Clinical Backgrounds and the Time Course of Sleep-disordered Breathing in Patients after Myocardial Infarction

Introduction: Previous studies have suggested that sleep-disordered breathing (SDB) frequently develops after myocardial infarction (MI) and leads to a poor prognosis. However, the details remain unclear. Therefore, we examined the clinical backgrounds and the time course of SDB in patients after MI. Methods: The subjects were 92 consecutive patients (mean age, 65 +/- 12 years) who had MI without decompensated heart failure or uncontrolled myocardial ischemia. All subjects underwent overnight sleep studies, and we investigated baseline clinical characteristics. Among the patients with confirmed SDB, the 38 patients who agreed underwent nighttime multichannel respiratory monitoring at both 14 days and 2 months after the onset of MI, and we investigated their clinical features. Results: The percentage of patients with SDB 14 days after MI was high (93.5%). Among all patients, 6.5% had no SDB, 39.1% had mild SDB, 29.3% had moderate SDB, and 25.0% had severe SDB. The clinical features of patients with moderate-to-severe SDB (apnea-hypopnea index [AHI] >= 15 times/hour) did not differ significantly from those of patients with mild SDB or patients without SDB (AHI <15 times/hour). In patients with central SDB and AHI >= 10 times/hour, there was a significant improvement in AHI from 14 days to 2 months after MI. Multiple regression analysis showed that central SDB and nighttime onset of MI were associated with a decrease in AHI. Conclusion: These findings suggest that SDB after MI should be managed on the basis of the type of SDB and the time of MI onset.