[Electrocardiogram in pulmonary heart disease--clinical evaluation of right chest leads].

A clinical study was made to evaluate the usefulness of electrocardiograms in right precordial leads (V3r or V4R) for the diagnosis of cardiac complications among patients with chronic pulmonary disease. Walsh and colleagues reported that the change of direction in the terminal vector of QRS loop in the vector cardiogram is useful for the evaluation of chronic pulmonary heart disease. They showed that the terminal vectors of QRS loops tend to deviate to the right and/or posterior direction in the early stage of chronic pulmonary heart disease. We utilized the electrocardiograms in the right precordial leads to detect the second R waves, which are thought to reflect the terminal vectors of QRS loops in the vectorcardiograms. When the electrocardiograms in the right precordial leads were compared, the second R waves in leads V3R or V4R were more frequently observed among patients with chronic pulmonary heart disease than those without. However, in the same two groups, the frequency of second R waves in leads V5R or V6R didn't differ. We conclude that the second R waves in leads V3R or V4R in a patient with chronic lung disease suggest the presence of chronic pulmonary heart disease as a complication.