Electrocardiographic studies in acute pericarditis with specific reference to ventricular involvement of non-specific pericarditis.

The authors investigated electrocardiographic changes minutely in five cases of acute pericarditis, and especially in two cases of non-specific pericarditis. The results indicated that the amplitudes of the R and S waves increased progressively immediately after the disease reached a peak, which was reached after abnormal heart shadow in the chest x-ray returned to normal. This increased curve of amplitude varied in association with changes in the ST segment and T wave, suggesting an inflammatory dilatation of the myocardium. On the other hand, however, the curve was indistinct and took a long time to reach a maximum in case of systemic lupus erythematosus pericarditis, and was found to decrease and remain stationary in cases of pericarditis secondary to lung cancer and/or tuberculosis. These facts should become a useful guideline for diagnosis of acute non-specific pericarditis (due to virus origin). Ischemic changes of the ST segment and T wave were manifested by an exercise test during recovery from acute pericarditis when ST segment and T wave abnormalities had already improved and high voltage was the only abnormal finding on the ECG. In the healing stage, regarding the finding of high voltage, it should be pointed out that the myocardium remains as yet with residual damage revealed by loading with exercise, and treatment may be necessary until the abnormal finding has improved.