P-wave indices: derivation of reference values from the Framingham Heart Study

Abstract

Background: P-wave indices, an electrocardiographic phenotype reflecting atrial electrophysiology and morphology, may be altered in multiple disease states or by cardiovascular risk factors. Reference values for P-wave indices, providing cut points for their classification and interpretation, have not yet been established and are essential toward facilitating clinical application and comparison between studies.

Methods: We randomly selected 20 men and 20 women from 10-year age intervals between <25 years to 76-85 years from the Framingham Heart Study Original and Offspring Cohorts, excluding subjects with prevalent cardiovascular disease, hypertension, diabetes or obesity. The total included 295 subjects; eligibility in women >75 years was limited by exclusion criteria. We used a digital measurement technique with demonstrated intrarater reproducibility to determine P-wave indices. P-wave indices examined included the maximum, mean, lead II and PR durations, dispersion, and the standard deviation of duration.

Results: All P-wave indices were significantly (P < 0.0001) correlated with advancing age. Means of all P-wave indices were lower in women as compared to men. PR-interval duration was strongly correlated with maximum, mean, and lead II mean P-wave durations. In multivariable models adjusting for significant anthropometric and clinical associations risk factors, significant differences persisted by age and sex in P-wave indices.

Conclusions: In our healthy sample without cardiovascular disease, hypertension, diabetes, or obesity, men and older subjects had longer mean P-wave indices. Our description of P-wave indices establishes reference values for future comparative studies and facilitates the classification of P-wave indices.

Figure 1

Maximum P‐wave duration (A) and dispersion (B) in men and women, showing the distribution according to age decile. Values shown are the median, 25th and 75th percentile, and the range from the 90th and 10th percentile. The number of subjects per each progressive 10‐year age group was 20, 20, 20, 23, 24, 24, and 22 for men, and 20, 20, 20, 20, 24, 23, and 17 for women.