Exercise oscillatory ventilation in heart failure

Ventilation inefficiency has become a matter of interest for heart failure (HF) specialists, the most remarkable being exertional oscillatory ventilation (EOV). EOV is an abnormal ventilatory phenomenon, originally described as anecdotal, but now considered a marker of disease severity and worst prognosis in HF. EOV is a cyclic fluctuation of minute ventilation (VE) and expired gas kinetics occurring during exercise: it is a slow, prominent, consistent rather than random, fluctuation in VE that may be evanescent or transient and can follow several distinct patterns. In contrast to the periodic breathing observed in Cheyne–Stokes respiration and central sleep apnea, the gradual increase and decrease in minute ventilation (VE) are not spaced by periods of apnea. This review will discuss EOV in HF and the overlap with Cheyne–Stokes respiration.