Long-term follow-up of P-wave duration and dispersion in patients with mitral stenosis.

Background: Patients with mitral stenosis have prolonged P-wave duration and increased P-wave dispersion (PWD) that have been associated with increased risk for atrial fibrillation.
Methods: Thirty mild-to-moderate mitral stenosis patients were followed for 38.4+/-10.7 (23-48) months. Baseline and last 12-lead electrocardiographic and transthoracic echocardiographic measurements were evaluated. Maximum and minimum P-wave durations (Pmax and Pmin) and PWD were calculated.
Results: Pmax and PWD were significantly higher in patients compared to control group. Left atrial (LA) size, mitral gradient, and pulmonary artery systolic pressure (PASP) were significantly increased and mitral valve area (MVA) was decreased during follow-up. There were significant increases in Pmax and PWD and significant decrease in Pmin (Pmax: 101.0+/-12.5 ms vs 105.0+/-16.5 ms, P=0.005; Pmin: 59.3+/-8.5 ms vs 55.0+/-12.3 ms P=0.004; PWD: 41.7+/-5.5 ms vs 50.0+/-6.2 ms, P<0.001). Baseline Pmax, Pmin, and PWD were significantly correlated with MVA (Pmax: r=-0.605, P<0.001, Pmin: r=-0.632, P<0.001, PWD: r=-0.402, P=0.0028) and mean mitral gradient (Pmax: r=0.412, P=0.024, Pmin: r=0.632, P=0.049, PWD: r=0.378, P=0.039). In addition to MVA and mean mitral gradient follow-up P-wave variables were significantly correlated with LA size (Pmax: r=0.573, P=0.001, Pmin: r=0.636, P=0.001, PWD: r=0.265, P=0.046) and PASP (Pmax: r=0.462, P=0.011, Pmin: r=0.472, P=0.008 PWD: r=0.295, P=0.047).
Conclusions: P-wave duration and PWD increase progressively in accordance with the progression of mitral stenosis.