Nocturnal hypoxemic burden is associated with epicardial fat volume in patients with acute myocardial infarction.

BACKGROUND

Increased epicardial fat volume (EFV) is a common feature of patients with sleep-disordered breathing (SDB), is considered as an established marker of cardiovascular risk, and is associated with adverse cardiovascular events after myocardial infarction (MI).

METHODS

To investigate the association between different measures of SDB severity and EFV after acute MI, we enrolled 105 patients with acute MI in this study. Unattended in-hospital polysomnography was performed to determine the number of apneas and hypopneas per hour during sleep (apnea-hypopnea index, AHI). To determine nocturnal hypoxemic burden, we used pulse oximetry and applied a novel parameter, the hypoxia load representing the integrated area of desaturation divided by total sleep time (HL). Of 105 patients, 56 underwent cardiovascular magnetic resonance to define EFV.

RESULTS

HL was significantly associated with EFV (r = 0.316, p = 0.025). Multivariate linear regression analysis accounting for age, sex, body mass index, smoking, and left ventricular mass demonstrated that the HL was an independent modulator of EFV (B-coefficient 0.435 (95% CI 0.021-0.591); p = 0.015). In contrast, AHI or established measures of hypoxemia did not correlate with EFV.

CONCLUSIONS

HL, a novel parameter to determine nocturnal hypoxemic burden, and not AHI as an event-based measure of SDB, was associated with EFV in patients with acute MI. Further studies are warranted to confirm the link between nocturnal hypoxemia and EFV and to determine the prognostic value of a more detailed characterization of nocturnal hypoxemic burden in patients with high cardiovascular risk.