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

Summary： Lead placement for ventricular pacing variably impacts the physiological benefit of the pa- tient. 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, 63-4-21 years old） with bradyarrhythmia were randomly divided into two groups. The right ventricular outflow tract septum （RVOTs） group had lead placement near the sep- tum （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 projec- tion. 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 dif- ferences were identified in threshold, impedance or R-wave sensing between the two groups at 1 st, 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.

Application of permanent left bundle branch pacing in patients with bradycardia after cardiac surgery

Background The study was to access the feasibility and effectiveness of permanent left bundle branch pacing(LBBP)in patients with bradycardia after cardiac surgery,in comparison with conventional right ventricular outflow tract septal pacing(RVOSP).Methods A total of 50 patients with cardiac surgery who underwent permanent pacemaker implantation(PPI)were enrolled,21 patients underwent LBBP(LBBP group)and 29 patients underwent RVOSP(RVOSP group).Pacing electrical parameters,QRS duration(QRSd),echocardiographic measurements,lead and device related complications were obtained at procedure and during follow-ups.Results There were no statistically significant differences between the LBBP group and the RVOSP group at procedure and at the twelfth month’s follow-up in pacing thresholds(0.64±0.16 V vs.0.63±0.22 V)and(0.91±0.28 V vs.0.85±0.20 V),R-wave amplitude(16.68±4.52 mV vs.15.09±4.53 mV)and(14.41±8.65 mV vs.12.65±6.17 mV),pacing impedances(719.24±152.65Ωvs.639.13±177.04Ω)and(534.01±96.92Ωvs.499.18±77.87Ω).But the average ventricular pacing percentage(VP%)at the first month’s follow-up(81.96±32.06%vs.58.37±42.96%)and at the twelfth month’s follow-up(84.65±35.84%vs.53.57±38.47%)showed significant difference between two groups(P<0.05);The LBBP group produced narrower QRSd(121.13±23.91 ms)than the RVOSP group(158.00±9.69 ms)(P=0.011).There were no significant differences between the LBBP group and the RVOSP group at pre-procedure and at the twelfth month’s follow-up in echocardiographic parameters,which included left ventricular end-diastolic dimension(LVEDD)(48.76±7.08 mm vs.47.34±6.91 mm)and(50.58±10.33 mm vs.45.97±7.11 mm),left ventricular ejection fraction(LVEF)(58.33±12.64%vs.61.50±8.40%)and(55.85±16.35%vs.61.50±10.52%),and area of tricuspid regurgitation(TR)(2.79±3.65 cm2 vs.2.85±2.26 cm2)and(3.09±2.34 cm2 vs.2.95±1.92 cm2).No lead and device related complication was observed during follow-ups.Conclusions LBBP is feasible and effective in patients with bradycardia after cardiac surgery.LBBP produces narrow QRSd,which may be a preferred pacing strategy for patients after cardiac surgery.[S Chin J Cardiol 2021;22(1):13-20]