Chest
Volume 88, Issue 3, September 1985, Pages 335-340
Journal home page for Chest

Clinical Investigations
Relationship of Ventricular Ectopy to Oxyhemoglobin Desaturation in Patients with Obstructive Sleep Apnea

https://doi.org/10.1378/chest.88.3.335Get rights and content

Patients with obstructive sleep apnea are considered to be at increased risk of sudden, presumably arrhythmia-related death during sleep. The present study was undertaken to determine the relationship between ventricular ectopy and the severity of oxyhemoglobin desaturation in these patients. Thirty-one male patients with obstructive sleep apnea (mean age, 55 ±11 years) underwent overnight polysomnography. Arterial oxyhemoglobin saturation (SaO2) was monitored by ear oximetry, and premature ventricular complexes (PVC) were detected using electrocardiographic leads CC5 and CM5. The data were recorded on electromagnetic tape for subsequent computer-assisted analysis to obtain PVC frequency as a function of decile levels of SaO2. Total sleep time averaged 333±75 minutes, the apnea index was 44 ± 26 per hour, and the hypopnea index was 18±24 per hour. Premature ventricular complexes were observed in 23 (74 percent) of the subjects. By analysis of variance, no significant relationship was found between PVC frequency and decile levels of SaO2 for saturations greater than 60 percent; however, in the 16 subjects with SaO2 below 60 percent, a significant increase in PVC frequency was detected with decreasing SaO2 (p<0.01). Ventricular bigeminy was observed with SaO2 below 60 percent in three of these 16 subjects. From these results, we conclude that patients with obstructive sleep apnea are at relatively low risk of developing ventricular arrhythmias provided SaO2 remains greater than 60 percent, while those with SaO2 below 60 percent are at increased risk and should be managed accordingly.

Section snippets

Patients

The population under study consisted of 31 male patients referred for diagnostic polysomnography because of clinically suspected obstructive sleep apnea. Routine spirometric testing was performed in each patient using a wedge spirometer (Med-Science). Thoracic gas volume at functional residual capacity (FRC) was determined with a body plethysmograph (Warren E. Collins). Values were expressed as a percentage of previously published normal values.12,13 Following informed consent, all subjects

Results

The anthropometric, spirometric, and arterial blood gas data for the 31 male patients with obstructive sleep apnea are presented in Table 1. On average the group was obese (weight/height ratio = 0.66 kg/cm) and mildly hypoxemic (arterial oxygen pressure [PaO2] = 70 ± 13 mmHg) but normocapnic (arterial carbon dioxide tension [PaCO2] = 40±4 mm Hg) while awake at rest. Tests of pulmonary function demonstrated slight reductions in forced vital capacity (FVC), functional residual capacity (FRC), and

Discussion

Although excessive daytime sleepiness is the major incapacitating clinical symptom experienced by patients with obstructive sleep apnea, the long-term morbidity and mortality of the disorder are importantly related to the cardiovascular consequences of the repetitive episodes of oxyhemoglobin desaturation. In one series, three out of 23 patients who did not undergo surgical therapy for their obstructive sleep apnea died suddenly during sleep within six months of diagnosis, and another patient

References (35)

  • G. Rosenblatt et al.

    Cardiac irritability during sleep and dreaming

    J Psychosom Res

    (1973)
  • M.R. Flick et al.

    Nocturnal vs diurnal cardiac arrhythmias in patients with chronic obstructive pulmonary disease

    Chest

    (1979)
  • J.W. Shepard et al.

    Relationship of ventricular ectopy to nocturnal oxygen desaturation in patients with chronic obstructive pulmonary disease

    Am J Med

    (1985)
  • W.C. Orr et al.

    Physiological sleep patterns and cardiac arrhythmias

    Am Heart J

    (1979)
  • J.R. De Olazabal et al.

    Disordered breathing and hypoxia during sleep in coronary artery disease

    Chest

    (1982)
  • G. Coccagna et al.

    Continuous recording of the pulmonary and systemic arterial pressure during sleep in syndromes of hypersomnia with periodic breathing

    Bull Physiopathol Respir

    (1972)
  • A.G. Tilkian et al.

    Hemodynamics in sleep apnea: studies during wakefulness and sleep

    Ann Intern Med

    (1976)
  • Cited by (234)

    View all citing articles on Scopus

    Supported by the Veterans Administration.

    View full text