High Ventricular Pacing Research Articles

Left ventricular volumes and function in successful and failed His-BundLe Pacing. A comparative prospective study.

Initial data suggest that His Bundle Pacing (HBP) could preserve long-term cardiac structure and function better than Right Ventricular Pacing (RVP), but evidence is limited. We studied consecutive patients with baseline ejection fraction (EF) ≥ 50% who underwent HBP attempt, either successful (HBP group) or failed (RVP group). Two-dimensional (2D) and three-dimensional (3D) echocardiography were carried out at baseline and after 6 months of ventricular pacing burden > 20%. Among 68 patients, 40 underwent successful HBP, and 28 RVP. The HBP and RVP groups did not differ for age, sex and pacing indication. At baseline, the HBP and RVP groups did not differ for 2D EF (62% vs. 62%), 3D EF (60% vs. 63%), 2D (-19% vs. -19%) and 3D global longitudinal strain (GLS) (-15% vs. -16%). After 6 months, 2D EF (-3.86%) and 3D EF (-5.71%) significantly decreased in the RVP group and did not change in the HBP group (p for interaction .006 and <.001, respectively). 2D GLS (3.08%) and 3D GLS (2.22%) significantly increased in the RVP group, but did not change in the HBP group (p for interaction .013 and <.016, respectively). Pacing induced cardiomyopathy (PICM) (EF drop ≥ 10% and EF < 50%) occurred in 14% (RVP) versus 0% (HBP) of patients (p = .025). Successful HBP was superior to RVP in preserving LV systolic function despite a high ventricular pacing burden, and was less frequently associated with PICM.

Comparison of clinical and echocardiographic outcomes between left bundle branch area pacing and right ventricular pacing in older patients.

Left bundle branch area pacing (LBBAP) is safe and effective, but studies in older patients are lacking. This study compared the clinical and echocardiographic outcomes of LBBAP and right ventricular pacing (RVP) in patients aged ≥75 years. This prospective observational study included older patients with symptomatic bradycardia who underwent LBBAP or RVP between 2019 and 2022. Clinical data, including pacing and electrophysiological characteristics, echocardiographic measurements, and device-related complications were collected. The primary endpoint was a composite of all-cause mortality, heart failure hospitalization, and upgrade to biventricular pacing. Secondary outcomes included changes in left ventricular ejection fraction (LVEF). Of 267 included patients, 110 underwent LBBAP and 157 underwent RVP. LBBAP was successful in 109 patients (success rate: 99.1%), with one patient eventually undergoing RVP. The pacing parameters of LBBAP were similar to those of RVP, except for a significantly narrower paced QRS duration (112.8±11.6vs. 138.3±23.9ms, p<.001). Ventricular lead implanting procedural duration was longer for LBBAP than RVP (14.0vs. 6.0min, p<.001), as was the fluoroscopy time (4.0vs. 2.0min, p<.001). During a mean follow-up period of 31.0±16.8 months, the primary outcome incidence was significantly lower following LBBAP than RVP (15.1%vs. 21.1%; hazard ratio, 0.471; 95% confidence interval, 0.215-1.032; p=.036) in 149 patients (55.8%) with ventricular pacing burden>20%. RVP reduced LVEF from 62.7±4.1% at baseline to 59.8±7.8% at the final follow-up (p=.001), whereas LBBAP preserved LVEF (61.4±6.3%vs. 60.1±7.4%, p=.429). LBBAP demonstrated improved clinical outcomes compared with RVP and maintained LVEF in older patients with high ventricular pacing burdens.

Comparing Left Bundle Branch Area vs Right-Ventricular Septal Pacing in High-Degree Conduction Disease After Transcatheter Aortic Valve Replacement: Randomized Trial Study Protocol

Left bundle branch area pacing (LBBAP) is a novel method of conduction-system pacing in the muscular interventricular septum. Although LBBAP has been shown to produce physiologic electrical and mechanical intraventricular synchrony, superiority of LBBAP, compared to right ventricular septal pacing (RVSP) at preserving normal left-ventricular (LV) systolic function after transcatheter aortic valve replacement (TAVR) has not been demonstrated. Left Bundle BRAVE is an investigator-initiated, multicentre, prospective, double-blinded, randomized, crossover study investigating the superiority of LBBAP, compared to RVSP, with respect to preservation of systolic function in patients with high-degree conduction disease after TAVR. Adults with severe aortic stenosis and normal systolic function who sustain high-grade atrioventricular block within 4 weeks of TAVR are eligible. All subjects receive a biventricular pacemaker generator with RVSP, and LBBAP leads. Participants are randomly assigned to 9 months of each pacing mode, in series. The primary endpoint is change in global longitudinal strain, tested in series with change in LV ejection fraction, comparing RVSP to LBBAP. Secondary endpoints include the following: echocardiographic markers of interventricular synchrony and right ventricular performance; heart failure functional status and symptom classification; 6-minute walk test results; pacemaker and lead performance; and brain natriuretic peptide concentration. The Left Bundle BRAVE study is designed to identify an upstream and clinically relevant marker of superiority in LBBAP, compared to RVSP, at preventing deterioration of LV function in patients with a high ventricular pacing burden after TAVR. ClinicalTrials.gov identifierNCT05541679

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

Right ventricular (RV) pacing is established as the most common ventricular pacing (VP) strategy for patients with symptomatic bradyarrhythmia. Some patients with high VP burden suffer deterioration of left ventricular (LV) function, termed pacing-induced cardiomyopathy (PICM). Patients who pace > 20% of the time from the RV apex are at increased risk of PICM, but independent predictors of increased RV pacing burden have not been elucidated in those who have a permanent pacemaker (PPM) inserted for bradyarrhythmia. We aimed to identify factors that are associated with increased VP burden > 20%, hence determining those at risk for resultant PICM. In this retrospective cohort study, we identified the most recent 300 consecutive cardiac implantable electronic device (CIED) implants in our center and collected past medical history, electrocardiogram (ECG), echo, medication and pacemaker check data. A total of 236 individuals met inclusion criteria. Of the patients, 35% had RV pacing burden < 20%, while 65% had VP burden ≥ 20%; 96.2% of patients with complete heart block (CHB) paced > 20% (P = 0.002). Utilization of DDD or VVI (75.2% and 89.2% of patients, respectively) without mode switch algorithms was associated with VP > 20% (P < 0.001). Male or previous coronary artery bypass grafting (CABG) patients also statistically paced > 20%. Other factors trending towards significance included prolonged PR interval, atrial fibrillation or more advanced age. High-grade atrioventricular (AV) block was associated with an RV pacing burden > 20% over 3 years but this was not consistent in patients with only transient episodes of high-grade AV block. We found a significant association between high VP% and male sex, previous CABG and the absence of mode switching algorithms.

Pacemaker-Related Factors and Outcomes of Fontan Patients - Impact of Paced QRS Duration.

Permanent pacemaker (PPM) implantation has been identified as a risk factor for morbidity and mortality after Fontan operation. This study investigated the factors associated with outcomes in patients with Fontan physiology who underwent PPM implantation. We retrospectively reviewed 508 patients who underwent Fontan surgery at Asan Medical Center between September 1992 and August 2022. Of these patients, 37 (7.3%) received PPM implantation. Five patients were excluded, leaving 32 patients, of whom 11 were categorized into the poor outcome group. Poor outcomes comprised death, heart transplantation, and "Fontan failure". Clinical, Fontan procedure-related, and PPM-related factors were compared between the poor and good outcome groups. Ventricular morphology, Fontan procedure-associated factors, pacing mode, high ventricular pacing rate, and time from first arrhythmia to PPM implantation did not differ significantly between the 2 groups. However, the poor outcome group exhibited a significantly longer mean paced QRS duration (P=0.044). Receiver operating characteristic curve analysis revealed a paced QRS duration cut-off value of 153 ms with an area under the curve of 0.73 (P=0.035). A longer paced QRS duration was associated with poor outcomes, indicating its potential to predict adverse outcomes among Fontan patients.

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

AimsStable 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.MethodsThis 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.ResultsDuring 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 (&amp;gt;20% and &amp;gt;40%).ConclusionCompared 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.

Prophylactic epicardial pacemaker implantation in tricuspid valve replacement.

Patients undergoing surgical tricuspid valve replacement (TVR) are at high risk of atrioventricular conduction disorders. Because implanting a lead through the tricuspid bioprosthesis is discouraged, the patients who undergo TVR in our centre are usually given a prophylactic epicardial pacemaker. Our aim was to assess the benefits and risks of this strategy. Among the patients who underwent TVR with prophylactic epicardial pacemaker implantation, clinical evaluations and pacemaker reports were analysed retrospectively after surgery. The need for cardiac pacing were assessed by characterizing the atrioventricular conduction, while the risks were evaluated by listing and adjudicating post-operative events. A total of 80 patients were analysed (mean age was 57 ± 16 years old, 30% males). TVR was isolated in 28 (35%) patients, but most often associated with another valve surgery. In the postoperative period, heart rhythm was analysed in 59/80 patients during a median follow-up of 35 months. Cardiac pacing was needed in 46% patients: 14% had complete pacing dependency, 17% had high degree AV block, while 15% had a high ventricular pacing rate (>80%). No pre- or per-operative variables could predict cardiac pacing requirement. Post-operatively, a spontaneous heart rate >70bpm (P = 0.02) and the presence of narrow QRS (P = 0.03) were significantly associated with a lower risk of cardiac pacing requirement. Complications related to epicardial pacemaker were documented in 2 (2.5%) patients. After TVR, cardiac pacing was needed in 46% of patients for post-operative atrioventricular conduction disorders. This high incidence associated with an acceptable safety profile supports a prophylactic epicardial pacing strategy for the patients undergoing TVR.

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

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. 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. 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. 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.

PO-03-019 ECHOCARDIOGRAPHIC OUTCOMES OF HIS BUNDLE AND LEFT BUNDLE BRANCH AREA PACING: A SINGLE CENTER EXPERIENCE

Traditional right ventricular apical pacing is associated with risk of pacing induced cardiomyopathy (PICM), atrial fibrillation, and heart failure. Conduction system pacing (CSP) via the His or left bundle branch area (HBP, LBBAP) may mitigate or even prevent the development of these complications. To evaluate the effects of CSP on cardiac function as measured by standard 2D-echocardiography. Consecutive patients undergoing HBP or LBBAP implantation between Feb 2014 and July 2022 at Virginia Commonwealth University were analyzed. Ejection fraction (EF), left ventricular diastolic dimension (LVIDd), left ventricular systolic dimension (LVIDs), tricuspid regurgitation severity, and mitral regurgitation severity were compared pre- and post- CSP. Only patients with echo data at 90 days or greater from time of implant were included. A total of 340 patients with CSP had echocardiographic data available. Mean clinical follow up time was 810 days from implant, and median time until post-implant EF was 483 days (IQR 324-763). 77 had reduced EF (<50%) at baseline. Pacing burden exceeded 20% across the cohort. The mean pre- and post- CSP implantation EF in the overall group was 53.8% ±10.9% vs 54.7% ±9.1% (p=0.08). Mean pre- and post- CSP implant LVIDd was 4.59±0.73cm vs 4.37 ±0.72 cm (p<0.001). Mean pre- and post- CSP implant LVIDs was 3.23± 0.79cm vs 3.05± 0.76cm (p<0.001). TR and MR severity were unchanged after pacemaker implantation. In the subset of patients with reduced EF, mean pre-implant EF was 37% ±9.4% and post-implant EF was 47% ±11.6% (p<0.001). Mean pre-implant LVIDd was 5.02cm ±0.86cm and post-implant LVIDd was 4.60cm ±0.75cm (p<0.001). Mean pre-implant LVIDs was 4.05cm ±1.0cm and post-implant this dropped to 3.44cm ±0.96 (p<0.001). CSP via HBP or LBBAP is not associated with PICM in patients requiring high ventricular pacing burdens. In patients with a reduced EF, it may significantly improve systolic function along with positive structural remodeling.

Evaluation of the association between right ventricular lead placement and future need for upgrade from pacemaker or ICD to cardiac resynchronization therapy. A population-based comparative study

Abstract Background Between 10–20% of patients who are implanted with a pacemaker due to AV block, are diagnosed with heart failure within two years post-implant. It has been suggested that septal placement of the right ventricular lead is associated with lower risk of heart failure for patients who receive ventricular pacing. However, randomized trials and registry studies have yielded conflicting data on this topic. We therefore sought to use a nationwide pacemaker-registry to investigate whether septal lead placement at primary pacemaker implantation due to bradycardia is associated with lower risk of need for upgrade to cardiac resynchronization therapy (CRT). Purpose To investigate the association between right ventricular lead placement and risk of future upgrade to CRT, either within two years or later during follow-up. Methods The rates of CRT upgrades were compared between patients who received their pacemaker implants at two tertiary care centers who implant pacemakers and perform all CRT implantations in their respective regional uptake areas. One center consistently used septal RV lead placement for all implants, while the other used apical lead placement. CRT indications were guideline-based and did not differ between sites. Data from the national pacemaker-registry was extracted for all patients and compared between the sites. Pacemaker indications with presumed high ventricular pacing need were defined as AV block II/III or chronic atrial fibrillation with bradycardia. Results 15809 patients with either pacemaker (n=14258) or implantable cardioverter defibrillator (ICD, n=1553) were included and followed for a median of 9 years. Mean age at implant was 75±13 years and 40% were female (see table 1 for demographic details). A total of 358 CRT upgrades (2.3%) were performed, of which 91 (25%) occurred within two years of the primary implant. Univariate and multivariate logistic regression analysis results are presented in table 2. Independent predictors of CRT upgrade included apical lead placement (odds ratio 1.4 [95% CI 1.0–1.7], p=0.02 and presumed high ventricular pacing need (AV block or chronic atrial fibrillation, OR 1.6 [1.2–2.0] p&amp;lt;0.001). In a prespecified sub-analysis for CRT upgrade within two years post-implant, the OR for apical lead placement was similar (1.5 [0.9–2.6]) but non-significant (p=0.14). Conclusions In pacemaker therapy, apical RV lead placement (compared to septal lead placement) was associated with higher risk for CRT upgrade. Other factors such as gender and high likelihood of ventricular pacing need were also associated to CRT upgrades. In general, upgrade to CRT was relatively uncommon in this large population-based material, perhaps indicating an undertreatment with CRT for pacemaker-induced cardiomyopathy. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung FoundationALF governmental grant within the Swedish healthcare system

New-onset atrial fibrillation following left bundle branch area pacing vs. right ventricular pacing: a two-centre prospective cohort study.

To investigate whether left bundle branch area pacing (LBBAP) can reduce the risk of new-onset atrial fibrillation (AF) compared with right ventricular pacing (RVP). Patients with indications for dual-chamber pacemaker implant and no history of AF were prospectively enrolled if they underwent successful LBBAP or RVP. The primary endpoint was time to the first occurrence of AF detected by pacemaker programming or surface electrocardiogram. Follow-up at clinic visit was performed and multivariate Cox regression models were applied to evaluate the effect of LBBAP on new-onset AF. The final analysis included 527 patients (mean age 65.3 ± 12.6, male 47.3%), with 257 in the LBBAP and 270 in the RVP groups. During a mean follow-up of 11.1 months, LBBAP resulted in significantly lower incidence of new-onset AF (7.4 vs. 17.0%, P < 0.001) and AF burden (3.7 ± 1.9 vs. 9.3 ± 2.2%, P < 0.001) than RVP. After adjusting for confounding factors, LBBAP demonstrated a lower hazard ratio for new-onset AF compared with RVP {hazard ratio (HR) [95% confidence interval (CI)]: 0.278 (0.156, 0.496), P < 0.001}. A significant interaction existed between pacing modalities and the percentage of ventricular pacing (VP%) (P for interaction = 0.020). In patients with VP ≥ 20%, LBBAP was associated with decreased risk of new-onset AF compared with RVP [HR (95% CI): 0.199 (0.105, 0.378), P < 0.001]. The effect of pacing modalities was not pronounced in patients with VP < 20% [HR (95% CI): 0.751 (0.309, 1.823), P = 0.316]. Left bundle branch area pacing demonstrated a reduced risk of new-onset AF compared with RVP. Patients with a high ventricular pacing burden might benefit from LBBAP.

Clinical Outcomes of Left Bundle Branch Area Pacing in Comparison with Right Ventricular Septal Pacing in Patients with High Ventricular Pacing Ratio ≥40.

BackgroundThe aim of the present study is to compare the clinical outcomes between left bundle branch area pacing (LBBaP) and right ventricular septal pacing (RVSP) in patients with percent ventricular pacing (VP%) ≥40%.MethodsFifty-four patients with VP% ≥40% were retrospectively studied, including 33 patients with LBBaP and 21 patients with RVSP. QRS duration (QRSd), interventricular mechanical delay (IVMD) and septal-posterior wall motion delay (SPWMD) were measured to evaluate ventricular synchrony. Heart failure hospitalization (HFH), pacing parameters, and complications were evaluated postoperatively and at follow-ups.ResultsThe mean follow-up duration of the study participants was 13.80 ± 4.47 months. In the LBBaP group, no significant differences were noted in paced QRSd, IVMD and SPWMD of the LBBaP capture and intrinsic-conduction modes, but the paced QRSd was narrower (QRSd, 110.88 ± 7.37 vs 132.90 ± 14.78 ms, P< 0.0001) and the IVMD and SPWMD were lower when compared with the RVSP group (IVMD, 28.16 ± 4.76 vs 40.28 ± 6.97 ms, P <0.0001; SPWMD, 43.68 ± 26.41 vs 97.94 ± 12.77 ms, P <0.0001). LBBaP was associated with better left ventricular function in comparison with RVSP during follow-ups (LVEDD, 47.09 ± 4.47 vs 51.28 ± 7.58, P = 0.017; LVEF, 64.81± 5.49 vs 60.44 ± 9.28, P = 0.041). Patients with LBBaP had lower occurrences of HFH than patients with RVSP (3.13% vs 27.78%, P = 0.034). Pacing parameters showed no differences between the two groups and remained stable throughout the study period.ConclusionThe results of this study suggest that LBBaP may be more suitable for patients requiring long-term high ventricular pacing ratio.

A real-world experience of atrioventricular synchronous pacing with leadless ventricular pacemakers.

The MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer-based atrial sensing. Data regarding the real-world experience with this novel system are scarce. We sought to characterize patients undergoing MicraTM -AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony. In this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM -AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow-up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous ventricular pacing (AsVP) ≥ 70%. Sixty-five percent of patients achieved AsVP ≥ 70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure, and prior cardiac surgery. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were small A4-wave amplitude, high ventricular pacing burden, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow-up. With the increasing popularity of leadless pacemakers, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM -AV devices.

Dual-chamber cardiac pacing effect on left and right atria morphometric parameters and function

Abstract Background Dual-chamber pacemaker implantation is a standard interventional treatment strategy for atrioventricular block (AVB) and sick sinus syndrome (SSS). It has been proven that a high percentage of right ventricular pacing might have detrimental effects on cardiac function. However, there is a lack of data on atrial pacing effect on left (LA) and right (RA) atria function. Purpose To assess the impact atrial pacing on left and right atria morphologic and functional parameters in patients after dual-chamber pacemaker implantation. Methods We conducted a prospective study that included patients who received a dual-chamber pacemaker for an indication of AVB or SSS. After signing of the informed consent pacemaker was programmed for base rate of 40 bpm and no rate response in case of clear AVB indication or for base rate of 60 bpm and rate response if indication was SSS. An transthoracic echocardiography was done the next day after pacemaker implantation and after one month at follow up (FU). During the FU the atrial pacing (AP) and ventricular pacing (VP) percentage were captured. To exclude the impact of right ventricular pacing, patients with high VP percentage (&amp;gt;40%) were excluded from analysis. Patients were divided into two groups – group A with high AP (&amp;gt;50%), and group B – low AP (&amp;lt;50%). LA expansion fraction reflecting reservoir function, emptying – reflecting conduit, and active emptying reflecting “atrial kick” were analysed. To compare means the Mann Whitney U test, and for categorical variables – X2 test were used. Results A total of n=100 patients underwent dual-chamber implantation and signed informed consent. Due to significant structural heart disease or reduced ejection fraction (&amp;lt;50%) 11 patients were excluded. Out of those, n=30 were excluded due to a high VP percentage. Group consisted of n=28 and group B of – n=31 patients. Average AP in group A was 66.2% and 5.0% in group B. The mean age (group A 73.6 SD 8.8 years vs group B 79.2 SD 7.3 years, p=0.197), gender distribution (group A males 45.5% vs group B 50.0%, p=0.773), and mean BMI (group A 26.5 SD 4.7 kg/m2 vs group B 29.2 SD 3.3 kg/m2, p=0.191) did not differ significantly between the two groups. The baseline LA and RA morphometric and functional parameters presented in figure 1 and did not differ significantly between the two groups. The change in LA and RA functional parameters presented in figure 2. Even though it did not reach statistical significance, a tendency for lower LA expansion fraction, active emptying fraction and LA ejection fraction were observed in group A. RA morphometric parameters did not change significantly between the two groups at FU. Conclusion A higher percentage of atrial pacing in dual-chamber pacemaker population could lead to impaired LA function over time. Though, longer observational period is needed. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2

How good is operator opinion at predicting high ventricular pacing burden among patients receiving device therapy for bradycardia?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Current guidelines indicate that pacing methods that maintain physiologic ventricular activation (biventricular pacing or His-bundle pacing) should be chosen over right ventricular pacing (Vp) among patients with EF 36-50% who are expected to Vp &amp;gt;40% of the time. There are no guidelines to help predict which patients will receive a high burden of Vp and this is left to operator opinion. We sought to ascertain whether operator opinion is an accurate predictor of high burden of Vp. Methods This was a single-centre single-blinded observational study of patients who received pacemaker implant for treatment of bradycardia between April 2015 and 2019 and had at least 12 month follow-up data on record. Patients’ demographic, clinical, electrocardiographic and echocardiographic data were reviewed in a blinded fashion by a senior implanting physician, who estimated whether the Vp at 12 months would exceed 40%. The Vp at approximately 12 months was obtained from the pacing records and compared with the prediction. Results Some 982 patients underwent pacemaker implantation during the study period, 698 for conduction system disease (CSD), 267 for sinus node disease (SND) and 17 for other conditions. Overall, 856 had valid follow-up data. Of these, 543 (63.4%) were predicted to Vp &amp;gt;40% , and 527(61.6%) were documented as having Vp &amp;gt;40%. The sensitivity and specificity of operator prediction were 93.2% and 84.2%, with positive and negative predictive values of 90.4% and 88.5%. Table 1 illustrates analyses of different populations by clinical parameter. In sub-group analysis, complete heart block and PR &amp;gt; 300ms were significant factors for accurate prediction of Vp &amp;gt; 40%, however clinical features, such as syncope, were poor discriminators. Conclusion In this single-centre study, among patients receiving pacemaker implant for treatment of bradycardia, operator prediction of the burden of Vp &amp;gt;40% has an acceptable degree of accuracy. Sub-group analysis suggests that certain clinical parameters could make this prediction easier. Table 1. Comparison of operator opinion SND CSD CHB SND+PR &amp;lt; 160 PR &amp;gt; 300 Syncope Non-syncope n 698 267 216 84 60 409 344 Sensitivity 44.4% 97.7% 100% 6.3% 100% 86.4% 87.9% Specificity 98.3% 62.0% 45.2% 97.1% 0%* 89.9% 79.6% PPV 87.0% 90.6% 91.6% 33.3% 98.3% 94.2% 92.2% NPV 87.9% 87.9% 100% 81.5% - 77.6% 70.5% * only 1 patient did not RV pace &amp;gt;40% - this was not predicted. SND – sinus node disease; CSD – conduction system disease; CHB – complete heart block, PPV – positive predictive value; NPV – negative predictive value

Abstract 16813: The Prevalence and Predictors of Pacing-Induced Cardiomyopathy (PICM) in Younger Patients

Background: Pacing-induced cardiomyopathy (PICM) has been increasingly recognized as a cause of heart failure in patients with pacemakers. Thus far, clinical trials and observational studies of PICM have largely included elderly patients with mean age &gt; 70 years. The prevalence and predictors of PICM in younger patients (age ≤ 59 years) after pacemaker implantation are not known. Methods: We retrospectively studied the prevalence and predictors of PICM in younger adults (18-59 years) who received single ventricular chamber or dual chamber pacemakers at Vanderbilt University Medical Center from 1986-2015. Patients without documented ventricular pacing burden, and patients with baseline left ventricular ejection fraction (LVEF) &lt; 30% were excluded. PICM was defined as LVEF drop of ≥ 10% and LVEF &lt; 50% during follow up in the setting of significant right ventricular pacing (≥ 20%), without alternative explanations for cardiomyopathy. Univariate and multivariable Cox proportional hazards regression models were utilized to study the factors associated with hazard of developing PICM. Results: A total of 325 patients were included in the study. 182 patients had high ventricular pacing (≥ 20%), which was associated with pre-existing atrial fibrillation (AF) and reduced baseline LVEF in addition to atrioventricular block (AVB) in the multivariate analysis. During the median follow up duration of 11.5 (Interquartile range 7 - 17) years, 38 patients (11.7%) developed PICM (1.3 per 100 patient-year). The median time to the development of PICM was 5 (Interquartile range 2 - 10) years. Older age (HR 2.5 for age ≥ 50 years, P = 0.013), reduced baseline LVEF (HR 2.4, P = 0.022), and AVB (HR 2.7, P = 0.007) were associated with an increased risk of PICM in the multivariate analysis. Furthermore, pre-existing AF was associated with an increased risk of PICM in patients without pre-implant AVB (HR 8.8 compared to the absence of both AF and AVB, P = 0.039). Conclusion: The incidence of PICM in young patients was low in this cohort of younger patients. Older age, baseline reduced LVEF, and AVB were associated with an increased risk of PICM in the young patient cohort. AF was associated with an increased risk of PICM in a subset of patients without pre-existing AVB at implant.

Effect of Ventricular Pacing on Morbidity in Adults After Fontan Repair

Implantation of a permanent pacemaker is a negative prognostic marker in patients with Fontan palliation; however, data delineating outcomes in adult patients with pacemaker requirements are lacking. We hypothesize that high ventricular pacing burden is associated with adverse outcomes in adult Fontan patients. We performed a retrospective review comprising adult patients with history of Fontan repair. A high burden of ventricular pacing was defined as ≥40% pacing. Major adverse clinical events (MACE) were defined as all-cause mortality or need for advanced cardiac therapies (ventricular assist device or heart transplant). A total of 145 adult patients with Fontan were studied for a median of 3.1 years. Twenty (14%) patients had implanted pacemakers with ≥40% ventricular pacing. Twelve events occurred in those with ≥40% ventricular pacing (incidence 60.0%) versus 11 in those without (incidence 8.8%). In multivariable analysis, ≥40% ventricular-pacing (odds ratio 12.51, confidence interval [CI] 3.56 to 43.83, p <0.001) was associated with MACE independent of initial Fontan type, New York Heart Association functional class at baseline, or history of atrial tachyarrythmia. In survival analysis, patients with ≥40% ventricular pacing had nearly 8 times the risk of MACE compared with those with a lower ventricular pacing burden (hazard ratio 7.79, 95% CI 2.56 to 23.66, p <0.001), whereas patients with atrial-only or <40% ventricular pacing burden had a trend toward higher hazard of MACE compared with those without permanent pacemaker (hazard ratio 3.38, 95% CI 0.92 to 12.47, p = 0.07) that did not meet statistical significance. These findings suggest that high ventricular pacing burden contributes to poor outcomes in the adult Fontan patients and bear consideration when determining optimal treatment of tachyarrhythmias in this population.

Deactivation of cardiovascular implantable electronic devices in patients nearing end of life : Reality or only recommendation?

Current guidelines recommend considering deactivation of cardiac implantable electronic devices (CIEDs) in patients nearing death. We evaluated the implementation of this recommendation in unselected deceased individuals with CIEDs. Over a7-month period in 2016, all deceased persons taken to the Rostock crematorium were prospectively screened for CIEDs and these were interrogated in situ. Pacing rate, pacing mode, and lead output were documented as well as patient data including location and time of death. In implantable cardioverter-defibrillators (ICDs), tachycardia therapy adjustment and occurrence of shocks 24 h prior to death were also recorded. We examined 2297 subjects, of whom 154 (6.7%) had CIEDs. Of these subjects, 125 (100%) pacemakers (PMs) and 27 (96.4%) ICDs were eligible for analysis. Death in persons with ICDs occurred most frequently in hospital (55.6%), while this was less frequently the case for individuals with PMs (43.2%). Furthermore, 33.3% of subjects with ICDs and 18.5% with PMs died in palliative care units (PCU). Shock therapies were switched off in three (60%) individuals with ICDs who died in the PCU, whereas antibradycardia therapy was not withdrawn in any PM patient in the PCU. Therapy withdrawal occurred in two patients with PMs (1.3%) who died in hospital. Patients with PMs had high ventricular pacing rates at the last interrogation (69 ± 36.0%) and often suffered atrioventricular block (39.2%). Six (25%) of the 24active ICDs presented shocks near the time of death. Many CIED patients died in hospital; nonetheless, in practice, CIED deactivation near death is rarely performed and might be less feasible in subjects with PMs. However, there is still aneed to consider deactivation, especially in individuals with ICDs, as one fourth of them received at least one shock within 24 h prior to death.

Outcome of patients with functional single ventricular heart after pacemaker implantation: What makes it poor, and what can we do?

Pacemaker implantation in patients with single ventricle is associated with poor outcomes. The purpose of this study was to determine the reasons for the poor outcomes of pacemaker implantation. We performed a retrospective chart review of patients with single ventricle who had undergone permanent pacemaker implantation. Patients were categorized into 3 groups based on the site of pacing and the proportion of ventricular pacing (VP) as follows: (1) atrial pacing group with atrial pacing only (n = 11); (2) low VP group with low daily VP proportion (<50%; n = 12); and (3) high VP group with high daily VP proportion (≥50%; n = 15). Pacing leads were placed at the epicardium in all patients. No patients in the atrial pacing or low VP groups died, whereas the survival rate in the high VP group was 58.9% and 39.3% at 10 and 20 years, respectively, after pacemaker implantation. Among the post-Fontan patients, plasma brain natriuretic peptide (BNP) levels significantly increased with the proportion of VP: 11.7, 20.3, and 28.4 pg/mL in the atrial pacing, low VP, and high VP groups, respectively (P = 0.04). In the high VP group, the plasma BNP level was significantly lower in patients with an apical pacing lead than in those with a nonapical pacing lead (27.0 pg/mL vs 82.8 pg/mL, respectively; P = .03). A higher proportion of VP was associated with poor outcome and higher plasma BNP levels, probably due to ventricular dyssynchrony. In epicardial ventricular pacing, apical pacing is better to avoid the increase in ventricular stress and plasma BNP level.

Evolution of conduction disturbances induced by transcatheter aortic valve implantation, and implication in their management

Managing conduction disturbances after transcatheter aortic valve implantation (TAVI) remains challenging. Predicting factors of permanent pacemaker (PPM) implantation have been studied but there are scarce data about the type and the long term TAVI induced conduction disturbances. This work aimed to specifically assess each conduction disturbance after TAVI, their incidence and evolution, to improve their management in indication and delay of PPM implantation. This retrospective study included all patients undergoing TAVI at Nancy University Hospital from 2009 to 2016. Patients were followed over 1 year after procedure, with an electrocardiographic control at 3 and 12 months and a device control when implanted with a PPM. A total of 505 TAVI procedures were realized, with a 16.2% PPM implantation rate. Left bundle branch block occurrence (26.9%) seems insufficient to implant a PPM early (at 3 months 53.4% had disappeared, there was no PPM dependency and low ventricular pacing rates; non-implanted patients had good outcomes at 1 year) and should only extend duration of monitoring (34.1% developed a high-degree block, during the first 7 days). Per-procedural high-degree atrioventricular (AV) block should lead to an early PPM implantation when persisting after the procedure day (PPM controls confirmed high ventricular pacing rates), but lead to a conservative approach otherwise (10.3% risk of recurrence during hospitalization, no risk after discharge). Post-procedural transient complete AV block is associated with good outcomes since only 7.1% were PPM-dependent at 3 months and 30.8% had a ventricular pacing rate < 1%; a conservative approach would need further investigations. Specific situations of conduction disturbance lead to different prognosis and should be managed specifically. After 3 months most of patients implanted with PPM have recovered a spontaneous AV conduction, with a low ventricular pacing rate.