Mechanism of decrease in the atrial potential after implantation of a single-lead VDD pacemaker: atrial histological changes after implantation of a VDD pacemaker lead in XXXX .

@entity1 @entity713 @entity235 @entity1184 @entity262 @entity2224 @entity715
The single-lead @entity262 ( @entity262 ) enables @entity2224 with only one lead in @entity1 with an @entity713 . There are some cases in which the atrial potential decreases after implantation of a @entity262 , making physiological pacing difficult. The mechanism of this decrease has not been elucidated yet. To elucidate the possible relationship between the decrease of the atrial potential after implantation of a @entity262 and histopathological changes of the atrium. We implanted a @entity262 from the jugular vein under anesthesia in 10 adult @entity235 . The tip of the pacing lead was fixed in the right ventricular apex of the heart under fluoroscopic guidance. Then, the lead was ligated and fixed to the jugular vein at a point where a favorable atrial potential was obtained. The end of the lead was passed from the neck to the back subcutaneously; then pulled outside and fixed there to measure the atrial potential. The atrial potential was measured using a pacing system analyzer under anesthesia on days 3 (n = 9) and 7 (n = 8), as well as on weeks 2 (n = 6), 3 (n = 4), and 4 (n = 3), after the implantation. The heart was removed from the @entity235 on day 3 (n = 2), day 7 (n = 2), week 2 (n = 2), and week 4 (n = 4) to examine the atrial histological findings. The atrial potential was 2.7 +/- 0.7 mV at the time of the implantation, 1.7 +/- 1.1 mV (P < 0.05) on day 3, and 1.7 +/- 0.7 mV on week 4 after the implantation. Macroscopically, the pacemaker lead was covered with @entity715 , and adhered to the atrial wall in 80% of animals. Microscopically, the endocardium was @entity1184 due to fibrous tissue; besides RBC extravasation, inflammatory cells infiltration and degeneration of myocardial cells, were observed under the endocardium. Inflammatory changes developed in the atrial wall after implantation of the @entity262 , and this seemed to be one of the mechanisms for the decrease of the atrial potential of the @entity262 .
