Study On Optimizing Left Bundle Branch Pacing Time Interval With Rate-Adaptive Atrioventricular Delay Algorithm In The Treatment Of Heart Failure

Purpose:The newly developed left bundle branch pacing has achieved cardiac resynchronization therapy(CRT)by pacing below the left bundle branch block,but the optimization of its time interval is still to set a short and fixed atrioventricular room(AVI)to ensure biventricular pacing,which abandons the atrioventricular node physiological atrioventricular delay function,and the right ventricular excitation is nonphysiological during biventricular pacing,and the frequency-adaptive atrioventricular delay algorithm can be dynamically adjusted by AVI In order to coordinate the filling of the atrium to the ventricle,patients with left bundle branch block usually have normal right-hepatic conduction and no pacing in the right ventricle.This suggests that the frequency of adaptive atrioventricular delay is used to optimize the pacing time in the left bundle branch area.The exciting fusion of the right bundle branch with the right bundle may be more physiological.The purpose of this study was to explore whether the frequency-adaptive atrioventricular delay algorithm was used to optimize the pacing time interval in the left bundle branch area,and whether it was better or not better in terms of acute hemodynamic improvement,ECG QRS complex time limit,cardiac function improvement,etc.Inferior to the traditional CRT standard biventricular pacing method.Method:The study was selected from 35 patients with chronic congestive heart failure who were admitted to the First Affiliated Hospital of Kunming Medical University from October 2018 to December 2019 and met the 2016 ESC guidelines for CRT Class Ia indications,of which 28 were dilated cardiomyopathy.7 patients with ischemic cardiomyopathy.All patients agreed to participate in the study and successfully implanted a dual-or triple-chamber pacemaker with RAAV function.The two groups of patients were given the best drug treatment,and were divided according to gender,age,and QRS group.Baseline data such as wave width and New York heart function(NYHA)classification were matched 1:1,and were divided into 20 patients in the left bundle branch pacing group(LBBP)and 15 in the standard double-chamber group(BVP)group.There were 11 cases of true left bundle branch block and 9 cases of non-true left bundle branch block.All patients enrolled were followed up at 3,6,and 1 year postoperatively.Postoperative follow-up and research were completed under the guidance of ECG and echocardiographic indicators.The clinical symptoms improvement(including NYHA cardiac function classification,6-minute walking test),the time limit of the QRS complex of the electrocardiogram,and the improvement of cardiac color Doppler ultrasound evaluation indexes(including conventional ultrasound measurements and ultrasound evaluation of cardiac synchronization indexes)were compared between the two groups.Optimize the application of frequency-adaptive atrioventricular delay to optimize the pacing interval of the left bundle branch area to achieve CRT whether it is better or not worse than the traditional standard double ventricle pacing in terms of acute hemodynamic improvement,cardiac function improvement,and cardiac synchronization indicators SPSS 17.0 statistical software package was used for data analysis.P<0.05 was considered statistically significant.Result:Compared with the standard two-ventricular pacing group,the QRS complex of the left bundle branch pacing group was narrower[(121.7±10.99)ms vs(134.73±10.78)ms,P<0.05],and IVMD was shortened[(59.45±11.51)ms vs(70.06±12.83)ms,P<0.05],AVTI increased[(22.05±2.26)cm vs(20.45±2.11)cm,P<0.05],there was no significant difference in the other indicators between the two groups Significance(P>0.05);in the left bundle branch pacing subgroup,there was no statistically significant difference in each index between the true complete left bundle branch block and the non-true complete left bundle branch block groupConclusion:The application of rate-adaptive atrioventricular delay algorithm to optimize the pacing time interval in the right atrium-left bundle branch area can achieve biventricular resynchronization.