Left atrial size in childhood.

To determine the accuracy of the diagnosis of left atrial enlargement (LAE) by vectorcardiogram (VCG) and electrocardiogram (ECG), we analyzed the magnitude of the P loop on VCG and the P wave duration, amplitude, and deflection on the ECG and compared them with echographic and angiographic data. Twenty-eight children with LAE were selected who had congenital or acquired heart disease. The control population consisted of 24 children with normal left atrial (LA) dimensions. No significant difference in P wave amplitude or duration was found in the two groups on ECG. Negative terminal deflection greater than orequal to - 1 mm in V1 predicted LAE in only 25% of the patients with LAE. P loop magnitudes in all vector planes showed considerable overlap in both groups. When magnitude and direction were considered on VCG, only 29% of the patients with LAE would have been diagnosed as LAE by VCG criteria. Patients with large LA volumes, determined from biplane angiography,were compared with echocardiography, VCG and ECG. All had echocardiographic LAE, 50% had LAE by ECG criteria and only 33% by VCG criteria. It is concluded that more sensitive ECG and VCG criteria for diagnosing LAE by ECG and VCG need to be developed. It must also be determined which of these changes correlate with conduction delay, atrial hypertrophy and/or enlargement.