Obstructive sleep apnea syndrome in cardiac rehabilitation patients

Abstract

While regular physical activity improves obstructive sleep apnea (OSA) syndrome in the general population, this was not assessed in post-myocardial infarction (MI) patients in a rehabilitation setting (coronary artery disease, CAD). We aimed to determine if cardiac rehabilitation may benefit post-MI patients in terms of OSA disease and associated autonomic nervous system (ANS) activity. Consecutive post-MI patients participating in the ambulatory cardiac rehabilitation program of St-Etienne University Hospital were included in this study. The apnea-hypopnea index calculated from ECG-derived respiration (AHI EDR ) was obtained through nocturnal Holter ECG recordings. According to AHI EDR , patients were classified as normal, mild, moderate or severe OSA (< 5, 5–14, 15–29, ≥ 30, respectively). Physiological performance (peak VO 2 ) was established though cardiopulmonary exercise testing. ANS activity was evaluated through spontaneous baroreflex sensibility as well as heart rate variability analysis. Out of the 105 CAD patients suffering OSA included (95 men, 55.2 ± 12.4 years), 100 had at least one cardiovascular risk factor (98%) and 51% had an ANS dysfunction. Surprisingly, 65% of these OSA patients were free of classical diurnal symptoms usually associated with sleep apnea. In response to cardiac rehabilitation, AHI EDR decreased significantly (−9.3 ± 9.5, P < 0.0001) only in severe OSA patients, and the decrease was even greater when peak VO 2 and baroreflex sensibility improved beyond 20% compared to basal values (−11.6 ±9.1, P < 0.001). Severe OSA in CAD patients is significantly improved after 2 months of cardiopulmonary rehabilitation. Reviving ANS activity through physical activity might be a target for complementary therapy of OSA in CAD patients.