title: Significant increase in the incidence of ventricular arrhythmic events after an intrathoracic impedance change measured with a cardiac resynchronization therapy defibrillator.
abstract: BACKGROUND
  Cardiac resynchronization therapy defibrillator (CRT-D) devices are now capable of monitoring changes in intrathoracic impedance. Intrathoracic impedance monitoring resulting in a fluid index threshold crossing has been proven to predict heart failure (HF) exacerbations. We retrospectively investigated the relationship between changes in intrathoracic impedance and the occurrence of arrhythmic events.
  
  
  RESULTS
  From 282 patients with New York Heart Association class III or IV HF who were implanted with a CRT-D device with a fluid index feature based on intrathoracic impedance monitoring capabilities, arrhythmic events were retrospectively analyzed in terms of the threshold crossings. The patients were divided into 2 groups: those with fluid index threshold crossings and those without threshold crossings. A total of 4,725 tachyarrhythmic events were reported in 129 patients (46%), and there were 221 fluid index crossing events in 145 patients (51%) during 10.0 ± 3.2 months. Tachyarrhythmic events were more frequently recorded in patients with threshold crossing events than in those who did not experience a threshold crossing (3,241 vs. 1,484 events, P<0.0001). Ventricular tachyarrhythmic events mainly occurred within the first 30 days after the threshold crossing event; however, a similar trend was not observed for the atrial tachyarrhythmic events.
  
  
  CONCLUSIONS
  Intrathoracic impedance monitoring may predict arrhythmic events, especially ventricular arrhythmias, in patients with HF and provides an additional management tool.
authors: Cardiovascular Division, Institute of Clinical Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Japan. yysekiguchi@hotmail.co.jp
authors: Yukio
authors: Y
authors: Sekiguchi
authors: Hiroshi
authors: H
authors: Tada
authors: Kentaro
authors: K
authors: Yoshida
authors: Yoshihiro
authors: Y
authors: Seo
authors: Shelby
authors: S
authors: Li
authors: Tomoyuki
authors: T
authors: Tejima
authors: Morio
authors: M
authors: Shoda
authors: Shiro
authors: S
authors: Kamakura
authors: Kazutaka
authors: K
authors: Aonuma
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D058406:Cardiac Resynchronization Therapy; D002307:Cardiography, Impedance; D017147:Defibrillators, Implantable; D005260:Female; D006333:Heart Failure / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D011446:Prospective Studies; D012189:Retrospective Studies