Incremental value of P-wave indices for predicting left atrial dysfunction in patients with primary mitral regurgitation using speckle tracking echocardiography.

The correlation of P wave indices on surface ECG and phasic LA dysfunction in patients with significant primary mitral regurgitation (MR) due to the adverse LA adaptive structural and functional changes needs to be more studied. This study aims to investigate the diagnostic value of P wave indices to predict LA function assessed both by volumetric analysis using 3-dimensional (3D)echocardiography, and by strain analysis using speckle tracking echocardiography. (STE). The study included 107 subjects, we measured maximum P-duration (Pmax), P dispersion (PD), and V1 negative terminal force (V1-NTF) (negative duration x negative amplitude) on surface ECG. Both Basic and Dynamic LA volumes (LAV) during reservoir, conduit, and contractile phases were measured. The global LA strain and strain rate parameters were calculated By STE. LA ejection fraction (LAEF) and ejection force were also calculated.V1-NTF showed a significant positive correlation while P-max a significant negative correlation with global peak atrial longitudinal strain (GPALS) (r = 0.75; P   110 ms, 1-NTF ≥ 4 ms.mV and P notching > 40 ms had a sensitivity of 90%, 95% and 50% and a specificity of 87.4%, 94.3% and 100% respectively in predicting GPALS ≤ 30%. P notching > 40 ms was associated with severe LA dysfunction. ECG P wave indices represent a simple bedside tool that could have an incremental role in predicting LA dysfunction as well as size in patients with significant primary MR.