The influence of tumor size on the electrocardiographic changes in patients with left atrial myxoma

The authors assessed the usefulness of the electrocardiography in patients with left atrial myxoma. The authors retrospectively reviewed the records of 15 patients with left atrial myxoma before and after tumor excision. The 12-lead electrocardiogram presented the P-wave abnormality shown by a broad P wave in lead II (PDII) and/or a deep and broad negative P terminal force in lead V1 (PTFV1). These abnormal findings were shown in the 13 patients whose tumor weight was 16 g or more. However, the other 2 patients whose tumor weight were 7 g or less did not have a prolonged PDII or an increased PTFV1. Both PDII and PTFV1 were correlated not only with the tumor size but also with the left atrial dimension and/or the left atrial pressure. These P-wave abnormalities were markedly improved or disappeared, and the left atrial dimension and pressure decreased immediately after tumor excision. The increasing size of the tumor brings about the P-wave abnormalities, which may result from enlargement of the left atrial cavity. It is suggested that while not specific the 12-lead ECG findings of PDII and PTFV1 may be useful for detecting a myxoma weighting 16 g or more, but was an insensitive technique for smaller ones.