Table 1.

Normal maximal values of the P-wave duration with the advancement of age [52].

Age	P-wave duration (ms)
From the 18th to the 22nd week of pregnancy	44
≥37 weeks	52.9
Premature newborn baby	80 (60 ± 20)
Full-term newborn baby at 12 months	80 (2 small boxes)
From 1 to 12 years old	90
From 12 years old until the adult life	The normal maximal value is 110 ms (2.5 small squares). In adults, P-wave ≥ 110 ms indicates the presence of LAE, anomaly in LA activation by Bachman's fascicle.
Elderly people	≤120 ms

LA: Left atrial; LAE: Left atrial enlargement.