Cumulative Pacing Research Articles

Cardiac resynchronization therapy is appropriate for all patients requiring chronic right ventricular pacing: the pro perspective.

Long-term right ventricular pacing has deleterious effects on the left ventricle (LV). The risk of pacemaker-induced cardiomyopathy (PICM) seems to be lower in patients with a normal LV ejection fraction (LVEF). Patients developing PICM respond favorably to a cardiac resynchronization therapy upgrade, suggesting that the dysfunction is partially reversible. Biventricular pacing has emerged as a treatment and/or prevention of PICM. Cumulative pacing greater than 40% of the time is considered the most important risk factor for PICM. No organizational guidelines exist for preventive biventricular pacing. The decision to pursue biventricular pacing should be individualized.

Cumulative Pacing During Antibradycardia Therapy

Cumulative Pacing During Antibradycardia Therapy

Long‐Term Effect of Septal or Apical Pacing on Left and Right Ventricular Function after Permanent Pacemaker Implantation

Right ventricular (RV) pacing is associated with left ventricular (LV) dysfunction. However, the effects of RV pacing at different sites on both LV and RV function have rarely been studied before. We want to determine whether different RV pacing sites differentially affect LV and RV deformation by using speckle tracking echocardiography (STE). The subjects were 73 patients who had undergone dual-chamber permanent pacemaker implantation and did not have structural heart diseases. LV and RV global longitudinal strains (GLS) were measured using STE to determine subtle changes in LV function. Twenty-three patients without pacing after pacemaker implantation served as controls; 14 and 36 patients showed apical and septal pacing, respectively. There were no significant intergroup demographic differences. LV biplane ejection fractions in the septal- and apical-pacing groups were significantly lower than those in the controls. The GLS LV values were similar between the control and septal-pacing groups, but they were lower in the apical-pacing group. Multivariate analysis revealed that cumulative pacing loads and apical pacing were independent factors associated with lower GLS LV values. The GLS RV values were similar between the control and apical-pacing groups; however, they were lower in the septal-pacing group. We concluded that patients with septal pacing have significantly higher GLS LV and more modest decreases in GLS RV values than patients with apical pacing. Thus, septal pacing may be not necessarily preferable in patients without significant heart disease undergoing dual-chamber permanent pacemaker implantation.

146 Is there an association between thrombogenesis markers and atrial fibrillation burden in pacemaker population?

<h3>Background and Objectives</h3> Contemporary pacemaker devices are able to quantify atrial high-rate episodes (AHREs) and atrial fibrillation burden (AFB) accurately. In this study, we aim to assess the relationship of thrombogenesis markers in association with AHREs and AFB. <h3>Methods</h3> We studied 87 patients with dual-chamber pacemaker. Patients on warfarin were excluded. AHREs were defined as atrial-rate ≥220 beats/min and ≥5 minutes. AFB and percentage of cumulative pacing were derived from pacemaker diagnostics. Plasma levels of von Willebrand factor (vWf), tissue factor (TF), soluble P-selectin (P-sel) and D-dimer (DDM) were analysed using ELISA. <h3>Results</h3> Baseline characteristics and co-morbidities were comparable between groups (Abstract 146 table 1). Patients with AHREs had significantly higher cumulative percentage ventricular pacing (p=0.012). There were no significant differences in levels of vWf, TF, P-sel and DDM between patients with and without AHREs. The AFB ranged from 0 to 99% in AHRE group. TF (r=0.516, p=0.086), P-sel (r=0.795, p&lt;0.001) and DDM (r=0.643, p=0.045) correlated with AFB. On linear regression analysis, both P-sel and DDM were independently associated with AFB (p&lt;0.05). <h3>Conclusion</h3> AFB is independently associated with increased indices of P-sel and D-dimer which indicate platelet activation and thrombosis respectively.

The Clinical Implications of Cumulative Right Ventricular Pacing in the Multicenter Automatic Defibrillator Trial II

This study was designed to assess whether right ventricular pacing in the implantable cardioverter defibrillator (ICD) arm of the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II was associated with an unfavorable outcome. Data on the number of ventricular paced beats were available in 567 (76%) of 742 MADIT II patients with ICDs. The number of ventricular paced beats over the total number of beats showed a bimodal distribution with patients being predominantly paced or nonpaced. Therefore, patients were dichotomized at 0-50% and 51-100% of cumulative pacing with median pacing rate 0.2% and 95.6%, respectively. Endpoints included new or worsening heart failure, appropriate ICD therapy for VT/VF, and the combined endpoint of heart failure or death. Clinical features associated with frequent ventricular pacing included age >or=65 years, advanced NYHA heart failure class, LVEF < 0.25, first degree AV and bundle branch block, and amiodarone use. During follow-up, 119 patients (21%) had new or worsened heart failure, 130 (23%) had new or worsened heart failure or death, and 142 (25%) had appropriate therapy for VT/VF. In comparison to patients with infrequent pacing, those with frequent pacing had significantly higher risk of new or worsened heart failure (hazard ratio = 1.93; P = 0.002) and VT/VF requiring ICD therapy (HR = 1.50; P = 0.02). Patients in MADIT II who were predominantly paced had a higher rate of new or worsened heart failure and were more likely to receive therapy for VT/VF. These results suggest the deleterious consequences of RV pacing, particularly in the setting of severe LV dysfunction.