Pulmonary gas exchange after propranolol in patients with ischaemic heart disease

Pulmonary gas exchange was evaluated after 10 mg i.v. propranolol in 12 patients 3-6 months after acute myocardial infarction undergoing haemodynamic examination in our outpatient department. None of them exhibited clinical signs of heart failure or obstructive airways disease. Routine spirometric examination was normal in all patients. Propranolol led to a distinct deterioration of LV function and to a fall in left ventricular filling pressure both at rest and during exercise. At rest, the administration of propranolol resulted only in a significant decrease of total ventilation. During exercise, its administration was followed by a significant decrease of the tidal volume, alveolar ventilation and VA/VE index. Arterial CO2 tension and physiological dead space ventilation increased significantly. Arterial oxygen tension decreased after propranolol insignificantly both at rest and during exercise. No patient reported dyspnoea after propranolol; 8 patients reported a decrease or disappearance of effort dyspnoea. None exhibited clinical signs of bronchospasm.