title: Changes of conductivity in patients with second- or third-degree atrioventricular block after pacemaker implantation.
abstract: The purpose of this study was to examine the long-term course of conductivity in patients with second- or third-degree atrioventricular (AV) block after pacemaker implantation. Fifty-four patients (30 males and 24 females, mean age 59.5 years) had a 12-lead electrocardiogram (ECG) recorded prior to pacemaker implantation and again after a follow-up of more than 5 years (mean 108 months). The degree of AV block and the morphology of the QRS complex in the two ECGs were compared. Twenty-eight (85%) of the 33 patients with complete AV block and 15 (71%) of the 21 patients with second-degree AV block before implantation showed complete AV block after the follow-up period. The progression of AV block was recognized only in patients with intra-His (BH) or infra-His (H-V) block. In 29 patients, escape QRS complexes were recorded in both ECGs. A change in the QRS complex was noted in 6 patients (21%), including 2 with new bundle branch block (BBB), 2 with wider BBB, 1 with new left axis deviation, and 1 with a change to another BBB. This change was particularly notable in the H-V block group (44%).
  
  
  CONCLUSIONS
  (1) Most patients with complete AV block did not recover AV conductivity after the long-term follow-up. (2) Second-degree BH and H-V block tended to progress to complete AV block.
authors.affiliation: Department of Cardiology, Juntendo University School of Medicine Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sumiyoshi
authors.forename: Y
authors.initials: Y
authors.lastname: Nakata
authors.forename: M
authors.initials: M
authors.lastname: Yasuda
authors.forename: T
authors.initials: T
authors.lastname: Tokano
authors.forename: Y
authors.initials: Y
authors.lastname: Ohno
authors.forename: S
authors.initials: S
authors.lastname: Ogura
authors.forename: Y
authors.initials: Y
authors.lastname: Nakazato
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000503:physiopathology* / Q000628:therapy; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial