The ups and downs in ventilation during exercise: investigation exercise oscillatory ventilation
24 August 2017
Antwerp University Hospital (UZA), Auditorium Kinsbergen (route 12) - Wilrijkstraat 10 - 2650 EDEGEM
Organization / co-organization:
Faculty of Medicine and Health Sciences
Prof D. Vissers & Prof C. Vrints
PhD defence Justien Cornelis - Faculty of Medicine and Health Sciences
Cardiopulmonary exercise testing (CPET) is generally used to provide information about aerobic capacity, ventilatory efficiency and diagnostic insights in multiple populations. It is applied to obtain a save training intensity, to evaluate therapy and to assess prognosis. Exercise oscillatory ventilation (EOV) is an abnormal breathing pattern assessed during CPET and is characterized by fluctuations, due to hyper- and hypoventilation. The general aim of this dissertation was to obtain more insight into the EOV pattern towards the clinical relevance, assessing, defining, therapy and possible pathophysiology.
The results showed that with appearance of EOV a crucial prognostic burden is exceeded, with severe consequences towards pathophysiology, exercise capacity and quality of life (QOL). The numerous definitions and vaguely described assessment methods are hindering its clinical investigation. Therefore, a graphical user interface named VOdEX-tool was developed to detect EOV automatically. Concerning possible therapies to diminish EOV, insufficient information was available on the effect of exercise training (ET) in heart failure (HF) patients with EOV. However, the fact that patients with HF are actively involved in any kind of ET program seems sufficient to improve the prognosis, QOL and anatomic function. A remarkable prevalence of 18.9% EOV was noted in the included stroke population. Aerobic ET had no significant effect comparing regular therapy in subacute stroke patients with and without EOV but diminished EOV after three months. Patients where EOV diminished over time, significantly improved their initial severely deteriorated CPET derived prognostic markers and heart rate variables. Patients where EOV remained, initially presented better values but they did not improve them significantly over time. Surprisingly, no EOV was found in a carefully diagnosed HF with preserved ejection fraction population although the chance on a null result was very low (1.3%) based on the earlier reported prevalence. Therefore, the effect of ET on EOV in this population could not be investigated. Both studies pointed out the excellent reliability of the VOdEX-tool. Moreover, both studies discovered important facts concerning the pathophysiological origin of EOV but the exact mechanism is not yet revealed.
Long-time follow-up multicenter data are necessary to investigate the effect of ET towards prognosis in diverse chronic pathologies and towards prevalence and diminishment of EOV.