Relationship between P-wave duration and atrial electromechanical delay assessed by tissue Doppler echocardiography

The aim of the study was to assess the relationship between P-wave duration on the surface electrocardiogram (ECG) and echocardiographic parameters of atrial electromechanical delay (EMD), as well as contraction synchrony during different atrial pacing modalities.

In 57 patients with sinus node disease and prolonged sinus P-wave duration treated with multisite atrial pacing (MSAp), the EMD was measured by tissue Doppler in several left and right atrial sites during sinus rhythm, MSAp, and single-site pacing at right atrial appendage (RAAp), Bachmann's bundle (BBp) region, and coronary sinus (CSp) ostium. Regional atrial synchrony was calculated on the basis of EMD.

P-wave duration was 141 ± 16, 120 ± 17, 138 ± 17, 144 ± 16, and 160 ± 19 ms during sinus rhythm, MSAp, BBp, CSp, and RAAp, respectively (P < 0.001 RAAp and MSAp vs other). P-wave duration correlated with all atrial EMDs as well as interatrial and intraleft atrial parameters of dyssynchrony. In multivariate analysis, the EMD in lateral left atrial wall was the strongest predictor of P-wave duration (β 0.41; P < 0.001). The relationship between P-wave duration and the atrial EMDs was most prominent during RAAp (all left atrial walls r > 0.51; P < 0.01) and BBp (all atrial walls r > 0.42; P < 0.05), while during sinus rhythm and CSp, only weak correlation between echo and ECG was found. Neither of the tissue Doppler parameters correlated with P-wave duration during MSAp. Interatrial dyssynchrony correlated with P-wave duration during sinus rhythm and RAAp and intraleft atrial dyssynchrony only during sinus rhythm.

P-wave duration of the surface ECG is highly correlated with the atrial EMD, the relationship is specific for each pacing modality.