title: Usefulness of extended holter ECG monitoring for serious arrhythmia detection in patients with heart failure and sleep apnea.
abstract: BACKGROUND
  In patients with systolic heart failure (HF), coexisting sleep apnea may promote arrhythmia. Ambulatory Holter electrocardiogram (ECG) monitoring (AECG) is a method of arrhythmia and apnea evaluation. We hypothesized that 24-hour AECG in patients with HF who have a high risk of serious arrhythmia may be less accurate than AECG extended to 48 hours and that, moreover, arrhythmia may be related to apnea.
  
  
  METHODS
  Eighty-four recordings of 48-hour AECG in 84 patients with ischemic HF (mean ejection fraction 34 ± 7%) were analyzed. Day 1, Day 2 were checked for ventricular tachycardia (VT) and supraventricular tachycardia (SVT). Estimated apnea-hypopnea index (est.AHI) was calculated using Holter, monitoring where est.AHI >15 indicates apnea.
  
  
  RESULTS
  In 48-hour AECG, VT occurred in 34 patients (40.5%) whereas SVT in 17 patients (20.2%), and patients with est.AHI > 15 had higher VT occurrence. In two-sample one-sided test for proportions, 24-hour AECG from Day 1 showed a significantly lower percentage of patients with detected VT than 48-hour AECG-it was 23.8% (20 patients), meaning a significant underestimation with P = 0.0089. We assessed VT underestimation in the subgroups with regard to est.AHI, and found that it was present in Day 1 monitoring in the subgroups with est.AHI > 15. It was absent in the subgroups with est.AHI ≤ 15 and also in Day 2 monitoring.
  
  
  CONCLUSIONS
  In patients with systolic HF, 24-hour AECG may have insufficient sensitivity regarding serious arrhythmia occurrence. If significant apnea was detected in the first day, extending the monitoring may be recommended.
authors.affiliation: Chair and Clinic of Cardiology, Medical University of Łódź, Łódź, 91-347 Poland. tyhe@op.pl
authors.forename: Barbara
authors.initials: B
authors.lastname: Uznańska-Loch
authors.forename: Ewa
authors.initials: E
authors.lastname: Trzos
authors.forename: Karina
authors.initials: K
authors.lastname: Wierzbowska-Drabik
authors.forename: Janusz
authors.initials: J
authors.lastname: Smigielski
authors.forename: Tomasz
authors.initials: T
authors.lastname: Rechciński
authors.forename: Urszula
authors.initials: U
authors.lastname: Cieślik-Guerra
authors.forename: Jarosław D
authors.initials: JD
authors.lastname: Kasprzak
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Kurpesa
mesh_terms: D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000175:diagnosis*; D004562:Electrocardiography / Q000379:methods; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012891:Sleep Apnea Syndromes / Q000150:complications*