Electrocardiographic diagnosis of left atrial enlargement.

Established scalar electrocardiographic criteria for left atrial enlargement are based on abnormalities of the P-terminal force, total P-wave duration, and the relationship of total P-wave duration to PR-interval duration. These electrocardiographic signs may also result from left atrial hypertension, left atrial hypertrophy, and interatrial conduction defects. This article describes the scalar electrocardiographic criteria for left atrial enlargement in current use, and provides a critical appraisal of their efficacy in diagnosis.