Exercise Oscillatory Ventilation

Recently I was trying to make some sense of an exercise test report that had come across my desk. Numerical results on our CPET reports are averaged over 30 second periods and there seemed to be a lot of variability from one time interval to the next. This isn’t uncommon in the first couple of minutes of an exercise test because patients often start off too hard and too fast, overshoot and then take a while to settle down into a steady pattern. This variability however, persisted throughout the entire test. I finally realized that what I was seeing was Exercise Oscillatory Ventilation (EOV).

It has been a while since I last saw a patient with EOV. Part of the reason for this is that EOV is a sign of relatively advanced heart failure and most of the patients who have cardiac disease have already had standard ECG stress testing and tend not to get referred for a cardiopulmonary exercise test (CPET). Having said that, it is a bit surprising that we don’t see this more often since there tends to be an association between pulmonary disease and cardiac disease and we do exercise tests relatively frequently on patients with combined lung and heart disease in order to determine their primary cause for shortness of breath. Nevertheless, even though one study estimated that up to 30% of patients with heart failure exhibit EOV (although most studies estimate it somewhere between 7% and 12%), it is not something we have ever seen with any frequency.

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