Pulmonary Hypertension and Respiratory Failure in the Development of Right Ventricular Hypertrophy in Patients with Chronic Obstructive Airway Disease

The high incidence of right ventricular hypertrophy in patients with chronic obstructive pulmonary disease is a well-known fact. In clinical medicine according to our present status of thinking, severe impairment of ventilatory function and pulmonary hypertension are the two essential prerequisites for right ventricular involvement. To investigate this accepted assumption we studied 51 patients with chronic obstructive pulmonary disease, while they were in a remission period. The patients were subjected to clinical examination, chest roentgenography, spirometry, blood gas examination, electrocardiography, vectorcardiography, echocardiography, and right heart catheterization. The majority of the patients with significantly compromised ventilatory function and abnormal blood gases had right ventricular hypertrophy with elevation of the pulmonary artery pressure. Two subgroups of patients could be distinguished: One included 15 patients (29.4% of all patients) with normal pulmonary artery pressure and evidence of right ventricular hypertrophy. In this subgroup are included 10 patients (19.6% of all patients) showing mild ventilatory impairment and mild hypoxaemia. The second subgroup consisted of 5 patients (9.8% of all patients) with elevated mean pulmonary artery pressure at rest and right ventricular hypertrophy showing relatively mild ventilatory impairment and moderate hypoxaemia. Two conclusions could be drawn: (1) the pulmonary artery pressure at rest could be normal despite the evidence of right ventricular hypertrophy, and (2) a mild ventilatory impairment does not exclude an elevated pulmonary artery pressure or the development of right ventricular hypertrophy in patients with chronic obstructive pulmonary disease.