Sleep-disordered breathing does not directly affect early cardiac rehabilitation efficacy after myocardial infarction

Abstract

Background: Sleep-disordered breathing (SDB) impairs exercise capacity after myocardial infarction (MI).
Aims: This study aimed to evaluate the impact of SDB on the efficacy of post-MI cardiac rehabilitation (CR).
Methods: The study evaluated consecutive patients up to 28 days after MI who participated in outpatient CR as part of the Polish Managed Care after Acute Myocardial Infarction program. Improvements in exercise capacity during CR were assessed based on changes in metabolic equivalents (MET) on the treadmill exercise stress test and distance on the six-minute walk test (6MWT). Home sleep apnea tests were performed to assess the presence/severity of SDB.
Results: The study included 254 patients aged 58.52 (10.51) and 39 (15.4%) women. Mild SDB with respiratory event index (REI) of 5–15 events/h was found in 82 patients (32.3%), moderate (REI of 15–30 events/h) in 54 (21.3%), and severe (REI >30 events/h) in 51 (20.1%). Obstructive sleep apnea was the dominant SDB type (89.8%). The severe-SDB group was older, with a higher body mass index and lower pre-CR exercise capacity than the others. After completing a four-week CR program, the entire group improved their MET (7.52 [2.26] to 9.02 [2.55]; P <0.001) and the 6MWT (645.00 m [518.00–814.00] to 786.500 m [638.00–998.50]; P <0.001). The severity of SDB did not influence the degree of improvement in MET and 6MWT in absolute values (P = 0.59 and P = 0.21) and percentages (P = 0.86 and P = 0.28).
Conclusions: Although severe SDB is one factor that negatively affects post-MI exercise capacity, it does not worsen the efficacy of early CR.