Assessment of atrial conduction time in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder resulting in multisystemic inflammatory damage. Recent articles report that 20% to 30% of deaths in patients with SLE have cardiovascular origin. The aim of this study was to investigate the atrial conduction time in patients with SLE by using high-usefulness tissue Doppler echocardiography (TDI).

The study population included 56 patients with SLE (49 women; mean [SD] age, 46.2 [12.2] years, and mean [SD] disease duration, 30.7 [10.9] months) and 45 healthy subjects as control group (39 women; mean [SD] age, 45.8 [12.3] years). P-wave dispersion (PWD) was calculated by using 12-lead electrocardiogram. The timing of atrial contractions (PA) was measured as the interval between the onset of P wave on electrocardiogram and the beginning of A wave on TDI. Atrial electromechanical delay (EMD) was calculated from the lateral (PA lateral), septal (PA septal) mitral annulus, and lateral tricuspid annulus (PA tricuspid).

Lateral mitral annulus and PA septal were significantly longer in the patients with SLE than in the control subjects (66.7 [15.9] vs 56.5 [13.7], P = 0.001, and 53.5 [15.0] vs 45.0 [15.1] milliseconds, P = 0.006, respectively). Interatrial (PA lateral - PA tricuspid) and intra-atrial (PA septal - PA tricuspid) EMD were significantly higher in SLE groups (25.5 [9.7] vs 19.9 [8.3], P = 0.003 and 13.3 [7.7] vs 8.4 [8.0] milliseconds, P = 0.002, respectively). Similarly, maximum P-wave duration and PWD were significantly longer in the patients with SLE than in the control subjects (104.9 [13.5] vs 98.1 [15.1], P = 0.021 and 24.6 [7.4] vs 20.0 [8.1] milliseconds, P = 0.004, respectively). There were significant positive correlations between the disease duration and interatrial EMD (r = 0.611, P < 0.001) and intra-atrial EMD (r = 0.565, P < 0.001). Positive correlation was also present between the disease duration and PWD (r = 0.457, P < 0.001).

Atrial EMD is prolonged in patients with SLE. We have also shown that PWD, intra-atrial EMD, and interatrial EMD were significantly correlated with disease duration. This study calls attention to the following: the measurement of atrial conduction time may be clinically helpful in the definition of cardiac involvement.