[Effect of beta-adrenoreceptor blockade on gas exchange in patients with angina pectoris during physical load]

Changes in ventilation, gas exchange and hemodynamic parameters were examined in 16 anginal patients, exposed to stepwise stress in the presence of beta-block. Physical stress of 30-60-90 W was associated with less pronounced hemodynamic response, as compared to a control bicycle-ergometric test, in anginal patients. Propranolol reduced ventilation, oxygen consumption and carbon dioxide expiration during a 30-60 W exercise. When stress was increased to 90 W following beta-block, oxygen consumption decreased further, while the increment of ventilation and the respiratory coefficient was more marked, as compared to the controls. The pattern of ventilation and gas exchange variation was dependent on the magnitude of stress and related to hemodynamic shifts due to the beta-block.