title: Effects of adenotonsillectomy on R-R interval and brain natriuretic peptide levels in children with sleep apnea: a preliminary report.
abstract: OBJECTIVE
  Obstructive sleep apnea is associated with decreased R-R interval length and overall R-R interval variability in the electrocardiogram along with increased morning brain natriuretic peptide (BNP) blood levels. These findings indicate enhanced sympathetic tone and cardiac strain. In this study, it was hypothesized that adenotonsillectomy (AT) in children with sleep apnea is accompanied by improvement in polysomnography indices, increase in length and variability of R-R interval, and reduction in BNP levels.
  
  
  METHODS
  Polysomnography and measurements of morning BNP levels were performed before and 4-6months after AT. Mean and standard deviation of R-R interval were calculated from polysomnography electrocardiogram recordings.
  
  
  RESULTS
  Twenty-one children were studied. Apnea-hypopnea index and log-transformed BNP levels decreased postoperatively from 8.4±7.6 episodes/h and 2.2±0.7, to 1.8±1.4 episodes/h and 1.9±0.3, respectively (p<0.05). Mean R-R interval increased from 703.2±137.4ms (Stage 2), 699.3±135.8ms (Stage 3), 707.4±128.9ms (Stage 4) and 660.5±140.1ms (Stage REM), to 773.5±122.7ms (Stage 2), 765.7±73.7ms (Stage 3), 771.2±71.6ms (Stage 4), and 738.6±81.7ms (Stage REM), respectively (p<0.05 for comparisons pre- vs. post-operatively). Standard deviation of R-R in Stage 2 increased from 88.5±29.6 to 122.7±67ms (p=0.045).
  
  
  CONCLUSIONS
  Increase in nocturnal length of R-R interval and decrease in BNP levels after AT for sleep apnea may reflect postoperative reduction in sympathetic tone and cardiac strain.
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece. KADITIA@hotmail.com
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Kaditis
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Chaidas
authors.forename: Emmanouel I
authors.initials: EI
authors.lastname: Alexopoulos
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Varlami
authors.forename: Georgia
authors.initials: G
authors.lastname: Malakasioti
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Gourgoulianis
mesh_terms: D000233:Adenoidectomy; D002648:Child; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010865:Pilot Projects; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000503:physiopathology / Q000601:surgery; D012913:Snoring / Q000097:blood / Q000503:physiopathology / Q000601:surgery; D013564:Sympathetic Nervous System / Q000502:physiology*; D014068:Tonsillectomy
chemical_list: D020097:Natriuretic Peptide, Brain