title: Development of Atrioventricular Block and Diagnostic Value of Stored Electrograms in Patients With Sick Sinus Syndrome and Implanted Pacemaker.
abstract: BACKGROUND
  The incidence of atrioventricular block (AVB) in pacemaker patients with sick sinus syndrome (SSS) is not yet known. The aim of this study was to analyze AVB episodes in SafeR mode based on stored electrograms (EGM), and determine the occurrence rate and risk factors for advanced AVB in a pacemaker population with SSS.
  
  
  RESULTS
  The study included 50 consecutive patients with SSS without a history of advanced AVB who had a dual-chamber pacemaker programmed in SafeR mode. A total of 377 EGM stored in the pacemakers as AVB episodes fulfilling the second- or third-degree criterion were analyzed. Of 377 EGM, 73 EGM (19.4%) were appropriate episodes, whereas the other EGM did not show actual AVB, and showed atrial tachyarrhythmia, ventricular event in the blanking period, or premature atrial contractions with block. On EGM analysis, advanced AVB occurred in 9 patients (18%), and the occurrence rate was 11.7% per year. Moreover, on multivariate analysis β-blocker use was an independent risk factor for advanced AVB (OR, 9.10; P=0.004).
  
  
  CONCLUSIONS
  The occurrence rate of advanced AVB in patients with SSS is much higher than previously reported, and β-blocker use is an independent risk factor for advanced AVB. SafeR is useful to detect latent AVB. Stored EGM, however, sometimes include inaccurately classified events.
authors.affiliation: Department of Cardiology, Yokohama City University Hospital, Yokohama; Department of Cardiovascular Center, Yokohama City University Medical Center, Yokohama, Japan; Department of Cardiology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.  j_hosoda@yokohama-cu.ac.jp
authors.forename: Junya
authors.initials: J
authors.lastname: Hosoda
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sumita
authors.forename: Kohei
authors.initials: K
authors.lastname: Matsushita
authors.forename: Katsumi
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kimura
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ogino
authors.forename: Yuka
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Hirooki
authors.initials: H
authors.lastname: Matsushita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Teruyasu
authors.initials: T
authors.lastname: Sugano
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Ishigami
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Umemura
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000009:adverse effects / Q000627:therapeutic use; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000209:etiology; D054537:Atrioventricular Block / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D003625:Data Collection; D058065:Diabetic Cardiomyopathies / Q000453:epidemiology; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D006801:Humans; D015994:Incidence; D016247:Information Storage and Retrieval; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012189:Retrospective Studies; D012307:Risk Factors; D012804:Sick Sinus Syndrome / Q000150:complications*
chemical_list: D000319:Adrenergic beta-Antagonists