[Role of ambulatory blood pressure measurement in the evaluation of the cardiovascular load in high altitude workers].
This study evaluates ambulatory blood pressure ABP measurement as a technique for measuring the cardiovascular load in maintenance mechanics working on mechanical lifts at altitudes of over 2,500 meters (stress due to altitude and intensive static and dynamic work).


METHODS
25 normotensive workers were studied during real working conditions. Each subject underwent a maximal stress test, and echocardiography. An ABP recording (Spacelab 90207) with BP measurement every 15 minutes and continuous heart rate (HR) monitoring (Essilor IFC85), during 24 hours were performed on the same day.


METHODS
study of BP levels and their factors of variation, comparison of this data with continuous HR measurements, and with results of the stress test and echocardiography.


RESULTS
even in difficult conditions (while balancing on cables and cable towers), ABP measurements is possible (less than 10% missing values). Systolic (SBP) and diastolic (DBP) blood pressure and HR values adjusted for age are significantly higher during work activity (9:00-12:00, 14:00-15:00) in these subjects than in reference normotensive subjects. ABP did not differ significantly between different types of work while the equivalent mechanical load (work load that gives a stress test HR equal to the mean HR during work) reveals a different between work activities. At night SBP remains higher and HR values lower than in control subjects. In comparison with reference criteria, 3 subjects were considered as having an abnormally high ABP during the daytime. ABP results were not linked with number of years in the profession nor with the altitude at which the subject worked or lived. Although 40% of subjects have a left ventricular mass index greater than 135 g:m2, there is no link between ultrasound and ABP parameters.


CONCLUSIONS
while ABP measurement seems possible in this type of professional activity, BP values do not appear to be correlated to work level measured. The absence of correlation with left ventricular mass, suggests that the process of cardiovascular adaptation is different from that in even moderately hypertensive subjects.
De Gaudemaris
R
R
Consultation d'hypertension artérielle, hôpital André-Michallon, Grenoble.
Jalbert
M
M
Isnard
E
E
Flores
J L
JL
Siché
J P
JP
Perdrix
A
A
Maître
A
A
Mallion
J M
JM
D000222:Adaptation, Physiological; D000328:Adult; D000531:Altitude; D000553:Ambulatory Care; D001794:Blood Pressure; D015924:Blood Pressure Monitors; D004452:Echocardiography; D006339:Heart Rate; D006801:Humans; D005082:Physical Exertion; D016276:Ventricular Function
Place de la mesure de la pression artérielle en ambulatoire dans l'évaluation de la charge cardiovasculaire de salariés travaillant en haute altitude.