Research Progress in the Effect of His-Purkinje Conduction System Pacing on Cardiac Function / 中山大学学报(医学科学版)

Cardiac pacing is an effective treatment for cardiac pacing and conduction dysfunction and severe heart failure. However， the conventional right ventricular pacing may increase the incidences of heart failure and atrial fibrillation， and biventricular pacing has a relatively high non-response rate. As a new technique of physiological pacing， a number of studies in recent years have been conducted to show the stability of pacing parameters and good cardiac synchronization of his-purkinje system pacing. This article reviews the current status of research and progress in the effects of his-purkinje conduction system pacing on cardiac function， so as to provide a theoretical basis for promoting the development of this technology.

Prevalence and Clinical Predictors of Right Ventricular Dysfunction in Patients with Chronic Right Ventricular Pacing

BACKGROUND AND OBJECTIVES: Numerous clinical studies have demonstrated chronic right ventricular (RV) pacing induced left ventricular (LV) dyssynchrony and LV systolic dysfunction in patients with permanent pacemaker. However, only a limited number of studies have focused on RV dysfunction. We sought to determine the prevalence and identify the clinical predictors of RV dysfunction in patients with chronic RV pacing. SUBJECTS AND METHODS: We enrolled 72 patients (mean age 72.7±11.1 years, men 36.1%) who underwent permanent pacemaker implantation without RV dysfunction in baseline examination. Baseline clinical characteristics, laboratory data, echocardiographic parameters and pacing profiles were assessed. Follow up 2-dimentional echocardiography was used to identify the presence of RV dysfunction. RESULTS: We divided patients based on the criteria of either presence or absence of RV dysfunction, where RV dysfunction is defined as decreased tricuspid annulus systolic velocity (<11 cm/sec) in tissue Doppler image. Sixteen patients (22.2%) in our study showed meaningful RV dysfunction. Patients with RV dysfunction had lower LV ejection fraction (57.5±10.8% versus 64.6±9.1%, p<0.05) and higher B-type natriuretic peptide (BNP) levels (700.3±152.9 pg/mL versus 329.4±332.4 pg/mL, p<0.05) compared to patients without RV dysfunction. Implantation of VVI type pacemaker was associated with presence of RV dysfunction (81.3% versus 33.3%, p<0.05). Higher cumulative ratio of total RV pacing was associated with increased tendency for RV dysfunction. No statistically significant correlation was observed between the groups (70.7±13.2% in RV dysfunction group, 61.7±38.3% in non-RV dysfunction group, p=0.094). CONCLUSION: In this study, meaningful proportion of patients showed chronic RV pacing induced RV dysfunction. RV dysfunction was associated with lower LV systolic function, higher BNP level and VVI type pacemaker.

Impact of paced QRS duration on heart function in patients with right ventricular apical pacing / 实用医学杂志

Objective To investigate the impact of paced QRS duration (pQRSd) on heart function in patients with right ventricular apical pacing. Methods Seventy-six patients with Ⅲ° atrioventricular block received pacemaker treatment were enrolled and randomized into group A (pQRSd 0.05). At 24 months after implanting, LAD、LVEDD、LVESD of group B increased significantly compared with those of group A [LAD,( 44.5 ± 6.2) mm vs (41.6 ± 5.1) mm, LVEDD, (52.7 ± 9.3) mm vs (48.2 ± 7.5) mm, LVESD, (37.5 ± 5.6) mm vs (33.8 ± 4.9)mm, each P 0.05)between two groups during 24-month follow-up. Conclusion The prolonged paced QRS duration has a detrimental effect on long-term cardiac function during RVA pacing in patients with Ⅲ°atrioventricular block.

Controlled transient respiratory arrest along with rapid right ventricular pacing for improving balloon stability during balloon valvuloplasty in pediatric patients with congenital aortic stenosis - A retrospective case series analysis.

Rapid right ventricular pacing is safe, effective, and established method to provide balloon stability during balloon aortic valvuloplasty (BAV). Controlled transient respiratory arrest at this point of time may further reduce left ventricular stroke volume, providing an additional benefit to maintain balloon stability. Two groups were studied. Among the 10 patients, five had rapid pacing alone (Group A), while the other five were provided with cessation of positive pressure breathing as well (Group B). The outcomes of BAV in the two groups of patients were studied. One patient in Group A had failed balloon dilatation even after the fourth attempt, while in Group B there were no failures. The peak systolic gradient reduction was higher in Group B (70.05% in comparison to 52.16% of group A). In Group A, five subjects developed aortic regurgitation (grade 2 in four and grade 3 in one, while no grade 3 aortic regurgitation developed in any patient in Group B). Controlled transient respiratory arrest along with rapid ventricular pacing may be effective in maintaining balloon stability and improve the outcome of BAV.

Improvement of minimizing ventricular pacing in dual chamber pacemaker / 中国实用内科杂志

The data from clinical studies have shown that conventional dual chamber pacing results in high percentages of right ventricular apical pacing,which causes electromechanical desynchronization and has been linked to an increased risk of heart failure and atrial fibrillation.Nowadays,we can use some special algorithms to minimize ventricular pacing,promote atrioventricular conduction and improve hemodynamics in patients with pacemakers.This review summarizes the genesis,some algorithms and clinical studies about minimizing ventricular pacing.

Alterations in Myocardial Perfusion and Regional Wall Motion in Patients with Permanent Pacemaker

BACKGROUND: The effect of right ventricular pacing on myocardial perfusion and regional wall motion is not well known, although some studies have suggested that it may be adverse. We investigated the effects of right ventricular pacing on myocardial perfusion and regional wall motion in patients with permanent pacemakers. METHOD: Thirty patients receiving permanent pacemakers for complete heart block or sick sinus syndrome were included in this study. All the patients showed normal coronary angiograms. Myocardial scintigraphy and two-dimensional echocardiography were performed to assess myocardial perfusion and to evaluate regional wall motion and global function of the left ventricle (LV). RESULTS: 1) Mean age was 66.2+/-8.2 (41-84) years, and the male-to-female ratio was 1 : 1.7 (11 male, 19 female). Indications for permanent pacemaker implantation were complete atrioventricular (AV) block in 21 patients and sick sinus syndrome in 9. The selected pacing modes were VVI in 14 patients, DDD in 8, VDD in 6, and AAI in 2. LV ejection fraction estimated by 2-dimensional echocardiography was 62.7+/-5.8 (53-86)%. 2) Perfusion defects were noted in 26 (87%) patients including 25 (89%) out of 28 patients with ventricular pacing modes such as VVI, DDD, and VDD, and 1 (50%) out of 2 patients with AAI mode. Locations of perfusion defects were septal in 19 (63%) patients, inferior in 17 (57%), apical in 16 (53%), lateral in 3 (10%), and anterior in 2 (7%). Extent of maximal perfusion defects was 17.0+/-9.5 (0-44)%. 3) Regional wall motion abnormalities were noted mainly over the apical region of the LV in 26 (93%) of 28 patients with ventricular pacing. However, LV ejection fraction did not differ significantly before and early after implantation of the pacemaker (62.7+/-5.8% vs. 61.0+/-5.8%, p-0.313). CONCLUSIONS: Right ventricular apical pacing frequently caused myocardial perfusion defects and regional wall motion abnormalities. These might be due to abnormal ventricular activation and abnormal interventricular septal motion. The long-term effects of these abnormalities remain to be determined, and the pacing technique to minimize these adverse effects should be developed.