title: Predicting sleep apnoea syndrome from heart period: a time-frequency wavelet analysis.
abstract: Heart rate fluctuations are a typical finding during obstructive sleep apnoea, characterised by bradycardia during the apnoeic phase and tachycardia at the restoration of ventilation. In this study, a time-frequency domain analysis of the nocturnal heart rate variability (HRV) was evaluated as the single diagnostic marker for obstructive sleep apnoea syndrome (OSAS). The predictive accuracy of time-frequency HRV variables (wavelet (Wv) decomposition parameters from level 2 (Wv2) to level 256 (Wv256)) obtained from nocturnal electrocardiogram Holter monitoring were analysed in 147 consecutive patients aged 53.8+/-11.2 yrs referred for possible OSAS. OSAS was diagnosed in 66 patients (44.9%) according to an apnoea/hypopnoea index > or = 10. Using receiver-operating characteristic curves analysis, the most powerful predictor variable was Wv32 (W 0.758, p<0.0001), followed by Wv16 (W 0.729, p<0.0001) and Wv64 (W 0.700, p<0.0001). Classification and Regression Trees methodology generated a decision tree for OSAS prediction including all levels of Wv coefficients, from Wv2 to Wv256 with a sensitivity reaching 92.4% and a specificity of 90.1% (percentage of agreement 91.2%) with this nonparametric analysis. Time-frequency parameters calculated using wavelet transform and extracted from the nocturnal heart period analysis appeared as powerful tools for obstructive sleep apnoea syndrome diagnosis.
authors.affiliation: Physiology Laboratory, PPEH Group & Association SYNAPSE, CHU Nord, Faculté de Médecine Jacques Lisfranc, Université Jean Monnet, Saint-Etienne, France. Frederic.Roche@univ-st-etienne.fr
authors.forename: F
authors.initials: F
authors.lastname: Roche
authors.forename: V
authors.initials: V
authors.lastname: Pichot
authors.forename: E
authors.initials: E
authors.lastname: Sforza
authors.forename: I
authors.initials: I
authors.lastname: Court-Fortune
authors.forename: D
authors.initials: D
authors.lastname: Duverney
authors.forename: F
authors.initials: F
authors.lastname: Costes
authors.forename: M
authors.initials: M
authors.lastname: Garet
authors.forename: J C
authors.initials: JC
authors.lastname: Barthélémy
mesh_terms: D000328:Adult; D000368:Aged; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D011237:Predictive Value of Tests; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*