Periodic Breathing during Incremental Exercise.

Agostoni P, Corrà U, Emdin M.

Ann Am Thorac Soc. 2017 Apr 26. doi: 10.1513/AnnalsATS.201701-003FR. [Epub ahead
of print]

Periodic breathing during incremental cardiopulmonary exercise testing is a
regularly recurring waxing and waning of tidal volume due to oscillations in
central respiratory drive. Periodic breathing is a sign of respiratory control
system instability, which may occur at rest or during exercise. The possible
mechanisms responsible of exertional periodic breathing might be related to any
instability of the ventilatory regulation caused by: 1) increased circulatory
delay (i.e., circulation time from the lung to the brain and chemoreceptors, due
to reduced cardiac index leading to delay in information transfer), 2) increase
in controller gain (i.e., increased central and peripheral chemoreceptor
sensitivity to arterial partial pressure of oxygen and of carbon dioxide), or 3)
reduction in system damping (i.e., baroreflex impairment). Periodic breathing
during exercise is observed in several cardiovascular disease populations, but it
is a particularly frequent phenomenon in heart failure due to systolic
dysfunction. The detection of exertional periodic breathing is linked to outcome
and heralds worst prognosis in heart failure, independently of the criteria
adopted for its definition. In small heart failure cohorts, exertional periodic
breathing has been abolished with more than a few dedicated interventions, but
results have not been confirmed, yet. Accordingly, further studies are needed to
define the role of visceral feed-backs in determining periodic breathing during
exercise, as well as to look for specific tools for preventing/treat its
occurrence in heart failure.