title: Trying to predict the unpredictable: Variations in device-based daily monitored diagnostic parameters can predict malignant arrhythmic events in patients undergoing cardiac resynchronization therapy.
abstract: BACKGROUND
  The aim of this study was to evaluate the value of device-based diagnostic parameters in predicting ventricular arrhythmias in cardiac resynchronization therapy (CRT) recipients.
  
  
  METHODS
  Ninety-six CRT-D patients participating in TRUST CRT Trial were analyzed. The inclusion criteria were: heart failure in NYHA ≥ 3 class, QRS ≥ 120 ms, LVEF £ 35% and significant mechanical dyssynchrony. Patients were divided into those with (n = 31, 92 arrhythmias) and without (n = 65) appropriate ICD interventions within follow-up of 12.03 ± 6.7 months. Daily monitored device-based parameters: heart rate (HR), thoracic impedance (TI), HR variability and physical activity were analyzed in 4 time windows: within 10, 7, 3 days and 1 day before appropriate ICD interventions.
  
  
  RESULTS
  A consistent pattern of changes in three monitored factors was observed prior to arrhythmia: 1) a gradual increase of day HR (from 103.43% of reference within 10-day window to 105.55% one day before, all p < 0.05 vs. reference); 2) variations in night HR (104.75% in 3 days, 107.65% one day before, all p < 0.05) and 3) TI decrease (from 97.8% in 10 days to 96.81% one day before, all p < 0.05). The combination of three parameters had better predictive value, which improved further after exclusion of patients with atrial fibrillation (AF). The predictive model combining HR and TI together with LVEF and NT-proBNP was more prognostic than the model involving LVEF and NT-proBNP alone (difference in AUC 0.05, 95% CI 0.0005-0.09, p = 0.04).
  
  
  CONCLUSIONS
  Daily device-monitored parameters show significant variations prior to ventricular arrhythmia. Combination of multiple parameters improves arrhythmia predictive performance by its additive value to baseline risk factors, while presence of AF diminishes it.
authors.affiliation: Department of Cardiology, Congenital Hear t Disease and Electr otherapy, Silesian Medical Univer sity, Silesian Centre for Hear t Diseases, Zabrze, Poland. ewajczyk@op.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Jędrzejczyk-Patej
authors.forename: Oskar
authors.initials: O
authors.lastname: Kowalski
authors.forename: Beata
authors.initials: B
authors.lastname: Sredniawa
authors.forename: Patrycja
authors.initials: P
authors.lastname: Pruszkowska
authors.forename: Adam
authors.initials: A
authors.lastname: Sokal
authors.forename: Mariola
authors.initials: M
authors.lastname: Szulik
authors.forename: Michał
authors.initials: M
authors.lastname: Mazurek
authors.forename: Jacek
authors.initials: J
authors.lastname: Kowalczyk
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Kalarus
authors.forename: Radosław
authors.initials: R
authors.lastname: Lenarczyk
mesh_terms: D056044:Actigraphy; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D058409:Cardiac Resynchronization Therapy Devices; D002307:Cardiography, Impedance; D002940:Circadian Rhythm; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011044:Poland; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D013318:Stroke Volume; D013686:Telemetry / Q000295:instrumentation*; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left