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]