Formulaic quantification of echocardiographic left atrial volume

Area of Science:

• Cardiology
• Medical Imaging
• Biostatistics

Background:

• A regression formula links P-wave duration on ECG to left atrial volume index (LAVI) measured by transthoracic echocardiogram (TTE).
• This formula requires prospective validation in diverse inpatient populations.
• Abnormal atrial depolarization severity correlates with left atrial volume.

Purpose of the Study:

• To prospectively validate a regression formula for estimating left atrial volume index (LAVI) using P-wave duration from ECGs in inpatients.
• To assess the agreement between formula-derived LAVI and TTE-measured LAVI.
• To determine the optimal ECG lead for P-wave duration measurement in this formula.

Main Methods:

• Prospective collection of 12-lead ECGs and TTEs from consecutive inpatients.
• Independent P-wave duration assessment to the nearest 10 milliseconds for formula application.
• Bland-Altman analysis to compare formulaic LAVI estimation with TTE-derived measurements (Simpson's rule).

Main Results:

• Strong correlation found between formulaic LAVI and TTE-derived LAVI (r=0.67 to 0.89, P<.0001).
• Highest correlation (r=0.89) achieved using maximal P-wave duration from lead II.
• Good agreement shown by Bland-Altman analysis (8.8%-11.4% reproducibility for 2 SD).

Conclusions:

• The P-wave duration formula provides a validated, non-invasive method for estimating LAVI in inpatients.
• This formulaic estimation shows good agreement and correlation with TTE measurements.
• Formulaic LAVI can supplement TTE and aid in patient risk stratification.