Quantitative estimation of left atrial linear dimension on a transthoracic echocardiogram using an electrocardiographic formulaic assessment

A proportionate and incremental association between left atrial (LA) dilatation on a transthoracic echocardiogram (TTE) and increasing severity in abnormal atrial depolarization can be described by the regression formula: LA dimension in parasternal long-axis view (in millimeters) = 2.47 + 0.29 [P-wave duration (in milliseconds)]. However, prospective testing of this formula for LA quantification with comparison to other TTE indexes is lacking. We prospectively obtained 12-lead electrocardiograms for 72 consecutive patients before individual, nonemergent TTE assessment. P waves were assessed independently to the nearest 10 ms for application of the formula with a Bland-Altman plot. P-wave durations were obtained specifically from lead II and also from any lead that yielded the widest measurement. There was a strong formulaic correlation with LA measurement by TTE (p