Although cor pulmonale due to chronic lung disease was not uncommon, there was uncertainty in its diagnosis due to the difficulty in measuring functional and anatomical changes of right heart and pulmonary vascular system. Among various non-invasive diagnostic methods presented so far, no ideal standard diagnostic criterion has been established. The authors attempted to know positive diagnostic ratio of cor pulmonale and to study the presence of the relationship between these diagnostic criteria when electrocardiographic and echocardiographic diagnostic criteria for cor pulmonale were applied to the patients with chronic lung disease. And we investigated the usefulness of echocardiogaphic diagnostic criteria for the diagnosis.

One electrocardiographic and two echocardiographic diagnostic criteria were applied to 38 patients with chronic lung disease(21 pulmonary emphysema and 17 chronic advanced pulmonary tuberculosis) for the diagnosis of cor pulmonale. Comparison was also made in their relationship. Then pulmonary artery diameter, measurement of pulmonary function test and echocardiographic examination and radio-nuclear right ventricular ejection faction were compared between the groups to ensure each criterion was satisfied.

1) When the three diagnostic criteria for confirming the cor pulmonale, electrocardiographic rriterion(right ventricular hypertrophy), right ventricular dimension criterion(right ventricular end-diastolic dimension>25mm, RVDd>25mm), and right ventricular wall thickness criterion (right ventricular wall thickness>6mm, RVWT>6mm) were applied to the patients, the positive rate were 32%(12/37), 30%(10/33) and 17%(6/36) respectively. A statistically significant correlation between electrocardiographic criterion and right ventricular wall thickness criterion was found to exist. 2) Various parameters of pulmonary function test and echocardiographic examination were compared in the patient groups with and without cor pulmonale when each non-invasive diagnostic criterion was applied to all patients. Followings are the results. (1) In the positive group on electrocardiographic criteria, vital capacity, forced vital capacity, and arterial oxygen tension were significantly smaller than in the negative group on electrocardiographic criterion(p<0.05), and the echocardiographic parameters of right ventricle, ie. end-diastolic area, end-systolic area, end-diastolic dimension, end-systolic dimension, mid-ventricular short axis and maximal short axis in positive group were significantly larger than in the negative group. (2) In the positive group on right ventricular diastolic dimension criterion(RVDd>25mm), percentage forced expiratory volume in 1 second and forced expiratory flow 25-75% were significantly smaller than in the negative group on right ventricular diastolic dimension criterion. (3) In the positive group on right ventricular wall thickness criterion(RVWT>6mm), vital capacity, forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow 25-75% and arterial oxygen tension were significantly smaller than in the negative group on right ventricular wall thickness criterion.

When several non-invasive diagnostic criteria for cor pulmonale were applied to the patients with chronic lung disease, there were some differences in its positive diagnostic ratio depending on the applied diagnostic criteria. There was also a statistically significant correlation between electrocardiographic criterion and right ventricular wall thickness criterion. When each diagnostic criterion was applied to the patients, significant differences were found in several parameters resulted from pulmonary function test and echocardiographic examination based on presence or nonpresence of cor pulmonale. But no difference in the ejection fraction measured by radio-nuclear method was shown between cor pulmonale group and non cor pulmonale group. Consequently it was suggested that applying echocardiographic criteria in addition to electrocardiographic criterion for the diagnosis of cor pulmonale in the patients with chronic lung disease is clinically useful.