Cardiac arrhythmias in F-16 pilots during aerial combat maneuvers (ACMS): a descriptive study focused on G-level acceleration.
BACKGROUND
It is well known that acceleration during centrifuge training provokes cardiac arrhythmias. However, there is little research regarding cardiac arrhythmia during actual flight. Therefore, to identify the kinds of cardiac arrhythmias that occur in response to the Aerial Combat Maneuvers (ACM) environment, we analyzed electrocardiograms (ECG) of 35 male pilots.


METHODS
ECGs were recorded from 35 pilots (mean age 31 yr, range 27-39) from 1 h before take-off to 1 h after landing. G-load was simultaneously recorded. To see the patterns of the arrhythmia as Gz force increased, ECG data of each subject were classified into three G levels: a) G-level A was < +3 G; b) G-level B was > or = +3 G but < +6 G lasting longer than 3 s; and c) G-level C was > or = +6 G lasting longer than 3 s.


RESULTS
Mean total flying time of the 35 pilots was 1475 h (range 578-3300). Arrhythmias were observed in 17 of the pilots (49%) during ECG recording. Four pilots (11.4%) experienced arrhythmias before take-off, 16 pilots (45.7%) inflight and 4 pilots (11.4%) after landing. Arrhythmias were recorded in 13 of 35 pilots (37.1%) at G-level A, in 10 of 35 pilots (28.6%) at G-level B and in 1 of 21 pilots (5%) at G-level C. During flight, unifocal premature ventricular contractions (PVC) were experienced by three of the subjects (8.6%); supraventricular premature beats (SVPB) by four subjects (11.4%), and PVCs with bigeminy by one subject (2.9%). Eight subjects (22.9%) experienced combined arrhythmias.


CONCLUSIONS
There were no clinically significant arrhythmias recorded during ACM in these experienced pilots.
Chung
K Y
KY
The Aeromedical Center, Republic of Korea Air Force. chungkiyoung@yahoo.com
Lee
S J
SJ
D000054:Acceleration / Q000009:adverse effects*; D000328:Adult; D000337:Aerospace Medicine; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology*; D018880:Atrial Premature Complexes / Q000175:diagnosis / Q000209:etiology*; D015992:Body Mass Index; D015716:Electrocardiography, Ambulatory; D006112:Gravitation; D006327:Heart Block / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D015994:Incidence; D007723:Korea; D008297:Male; D008889:Military Personnel; D012907:Smoking / Q000009:adverse effects; D013997:Time Factors; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000209:etiology*; D014857:Warfare