Septal venous channel perforation during Bachmann bundle pacing.

It has recently been reported that simultaneous multisite atrial pacing, Bachmann's bundle (BB) pacing, and coronary sinus (CS) pacing are useful for preventing the induction of atrial fibrillation (AF). We investigated whether a simple pacing approach via BB could reduce the induction of AF by extrastimuli (S2) from the right atrial appendage (RAA). Programmed electrical stimulation was performed from the RAA and the area of BB at the superior aspect of the atrial septum, and bipolar recordings were obtained from the RAA, BB, and CS in 14 patients. In five patients, AF was induced with critically timed RAA-S2 delivered during RAA pacing. However, AF was not induced in any patient when RAA-S2 was delivered during BB pacing. The duration of the P wave during BB pacing was significantly shorter than that during RAA pacing and sinus rhythm (BB 80 +/- 16 ms vs. RAA 106 +/- 36 ms vs. sinus rhythm 100 +/- 24 ms, p < 0.05). The intra-atrial conduction time to the distal coronary sinus (CSd) caused by early S2 at the RAA was significantly reduced by BB pacing (BB 114 +/- 22 ms vs. RAA 157 +/- 35 ms, p < 0.001). Bachmann's bundle pacing reduces atrial conduction time caused by RAA-S2 and may be useful for preventing the induction of AF.

Atrial fibrillation (AF) occurs in about 30% of patients after open heart surgery and is associated with longer hospital stay and greater cost. Therefore, prophylactic measures are warranted to reduce the incidence of AF in postoperative patients. In addition to pharmacologic approaches, various atrial pacing strategies (right atrial, biatrial, and Bachmann's Bundle pacing) have been evaluated. Although, meta-analyses including several studies seem to demonstrate an overall benefit of atrial pacing, many findings are conflicting. The impact of Bachmann's bundle (BB) pacing on postoperative AF was studied in a recent randomized, prospective trial that included 161 patients. The incidence of postoperative AF was not reduced by BB pacing or right atrial pacing compared to non-paced controls (37% vs. 48% vs. 42%; P = ns). An important finding of this study was, however, that the paced P-wave duration, a risk factor for postoperative AF, was increased during right atrial pacing compared to BB pacing. In addition, pacing thresholds were significantly better at BB compared to right atrial locations. Thus, in contrast to biatrial pacing strategies, pacing at BB does not reduce the overall incidence of postoperative AF. However, BB offers favorable pacing capabilities and is less arrhythmogenic compared to right atrial pacing during the postoperative period.

Introduction Although atrial septal pacing has been reported to reduce atrial fibrillation (AF) burden, there is less evidence regarding its effect on the prevention of permanent AF and the improvement of long-term clinical outcomes. However, Bachmann's bundle pacing (BBp), which features P-wave morphology similar to sinus rhythm and shortened P-wave duration (PWD), was reported to significantly reduce permanent AF recurrences and occurrences compared with right atrial appendage pacing (RAAp) and non-specific right septal pacing. Purpose Possible mechanisms for AF suppression with BBp are that fast inter-atrial conduction through BB decreases global atrial activation time and the dispersion of the overall atrial refractoriness, and it prevents the decrease in left ventricular filling and increase in left atrial pressure associated with delayed left atrial contraction. Intra-and inter-atrial conduction during BBp was evaluated using longitudinal bi-atrial strain. Methods In patients with successful BBp implantation defined by electrocardiographic criteria using SelectSecure pacing lead and C315 delivery catheter (Medtronic, Inc), both left atrium (LA) and right atrium (RA) global longitudinal strain (GLS) in simultaneous phases were measured using Philips Ultrasound Workspace 2D Strain in apical 4-chamber view during atrial pacing to assess intra- and inter-atrial conduction delay. The atrial GLS were measured semi-automatically, and the strain rate was analyzed in the three segments of septal wall, lateral wall, and roof and their average. The negative peak of strain rate during atrial systole was the starting point of atrial contraction, and time to peak (TTP) was measured. The difference in TTP between septal and lateral walls in each atrium was measured as intra-atrial conduction delay and the difference in average TTP between LA and RA as inter-atrial conduction delay. Results Ten patients who underwent successful BBp were enrolled (Sick sinus syndrome: 3, advanced atrioventricular block: 2, complete atrioventricular block: 5). At implantation, bipolar atrial electrogram amplitude was 2.03±0.93 mV, atrial lead impedance was 632.7±157.6 Ω, and atrial pacing threshold was 0.7±0.2 V at 0.4 ms. The PWD during sinus rhythm on the 12-lead ECG was 132.8±10.6 ms, while during BBp it was 108.0±11.9 ms, which was significantly shorter in the BBp group (p&amp;lt;0.001). The intra-atrial conduction delay in RA and LA was 10.9 ± 12.1 ms and 12.1 ± 17.3 ms, respectively, and the inter-atrial conduction delay was 6.6 ± 8.6 ms. On the other hand, for the 10 RAAp and 10 sinus rhythm patients as control groups, the inter-atrial conduction delay was 29.7±13.8 ms and 8.5±9.5 ms, respectively. BBp had significantly less inter-atrial conduction delay than RAAp (p=0.005) and was comparable to sinus rhythm (p=0.719). Conclusion Longitudinal bi-atrial strain suggested that BBp significantly reduced inter-atrial delay and it might be effective in AF suppression.Longitudinal bi-atrial strain

Background and Objective Patients with non-obstructive HCM (nHCM) have advanced diastolic dysfunction and atrial remodeling, leading to increased heart failure hospitalisations. The objective of this study was to evaluate the role of Bachmann bundle pacing (BBP) in diastolic filling compared to right atrial appendage pacing (RAAP). Methods Forty patients with symptomatic nHCM and normal LV function were prospectively enrolled from January 2021 to June 2023. Inclusion criteria included electrocardiographic evidence of inter-atrial delay, E/e’ &amp;gt; 15, and an indication for ICD implantation. BBP was attempted in twenty patients, others underwent RAAP. A Biotronik Selectra 3D 40-S sheath was used for BBP in patients in whom initial lead implantation was unsuccessful. BBP was defined based on P-wave morphology and fluoroscopic lead position. The RV lead was implanted in the RV apex in all patients and the AV delay was optimized based on diastolic filling period and E/e’. Devices were programmed in DDD mode. During follow up, diastolic function, functional capacity, atrial fibrillation, and heart failure hospitalisations were assessed in both groups. Results Among the forty patients (age 48.2+7.8 yrs, males 75%, ESC-SCD Risk 4.3+0.6%), the baseline P wave duration, E/A, E/e’ were 138.4+16.4 ms, 2.5+0.5, and 17.5+2.4, respectively. Six patients (15%) had a history of paroxysmal AF (3 each in BBP and RAAP groups). Of the 16 patients (80%) who underwent successful BBP, the Selectra 3D 40-S sheath was used in 8 patients (Figure 1, Panel A). During BBP, a bachmann bundle potential was recorded in 7 of 16 patients (43.8%) (Figure 1, Panel C). The pacing threshold (1.5+0.5@0.4ms vs. 0.9+0.3@0.4ms, p=0.026) was higher and the atrial sensing (1.8+0.4 vs. 3.3+0.6, p=0.002) was lower in the BBP group compared to the RAAP group at 4 weeks and 6 months of follow up. There was an acute rise in threshold (2.1@0.4 ms) in 1 BBP patient at 4 weeks of follow up. Patients in the BBP group had a reduction in P wave duration compared to the patients in the RAAP group (-22.5 + 5.4 vs. +5.6 + 3.2 ms, p&amp;lt;0.001). During follow up (11.4 + 3.4 months), there was a significant improvement in diastolic function (E/e’), functional capacity (NYHA Class) and reduction in NT-proBNP in the BBB group compared to the RAAP group (Figure 1). The percentage of atrial pacing was similar in both groups (BBP 73.2 + 7.8 vs. RAAP 78.5 + 9.1 %, p=0.219). The risk of atrial fibrillation/tachycardia (12.5% vs. 35.0%, p=0.022) and heart failure hospitalisations (6.3% vs. 20%, p=0.042) was lower in the BBP group compared with RAAP during follow up. Conclusions BBP is safe and effective in improving diastolic function, functional capacity and heart failure hospitalizations in patients with nHCM.BBP Pacing using Selectra 3D 40-S SheathChange in E/e', NYHA, and NT-pro BNP

Evaluate whether Bachmann's bundle pacing (BBp) defined by electrocardiographic (ECG) criteria is associated with less atrial fibrillation/tachycardia (AF/AT) compared with anatomically defined right atrial septal pacing (RASp) and right atrial appendage pacing (RAAp). This is a retrospective study comparing BBp with non-specific RASp and RAAp on new incidence, burden, and recurrence of AF/AT. We included patients who underwent atrial lead placement between 2006 and 2019 and received > 20% atrial pacing. BBp was defined by paced P-wave morphology and fluoroscopic lead position. Compared with RASp (n = 107) and RAAp (n = 108), AF/AT burden was lower in the BBp (n = 134) group by repeated measures ANOVA (P < 0.001). Over 2-year follow-up, AF/AT burden increased in the RASp (P < 0.01) and RAAp (P < 0.01) groups but did not significantly change in the BBp group (P = 0.91). Atrial arrhythmia burden was lower in the BBp group than the RASp and RAAp groups at 12-15, 18-21, and 24-27 months (P < 0.05) after pacemaker placement. Risk of AF/AT recurrence was lower in BBp than RASp (HR 0.43; P < 0.01) and RAAp patients (HR 0.29, P < 0.01). Risk of de novo AF/AT was also lower in BBp than in RASp (OR 0.12; P < 0.01) and RAAp patients (OR 0.20, P < 0.01). Bachmann's bundle pacing defined using P-wave criteria was associated with decreased atrial arrhythmia burden, recurrence, and de novo incidence compared with right atrial septal pacing and right atrial appendage pacing.

Right atrial (RA) appendage (RAA) pacing is reported to impair hemodynamic benefits of cardiac resynchronization therapy (CRT) through a considerable delay of left atrial (LA) contraction, which compromises appropriate balance of atrioventricular (AV) and left ventricular (LV) synchrony. Potential usefulness of Bachmann's bundle (BB) pacing to solve the problem remains to be confirmed. Atrial synchrony and LV performance was investigated by echocardiography in 25 patients undergoing pacemaker implantation with preserved AV conduction and LV function (Group I), and 15 patients receiving CRT (Group II). In Group I, RAA pacing (AAI mode, n=10) increased P-wave duration (PWD) and RA-to-LA contraction delay (IAMD) compared with sinus rhythm (132±14 and 35±12 ms vs. 108±16 and 13±13 ms, P<0.001). The delayed LA contraction was associated with early interruption of LV filling, leading to an impairment of LV performance (Tei index: 0.43±0.12 vs. 0.34±0.09, P<0.01). BB pacing (AAI, n=15) did not cause such undesirable effects. In Group II, RA (BB)-paced biventricular pacing (DDD) reduced PWD and IAMD compared with RA-sensed biventricular pacing (VDD) (102±14 and -3±13 ms vs. 117±10 and 21±18 ms, P<0.001). This restoration of atrial synchrony was associated with significant improvement of LV performance (Tei index: 0.56±0.18 vs. 0.62±0.16, P<0.05). BB pacing preserves atrial synchrony, and might be more favorable than RAA pacing for maximizing hemodynamic efficacy of CRT.

The current treatment of patients with heart failure and concomitant atrioventricular conduction delay is difficult. Recommendations indicate the possibility to use the classic resynchronization but in the presence of narrow QRS-complex such approach could be even harmful. Without a sufficient LBBB morphology as indication for classical CRT, those patients would lose their narrow QRS complex with negative consequences for the hearts functional status. A new therapeutic option for those patients to re-establish the physiological atrioventricular mechanical sequence is the permanent His-bundle pacing (pHBP). Advantages like physiological activation sequence of the ventricular myocardium, less affected by AF compared to classical CRT and reversal of mitral regurgitation should be enumerated to show it's beneficial effect. Additionally the use of Bachmann's-bundle pacing can correct the prolonged interatrial conduction thus further contribute to the echocardiographic and clinical improvement. The aim of the study is to assess the influence of Bachmann's-bundle pacing and His-bundle pacing on the reversed remodeling of the heart in patients with heart failure and atrioventricular block. The study group included 21 patients (7 women and 14 men) undergoing cardiac resynchronization using Bachmann's-bundle pacing and permanent His-bundle pacing from LV channel for atrioventricular conduction delay. All the patients had narrow QRS-complex which prevented us to use classic resynchronization. 13 CRT-D and 8 CRT-P devices were implanted according to the ejection fraction and ventricular arrhythmia risk assessment. In all patients the direct His-bundle pacing was successfully achieved, selective in 17 and non-selective in 4 patients. The mean follow-up (FU) period was 8.8 months (1–26 months). The echocardiographic, clinical and ECG results are presented in the table 1. Conclusions 1. The correction of atrioventricular and interatrial conduction delay resulting in improvement of atrioventricular mechanical coupling can contribute to the reversed remodeling of the heart. 2. This also improves the patient's functional status. 3. In some patients this approach could lead to the normalization of echocardiographic parameters of the left ventricle. Funding Acknowledgement Type of funding source: None

While pacemaker therapy is well-established for sick sinus syndrome (SSS), the comparative electrophysiological benefits of different atrial pacing sites remain unresolved. This study aimed to compare the effects of right atrial appendage pacing (RAAP) and Bachmann's bundle pacing (BBP) on atrial synchrony in patients with SSS using two-dimensional speckle tracking imaging (2D-STI). A prospective, randomized, single-center analysis was conducted on 72 SSS patients, randomized into RAAP (n = 35) and BBP (n = 37) groups. Electrocardiogram and 2D-STI were employed to assess postoperative pacing parameters and echocardiographic indicators, including P-wave characteristics, atrial electromechanical delay (AEMD), and ventricular function metrics. Evaluations were performed preoperatively and at 1- and 3-month follow-ups, with additional device interrogation at 1year. At 1month post-surgery, significant differences were observed between the groups in paced P-wave duration, interatrial mechanical delay (IAMD), inter- and intra-right AEMD, and ventricular pacing percentage (P < 0.05 for all). By 3months, these differences persisted, with the BBP group demonstrating significantly greater improvements in atrial synchrony, reflected by lower IAMD and AEMD values (P < 0.05). The BBP group also showed favorable trends in ventricular dimensions. At the 1-year follow-up, the BBP group had a significantly lower atrial arrhythmia burden compared to the RAAP group (0.2 ± 0.5% vs. 2.1 ± 3.5%, P = 0.041). BBP significantly enhances atrial electromechanical synchrony and is associated with signals of favorable atrial remodeling and a lower long-term atrial arrhythmia burden compared to conventional RAAP. These findings support BBP as a potentially preferable pacing strategy for SSS patients, though confirmation in larger, multicenter trials is needed.

Patients treated for sick sinus syndrome may have interatrial conduction disorder leading to atrial fibrillation. This study was aimed to assess the influence of the atrial pacing site on interatrial and atrioventricular conduction as well as the percentage of ventricular pacing in patients with sick sinus syndrome implanted with atrioventricular pacemaker. The study population: 96 patients (58 females, 38 males) aged 74.1 ± 11.8 years were divided in two groups: Group 1 (n = 44) with right atrial appendage pacing and group 2 (n = 52) with Bachmann's area pacing. We assessed the differences in atrioventricular conduction in sinus rhythm and atrial 60 and 90 bpm pacing, P-wave duration and percentage of ventricular pacing. No differences in baseline P-wave duration in sinus rhythm between the groups (102.4 ± 17 ms vs. 104.1 ± 26 ms, p = ns.) were noted. Atrial pacing 60 bpm resulted in longer P-wave in group 1 vs. group 2 (138.3 ± 21 vs. 106.1 ± 15 ms, p < 0.01). The differences between atrioventricular conduction time during sinus rhythm and atrial pacing at 60 and 90 bpm were significantly longer in patients with right atrial appendage vs. Bachmann's pacing (44.1 ± 17 vs. 9.2 ± 7 ms p < 0.01 and 69.2 ± 31 vs. 21.4 ± 12 ms p < 0.05, respectively). The percentage of ventricular pacing was higher in group 1 (21 vs. 4%, p < 0.01). Bachmann's bundle pacing decreases interatrial and atrioventricular conduction delay. Moreover, the frequency-dependent atrioventricular conduction lengthening is much less pronounced during Bachmann's bundle pacing. Right atrial appendage pacing in sick sinus syndrome patients promotes a higher percentage of ventricular pacing.

The purpose of this randomized, prospective trial was to determine if Bachmann's bundle pacing reduces the incidence of AF after CABG. The study included 161 patients with no history of AF who were randomized to three groups. Group 1 included 50 patients as controls. Group 2 included 60 patients who had an epicardial wire placed at the lateral wall of the right atrium. In the 51 patients of group 3, the wire was placed at the Bachmann's bundle. In groups 2 and 3, atrial pacing (AAI 96 beats/min) was initiated immediately after CABG and continued for 5 days. The study endpoint was AF lasting > or = 1 minute. Baseline clinical parameters were similar in all three groups. The incidence of AF was not reduced by pacing (group 1: 42%; group 2:48%; group 3:37%; P = NS). The paced P wave duration was increased in group 2 (129 +/- 14 ms vs group 3: 96 +/- 21 ms; P < 0.05). Paced P wave duration was a risk factor for postoperative AF (odds ratio 1.015; 95% CI 1.0021-1.028; P < 0.05). Analysis comparing the pacing groups revealed a reduction in AF during Bachmann's bundle pacing (50 vs 29%; P < 0.01). Pacing thresholds were significantly better at Bachmann's bundle compared to group 2. In conclusion, an anatomically guided pacing at the Bachmann's bundle does not reduce the overall incidence of postoperative AF compared to controls. However, the Bachmann's bundle offers favorable capabilities for postoperative a trial pacing, and thus it is a preferable site for electrode placement if postoperative atrial pacing is required.

The site of atrial pacing influences atrial activation patterns. It is believed that disparities in atrial activation and repolarization are contributors to the development and recurrence of atrial arrhythmias. We hypothesized that pacing from Bachmann's Bundle would improve clinical outcomes in patients with paroxysmal atrial fibrillation compared to right atrial appendage pacing. Pacing from Bachmann's Bundle results in a significant reduction in P wave duration and improvement in biatrial activation symmetry compared to right atrial appendage pacing. Compared to right atrial appendage pacing, Bachmann's bundle pacing improves sinus rhythm (75% vs. 47% at two years, p < 0.01) in patients with a history of paroxysmal atrial fibrillation. Recent studies have confirmed the benefits of Bachmann's Bundle pacing on atrial activation and rhythm regulation. Thus, Bachman's Bundle should be considered the preferred site for atrial pacing in patients with a history of paroxysmal atrial fibrillation.

It has been proposed that multisite atrial pacing (MSAp) restores atrial electrical activation and prevents atrial fibrillation recurrence; however, single-site Bachmann's bundle pacing (BBp) has also been reported as providing effective atrial resynchronization. Coronary sinus pacing (CSp) leads to reversed impulse propagation within the atria. Acute echocardiographic examination was performed in 15 healthy subjects, and in 25 patients with sinus node dysfunction and recurrent atrial fibrillation during MSAp (atrial leads in the BB area and CS ostium), and single-site BBp and CSp. Regional atrial synchrony was assessed by tissue Doppler echocardiography. Pacing mode had no effect on stroke volume. CSp resulted in right atrial filling diminution, shortened mechanical atrioventricular delay in the right heart and diminished right ventricular inflow. The magnitude of reversion of the physiological right-to-left atrial contraction sequence was most prominent during CSp (15+/-11, 12+/-23, 3+/-21, 42+/-23 ms; control, MSAp, BBp, CSp respectively, P<0.0001). BBp provided the best atrial contraction synchrony, and had a comparable effect on global cardiac function to MSAp. Single-site BBp provides comparable hemodynamics to MSAp and is sufficient to restore atrial contraction synchrony. Single-site CSp induced echocardiographic pacemaker syndrome in the right heart.

Paroxysmal atrial arrhythmias occur in myotonic dystrophy type 1 (MD1) patients frequently. Pacemaker (PM) including detailed diagnostic functions may facilitate the diagnosis and management of frequent paroxysmal atrial tachyarrhythmias that may remain undetected during conventional clinical follow-up. Aim of our study was to evaluate the preventive effects of interatrial septum pacing in the Bachmann's Bundle region on atrial fibrillation (AF) in MD1 patients during 12 months follow up period. Thirty MD1 patients (age 50.3 +/- 7.3; 11 F) who underwent dual chamber PM implantation were randomized at implantation to receive right atrial appendage pacing (16 patients) or Bachmann's bundle pacing (14 patients). No statistically significant difference in the electrical parameters (P wave amplitude, pacing threshold and lead impedance) was found between the two groups at implantation. Patients were followed at 1 month, 3 months, and every 6 months thereafter. They underwent clinical assessment, a standard 12-lead ECG and assessment of device performance at every visit. We counted the number of episodes of atrial arrhythmia occurred during the collection period and the duration of each episode. At 12 months of follow-up, no statistically significant differences in the number of AF episodes or in AF duration were found. Lead parameters remained stable over time and there were no displacements of the electrodes after implantation. Implantation of an atrial-active fixation lead on the atrial septum is safe and feasible. However, this study showed no significant difference between septal pacing and high atrial pacing, using the endpoints of AF duration and number of AF episodes.

Bachmann bundle potential during atrial lead placement: A case series.

Atrial pacing locations that decrease atrial activation and recovery time may be preferable in patients with a history of atrial arrhythmias. This multicenter prospective randomized study compared the efficacy of Bachmann's bundle (BB) region pacing to right atrial appendage (RAA) pacing in patients with recurrent paroxysmal atrial fibrillation (AF). Patients with standard pacing indications (n = 120, 70+/-11 years) were randomized to atrial pacing in either the RAA (n = 57) or BB region (n = 63). Implantation time was similar between groups (88+/-36 min [n = 38] for BB vs 83+/-34 min [n = 34] for RAA). No differences in pacing threshold, impedance, or sensing between BB and RAA groups were observed at implantation or after the 6-week, 6-month, and 1-year follow-up periods. Average length of follow-up was 12.6+/-7.4 months for the BB group and 11.8+/-8.0 months for the RAA pacing group. The percentage of atrial pacing was similar between groups (61%+/-34% RAA vs 65%+/-31% BB at 2 weeks after implant). BB atrial pacing significantly (P < 0.05) shortened p wave duration compared with sinus rhythm (123+/-21 msec vs 132+/-21 msec, n = 50) 2 weeks after implant. In contrast, p wave duration was longer during atrial pacing from the RAA position compared with sinus rhythm (148+/-23 msec vs 123+/-23 msec, n = 37). Additionally, p wave duration was shorter during BB pacing than during RAA pacing. Patients with BB pacing had a higher (P < 0.05) rate of survival free from chronic AF (75%) compared with patients with RAA pacing (47%) at 1 year. BB region pacing is safe and effective for attenuating the progression of AF.