard ratio 1.95; P = .047) and immediately after (adjusted hazard ratio 2.55; P=.003) pacemaker implantation remained significant predictors of PICM.

CONCLUSION

Assessment of the SVG both before and immediately after pacemaker implantation can help identify patients at elevated risk of PICM and may identify a cohort of patients who would be better served with initial biventricular or conduction system pacing.

Left Bundle Branch Area Pacing Compared to Right Ventricular Outflow Tract Septal Pacing: Mid-term Results and Learning Curve

Our study evaluated the efficacy and feasibility of left bundle branch area pacing (LBBAP) compared to right ventricular outflow tract septal pacing (RVOSP). We conducted a prospective, single-center, observational study involving 200 consecutive patients who required pacemaker implantation. The patients were divided into two groups (LBBAP and RVOSP), with 100 patients in each group. We aimed to compare the safety and efficacy, as well as the procedure and fluoroscopy times, between the two groups. Additionally, we aimed to describe the learning curve for the LBBAP group. The success and acute complication rates were similar (P = .56 vs. P = .65). The procedure time was longer in the LBBAP group compared to the RVOSP group (18 [13-28] vs. 11 [7-17] min; P < .001), while the fluoroscopy time was shorter in the LBBAP group compared to the RVOSP group (2.8 [1.3-3.7] vs. 3.1 [2-5.9] min; P = .02). The paced QRS interval was narrower in the LBBAP group (123.77 ± 10.25 vs. 159.79 ± 17.0 ms; P = .001). There were no significant differences in pacing parameters like R-wave sensing (9.6 ± 5.2 vs. 9.1 ± 4.7 mV; P = .91), bipolar impedance (685.9 ± 151.8 vs. 686.5 ± 158.6 Ω; P = .98), or pacing threshold (0.70 ± 0.29 vs. 0.64 ± 0.26 V @ 0.4 ms; P = .63). In the LBBAP group, both the procedure time (12 [10.5-15] vs. 32 [28.5-38.5] min; P < .001) and the fluoroscopy time (2 [1-4.6] vs. 5.1 [3.4-12] min; P < .01) were shorter in the last quartile (Q4) compared to the first quartile (Q1). The procedure time was similar between LBBAP Q4 and RVOSP (12 [10.5-15] vs. 11 [7-17] min; P = .33). LBBAP is as safe as RVOSP and achieves a narrower paced QRS compared to RVOSP. After a rapid learning curve, a shorter fluoroscopy time and a similar procedure time can be achieved.

Comparison of Procedural Outcomes of Lumenless Fixed-Helix Versus Stylet-Driven Extendable-Helix Lead Systems in Left Bundle Branch Pacing: COMPARE LBBP

BACKGROUND

Left bundle branch pacing (LBBP) has emerged as a safe and effective alternative to right ventricular pacing. Traditionally, LBBP is performed with lumenless lead (LLL); however, the use of stylet-driven lead (SDL) is on rise. We aimed to assess acute success and procedural outcomes of SDL versus LLL for LBBP.

METHODS

One hundred consecutive patients with bradyarrhythmia, indication of cardiac resynchronization therapy, or ablate and pace strategy were randomized in a 1:1 fashion to the SDL and LLL arms. Tendril STS lead with a CPS Locator 3D catheter and SelectSecure 3830 lead with a C315HIS catheter were used in the SDL and LLL arms, respectively. LBBP was confirmed by standard criteria with measurements done on Labsystem Pro.

RESULTS

Patients in the LLL arm were significantly younger (71.9±11 versus 76.4±8.9 years; P=0.02); all other baseline characteristics were not significantly different. Acute success in LBBP was similar with SDL versus LLL (90% versus 92%; P=0.7). In patients with successful LBBP, screw attempts were not significantly different between the groups (2.3±1.7 in SDL versus 1.9±1.3 in LLL; P=0.2). Implant duration (11±9.6 versus 9.9±7.1 minutes; P=0.4), mean fluoroscopy dose (65.3±82.7 versus 53.5±50.5 mGy; P=0.5), and fluoroscopy time (7.8±4.8 versus 7.4±4 minutes; P=0.7) were also not different in the SDL versus the LLL arm, respectively. Incidence of lead failure (P=0.6), microdislodgement (P=1), and macrodislodgement (P=0.6) were not significantly different. Pacing threshold was comparable at implant and on follow-up at 1, 3, and 6 months.

CONCLUSIONS

LBBP was feasible with both lead systems with similar success rate and low capture threshold. No significant difference was observed in procedure duration or fluoroscopy use. No major complications were recorded with either lead.

REGISTRATION

URL: https://www.anzctr.org.au; Unique identifier: ACTRN12624000304538.

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.

Atrial pacing improves mitochondrial function in peripheral blood mononuclear cells in patients with cardiac implantable electronic devices

Mitochondrial dysfunction contributes significantly to the development of atrial fibrillation (AF). Conflicting data regarding the atrial pacing and the risk of AF existed, and the impact of atrial pacing on mitochondrial function remains unknown. Therefore, we sought to examine the association between atrial pacing percentage and mitochondrial function in patients with cardiovascular implantable electronic devices (CIEDs) with atrial pacing capability. This is a cross-sectional study involving 183 patients with CIEDs with atrial pacing capability. The oxidative stress and mitochondrial function were determined in peripheral blood mononuclear cells (PBMCs). Among 183 patients, 55.7% had permanent pacemakers, 7.7% had defibrillators, and 36.6% had cardiac resynchronization therapy. Mean age was 67.5 ± 14.7 yr with 51% being male. Mean left ventricular ejection fraction (LVEF) was 53.9 ± 16.8%. We demonstrated that the presence of atrial pacing above 50% correlated with higher levels of mitochondrial spared respiratory capacity (P = 0.043) and coupling efficiency (P = 0.045). After adjusting with multiple linear regression for age, sex, LVEF, history of AF, sick sinus syndrome, comorbidities, estimated glomerular filtration rate (eGFR), cardiac resynchronization therapy (CRT), and percentage of ventricular pacing, our findings revealed a statistically significant association between a higher percentage of atrial pacing and increased spared respiratory capacity (β, 0.217, P = 0.046), lower nonmitochondrial respiration (β, -0.230; P = 0.023), and proton leak (β, -0.247; P = 0.022). We demonstrated that atrial pacing enhances mitochondrial performance in PBMCs and left ventricular contractile performance in patients with CIEDs. This observation may serve as an additional support for the preventive effect of atrial pacing in the prevention of atrial arrhythmia.NEW & NOTEWORTHY Atrial pacing enhances mitochondrial spare respiratory capacity and reduces proton leak. This finding may provide further evidence supporting the preventive role of atrial pacing in reducing the risk of atrial fibrillation in patients with cardiac implantable electronic devices.

Left Bundle Branch Pacing for Bradycardia in Non-obstructive Hypertrophic Cardiomyopathy Patients: Feasibility, Safety, and Effect

PURPOSE

Left bundle branch pacing (LBBP) is as an innovative physiological pacing approach. The research on LBBP in non-obstructive hypertrophic cardiomyopathy (NOHCM) patients is scarce. This study aimed to assess the feasibility, safety, and effect of LBBP in bradycardia NOHCM patients with permanent pacemaker (PPM) implantation indication.

METHODS

Thirteen consecutive patients with NOHCM who received LBBP were retrospectively enrolled as a hypertrophic cardiomyopathy (HCM) group. Following 1:3 matching, 39 patients without HCM were randomly matched as a control group. Echocardiographic index and pacing parameters were collected.

RESULTS

The successful LBBP was achieved in 96.2% of all cases (50/52), and the success rate of the HCM group was 92.3% (12/13). In the HCM group, the paced QRS duration (from the pacing stimulus to QRS end) was 145.6±20.8 ms. The stimulus to left ventricular activation time (s-LVAT) was 87.4±15.2 ms. In the control group, the paced QRS duration was 139.4±17.2 ms, and the s-LVAT was 79.9±14.1 ms. During the implantation, R-wave sensing and the pacing threshold of the HCM group were significantly higher than the control group (20.2±10.5 vs 12.5±5.9 mV, P < 0.05; 0.8±0.3 vs 0.6±0.2V/0.4 ms, P < 0.05). In addition, the fluoroscopic duration and procedural duration were longer in the HCM group (14.8±8.3 vs 10.3±6.6min, P = 0.07; 131.8±50.5 vs 101.4±41.6 min, P < 0.05). The lead insertion depth was 15±2 mm in the HCM group, and no procedure-related complications occurred. During the 12-month follow-up, pacing parameters remained stable and were of no significance in the two groups. The cardiac function did not deteriorate, and the left ventricular outflow tract gradient (LVOTG) did not increase in the follow-up.

CONCLUSION

LBBP might be feasible and safe for NOHCM patients with conventional bradycardia pacing indication, and there is no deterioration in cardiac function and LVOTG of patients with NOHCM.

Outcomes of Surgical Versus Transcatheter Aortic Valve Replacement in Obese Patients: A Systematic Review and Meta-Analysis

Transcatheter aortic valve implantation (TAVI) has been increasingly preferred over surgical aortic valve replacement (SAVR) for treating patients with severe aortic stenosis and intermediate to high surgical risk. Recent studies have indicated that obesity may confer protective benefits in cardiac surgery, known as the obesity paradox. We conducted a systematic review and meta-analysis to explore how obesity influences outcomes of TAVI versus SAVR. We searched and reviewed relevant studies comparing TAVI and SAVR in obese patients with aortic stenosis indexed in PubMed, Embase, and Scopus databases. Data from 5 studies with 16,161 patients (TAVI, n = 2951; SAVR, n = 13,210) were included. There was a lower incidence of postprocedural in-hospital mortality [risk ratio (RR), 0.64; 95% confidence interval (CI), 0.41-0.98; P = 0.04], acute kidney injury (RR, 0.53; 95% CI, 0.38-0.73; P = 0.0001), and shorter duration of in-hospital stay (mean difference: -3.35; 95% CI, -4.93 to -1.76; P = 0.0001) in TAVI versus SAVR. There was no significant difference in the risk of postoperative stroke (RR, 0.93; 95% CI, 0.29-3.02; P = 0.91), major bleeding (RR, 0.71; 95% CI, 0.47-1.07; P = 0.10), and myocardial infarction (RR, 0.64; 95% CI, 0.39-1.06; P = 0.08) between TAVI and SAVR. Higher incidences of PPM implantation (RR, 2.0; 95% CI, 1.38-2.90; P = 0.0003) and major vascular complications (RR, 1.51; 95% CI, 1.01-2.27; P = 0.05) were observed with TAVI. In obese patients, TAVI offers similar results as in the general population when compared with SAVR, except for increased vascular complications. An individualized approach can lead to optimal outcomes in this subpopulation.

Observational study of left bundle branch area pacing: implantation of the solia S lead using the selectra 3D sheath at an inclined angle

BACKGROUND

Left Bundle Branch Area Pacing (LBBaP) is a cardiac pacing technique designed to mimic the natural conduction system of the heart. Traditional right ventricular apical pacing has been associated with increased risks of heart failure and atrial fibrillation. This study investigates the stability and safety of LBBaP using the Selectra 3D sheath (Biotronik) with an inclined angle for implanting the Solia S lead (Biotronik, SE & Co, KG).

METHODS

A single-center retrospective study was conducted on 25 patients who underwent LBBaP implantation using the Selectra 3D sheath at our hospital. The procedure involved inserting the Solia S lead into the interventricular septum at an inclined angle. Surgical and postoperative data were collected, including the success rate, depth and angle of electrode insertion, complications, and follow-up data.

RESULTS

The success rate of LBBaP implantation was 92%. The length of electrode insertion into the interventricular septum ranged from 12 to 23.0 mm, with an average of 18.1 ± 3.08 mm. The angle formed between the electrode and the septum ranged from 0° to 57.3°, with an average of 35.14°±14.31°. During the 3-month follow-up period, pacing parameters remained stable, and no complications were reported.

CONCLUSIONS

LBBaP implantation using the Selectra 3D sheath with an inclined angle for the Solia S implantation demonstrates stability and safety. The procedure boasts a high success rate and offers an effective option for LBBaP implantation.

Ventricular activation pattern of left ventricular septal pacing in a canine model

BACKGROUND

Left bundle branch pacing (LBBP) is a feasible and effective physiological pacing technique. The QRS morphology of left ventricular septal pacing (LVSP) is similar to that of LBBP. The ventricular activation pattern of LBBP is well-known, whereas the pattern of LVSP still needs further investigation. The present study aimed to determine ventricular activation pattern difference between LVSP and LBBP in a canine model.

METHOD

All six canines underwent successful LBBP and LVSP through trans-ventricular septum using intracardiac echocardiography and intracardiac electrogram. Their hearts were isolated and stained with Lugol's iodine to determine the position of the pacing lead. The activation sequences of the left ventricular myocardium and His-Purkinje system were recorded by placing multiple electrode catheters.

RESULTS

First, the left His-Purkinje system in LVSP was activated simultaneously from apical and basal regions to the left ventricular middle septal region, whereas the left ventricular septal myocardium was activated from the apical to basal region. The left His-Purkinje system activation in LBBP occurred in the direction of the apex from the pacing lead, but the left ventricular septal myocardium was activated in the apical to basal direction. Furthermore, the left intraventricular electrical synchrony was similar between LVSP and LBBP as determined by mapping the left ventricular septal to free wall activation time (46.7 ± 1.8 ms vs. 45.0 ± 1.4 ms, p = 0.11).

CONCLUSION

The ventricular activation sequence of LVSP was similar to LBBP. LVSP can capture LBB due to the wide distribution of LBB. These findings suggest a rationale for clinical application of LVSP.

Chronic Right Ventricular Pacing Post-Transcatheter Aortic Valve Replacement Attenuates the Benefit on Left Ventricular Function

Background: Conduction abnormality post-transcatheter aortic valve implantation (TAVI) remains clinically significant and usually requires chronic pacing. The effect of right ventricular (RV) pacing post-TAVI on clinical outcomes warrants further studies. Methods: We identified 147 consecutive patients who required chronic RV pacing after a successful TAVI procedure and propensity-matched these patients according to the Society of Thoracic Surgeons (STS) risk score to a control group of patients that did not require RV pacing post-TAVI. We evaluated routine echocardiographic measurements and performed offline speckle-tracking strain analysis for the purpose of this study on transthoracic echocardiographic (TTE) images performed at 9 to 18 months post-TAVI. Results: The final study population comprised 294 patients (pacing group n = 147 and non-pacing group n = 147), with a mean age of 81 ± 7 years, 59% male; median follow-up was 354 days. There were more baseline conduction abnormalities in the pacing group compared to the non-pacing group (56.5% vs. 41.5%. p = 0.01). Eighty-eight patients (61.6%) in the pacing group required RV pacing due to atrioventricular (AV) conduction block post-TAVI. The mean RV pacing burden was 44% in the pacing group. Left ventricular ejection fraction (LVEF) was similar at follow-up in the pacing vs. non-pacing groups (57 ± 13.0%, 59 ± 11% p = 0.31); however, LV global longitudinal strain (-12.7 ± 3.5% vs. -18.8 ± 2.7%, p < 0.0001), LV apical strain (-12.9 ± 5.5% vs. 23.2 ± 9.2%, p < 0.0001), and mid-LV strain (-12.7 ± 4.6% vs. -18.7 ± 3.4%, p < 0.0001) were significantly worse in the pacing vs. non-pacing groups. Conclusions: Chronic RV pacing after the TAVI procedure is associated with subclinical LV systolic dysfunction within 1.5 years of follow-up.

Long-Term Outcomes Associated With Permanent Pacemaker Implantation in Low-Risk Surgical Aortic Valve Replacement

Background

Permanent pacemaker implantation is associated with an increased risk of mortality and heart failure after surgical aortic valve replacement (SAVR).

Objectives

The purpose of this study was to analyze long-term prognosis of permanent pacemaker implantation following SAVR on low-risk patients.

Methods

This nationwide, population-based, observational cohort study included all patients who underwent SAVR in Sweden between 2001 and 2018 with low surgical risk, defined as logistic EuroSCORE I <10% or EuroSCORE II <4%. Patients received a permanent pacemaker implantation within 30 days after SAVR. Main outcomes were all-cause mortality, heart failure hospitalization, and endocarditis. Regression standardization addressed confounding.

Results

We included 19,576 patients with low surgical risk. Of these, 732 (3.7%) patients received a permanent pacemaker within 30 days after SAVR. The mean age was 68 years and 33% were women. We found no difference in all-cause mortality between patients who received a pacemaker compared to those who did not (absolute survival difference at 17 years: 0.1% (95% CI: -3.6% to 3.8%). After 17 years, the estimated cumulative incidence of heart failure in patients who received a pacemaker was 28% (95% CI: 24%-33%) vs 20% (95% CI: 19%-22%) in patients who did not (absolute difference 8.2% [95% CI: 3.8%-13%]). We found no difference in endocarditis between the groups.

Conclusions

We found an increased incidence of heart failure in patients with low surgical risk who received a permanent pacemaker after SAVR. Permanent pacemaker implantation was not associated with all-cause mortality or endocarditis. Efforts should be made to avoid the need for permanent pacemaker following SAVR.

Enhancing cardiac pacing strategies: a review of conduction system pacing compared with right and biventricular pacing and their influence on myocardial function

Traditional right ventricular pacing (RVP) has been linked to the deterioration of both left ventricular diastolic and systolic function. This worsening often culminates in elevated rates of hospitalization due to heart failure, an increased risk of atrial fibrillation, and increased morbidity. While biventricular pacing (BVP) has demonstrated clinical and echocardiographic improvements in patients afflicted with heart failure and left bundle branch block, it has also encountered significant challenges such as a notable portion of non-responders and procedural failures attributed to anatomical complexities. In recent times, the interest has shifted towards conduction system pacing, initially, His bundle pacing, and more recently, left bundle branch area pacing, which are seen as promising alternatives to established methods. In contrast to other approaches, conduction system pacing offers the advantage of fostering more physiological and harmonized ventricular activation by directly stimulating the His-Purkinje network. This direct pacing results in a more synchronized systolic and diastolic function of the left ventricle compared with RVP and BVP. Of particular note is the capacity of conduction system pacing to yield a shorter QRS, conserve left ventricular ejection fraction, and reduce rates of mitral and tricuspid regurgitation when compared with RVP. The efficacy of conduction system pacing has also been found to have better clinical and echocardiographic improvement than BVP in patients requiring cardiac resynchronization. This review will delve into myocardial function in conduction system pacing compared with that in RVP and BVP.

Cough-induced sudden acute chest pain and massive left hemothorax soon after pacemaker implantation

A 74-year-old man who recently undergone a definitive pacemaker implantation with an apical septal active lead fixation presented to the emergency department because of a new-onset acute chest pain that began soon after cough episodes. Pacemaker interrogation reported an increased bipolar pacing threshold (3.25 V at 1 ms). Contrast-enhanced chest CT scan and percutaneous angiography revealed the sequential perforation of the right ventricular apex and the left internal mammary artery by the ventricular pacemaker lead. Successful percutaneous embolization of the LIMA, blood transfusion and thoracentesis were then performed, and the patient subsequently underwent a percutaneous ventricular lead extraction followed by re-implantation, with an uneventful follow-up after 2 years. This unique case report highlights a potential rare complication of the active fixation of the ventricular lead at the apical interventricular septum and should lead the clinicians to keep in mind right ventricular perforation, even without cardiac tamponade, in patients presenting for cardio-pulmonary symptoms soon after pacemaker implantation.

Paced QRS morphology mimicking complete left bundle branch block induced by right ventricular pacing is associated with pacing-induced cardiomyopathy

INTRODUCTION

Right ventricular (RV) pacing sometimes causes left ventricular (LV) systolic dysfunction, also known as pacing-induced cardiomyopathy (PICM). However, the association between specifically paced QRS morphology and PICM development has not been elucidated. This study aimed to investigate the association between paced QRS mimicking a complete left bundle branch block (CLBBB) and PICM development.

METHODS

We retrospectively screened 2009 patients who underwent pacemaker implantation from 2010 to 2020 in seven institutions. Patients who received pacemakers for an advanced atrioventricular block or bradycardia with atrial fibrillation, baseline LV ejection fraction (LVEF) ≥ 50%, and echocardiogram recorded at least 6 months postimplantation were included. The paced QRS recorded immediately after implantation was analyzed. A CLBBB-like paced QRS was defined as meeting the CLBBB criteria of the American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society in 2009. PICM was defined as a ≥10% LVEF decrease, resulting in an LVEF of <50%.

RESULTS

Among the 270 patients analyzed, PICM was observed in 38. Baseline LVEF was lower in patients with PICM, and CLBBB-like paced QRS was frequently observed in PICM. Multivariate analysis revealed that low baseline LVEF (odds ratio [OR]: 0.93 per 1% increase, 95% confidence interval [CI]: 0.89-0.98, p = 0.006) and CLBBB-like paced QRS (OR: 2.69, 95% CI: 1.25-5.76, p = 0.011) were significantly associated with PICM development.

CONCLUSION

CLBBB-like paced QRS may be a novel risk factor for PICM. RV pacing, which causes CLBBB-like QRS morphology, may need to be avoided, and patients with CLBBB-like paced QRS should be followed-up carefully.

Concepts of Cardiac Dyssynchrony and Dynamic Approach

Cardiac conduction involves electrical activity from one myocyte to another, creating coordinated contractions in each. Disruptions in the conducting system, such as left bundle branch block (LBBB), can result in premature activation of specific regions of the heart, leading to heart failure and increased morbidity and mortality. Structural alterations in T-tubules and the sarcoplasmic reticulum can lead to dyssynchrony, a condition that can be treated by cardiac resynchronization therapy (CRT), which stands as a cornerstone in this pathology. The heterogeneity in patient responses underscored the necessity of improving the diagnostic approach. Vectocardiography, ultra-high-frequency ECG, 3D echocardiography, and electrocardiographic imaging seem to offer advanced precision in identifying optimal candidates for CRT in addition to the classic diagnostic methods. The advent of His bundle pacing and left bundle branch pacing further refined the approach in the treatment of dyssynchrony, offering more physiological pacing modalities that promise enhanced outcomes by maintaining or restoring the natural sequence of ventricular activation. HOT-CRT emerges as a pivotal innovation combining the benefits of CRT with the precision of His bundle or left bundle branch area pacing to optimize cardiac function in a subset of patients where traditional CRT might fall short.

Predictors, clinical impact, and management strategies for conduction abnormalities after transcatheter aortic valve replacement: an updated review

Transcatheter aortic valve replacement (TAVR) has increasingly become a safe, feasible, and widely accepted alternative surgical treatment for patients with severe symptomatic aortic stenosis. However, the incidence of conduction abnormalities associated with TAVR, including left bundle branch block (LBBB) and high-degree atrioventricular block (HAVB), remains high and is often correlated with risk factors such as the severity of valvular calcification, preexisting conditions in patients, and procedural factors. The existing research results on the impact of post-TAVR conduction abnormalities and permanent pacemaker (PPM) requirements on prognosis, including all-cause mortality and rehospitalization, remain contradictory, with varied management strategies for post-TAVR conduction system diseases across different institutions. This review integrates the latest research in the field, offering a comprehensive discussion of the mechanisms, risk factors, consequences, and management of post-TAVR conduction abnormalities. This study provides insights into optimizing patient prognosis and explores the potential of novel strategies, such as conduction system pacing, to minimize the risk of adverse clinical outcomes.

Delivery catheter system carries more physiological right ventricular septal pacing than stylet system

INTRODUCTION

The Mt. FUJI multicenter trial demonstrated that a delivery catheter system had a higher rate of successful right ventricular (RV) lead deployment on the RV septum (RVS) than a conventional stylet system. In this subanalysis of the Mt. FUJI trial, we assessed the differences in electrocardiogram (ECG) parameters during RV pacing between a delivery catheter system and a stylet system and their associations with the lead tip positions.

METHODS

Among 70 patients enrolled in the Mt FUJI trial, ECG parameters, RV lead tip positions, and lead depth inside the septum assessed by computed tomography were compared between the catheter group (n = 36) and stylet group (n = 34).

RESULTS

The paced QRS duration (QRS-d), corrected paced QT (QTc), and JT interval (JTc) were significantly shorter in the catheter group than in the stylet group (QRS-d: 130 ± 19 vs. 142 ± 15 ms, p = .004; QTc: 476 ± 25 vs. 514 ± 20 ms, p < .001; JTc: 347 ± 24 vs. 372 ± 17 ms, p < .001). This superiority of the catheter group was maintained in a subgroup analysis of patients with an RV lead tip position at the septum. The lead depth inside the septum was greater in the catheter group than in the stylet group, and there was a significant negative correlation between the paced QRS-d and the lead depth.

CONCLUSION

Using a delivery catheter system carries more physiological depolarization and repolarization during RVS pacing and deeper screw penetration in the septum in comparison to conventional stylet system. The lead depth could have a more impact on the ECG parameters rather than the type of pacing lead.

Age-Stratified Clinical Outcome in Patients with Known Heart Failure Who Receive Pacemaker, Resynchronization Therapy, or Defibrillator Implants

INTRODUCTION

Patients with heart failure (HF) and bradycardia may be eligible for different types of cardiac implantable electronic devices (CIED), depending on the presence of atrioventricular conduction disease, age, and comorbidities. We aimed to assess the prognosis for these patients, after CIED implantation, stratified for the type of CIED device.

METHODS

All patients with preexisting HF diagnosis who received a CIED with a right ventricular lead during the period 2005-2018 in Sweden were identified via the pacemaker registry. Data were crossmatched with the population registry and national disease registries. The outcome was 5-year risk of HF hospitalization and mortality.

RESULTS

A total of 37,745 patients were included in the study. Comparing demographics for implantable cardioverter defibrillator versus pacemaker implants, median age was 66 years versus 83 years, 20% versus 41% were female, 64% versus 50% had ischemic heart disease, and 35% versus 67% had atrial fibrillation (all p < 0.001). Five-year mortality was highest in single-chamber pacemaker recipients (61% compared to average 40%, p < 0.001), but the proportion of cardiovascular mortality was highest for cardiac resynchronization therapy (CRT) recipients (68% vs. 63% p < 0.001). Adjusted mortality was higher for pacemaker patients in all age decile groups (ranging from <60 to >90 years old, all p < 0.001), HF hospitalization occurred in 28% (dual-chamber pacemaker) to 39% (CRT-P) of patients, and cause of death was HF in 15% (dual-chamber pacemaker) to 25% (CRT-D), all p < 0.001.

CONCLUSION

In this large real-world cohort of CIED-treated patients with prior HF, demography and mortality data indicate that clinicians chose devices according to the overall status of the patient. HF-related events occurred in all groups but were more common in CRT-treated patients.

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.

Single operator experience, learning curve, outcomes, and insights gained with conduction system pacing

BACKGROUND

Conduction system pacing (CSP) is increasingly utilized to prevent and correct dyssynchrony. Barriers to CSP adoption include limited training, methodologic variability, laboratory slot allocation, and few data on learning curves. We report learning curves/clinical outcomes from a single experienced electrophysiologist who was new to CSP, and share gained insights.

METHODS

Retrospective analysis of all patients who underwent attempted CSP implantation (2016-2023). Patient characteristics, ECGs, echocardiograms, fluoroscopy/procedure times, lead data were recorded at implant and follow-up.

RESULTS

CSP leads were implanted successfully in 167/191(87.4%) patients with a follow-up of 278 ± 378 days. His-bundle pacing (HBP = 59) and left-bundle-area pacing (LBAP = 108) had similar procedure/fluoroscopy times, QRS duration decreases, and ejection fraction improvements (all p > NS). Eight HBP lead revisions were required for high capture thresholds LBAP demonstrated lower pacing thresholds, higher lead impedances, and greater R-wave amplitudes at implant and follow-up. After 25 HBP cases, implant pacing thresholds, fluoroscopy, procedural times did not decrease. After 25 LBAP cases, there were significant decreases in all these parameters (p < 0.05). A separate analysis in LBAP patients with recorded Purkinje signals showed no differences in paced ECG characteristics between patients with pre- QRS Purkinje signals versus patients with Purkinje signals post-QRS onset.

CONCLUSIONS

Experienced implanters who are new to CSP can achieve steady-state procedural/fluoroscopy times after a learning curve of 25 implants. LBAP showed lower capture thresholds and higher success rates. Adequate depth of lead deployment (as determined by published parameters) does not require Purkinje potential to be pre-QRS. Operators new to CSP.can forego HBP and directly implement LBAP.

High-rate pacing suppresses Torsade de Pointes arrhythmias and reduces spatial dispersion of repolarization in the chronic AV-block dog model

Background: An electrical storm of Torsade de Pointes arrhythmias (TdP) can be reproducibly induced in the anesthetized chronic AV-block (CAVB) dog by infusion of the IKr-blocker dofetilide. Earlier studies showed that these arrhythmias 1) arise from locations with high spatial dispersion in repolarization (SDR) and 2) can be suppressed by high-rate pacing. We examined whether suppression of TdP by high-rate pacing is established through a decrease in SDR in the CAVB dog. Methods: Dofetilide (25 μg/kg in 5 min) was administered to 5 anesthetized CAVB dogs to induce TdP arrhythmias. During the experiments, animals were continuously paced from the right ventricular apex at 50 beats/minute (RVA50). Upon TdP occurrence and conversion, RVA pacing was consecutively set to 100, 80 and 60 beats/minute for 2 min, referred to as pacing blocks. To determine the additional anti-arrhythmic effects of HRP over defibrillation alone, the number of arrhythmic events and SDR at RVA100 were compared to data from three previously conducted experiments, in which dogs underwent the same experimental protocol but were paced at RVA60 upon TdP occurrence (RVA60retro). In all experiments, recordings included surface electrocardiogram and mapping by 56 intramural needles, each recording four electrograms, evenly inserted into the ventricular walls and septum. For each pacing block, the number of ectopic beats (EB), and TdP severity were scored. SDR was quantified as the average difference in repolarization time within four squared needles (SDRcubic). Results: In 4 out of 5 animals, pacing at RVA100 suppressed TdP occurrence. One dog could not be converted by defibrillation after the initial TdP. Compared to RVA50, pacing at RVA100, but not RVA80 and RVA60, significantly reduced the TdP score (78 ± 33 vs. 0 ± 0, p < 0.05 and vs. 12.5 ± 25 and 25 ± 50, both p > 0.05). The reduction in TdP score was reflected by a significant decrease in SDRcubic (125 ± 46 ms before TdP vs. 49 ± 18 ms during RVA100, p < 0.05), and SDR was smaller than in the RVA60retro animals (101 ± 52 ms, p < 0.05 vs. RVA100). Conclusion: In CAVB dogs, high-rate pacing effectively suppresses TdP, which, at least in part, results from a spatial homogenization of cardiac repolarization, as reflected by a decrease in SDR.

Conduction system pacing and atrioventricular node ablation in heart failure: The PACE-FIB study design

AIMS

Atrial fibrillation (AF) worsens the prognosis of patients with heart failure (HF). Successful treatments are still very scarce for those with permanent AF and preserved (HFpEF) or mildly reduced (HFmrEF) ejection fraction. In this study, the long-term benefits and safety profile of heart rate regularization through left-bundle branch pacing (LBBP) and atrioventricular node ablation (AVNA) will be explored in comparison with pharmacological rate-control strategy.

METHODS AND RESULTS

The PACE-FIB trial is a multicentre, prospective, open-label, randomized (1:1) clinical study that will take place between March 2022 and February 2027. A total of 334 patients with HFpEF/HFmrEF and permanent AF will receive either LBBP followed by AVNA (intervention arm) or optimal pharmacological treatment for heart rate control according to European guideline recommendations (control arm). All patients will be followed up for a minimum of 36 months. The primary outcome measure will be the composite of all-cause mortality, HF hospitalization, and worsening HF at 36 months. Other secondary efficacy and safety outcome measures such as echocardiographic parameters, functional status, and treatment-related adverse events, among others, will be analysed too.

CONCLUSION

LBBP is a promising stimulation mode that may foster the clinical benefit of heart rate regularization through AV node ablation compared with pharmacological rate control. This is the first randomized trial specifically addressing the long-term efficacy and safety of this pace-and-ablate strategy in patients with HFpEF/HFmrEF and permanent AF.

Feasibility and safety of left bundle branch area pacing for patients with stable coronary artery disease

Aims

Stable coronary artery disease (CAD) is a prevalent comorbidity among patients requiring pacemaker implantation. This comorbidity may have an impact on the safety and prognosis of traditional right ventricular pacing (RVP). Left bundle branch area pacing (LBBaP) is a new physiological pacing modality. Our aim was to investigate the feasibility and safety of LBBaP in patients with the stable CAD.

Methods

This study included 309 patients with symptomatic bradycardia who underwent LBBaP from September 2017 to October 2021. We included 104 patients with stable CAD (CAD group) and 205 patients without CAD (non-CAD group). Additionally, 153 stable CAD patients underwent RVP, and 64 stable CAD patients underwent His-bundle pacing (HBP) were also enrolled in this study. The safety and prognosis of LBBaP was assessed by comparing pacing parameters, procedure-related complications, and clinical events.

Results

During a follow-up period of 17.4 ± 5.3 months, the safety assessment revealed that the overall rates of procedure-related complications were similar between the stable CAD group and the non-CAD group (7.7% vs. 3.9%). Likewise, similar rates of heart failure hospitalization (HFH) (4.8% vs. 3.4%, stable CAD vs. non-CAD) and the primary composite outcome including death due to cardiovascular disease, HFH, or the necessity for upgrading to biventricular pacing (6.7% vs. 3.9%, stable CAD vs. non-CAD), were observed. In stable CAD patients, LBBaP demonstrated lower pacing thresholds and higher R wave amplitudes when compared to HBP. Additionally, LBBaP also had significantly lower occurrences of the primary composite outcome (6.7% vs. 19.6%, P = 0.003) and HFH (4.8% vs. 13.1%, P = 0.031) than RVP in stable CAD patients, particularly among patients with the higher ventricular pacing (VP) burden (>20% and >40%).

Conclusion

Compared with non-CAD patients, LBBaP was found to be attainable in stable CAD patients and exhibited comparable mid-term safety and prognosis. Furthermore, in the stable CAD population, LBBaP has demonstrated more stable pacing parameters than HBP, and better prognostic outcomes compared to RVP.

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 ).

Transcatheter Aortic Valve Implantation and Conduction Disturbances: Focus on Clinical Implications

Transcatheter aortic valve implantation (TAVI) is an established alternative to surgery in patients with symptomatic severe aortic stenosis and has expanded its indications to even low-surgical-risk patients. Conduction abnormalities (CA) and permanent pacemaker (PPM) implantations remain a relatively common finding post TAVI due to the close proximity of the conduction system to the aortic root. New onset left bundle branch block (LBBB) and high-grade atrioventricular block are the most commonly reported CA post TAVI. The overall rate of PPM implantation post TAVI varies and is related to pre- and intra-procedural factors. Therefore, when screening patients for TAVI, Heart Teams should take under consideration the various anatomical, pathophysiological and procedural conditions that predispose to CA and PPM requirement after the procedure. This is particularly important as TAVI is being offered to younger patients with longer life-expectancy. Herein, we highlight the incidence, predictors, impact and management of CA in patients undergoing TAVI.

Transcatheter Aortic Valve Implantation and Cardiac Conduction Abnormalities: Prevalence, Risk Factors and Management

Over the last decades, transcatheter aortic valve implantation (TAVI) or replacement (TAVR) has become a potential, widely accepted, and effective method of treating aortic stenosis in patients at moderate and high surgical risk and those disqualified from surgery. The method evolved what translates into a noticeable decrease in the incidence of complications and more beneficial clinical outcomes. However, the incidence of conduction abnormalities related to TAVI, including left bundle branch block and complete or second-degree atrioventricular block (AVB), remains high. The occurrence of AVB requiring permanent pacemaker implantation is associated with a worse prognosis in this group of patients. The identification of risk factors for conduction disturbances requiring pacemaker placement and the assessment of their relation to pacing dependence may help to develop methods of optimal care, including preventive measures, for patients undergoing TAVI. This approach is crucial given the emerging evidence of no worse outcomes for intermediate and low-risk patients undergoing TAVI in comparison to surgical aortic valve replacement. This paper comprehensively discusses the mechanisms, risk factors, and consequences of conduction abnormalities and arrhythmias, including AVB, atrial fibrillation, and ventricular arrhythmias associated with aortic stenosis and TAVI, as well as provides insights into optimized patient care, along with the potential of conduction system pacing and cardiac resynchronization therapy, to minimize the risk of unfavorable clinical outcomes.

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.

Conduction system pacing on track to replace CRT? Review of current evidence and prospects of conduction system pacing

Conduction system pacing (CSP) has been emerging over the last decade as a pacing option instead of conventional right ventricular (RV) pacing and biventricular (BiV) pacing. Numerous case reports, some observational studies and a few randomized control trials have looked at optimum pacing strategies for heart failure (HF) with left bundle branch block (LBBB) or cases where left ventricular (LV) dysfunction is anticipated due to chronic RV pacing (RVP). Evolution of pacing strategies from standard RVP to septal RVP, BiV pacing and now CSP have shown improving hemodynamic responses and possible ease of implantation of CSP systems. In this review article, we review the literature on the evolution of CSP and common scenarios where it might be beneficial.

Consecutive Experience with Left Bundle Branch Area Pacing in a High-Volume Australian Centre

INTRODUCTION

Left-bundle branch area pacing (LBBAP) is a relatively new technique for conduction system pacing. Australian safety and efficacy data is currently lacking. We aim to evaluate the learning curve, medium-term safety, and lead performance in a high-volume Australian setting.

METHODS

We performed a retrospective cohort study of 200 consecutive LBBAP procedures performed by a single operator at two centres between January 2019 and May 2020. Left bundle branch area pacing was performed predominantly via left subclavian access using a 69 cm Medtronic SelectSecure 3830 pacing lead and a preformed non-steerable C315-His sheath. Procedural success was defined as evidence of left septal or left bundle branch area capture as evidenced by a right bundle branch block-like paced morphology. Procedural characteristics, and follow-up (including lead performance) data were collected. Procedural efficiency over time, as well as safety data, were collected.

RESULTS

Median age was 78.26 years (interquartile range [IQR] 71-85), 37% were female. Atrial fibrillation was present in 22%. The left ventricular ejection fraction <50% in 24%, atrioventricular (AV) block was present in 43.5%, left bundle branch block in 22.5% and right bundle branch block in 24.5%. Acute procedural success was 91.5%. Implant threshold was 0.6V @ 0.5 ms, and 0.75V @ 0.5 ms at 11.9 months of follow-up. The QRS was significant reduced (baseline 134 ms vs implant 114 ms, p<0.001) There was a reduction in procedural time and X-ray dose over the course of the study. There were no complications specific to LBBAP.

CONCLUSION

LBBAP appears to be a safe and effective pacing strategy. The QRS duration was significantly reduced compared to baseline. There appears to be an early learning curve with LBBAP.

Outcomes of Atrioventricular Node Ablation and Pacing in Patients with Heart Failure and Atrial Fibrillation: From Cardiac Resynchronization Therapy to His Bundle Pacing

Objective: To review the relevant literature on the use of atrioventricular node ablation and pacing in patients with heart failure and atrial fibrillation. Methods: APubMed/MEDLINE and SCOPUS search was performed in order to assess the clinical outcomes of atrioventricular node ablation and pacemaker implantation, as well as the complications that may occur. Results: Several clinical trials, observational analyses and meta-analyses have shown that the "pace and ablate" strategy not only improves symptoms but also can enhance cardiac performance in patients with heart failure and atrial fibrillation. Although this procedure is effective and safe, some complications may occur including worsening of heart failure, permanent fibrillation, arrhythmias and sudden death. Regarding pacemaker implantation, cardiac resynchronization therapy is shown to be the optimal choice compared to right ventricle apical pacing. His bundle pacing is a promising alternative to cardiac resynchronization therapy and has shown beneficial effects, while left bundle branch pacing is an innovative modality. Conclusions: Atrioventricular node ablation and pacemaker implantation is shown to have beneficial effects on clinical outcomes of patients with atrial fibrillation ± heart failure who do not respond or are intolerant to medical treatment. Cardiac resynchronization therapy is the treatment of choice and His bundle pacing seems to be an effective alternative way of pacing in these patients.

Impact of Right Ventricular Pacing in Patients With TAVR Undergoing Permanent Pacemaker Implantation

BACKGROUND

Long-term right ventricular pacing (VP) has been related to negative left ventricular remodeling and heart failure (HF), but there is a lack of evidence regarding the prognostic impact on transcatheter aortic valve replacement (TAVR) patients.

OBJECTIVES

The aim of the PACE-TAVI registry is to evaluate the association of high percentage of VP with adverse outcomes in patients with pacemaker implantation after TAVR.

METHODS

PACE-TAVI is an international multicenter registry of all consecutive TAVR patients who underwent permanent pacemaker implantation for conduction disturbances in the first 30 days after the procedure. Patients were divided into 2 subgroups according to the percentage of VP (<40% vs ≥40%) at pacemaker interrogation. The primary endpoint was the composite of cardiovascular mortality or hospitalization for HF.

RESULTS

A total of 377 patients were enrolled, 158 with VP <40% and 219 with VP ≥40%. After multivariable adjustment, VP ≥40% was associated with a higher incidence of the primary endpoint (HR: 2.76; 95% CI: 1.39-5.51; P = 0.004), first HF hospitalization (HR: 3.37; 95% CI: 1.50-7.54; P = 0.003), and cardiovascular death (HR: 3.77; 95% CI: 1.02-13.88; P = 0.04), while the incidence of all-cause death was not significantly different (HR: 2.17; 95% CI: 0.80-5.90; P = 0.13). Patients with VP ≥ 40% showed a higher New York Heart Association functional class both at 1 year (P = 0.009) and at last available follow-up (P = 0.04) and a nonsignificant reduction of left ventricular ejection fraction (P = 0.18) on 1-year echocardiography, while patients with VP <40% showed significant improvement (P = 0.009).

CONCLUSIONS

In TAVR patients undergoing permanent pacemaker implantation, a high percentage of right VP at follow-up is associated with an increased risk for cardiovascular death and HF hospitalization. These findings suggest the opportunity to minimize right VP through dedicated algorithms in post-TAVR patients without complete atrioventricular block and to evaluate a more physiological VP modality in patients with persistent complete atrioventricular block.

The role of contractile dyssynchrony in pacing-induced cardiomyopathy: detailed assessment using index of contractile asymmetry

AIMS

The pathophysiological effects of chronic right ventricular pacing and the role of right ventricular lead position are not well understood. Therefore, we investigated the association between left ventricular contractile dyssynchrony and pacing-induced cardiomyopathy (PICM) in patients with chronic right ventricular pacing. Furthermore, we assessed the association between right ventricular lead location and left ventricular contractile dyssynchrony.

METHODS

This was a retrospective study using data from 153 pacemaker patients with normal (≥ 50%) pre-implant left ventricular ejection fraction (LVEF). Baseline and follow-up echocardiograms were analyzed, and PICM was defined as LVEF < 50% with ≥ 10% decrease in LVEF after pacemaker implantation. Relative index of contractile asymmetry (rICA), a novel strain rate-based method, was calculated to quantify left ventricular contractile dyssynchrony between opposing walls in the three apical views. Right ventricular lead position was categorized into anterior septum, posterior septum, free wall, and apex based on contrast-enhanced cardiac computed tomography.

RESULTS

Forty-seven (31%) developed PICM. Overall contractile dyssynchrony, measured by mean rICA, was higher in the PICM group compared with the non-PICM group (1.19 ± 0.21 vs. 1.03 ± 0.19, p < 0.001). Left ventricular anterior-inferior dyssynchrony, assessed in the apical two-chamber view, was independently associated with PICM (p < 0.001). Thirty-seven (24%) leads were implanted anterior septal, 11 (7.2%) posterior septal, 74 (48.4%) apical, and 31 (20.3%) free wall. Left ventricular anterior-inferior dyssynchrony was significantly different between the four pacing lead locations (p < 0.01) with the highest rICA observed in the posterior septal group (1.30 ± 0.37).

CONCLUSIONS

PICM is significantly associated increased contractile dyssynchrony assessed by rICA. This study suggests that especially left ventricular dyssynchrony in the anterior-inferior direction is associated with PICM, and pacing the right ventricular posterior septum resulted in the highest degree of anterior-inferior dyssynchrony. Quantification of left ventricular dyssynchrony by rICA provides important insights to the potential pathophysiology of PICM and the impact of right ventricular lead position.

Paradigm Shifts in Cardiac Pacing: Where Have We Been and What Lies Ahead?

The history of cardiac pacing dates back to the 1930s with externalized pacing and has evolved to incorporate transvenous, multi-lead, or even leadless devices. Annual implantation rates of cardiac implantable electronic devices have increased since the introduction of the implantable system, likely related to expanding indications, and increasing global life expectancy and aging demographics. Here, we summarize the relevant literature on cardiac pacing to demonstrate the enormous impact it has had within the field of cardiology. Further, we look forward to the future of cardiac pacing, including conduction system pacing and leadless pacing strategies.

Electrophysiological demonstration of nonselective His-Purkinje system capture with para-Hisian pacing

BACKGROUND

The adverse effects of conventional right ventricular (RV) apical pacing prompted the search for more physiological pacing sites, such as selective and nonselective His bundle pacing (HBP), a variant of nonselective HBP (para-Hisian pacing), and mid-septal pacing. However, knowledge of their true benefit on the physiology of ventricular activation, lead stability, and pacing thresholds is limited.

METHODS AND RESULTS

We included 152 consecutive patients (mean age 61 ± 24, 63% men) in this retrospective study. Of these, 137 patients with different bradyarrhythmias underwent active fixation lead implantation at the RV apex (n = 54), para-Hisian region (n = 66), or mid interventricular septum (n = 17). Fifteen patients with ventricular preexcitation due to an accessory pathway not undergoing pacing were included as controls. A 12‑lead ECG was recorded in all patients, and cardiac electrical synchrony was assessed using the Synchromax® cross-correlation cardiac synchrony index (CSI).

RESULTS

QRS duration was prolonged in all pacing sites: from 114 ± 28 to 160 ± 29 (RV apex), from 110 ± 28 to 122 ± 29 (para-Hisian), and from 121 ± 24 to 154 ± 30 (mid interventricular septum). The CSI was significantly improved only in patients undergoing para-Hisian pacing, despite a slight widening of the QRS interval. There was no difference in pacing thresholds and sensed R-wave voltage between pacing sites. Only 1 lead, implanted at the para-Hisian region (1.5%), was dislodged towards the mid septum 48 h after implantation but did not require repositioning.

CONCLUSIONS

QRS duration was not associated with changes in CSI, meaning that QRS width does not significantly affect electrical synchrony.

Increased Risk of Heart Failure in Elderly Patients Treated with Beta-Blockers After AV Node Ablation

INTRODUCTION

Controversy exists regarding the indication of beta-blockers (BB) in different scenarios in patients with cardiovascular disease. We sought to evaluate the effect of BB on survival and heart failure (HF) hospitalizations in a sample of pacemaker-dependent patients after AV node ablation to control ventricular rate for atrial tachyarrhythmias.

METHODS

A retrospective study including consecutive patients that underwent AV node ablation was conducted in a single center between 2011 and 2019. The study's primary endpoints were the incidence of all-cause mortality, first HF hospitalization and the cumulative incidence of subsequent hospitalizations for HF. Competing risk analyses were employed.

RESULTS

A total of 111 patients with a mean age of 73.9 years were included in the study. After a median follow-up of 45.5 months, 43 patients had died (38.7%) and 31 had been hospitalized for HF (27.9%). The recurrent HF hospitalization rate was 74/1000 patients/year. Patients treated with BB had a non-significant trend to higher mortality rates and a higher risk of recurrent HF hospitalizations (incidence rate ratio 2.23, 95% confidence interval 1.12-4.44; p = 0.023).

CONCLUSION

After an AV node ablation, the use of BB is associated with an increased risk of HF hospitalizations in a cohort of elderly patients.

Electrocardiographic parameters associated with pacemaker induced cardiomyopathy

BACKGROUND

Chronic right ventricular (RV) pacing can induce left ventricular (LV) dyssynchrony and cause pacemaker induced cardiomyopathy (PiCM). Identifying which patients are at risk for PiCM is limited.

METHODS

Patients receiving RV-only permanent pacemakers (PPMs) at Duke University Medical Center between 2011 and 2017 who had normal baseline ejection fractions (EFs) were identified. Patients who developed a subsequent decrease in EF, died, or underwent cardiac resynchronization therapy, left ventricular assist device, or heart transplant without a competing cause were considered as the primary endpoint. Pre-PPM and post-PPM electrocardiograms (ECGs) were analyzed to extract scalar measurements including the lead one ratio (LOR) as well as advanced-ECG (A-ECG) features to identify predictors of PiCM. Traditional and penalized Cox regression were used to identify variables predictive of the primary endpoint.

RESULTS

Pre-PPM ECGs were evaluated for 404 patients of whom 140 (35%) experienced the primary endpoint. Predictors included female sex (hazard ratio [HR] 1.14), a T' wave in V6 (HR 1.31), a P' wave in aVL (HR 0.88), and estimated glomerular filtration rate (HR 0.88). Post-PPM ECGs were evaluated for 228 patients for whom 94 (41%) experienced the primary endpoint. Predictors included female sex (HR 0.50), age (HR 1.06), and a history of congestive heart failure (HR 1.63). Neither LOR nor A-ECG parameters were strong predictors of the primary endpoint.

CONCLUSIONS

Baseline and paced ECG data provide limited insight into which patients are at high risk for developing PiCM.

Adverse effects of right ventricular pacing on cardiac function: prevalence, prevention and treatment with physiologic pacing

Right ventricular (RV) pacing is the main treatment modality for patients with advanced atrioventricular (AV) block. Chronic RV pacing can cause cardiac systolic dysfunction and heart failure (HF). In this review, we discuss studies that have shown deleterious effects of chronic RV pacing on systolic cardiac function causing pacing-induced cardiomyopathy (PiCM), heart failure (HF), HF hospitalization, atrial fibrillation (AF) and cardiac mortality. RV apical pacing is the most widely used and studied. Adverse effects of RV pacing appear to be directly related to pacing burden and are worse in patients with pre-existing left ventricular (LV) dysfunction. Chronic RV pacing is also associated with heart failure with preserved ejection fraction (HFpEF). Mechanisms, risk factors, clinical and echocardiographic features, and strategies to minimize RV pacing-induced cardiac dysfunction are discussed in light of the latest data. Studies on biventricular (Bi-V) pacing upgrade in patients who develop RV PiCM, use of alternate RV pacing sites, de novo Bi-V pacing, and physiologic pacing using HIS bundle pacing (HBP) and left bundle area (LBBA) pacing in patients with an anticipated high RV pacing burden are discussed.

His bundle pacing versus right ventricular pacing: A comparative study

BACKGROUND

Pacing is the most effective and dependable method for treating complete atrioventricular block (AVB).

OBJECTIVE

The purpose of this study is to investigate the use of His bundle pacing (HBP) in patients with atrioventricular block.

METHODS

Patients who underwent HBP or right ventricular pacing (RVP) were enrolled and divided into two groups: the HBP group and the RVP group, respectively. We compared baseline clinical data, fluoroscopy duration, operation duration, pacing electrode parameters during the operation or follow-up, baseline QRS duration, and pacing QRS duration.

RESULTS

HBP was attempted in 48 patients and was successful in 34 patients who were included in the HBP group. In addition, 30 RVP patients were included in the RVP group. Fluoroscopy duration and operation duration were significantly longer in the HBP group compared to the RVP group. Compared to the RVP group, the HBP group had a higher pacing threshold, a lower R wave amplitude, and a shorter pacing QRS duration. At 6 months of follow-up, the pacing threshold remained higher, the R wave amplitude was significantly lower, and the end-diastolic diameter of the left ventricle was smaller in the HBP group.

CONCLUSION

HBP was safe and effective for atrioventricular block despite the longer fluoroscopy and operation duration in the HBP group when compared to the RVP group.

Electroanatomical mapping-guided left bundle branch area pacing in patients with structural heart disease and advanced conduction abnormalities

AIMS

Left bundle branch area pacing (LBBAP) can be technically challenging and fluoroscopy-intense. Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and electrogram mapping. We sought to prospectively evaluate the feasibility, safety, and outcomes of routine EAM-guided LBBAP in patients with structural heart disease (SHD) and advanced conduction abnormalities.

METHODS AND RESULTS

Consecutive patients with SHD and conduction abnormalities who underwent an attempt at EAM-guided LBBAP were included. The feasibility, safety, procedural, and mid-term outcomes were evaluated. Electrical, echocardiographic, and clinical parameters were assessed at implantation and last follow-up. Thirty-two patients (68 ± 18 years; 19% female) were included, of which 75% had intrinsic QRS > 150 ms, 53% left bundle branch block, and 25% right bundle branch block. Primary EAM-guided LBBAP was successful in 29 patients (91%). The procedural duration was 95 (70-110) min, total fluoroscopy time 0.93 (0.40-1.73) min, and total fluoroscopy dose 35.4 (20.5-77.2) cGy cm2. Paced QRS duration (QRSd) was significantly shorter than intrinsic QRSd (121.9 ± 10.7 vs. 159.2 ± 34.4 ms; P < 0.001) and remained stable during the mean follow-up of 7.0 ± 5.9 months. The LBBAP capture threshold was 0.57 ± 0.23 V/0.4 ms at implantation and remained low during follow-up (0.58 ± 0.18 V/0.5 ± 0.2 ms; P = 0.877). Overall left ventricular ejection fraction improved significantly from 44.2 ± 14.3% at baseline to 49.4 ± 13.1% at follow-up (P = 0.009), New York Heart Association class from 2.4 ± 0.6 to 1.8 ± 0.6 (P = 0.002), respectively. No complications occurred that required intervention.

CONCLUSION

Routine near-zero fluoroscopy EAM-guided LBBAP can safely be performed in patients with SHD and advanced conduction abnormalities with high success rates and favourable mid-term outcomes. Further studies are needed to investigate whether the use of EAM improves the overall outcome of conduction system pacing and to identify specific patient populations who benefit the most from EAM-guided lead implantation.

Results of Using Various Conduction System Pacing Options in Patients with Bradyarrhythmia

Chronic right ventricular myocardial pacing causes an asynchronous pattern of left ventricular activation, reduces left ventricular ejection fraction (LVEF), and may be associated with worsening of clinical outcomes in the long term. Although with the emergence of algorithms that minimize ventricular pacing it became possible to reduce the percentage of paced complexes in patients with sinus node dysfunction, permanent ventricular pacing is still inevitable in patients with high-degree atrioventricular (AV) block. The use of permanent conduction system pacing is a promising method for preserving the physiological activation of the ventricular myocardium and preventing the development of heart failure due to ventricular dyssynchrony. The aim. To analyze the immediate and long-term results of the use of conduction system pacing in patients with indications for permanent ventricular pacing. Materials and methods. This study included 18 patients with indications for permanentventricular pacing who were operated at the National Amosov Institute of Cardiovascular Surgery of the National Academy of Medical Sciences of Ukraine in the period from 01/01/2013 to 12/31/2022, in whom permanent conduction system pacing was used. There were 17 patients with bradyarrhythmias, of these 16 (88%) suffered from high-degree AV block (including 1 patient with Frederick’s syndrome and 1 (5%) patient with atrial ϐibrillation with slow ventricular response) and 1 (5%) patient with ischemic cardiomyopathy with left bundle branch block and ϐirstdegree AV block with indications for cardiac resynchronization therapy. The mean age of the patients was 55 ± 16 years (8 men, 10 women), LVEF at the time of the intervention was 56.42 ± 9.13 %, end diastolic volume 130.2 ± 23.8 ml, end systolic volume 55.1 ± 17.7 ml, diameter of the left atrium 4.01 ± 0.6 cm. The average QRS width before implantation was 116.5 ± 27.7 ms. In 6 (33%) patients, a special delivery system (С304-L69, Medtronic in 1 patient [5%], C315HIS in 5 [27%] patients) and 4.1F active ϐixation lead Medtronic 3830 Select Secure (69 or 74 cm) were used; in other cases (66%) standard 6F leads with active ϐixation and a lumen for a stylet without a delivery system were used. Results. The average follow-up period after implantation of pacemaker was 36.35 ± 29.65 months. During the observation period, LVEF was 57.07 ± 5.38 %, end diastolic volume111.5 ± 18.09 ml, end systolic volume 49.5 ± 13.4 ml, diameter of the left ventricle 3.9 ± 0.5 cm. The mean duration of paced QRS was 119.1 ± 10.09 ms. In 6 patients (33%), it was possible to demonstrate a change in the QRS width when the amplitude of ventricular stimulation was reduced, with 2 variants of transitions: 1) 4 (22%) patients with a transition from non-selective His bundle pacing (NSHBP) to selective His bundle pacing (SHBP), in 2 (11%) of these patients with a transition from SHBP with correction of right bundle branch block (RBBB) to SHBP without correction of RBBB, and then loss of capture of the myocardium of the ventricles; 2) 2 patients (11%) with a transition from NSHBP to myocardial septal ventricular pacing and further with a decrease in amplitude to the loss of capture of the myocardium of the ventricles. One (5%) patient with complete heart block had permanent non-selective left bundle branch area pacing. The other 11 (61%) patients met the criteria for parahisian pacing without visible transitions with a change in the amplitude of ventricular pacing. The average global longitudinal strain was -17.6 ± 2.7 %. The average interval from the stimulus to the peak of the R-wave in lead V6, which indicated the time of left ventricular activation, was 73.2 ± 8.7 ms. Pacing parameters were standardly set according to the primary indications, but with correction of the amplitude of ventricular stimulation relative to the thresholds of pacing of the conduction system. AV delay was corrected for the latency from the stimulus to the onset of the QRS in SHBP or for the duration of the “pseudodelta” wave in NSHBP which in both cases was the duration of the H-V interval. There were no complications in the acute or long-term postoperative period. Conclusions. Conduction system pacing is a challenge in the practice of cardiologist for treating life-threatening bradyarrhythmias and heart failure, but at the same time it is a safe method that provides physiological electrical and mechanical activation of the myocardium of the ventricles, that allows to effectively avoid the consequences of dyssynchrony due to permanent myocardial ventricular pacing.

His-bundle pacing and atrioventricular nodal ablation for noncontrolled atrial arrhythmia: A technical challenge with major clinical benefits

BACKGROUND

His-bundle pacing (HBP) is an appealing alternative to right ventricular pacing in patients referred for permanent ventricular pacing and atrioventricular nodal ablation (AVNA) because it preserves physiological ventricular activation. Only limited data regarding HBP combined with AVNA are available in the literature.

OBJECTIVE

The purpose of this study was to provide further evidence on the feasibility and efficacy of this therapeutic approach in patients with uncontrolled atrial arrhythmia.

METHODS

We prospectively included all patients who had undergone AVNA after HBP in 3 different hospitals between 2017 and 2022.

RESULTS

AVNA following HBP lead implantation was performed in 75 patients. Complete atrioventricular (AV) block was obtained in 58 patients (77%), and significant modulation of AV nodal conduction (heart rate <60 bpm) was obtained in 12 patients (16%). AVNA failure was observed in 5 patients (7%). Recording of an atrial signal by the HBP lead was more frequently observed in patients with AVNA modulation/failure than in patients with complete AV block (11/17 vs 5/58; P <.001). No lead dislodgment occurred during the AVNA procedures. Acute His-bundle (HB) capture threshold increase >1 V occurred in 11 patients (15%), with return to baseline value on day 1 in 9 patients. New York Heart Association functional class and left ventricular ejection fraction significantly improved from baseline to last follow-up (3.0 ± 0.7 vs 1.6 ± 0.5; P <.001; and 47% ± 14% vs 60% ± 9%; P <.0001, respectively).

CONCLUSION

AVNA combined with HBP for noncontrolled atrial arrhythmia was feasible and clinically efficient. Implanting the HB lead on the ventricular aspect of the tricuspid annulus avoiding atrial signal recording can facilitate AVNA.

Risk of Pacing-Induced Cardiomyopathy in Patients with High-Degree Atrioventricular Block-Impact of Right Ventricular Lead Position Confirmed by Computed Tomography

Prospective studies applying fluoroscopy for assessment of right ventricular (RV) lead position have failed to show clear benefits from RV septal pacing. We investigated the impact of different RV lead positions verified by computed tomography (CT) on the risk of pacing-induced cardiomyopathy (PICM). We retrospectively included 153 patients who underwent routine fluoroscopy-guided pacemaker implantation between March 2012 and May 2020. All patients had normal pre-implant left ventricular ejection fraction (LVEF). Patients attended a follow-up visit including contrast-enhanced cardiac CT and transthoracic echocardiography. Patients were classified as septal or non-septal based on CT analysis. The primary endpoint was PICM (LVEF < 50% with ≥10% decrease after implantation). Based on CT, 48 (31.4%) leads were septal and 105 (68.6%) were non-septal. Over a median follow-up of 3.1 years, 16 patients (33.3%) in the septal group developed PICM compared to 31 (29.5%) in the non-septal group (p = 0.6). Overall, 13.1% deteriorated to LVEF ≤ 40%, 5.9% were upgraded to cardiac resynchronization therapy device, and 14.4% developed new-onset atrial fibrillation, with no significant differences between the groups. This study demonstrated a high risk of PICM despite normal pre-implant left ventricular systolic function with no significant difference between CT-verified RV septal or non-septal lead position.