[Pulmonary or circulatory causes of dyspnea - value of spiroergometry]

Patients often report of dyspnea during exertion which should be further analysed as a hint of heart or lung disease. When case history, chest X-ray, ECG, spirometry, and methacholine test do not explain the complaints, a cardiopulmonary exercise test is recommended. Parameters of spiroergometry can often elucidate cardiocirculatory or pulmonary causes. In cardiocirculatory triggered dyspnea the following pattern can be found: reduced maximal oxygen consumption and work rate (WR), an early plateau of oxygen consumption/WR, reduced increase of oxygen consumption/WR, reduced heart rate reserve < 15 beats/min, reduced oxygen pulse and an early plateau, increased breathing reserve, an increased minute ventilation/CO (2) production indicating increased dead space ventilation. In pulmonary triggered dyspnea the following pattern can be found: reduced maximal oxygen consumption, increased heart rate reserve, reduced breathing reserve. With the exercise tidal flow volume loop plotted within the maximal flow volume loop a more thorough interpretation is possible. In a case presentation, the decision-making process using the 9-panel display of Wasserman is demonstrated.