起搏器电极植入选择部位起搏新进展.ppt

* Early work by Karpawich demonstrated that, in contrast to RV apical pacing, RV septal pacing (with participation of the conduction system) does not result in myofibrillar disarray of the LV free wall. These illustrations are from a canine heart. * The “Pacing Mode” trials (DANISH I., II, CTOPP and MOST) all required very long follow-up periods before demonstrating negative effects of RVA pacing. Even the DAVID trial, that looked at ICD patients with relatively poor LV function and no indication for pacing, still required a significant follow-up period (6 mo) to demonstrate the negative effects of RVA pacing. * Recently reported results of longer-term trials show a consistent benefit of selective site RV pacing. * Main Points: LV function changes with pacing site as evidenced by changes in the width of the PV loop. Interestingly, the optimal site of pacing may vary with different patients.1 The results of the study conducted by Hung-Fat Tse, MD, et. al., demonstrate that RVA pacing leads to a high incidence of regional myocardial perfusion and wall motion abnormalities near the sites of electrical stimulation, which increase with the duration of pacing. These functional abnormalities during RVA pacing are associated with impairment of LV diastolic function and progressive deterioration of regional LVEF over time in regions remote from the site(s) of electrical stimulation, which result in a significant reduction in global LV function. Pacing at the RVOT is associated with more synchronous ventricular activation with a narrower QRS duration, and lower incidence of regional myocardial perfusion and wall motion abnormalities, compared with RVA pacing, and it preserves global LV systolic and diastolic function over long-term follow-up.2 Asynchronous electrical activation during ventricular pacing has been shown to reduce LV function, and to alter regional myocardial blood flow and work.2 1Lieberman RA, et. al. Pressure-Volume Plane Analysis to Determine Optimal