Age-related changes in P wave morphology in healthy subjects.
BACKGROUND
We have previously documented significant differences in orthogonal P wave morphology between patients with and without paroxysmal atrial fibrillation (PAF). However, there exists little data concerning normal P wave morphology. This study was aimed at exploring orthogonal P wave morphology and its variations in healthy subjects.


METHODS
120 healthy volunteers were included, evenly distributed in decades from 20-80 years of age; 60 men (age 50+/-17) and 60 women (50+/-16). Six-minute long 12-lead ECG registrations were acquired and transformed into orthogonal leads. Using a previously described P wave triggered P wave signal averaging method we were able to compare similarities and differences in P wave morphologies.


RESULTS
Orthogonal P wave morphology in healthy individuals was predominately positive in Leads X and Y. In Lead Z, one third had negative morphology and two-thirds a biphasic one with a transition from negative to positive. The latter P wave morphology type was significantly more common after the age of 50 (P < 0.01). P wave duration (PWD) increased with age being slightly longer in subjects older than 50 (121+/-13 ms vs. 128+/-12 ms, P < 0.005). Minimal intraindividual variation of P wave morphology was observed.


CONCLUSIONS
Changes of signal averaged orthogonal P wave morphology (biphasic signal in Lead Z), earlier reported in PAF patients, are common in healthy subjects and appear predominantly after the age of 50. Subtle age-related prolongation of PWD is unlikely to be sufficient as a sole explanation of this finding that is thought to represent interatrial conduction disturbances. To serve as future reference, P wave morphology parameters of the healthy subjects are provided.
Havmoller
Rasmus
R
Department of Cardiology, Lund University Hospital, Lund, Sweden. Rasmus.Havmoller@med.lu.se
Carlson
Jonas
J
Holmqvist
Fredrik
F
Herreros
Alberto
A
Meurling
Carl J
CJ
Olsson
Bertil
B
Platonov
Pyotr
P
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged