Dynamic cycling in atrial size and flow during obstructive apnoea

Area of Science:

• Cardiology
• Sleep Medicine
• Physiology

Background:

• Obstructive sleep apnoea (OSA) is strongly linked to cardiovascular disease.
• The acute cardiovascular effects of repetitive airway obstruction are not well understood.
• Previous research used sustained maneuvers, but gasping efforts better simulate obstructive apnoeas.

Purpose of the Study:

• To investigate acute cardiac anatomical and flow changes during simulated obstructive apnoeas.
• To compare gasping efforts with sustained maneuvers for simulating OSA.

Main Methods:

• 26 healthy participants performed gasping efforts to simulate OSA.
• Doppler echocardiography was used to monitor cardiac anatomy and flow.
• Atrial areas and Doppler flow velocities (mitral and tricuspid E-wave and A-wave) were compared pre- and post-maneuver.

Main Results:

• Atrial areas showed increased variance, with inverse changes in left and right atria during inspiratory efforts.
• Significant inverse changes in Doppler flow were observed immediately post-maneuver.
• Mitral E-wave velocity increased, while tricuspid E-wave velocity decreased, returning to baseline by the eighth beat.

Conclusions:

• Repetitive obstructive apnoeas induce dynamic, inverse changes in atrial size and atrioventricular valve flow.
• These findings are crucial for understanding the pathophysiology of OSA and its cardiovascular implications.