The relationship between P wave dispersion and diastolic dysfunction.

We investigated the relationship between P wave dispersion, which is easily measured on the surface electrocardiogram and may be used in evaluating the risk of atrial fibrillation, and left ventricular diastolic function. There were 133 patients: 73 with diastolic dysfunction and 60 without. P wave dispersions were calculated by measuring minimum and maximum P wave duration values on the surface electrocardiogram. The relationships between P wave dispersion and the presence, cause, severity, and echocardiographic measurements of diastolic dysfunction were investigated. P wave dispersion was 53 +/- 9 ms in patients with diastolic dysfunction and 43 +/- 9 ms in the control group (P < 0.01). When patients were grouped according to stage of diastolic dysfunction, P wave dispersion was 48 +/- 7 ms in stage 1, 54 +/- 8 ms in stage 2, and 58 +/- 9 ms in stage 3. As the severity of diastolic dysfunction increased, P wave dispersion increased but the difference did not reach statistical significance (P < 0.05). When the cause of diastolic dysfunction was considered, P wave dispersion was 53 +/- 8 ms in patients with ischemic heart disease and 52 +/- 9 ms in patients with left ventricular hypertrophy (P > 0.05). We conclude that P wave dispersion increases in diastolic dysfunction, but that this increase is not related to the severity or cause of diastolic dysfunction. When clinical and echocardiographic variables are taken into account, there is a weak but significant correlation only between P wave dispersion and left ventricular ejection fraction.