Ventricular Outflow Tract Septal Pacing Research Articles

Left bundle branch area pacing improving the left atrial outcomes in pace-dependent patients compared with right ventricular outflow tract septal pacing.

Recent studies suggested that the left bundle branch area pacing (LBBAP) has a better efficacy to reduce QRS duration and produce a lower pacing threshold than the conventional right ventricular outflow tract septal pacing (RVOP), which resulted in a better cardiac function and ventricular synchronization. However, whether the LBBAP has a better efficacy in improving left atrial structure, function in pace-dependent patients compared with RVOP has not been well studied. The purpose of this study was to compare the atrial outcomes of pace-dependent patients who received LBBAP or RVOP procedures. A total of 72 patients (including II° AVB, high AVB, and III° AVB, excluding atrial fibrillation patients with atrioventricular block) consecutively enrolled in this single-center prospective clinical study and randomly assigned to the RVOP group and the LBBP group with 36 patients. All patients were pace-dependent. The changes in echocardiogram, speckle-tracking echocardiography, brain natriuretic peptide (BNP), and 6-min walking distance were documented and compared between two groups at baseline, 7 days, 1, 3, and 6 months after the implantation. There were no significant differences in baseline characteristics between thetwo groups. The results of the study were as following: (1) left atrial structure index: Our study indicated that there are no significant differences in left atrial anteroposterior dimension (LAAPD), left atrial superoinferior dimension, and left atrial mediolateral dimension between two groups. While the LAAPD in the LBBAP group was significantly reduced at 6 months after implantation ([38.22 ± 2.17] mm vs. [34.13 ± 1.59] mm, p < .05). (2) Left atrial strain index: We observed that the S% was significantly improved in both groups at 3 and 6 months after implantation but more prominent in the LBBAP group at 6 months (36.94 ± 11.67 vs. 25.87 ± 8.93, p = .01). SRs, SRe were improved in the RVOP group at 6 months after implantation but was further significantly increased in the LBBAP group. Similarly, the SRa in the LBBAP group was significantly better than the RVOP group after 6 months (-2.11 ± 0.75 vs. -2.51 ± 0.70, p = .04). (3) Left atrial ejection index: LAEF% in the LBBAP group was significantly improved compared with the RVOP group (60.02 ± 1.88 vs. 53.65 ± 2.45, p = .047) and baseline (60.02 ± 1.88 vs. 49.68 ± 2.75, p < .05) at 6 months after the surgery. (4) Left ventricular ejection index: The LVEF% in the LBBAP group was significantly increased than the RVOP group after 6 months (69.14 ± 4.99 vs. 64.60 ± 4.84, p = .01) and the BNP level was significantly lower in the LBBAP group compared with the RVOP group at 7 days, 1, 3, and 6 months after implantation (p < .05). (5) 6-min walking distance: the 6-min walking distance was significantly increased at 3 and 6 months after implantation compared with that before (p < .05) in both groups, but was more prominent in LBBAP groups ([483.03 ± 11.02] m vs. [431.09 ± 10.69] m,p < .05). Compared with the traditional RVOP, the LBBAP procedure increased left atrial myocardial stress as well as left atrial ejection in pace-dependent patients at follow-up to 6 months.

Posterior right ventricular outflow tract septal pacing using His-bundle catheter guidance – Is it the closest we get to LV pacing?

Posterior right ventricular outflow tract septal pacing using His-bundle catheter guidance – Is it the closest we get to LV pacing?

Comparison of cardiac function between left bundle branch pacing and right ventricular outflow tract septal pacing in the short-term: A registered controlled clinical trial

BackgroundThe novel method of left bundle branch pacing (LBBP) has been reported to produce a narrower QRS duration and lower pacing threshold than right ventricular outflow tract septal pacing (RVOP). However, whether LBBP is superior to traditional RVOP in improving cardiac function still lacks sufficient evidence. ObjectiveThe purpose of this study was to compare the changes in cardiac function (especially in brain natriuretic peptide (BNP)levels, left atrial function, and left ventricular diastolic function) within 7 days between LBBP and RVOP. Methods and resultsA single-centre prospective controlled registered clinical study was conducted with 84 patients with bradycardia indications. Forty-two patients underwent RVOP, and 42 patients underwent LBBP. The pacemaker parameters were adjusted so that the ventricular ratio was over 90% and rate was 60–70 bpm. The changes in BNP levels and echocardiogram and speckle-tracking echocardiagraphy findings were compared between the two groups before and within 7 days after implantation: (1) BNP: there was no significant difference in BNP level between the two groups before and 1 day after implantation, while the LBBP group had significantly lower levels than the RVOP group on day 7 [(65.15 ± 56.96)pg/ml vs.(129.82 ± 101.92)pg/ml, P < 0.001]. (2) Cardiac echocardiography: the e’ value of the LBBP group was higher than that of the RVOP group 7 days after implantation[(6.39 ± 2.65) cm/s vs. (5.45 ± 1.35)cm/s, P = 0.049]. The E/e’ and peak E-wave velocity in the LBBP group decreased significantly after 7 days [16.57 ± 6.55 vs. 12.75 ± 5.16 P = 0.043, (88.6 ± 24.37)cm/s vs. (75.68 ± 28.10)cm/s P = 0.030]; in contrast, there were no significant changes in the RVOP group [14.13 ± 3.85 vs.14.10 ± 4.85 P = 0.50, (77.33 ± 21.14)cm/s vs. (74.45 ± 23.03)cm/s P = 0.56). (3)Speckle-tracking echocardiagraphy: there was no significant difference in left atrial strain or the strain rate between the LBBP and RVOP groups，but the absolute values of left atrial strain and strain rate in the LBBP group increased, while those in the RVOP group decreased. ConclusionThis study demonstrates that compared to RVOP, LBBP can increase left ventricular early diastolic function, improve BNP levels, and has a tendency to increase left atrial myocardial elasticity and left atrial strain capacity in the short term in pacemaker-dependent patients.

Electrocardiographic predictors of validated right ventricular outflow tract septal pacing for correct localization of transthoracic echocardiography.

Electrocardiographic (ECG) characteristics of true right ventricular outflow tract (RVOT) septal pacing have not been clearly demonstrated. We hypothesized that ECG parameters would help operators differentiate true RVOT septum from non-septal septum. We analyzed 151 patients who underwent pacemaker implantation with a ventricular lead in the RVOT. Transthoracic echocardiographic (TTE) determination of pacing sites was applied in all patients after implantation. A 12-lead ECG was recorded during forced ventricular pacing. According to TTE orientation, pacing at the RVOT septum was achieved in 94 patients (62.3%). Compared with nonseptal pacing, septal pacing had significantly shorter QRS duration (139.2 ± 18.5 ms vs 155.5 ± 14.7 ms; P < 0.001). More frequent negative or isoelectric QRS vector in lead I (76% vs 32%; P < 0.001), lead II/III R-wave amplitude ratio < 1 (52% vs 25%; P = 0.001), and aVR/aVL QS-wave amplitude ratio < 1 (59% vs 32%; P = 0.001) were observed in septal pacing. Transitional zone (TZ) score (3.8 ± 0.96 vs 4.2 ± 0.90; P = 0.004) and TZ index (0.3 ± 0.5 vs 0.6 ± 0.7; P = 0.008) were significantly lower in septal pacing than in nonseptal pacing, respectively. In multivariate analysis, paced QRS duration and negative or isoelectric QRS vector in lead I independently predicted RVOT septal pacing (P < 0.001). At ROC curve analysis, paced QRS duration ≤145 ms identified RVOT septal pacing with 85.1% sensitivity and 78.9% specificity. This study reveals the heterogeneity of lead placement within the RVOT. Narrower paced QRS duration and negative or isoelectric QRS vector in lead I independently predict RVOT septal pacing.

Right ventricular outflow tract septal pacing versus apical pacing: A prospective, randomized, single-blind 5-years follow-up study of ventricular lead performance and safety

Lead placement for ventricular pacing variably impacts the physiological benefit of the patient. This study evaluated the ventricular lead performance and safety of right ventricular outflow tract septal pacing in patients with bradyarrhythmia in South China over 60-month follow-up. Totally, 192 patients (108 males, and 84 females, 63±21 years old) with bradyarrhythmia were randomly divided into two groups. The right ventricular outflow tract septum (RVOTs) group had lead placement near the septum (n=97), while the right ventricular apex (RVA) group had a traditional apical placement (n=95). RV septal lead positioning was achieved with a specialized stylet and confirmed using fluoroscopic projection. All patients were followed up for 60 months. Follow-up assessment included stimulation threshold, R-wave sensing, lead impedance and lead complications. The time of electrode implantation in both the ROVTs and RVA groups were significantly different (4.29±0.61 vs. 2.16±0.22 min; P=0.009). No differences were identified in threshold, impedance or R-wave sensing between the two groups at 1st, 12th, 36th and 60th month during the follow-up period. No occurrence of electrode displacement, increased pacing threshold or inadequate sensing was found. The long-term active fixation ventricular electrode performance in RVOTs group was similar to that in RVA group. RVOTs pacing near the septum using active fixation electrodes may provide stability during long-term follow-up period.

Right Ventricular Outflow Tract Septal Pacing Is Superior to Right Ventricular Apical Pacing

BackgroundThe effects of right ventricular apical pacing (RVAP) and right ventricular outflow tract (RVOT) septal pacing on atrial and ventricular electrophysiology have not been thoroughly compared.Methods and ResultsTo identify a more favorable pacing strategy with fewer adverse effects, 80 patients who had complete atrioventricular block with normal cardiac function and who were treated with either RVAP (n=42) or RVOT septal pacing (n=38) were recruited after an average of 2 years of follow‐up. The data from electrocardiography and echocardiography performed before pacemaker implantation and at the end of follow‐up were collected. The patients in the RVOT septal pacing and RVAP groups showed similar demographic and clinical characteristics before pacing treatments. After a mean follow‐up of 2 years, the final maximum P‐wave duration; P‐wave dispersion; Q‐, R‐, and S‐wave complex duration; left atrial volume index; left ventricular end‐systolic diameter; ratio of transmitral early diastolic filling velocity to mitral annular early diastolic velocity; and interventricular mechanical delay in the RVOT septal pacing group were significantly less than those in the RVAP group (P<0.05). The final left ventricular ejection fraction of the RVOT septal pacing group was significantly higher than that of the RVAP group (P<0.05).ConclusionsCompared with RVAP, RVOT septal pacing has fewer adverse effects regarding atrial electrical activity and structure in patients with normal cardiac function.

Right Ventricular Outflow Tract Septal Pacing: Long‐Term Follow‐Up of Ventricular Lead Performance

The detrimental effects of right ventricular apical pacing on left ventricular function has driven interest in selective site pacing, predominantly on the right ventricular outflow tract (RVOT) septum. There is currently no information on long-term ventricular lead electrical performance from this site. A total of 100 patients with ventricular lead placement on the RVOT septum undergoing pacemaker implantation for bradycardia indications were analyzed retrospectively. Lead positioning was confirmed with the use of fluoroscopy. Long-term (1 year) follow-up was obtained in 92 patients. Information on stimulation threshold, R-wave sensing, lead impedance, and lead complications were collected. Lead performance at the RVOT septal position was stable in the long term. Ventricular electrical parameters were acceptable with stable long-term stimulation thresholds, sensing, and impedance for all lead types. One-year results demonstrated mean stimulation threshold of 0.71 +/- 0.25 V, mean R wave of 12.4 +/- 6.05 mV, and mean impedance values of 520 +/- 127 Omega. There were no cases of high pacing thresholds or inadequate sensing. This study confirms satisfactory long-term performance with leads placed on the RVOT septum, comparable to traditional pacing sites. It is now time to undertake studies to examine the long-term hemodynamic effects of RVOT septal pacing.

Right Ventricular Outflow Tract Septal Pacing: Long-Term Follow-Up of Ventricular Lead Performance

Background: The detrimental effects of right ventricular apical pacing on left ventricular function has driven interest in selective site pacing, predominantly on the right ventricular outflow tract (RVOT) septum. There is currently no information on long-term ventricular lead electrical performance from this site. Methods: A total of 100 patients with ventricular lead placement on the RVOT septum undergoing pacemaker implantation for bradycardia indications were analyzed retrospectively. Lead positioning was confirmed with the use of fluoroscopy. Long-term (1 year) follow-up was obtained in 92 patients. Information on stimulation threshold, R-wave sensing, lead impedance, and lead complications were collected. Results: Lead performance at the RVOT septal position was stable in the long term. Ventricular electrical parameters were acceptable with stable long-term stimulation thresholds, sensing, and impedance for all lead types. One-year results demonstrated mean stimulation threshold of 0.71 ± 0.25 V, mean R wave of 12.4 ± 6.05 mV, and mean impedance values of 520 ± 127 Ω. There were no cases of high pacing thresholds or inadequate sensing. Conclusions: This study confirms satisfactory long-term performance with leads placed on the RVOT septum, comparable to traditional pacing sites. It is now time to undertake studies to examine the long-term hemodynamic effects of RVOT septal pacing.