title: Relationship among the severity of sleep apnea syndrome, cardiac arrhythmias, and autonomic imbalance.
abstract: The relationship between obstructive sleep apnea syndrome (OSAS), cardiac arrhythmias, and conduction disturbances in adults remains controversial. Early studies showed a higher prevalence than more recent and designed epidemiological studies. To clarify the actual prevalence of cardiac arrhythmias and conduction disturbances in patients referred for assessment of OSAS, a prospective cohort study was conducted: 147 consecutive patients (103 men; mean age of 54.5 +/- 10.7 years) underwent time-synchronized polysomnography and ECG Holter monitoring. OSAS was diagnosed in 66 (44.9%) of them based on an apnea hypopnea index (AHI) > or = 10. Prevalence of heart failure, of prior myocardial infarction, of hypertension, and of ventricular arrhythmias were similar in patients with or without OSAS. Nocturnal paroxysmal asystole was significantly more prevalent in OSAS patients (10.6 vs 1.2%; P < 0.02) and the number of episodes of bradycardia and pauses increased with the severity of the syndrome. Almost all bradycardic events occurred in patients with severe OSAS (AHI > 30), prolonged periods of arterial oxyhemoglobin desaturation, and low diurnal awake PaO2. Moreover, using heart rate variability analysis, nocturnal sinusal dysfunction contrasted with a blunted diurnal parasympathetic modulation of the sinus node. Frequent nocturnal nonsustained supraventricular tachycardias were predominantly found in patients with severe sleep related breathing disorders; however, an increased risk of ventricular arrhythmias was not found. Under continuous positive airway pressure treatment, the 1-year follow-up of OSAS patients with nocturnal pauses did not reveal any arrhythmic event justifying a specific intervention.
authors.affiliation: Service d'Exploration Fonctionnelle CardioRespiratoire, Laboratoire de Physiologie, GIP-ESS, CHU Nord, Faculté de Médecine Jacques Lisfranc Université Jean Monnet, Saint-Etienne, France. Frederic.Roche@univ-st-etienne.fr
authors.forename: Frédéric
authors.initials: F
authors.lastname: Roche
authors.forename: Alain Nguyen Thanh
authors.initials: AN
authors.lastname: Xuong
authors.forename: Isabelle
authors.initials: I
authors.lastname: Court-Fortune
authors.forename: Frédéric
authors.initials: F
authors.lastname: Costes
authors.forename: Vincent
authors.initials: V
authors.lastname: Pichot
authors.forename: David
authors.initials: D
authors.lastname: Duverney
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Vergnon
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Gaspoz
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Barthélémy
mesh_terms: D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000503:physiopathology; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015995:Prevalence; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D013997:Time Factors