Abstract
Changes in the shape of the complexes of the electrocardiogram have been observed in pathologic intrathoracic conditions not primarily cardiac. These conditions include pericarditis, 1 pericardial effusion without demonstrable inflammation, 2 and lobar pneumonia. 3 Bettman and Priest 4 described the electrocardiograms of patients before and after chest operations, including in their series 7 patients on whom extrapleural thoracoplasty was performed. One of the 7 developed the so-called “coronary type” T-wave and 3 others diminution in the amplitude of the QRS complex. These findings suggested a study of the electrocardiograms of dogs following the production of atelectasis or the removal of one or more lobes of lung. The operations were done as described elsewhere by Adams 5 and the amount of functioning lung tissue calculated according to his table.
Nine dogs were studied in which collapse of one or more of the pulmonary lobes had taken place more than a month previously. In this group 2 had sinoauricular block and 4 had inversion of the T-waves in leads 2 and 3. One had depression of the ST segment below the isoelectric line with inversion of T in leads 2 and 3. ORS was of very low amplitude in all leads in one dog. This finding was confirmed in repeated tracings. The dogs in this series had from 43% to 57% of functional lung tissue.
On one dog a tracing was taken the next day after the collapse of the left upper lobe. The entire right lung had been collapsed more than a month previously, so that at the time the tracing was taken only 28% of the original lung tissue remained functional. This dog had a notched but upright T-wave in all leads. The rate averaged 60 per minute. There were a few points in the tracing where the intervals between beats were exactly half the adjacent intervals and it was felt that this dog probablv had a marked sinoauricular block.
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