The influence of the permanent pacemaker on myocardial tissue characterization

This study was designed to investigate how pacemaeker would influence the myocardial tissue, accessing tissue characterization by ultrasonic integrated backsatter (IBS). Study Group included 30 cases underwent pacemaker implantation from Jan. 1 1988 to Apr. 30 2002. The group was divided into two subgroups; one group included patients implanted DDD mode pacemaker (DDD:16cases) and the other included patients implanted VVI mode pacemaker (VVI:14cases). Parasternal short axis view was shown using SONOS 5500 and recorded with IBS mode. The ROI was set in the interventricular anteroseptum (AS) and the posterior wall (PW) and measured the value of IBS (IB), then was corrected to reduce the IB of left ventricular cavity as standard value from IB (CIB). The amplitude of cyclic variation (CVIB) was defined the difference between enddiastolic IB and endsystolic IB. There was no correlation between CIB and CVIB in AS or PW and the term during pacing but CIB in both AS and PW in VVI was greater than that in DDD (15.3 ± 2.1:12.5 ± 3.4 p