Association of stage of left ventricular diastolic dysfunction with P wave dispersion and occurrence of atrial fibrillation after first acute anterior myocardial infarction.

Objectives: The aim of this study was to investigate the association of stage of left ventricular diastolic dysfunction after acute myocardial infarction (AMI) with P maximum, P dispersion, and atrial fibrillation (AF) occurrence rate.

Background: The occurrence of AF following AMI is frequently associated with a left ventricle restrictive filling pattern. Increased P dispersion is also associated with the occurrence of AF after AMI. But, the relation between the stage of left ventricular diastolic dysfunction and the P wave measurements after AMI has not yet been investigated.

Methods: Electrocardiograms of 90 patients with first anterior AMI were recorded on admission, and P wave measurements were performed. The left ventricular diastolic functions were evaluated by transthoracic echocardiography. On the basis of mitral inflow, subjects were stratified into three left ventricular diastolic filling patterns. All patients were monitored continuously for the detection of AF in the Coronary Care Unit.

Results: Thirty patients had a normal filling pattern (33.3%) (NF group), 37 had impaired relaxation (41.1%) (IR group), and 23 had pseudonormal/restrictive filling pattern (25.6%) (PN/R group). P maximum was longer in the PN/R group (103 +/- 12 ms) compared with the NF group (94 +/- 9 ms, P = 0.019), but no significant difference was found between PN/R and IR (96 +/- 13 ms, P > 0.05) groups, and between NF and IR groups (P > 0.05). There was no significant difference for P minimum among the groups (P > 0.05). P dispersion was longer in the PN/R group (35 +/- 6 ms) than in the NF (26 +/- 7 ms, P < 0.001) and IR groups (26 +/- 6 ms, P < 0.001), but not different between the NF and IR groups (P > 0.05). Occurrence of AF was significantly more frequent in the PN/R group (52.2%) than in the NF (16.7%, P = 0.007) and IR groups (10.8%, P = 0.001). Frequency of AF was not different between the NF and IR groups (P > 0.05). In multivariate analyses, the stage of diastolic dysfunction was independently associated with P maximum, P minimum, P dispersion, and the occurrence of AF (P < 0.001, P = 0.035, P < 0.001, and P = 0.002, respectively).

Conclusions: P maximum and P dispersion are increased, and AF occurrence risk is higher in patients with pseudonormal/restrictive filling pattern after first anterior AMI. The stage of diastolic dysfunction is an independent predictor of P wave measurements and AF occurrence.