title: Monitoring of Daily Body Weight and Intrathoracic Impedance in Heart Failure Patients With a High Risk of Volume Overload Decompensation.
abstract: BACKGROUND
  Decompensation is frequent in heart failure (HF) patients and predicts poor prognosis.
  
  
  OBJECTIVE
  Volume-overload events in HF patients are preceded by changes in intrathoracic impedance (Z) and body weight (BW); monitoring these parameters may be useful to predict decompensation.
  
  
  METHODS
  Forty-three HF patients (LVEF 25% ± 12%) with a recent HF event and an implantable cardioverter-defibrillator providing daily Z were equipped with telemonitoring scales submitting daily BW. Changes in BW and Z 30 days prior to major (HF hospitalization) and minor (ambulatory adjustment of diuretics) were analyzed.
  
  
  RESULTS
  During median of 427 days follow-up 25 major and 41 minor events occurred. Z decreased by -4.8 (95% confidence interval [CI]: CI -6.7 to -3.0) and -4.3 (95% CI: -5.5 to -3.2) within 30 days prior to major and minor events respectively (P < 0.001). BW increased before major events by 2.3 kg (95% CI: 1.0 to 3.5, P < 0.01) and minor events 1 kg (95% CI: 0.5 to 1.4, P < 0.001). Sensitivity of Z for major/minor HF events was 83.3% (95% CI: 71.7 to 91.0) and for BW 43.9% (95% CI: 31.9 to 56.7). The unexplained detection rate per patient-year was 1.6 (interquartile range [IQR], 0-3.1) for Z and 4.8 (IQR 1.6-11.1) for BW. Combined Z and BW sensitivity was 42.4% (95% CI: 30.6 to 55.2) and unexplained detection rate was 0.8 (IQR, 0-1.5) per patient-year.
  
  
  CONCLUSIONS
  Decompensation is marked by a decrease in Z and increase in BW the preceding 30 days. Monitoring of Z predicts HF decompensations with better sensitivity and lower unexplained detection rate than BW.
authors.affiliation: Karolinska Institute, Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Kristjan
authors.initials: K
authors.lastname: Gudmundsson
authors.affiliation: Department of Clinical Science and Education (Lyngå), Stockholm South General Hospital, Stockholm, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Lyngå
authors.affiliation: Department of Cardiology, Danderyd University Hospital, Stockholm, Sweden.
authors.forename: Mårten
authors.initials: M
authors.lastname: Rosenqvist
authors.affiliation: Karolinska Institute, Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Frieder
authors.initials: F
authors.lastname: Braunschweig
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D058409:Cardiac Resynchronization Therapy Devices; D002307:Cardiography, Impedance / Q000295:instrumentation; D017147:Defibrillators, Implantable; D004232:Diuretics / Q000627:therapeutic use; D004554:Electric Countershock / Q000295:instrumentation; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012042:Registries; D015203:Reproducibility of Results; D013318:Stroke Volume; D013548:Sweden; D013686:Telemetry / Q000295:instrumentation; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D014882:Water-Electrolyte Balance / Q000187:drug effects; D015430:Weight Gain / Q000187:drug effects
chemical_list: D004232:Diuretics