Novel application of Poincaré analysis to detect and quantify exercise oscillatory ventilation.

OBJECTIVE Exercise oscillatory ventilation (EOV) is frequently observed in individuals with cardiac disease. Assessment of EOV relies on pattern recognition and this subjectivity and lack of quantification limits the widespread clinical use of EOV as a prognostic marker. Poincare analysis quantifies the short (SD1) and long term (SD2) variability of a signal and may provide an alternative means to identify and quantify unstable exercise breathing patterns. This study aimed to determine if Poincare analysis can distinguish between the breathing patterns of healthy control subjects and individuals being assessed for heart transplantation with and without EOV. APPROACH Thirty-nine subjects performed a cardiopulmonary exercise test as part of heart transplant assessment and were subjectively classified into two groups according to the presence of EOV: non-EOV (n=19) and EOV (n=20). The control group (n=24) consisted of healthy adults. Poincare analysis (SD1 and SD2) was performed for minute ventilation (VE) and tidal volume (VT) normalised to forced vital capacity (VEn and VTn), and breathing frequency (BF) for breath by breath data over the 10-15 mL·min-1·kg-1 VO2 range. MAIN RESULTS Poincare analysis showed similar exercise ventilatory responses between the non-EOV and control group. BF was found to discriminate between subjects with stable and unstable ventilation. BF SD1 was significantly higher in the EOV group compared to the non-EOV (7.9 vs 4.6, p<0.01) and control (7.9 vs 4.2, p<0.01) groups. The EOV group had significantly greater BF SD2 compared to the non-EOV (5.7 vs 3.5, p<0.01) and control (5.7 vs 3.5, p<0.01) groups. SIGNIFICANCE We demonstrated that this novel application of Poincare analysis can objectively distinguish and quantify unstable from stable breathing patterns during exercise. In subjects being assessed for heart transplantation the presence of EOV is associated with greater BF variability. Poincare analysis provides an objective measure to identify and quantify EOV.