Elevated red cell distribution width is associated with negative P wave amplitude in lead V1: national health and nutrition examination survey (NHANES III).

Introduction: Red cell distribution (RDW) is associated with atrial fibrillation (AF) incidence. However, its relationship with precursors of AF has not been established. We aim to investigate if association exists between RDW and negative P wave amplitude in V1, a marker of left atrial abnormality.

Methods: NHANES III is a complex, multistage, clustered design survey of noninstitutionalized United States population between 1988-94. A Sample of 6403 individuals was extracted after excluding missing demographic, laboratory, anthropometric and ECG data and major ECG abnormalities. Variables were selected and univariate analysis was done first with a level of significance at P<0.01 (99% confidence). All the significant variables were included in a multivariate linear regression model.

Results: 53.58% of subjects were female. Racial distribution was caucasian 50.2%, hispanic 23.9% and african american 21.7%. Age, PR interval, heart rate, systolic blood pressure, red cell distribution width, glycated hemoglobin, serum cholesterol, serum ferritin, and body mass index showed a significant correlation with negative P wave amplitude in V1 (P<0.001). After including all these variables in a multivariate regression model, only age, body mass index, systolic blood pressure, PR interval, heart rate and red cell distribution width had a P≤0.001.

Conclusions: Increased RDW is independently associated with negative P wave amplitude in V1 after correcting for other cardiovascular risk factors. Further studies are required to analyze the reason for this correlation.