Tobaldini E, et al. - This research was planned to study cardiovascular autonomic control (CAC) during sleep-wake cycle in myotonic dystrophy type 1 (DM1) patients, taking into account the effects of obstructive sleep apnea (OSA) comorbidity. Findings revealed that DM1 patients had preserved cardiac autonomic dynamics during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, and this phenomenon was not affected by the presence of OSA. Researchers reported that the comorbidity with OSA was characterized by a decline in total heart rate variability (HRV), which is a marker of the ability of autonomic control to respond to stressors stimuli.

Methods

• For this purpose, 23 patients with a diagnosis of DM1, and a control group, underwent a complete polysomnographic study (PSG).
• After that, electrocardiogram and respiration were extracted from PSG, divided according to the sleep stages, and analyzed utilizing spectral analysis (SpA) of heart rate variability (HRV).
• SpA identified 3 components: very low frequency (VLF); low frequency (LF), a marker of sympathetic modulation; and high frequency (HF), a marker of vagal modulation.

Results

• The consequences of this study demonstrated that in DM1 patients, the sympathovagal balance shifted towards a vagal predominance during non-rapid eye movement (NREM) sleep and a sympathetic predominance during rapid eye movement (REM) sleep.
• This preserved cardiac autonomic modulation was not affected by the comorbidity with obstructive sleep apnea syndrome (OSAS).
• OSAS comorbidity was correlated with a reduction in HRV during the whole sleep-wake cycle in DM1 patients.
• Cardiorespiratory coupling was reduced compared to controls in DM1 patients with OSA.