Evaluation Of Cardiac Synchronization In Patients With His Bundle Pacing

Part ? Evaluation of the safety of His bundle pacing[Objective]This study aimed to assess the short-term safety of His bundle pacing.[Methods]Patients who were eligible for permanent pacing according to ACC/AHA/HRS guidelines were selected for His bundle pacing(HBP).During procedure,we firstly attempted to obtain Selective His bundle pacing(S-HBP).While Non-selective His bundle pacing(NS-HBP)was also acceptable.HBP was performed using the C315 His sheath.An intracardiac electrogram was recorded from the lead tip by a digital electrophysiological recording system.The active fixation electrodes were positioned in the RV septum as backup pacing.HBP and RVSP threshold,R-wave amplitude,intracardiac electrogram and pacing lead impedance were measured during implantation.The parameters were followed up for one week and one year.[Results]Between July 2014 and March 2016,a total of 39 eligible patients underwent HBP implantation.Permanent HBP was successful in 37 patients(94%).Two unsuccessful patients finished RVSP.A total of 23 patients underwent effective S-HBP implantation.Fourteen patients underwent NS-HBP implantation.Thirty-three patients were in the RVSP group including two unsuccessful HBP patients.Thirty-one patients had one year follow-up,and 4 patients lost,and two patients were closed HBP because of the higher threshold(>5v),and the remaining patients completed one year follow-up.The threshold at implantation was 1.6±0.7 v/0.42 ms,1.0±0.4 v/0.42 ms and 0.5±0.2 v/0.42 ms in S-HBP,NS-HBP and RVSP groups respectively.One week later,the threshold was stable.In the S-HBP group,the thresholds were stable during implantation,one week and one year,and no statistically difference was observed.In NS-HBP,the initial threshold of implantation decreased slightly in one week,while at one year the threshold was(1.5±0.6 v,0.42 ms).There was no significant difference(1.5±0.6 vs 1.6±0.7,p=0.61)compared with S-HBP.Both of the thresholds in two groups were acceptable.The R-wave amplitude was significantly higher in the RVSP group than in the NS-HBP group(10.6±6.3 mv vs 5.8±4.5 mv,p<0.05).The R-wave amplitudes in the S-HBP group were smaller than that in the NS-HBP group(2.6±1.5 mv vs 5.8±4.5 mv,p<0.05).Pacing impedances in three groups were in normal range.The follow-up of the two groups was stable and no statistically significant difference.[Conclusion)HBP had high succsee rate of implantation.Meanwhile,whether S-HBP or NS-HBP were security and acceptable.Part ? The effect of His bundle pacing on cardiac electrical and mechanical synchronization[Objective]This study aimed to assess the acute effect of Selective His bundle pacing(S-HBP),Non-selective His pacing(NS-HBP)and right ventricular septum pacing(RVSP)patients with narrow QRS complex and normal left ventricular ejection fraction(LVEF)on electrical synchrony and left ventricular(LV)mechanical synchrony using electrocardiogram and phase analysis of gated single photon emission computed tomography(SPECT)myocardial perfusion imaging(MPI).[Methods]According to the ACC/AHA/HRS guidelines,between July 2014 and March 2016,patients who met the indications for permanent pacing were selected for HBP.During procedure,we firstly attempted to obtain S-HBP.While NS-HBP was also acceptable.We also recorded low voltage and high voltage thresholds for S-HBP and NS-HBP.The 12-lead electrocardiograms of intrisic and in different output in each patient were also recorded,which indicated the electrical synchronization.In one week after implantation,HBP patients underwent resting gated SPECT MPI scans in low output pacing,high output pacing and RVSP mode,and we measured the left ventricular mechanical synchrony parameters of phase standard deviation(PSD)and phase histogram bandwidth(PHB).[Results]In the S-HBP low output mode and high output groups,there were no differences between paced QRSd and the intrinsic QRSd.The QRSd was no difference between the S-HBP low output mode and the high output mode.Paced QRSd was significantly shorter both in the S-HBP low and high output mode than in the RVSP group.The QRSd in the RVSP group was markedly wider than the intrinsic QRSd.In the NS-HBP low output mode group,paced QRSd was wider than the intrinsic QRSd.The QRSd in low output mode was wider than in high output mode.In the NS-HBP high output mode group,QRSd was no difference from the intrinsic.The QRSd in NS-HBP low output mode was also significantly shorter than in the RVSP group.In the S-HBP group,PSD and PHB showed no significant differences between low output and high output modes.However,PSD and PHB in the RVSP group were significantly higher than in the S-HBP low output and high output mode.In the NS-HBP group,PSD and PHB in the high output mode were significantly lower compared to the low output mode.In the RVSP group,PSD and PHB were significantly higher than both in the NS-HBP low output and high output modes.[Conclusion]Phase analysis of gated single photon emission computed tomography(SPECT)myocardial perfusion imaging(MPI)is a useful technique to evaluate LV mechanical synchrony in His bundle pacing.S-HBP and high output NS-HBP have better electrical and mechanical synchrony.Part ? Evaluation of Cardiac Mechanical Synchronization of His bundle pacing using Three-dimensional Echocardiography[Objective]This study aimed to assess the acute effect of His bundle pacing(HBP)and right ventricular septum pacing(RVSP)patients with narrow QRS complex and normal cardiac function on ventricular mechanical synchrony using real-time three-dimensional echocardiography.[Methods]According to the ACC/AHA/HRS guidelines,between July 2014 and March 2016,patients who met the indications for permanent pacing were selected for HBP.During procedure,we firstly attempted to obtain S-HBP.While NS-HBP was also acceptable.One week after implantation,these patients accepted three-dimensionexamination.During three-dimensional echocardiography examine,pacemaker were programmed to Selective His bundle pacing(S-HBP),Non-selective His bundle pacing(NS-HBP)or RVSP mode.The data we collected included QRS duration?PR internal and synchronous data which consists of interventricular mechanical delay(IVMD)?LV filling ratio(LVFT/R-R)?the maximal difference of the time to the point with minimal systolic volume of 12,16 segments(Tmsv 12-SD,Tmsv 16-SD).LVFT/R-R represents interventricular synchronicity and IVMD represents the synchronization between the left and right ventricles.Tmsv 12-SD and Tmsv 16-SD LV represent the synchronization of the left ventricle.[Results]There were no significant differences in LVFT/R-R between HBP and RVSP.While the synchronization parameters such as IVMD,Tmsv 12-SD,Tmsv 16-SD in HBP group were significantly better than that of RVSP group.Moreover,These synchronization parameters(IVMD,Tmsv 12-SD,Tmsv 16-SD)in S-HBP and NS-HBP groups were also better than RVSP group.While there were no difference between S-HBP group and NS-HBP group.[Conclusion]Real-time three-Dimension echocardiography is a useful technique to evaluate LV mechanical synchrony in His bundle pacing.HBP have better mechanical synchrony than RVSP.