Electrocardiographic changes in massive pulmonary embolism. I. Analysis of the changes in P wave and QRS complex

A retrospective analysis of ECG changes during lung embolism has been made in 35 patients (16 male, 19 female) who died of massive lung embolism. The presence of lung embolism or infarct was confirmed at autopsy. According to the ECG the mean heart rate increased from 91 to 106. The amplitude of the P wave increased in leads I, II, III and aVL and decreased in all precordial leads. A small increase in the O wave occurred in leads II, III, aVF, V1, V2 and V6. Only a small decrease in the R wave occurred in leads I, II and aVL. A small increase in the S wave occurred in leads I, II, V2-V6 when compared with the controls. None of the differences was, however, statistically significant.