Logic Programs with Consistency-Restoring Rules

Abstract

This study used multi-detector row CT (MDCT) to evaluate the regional geometric parameters of left ventricle (LV) in patients and dogs after right ventricular apical (RVA) pacing. First, we measured and compared the global and regional wall motion parameters derived from MDCT images between three patients post RVA pacing and seven age-matched healthy subjects. The LV ejection fraction (LVEF), LV end-diastolic volume and LV end-systolic volume were measured. We also measured the regional wall thickness, wall thickening and regional wall motion in 12 different segments of the LV. Second, we performed MDCT scan on five dogs as the study group (pacing wire + RVA pacing, 2 months) and four dogs as the sham control group (pacing wire, 2 months). The global and regional geometric parameters were compared within both human and canine groups. Compared with normal subjects, patients post RVA pacing had low LVEF (60.4 ± 10.5 vs. 33.2 ± 17.6, P = 0.014), impaired regional wall thickening and regional wall motion, particularly in segments near the pacing lead. Some segments near the pacing lead were showing dyskinesia after pacing. These findings were successfully reproduced in the canine model. We found that RVA pacing can result in impaired regional wall thickening and regional wall motion, particularly in segments near the pacing lead.