The Changes of the Left Ventricular Contractility and the Cardiac Vector of the Pilot by the Flight Time

ABSTRACT

To study on the left ventricular contractility and the cardiac vector of fighter pilots, 56 pilots and 15 normal cadets were selected and they were divided into six groups by flight time (hours). To evaluate the left ventricu-lar contractility of subjects, R amplitude of chest V1 , V5 , V6 lead were recorded by ECG, and R-Z interval were recorded by ICG (impedance cardiography). And, to evaluate the cardiac vector of subjects, mean QRS vec-tor of I, II, V2 , V6 lead were recored by ECG. Results of this study are following, 1) Systolic and diastolic blood pressure were decreased against flight time. 2) Sv1 +Rv5 was decreased against flight time; Sv1 +Rv5 was 27.8 mm in 50 hr Group that is the longest among the group, and 23.7 mm in 2,000 hr Group that is the shortest among the groups. V6 /V5 was no significant difference among the groups. 3) R-Z interval was decreased against flight time; R-Z interval was 166.8 X10(-3) sec in 50 hr Group that is the longest among the group, and 154.4 X10(-3) sec in 2,000 hr Group that is the shortest among the groups. 4) In frontal plan, the range of QRS vector axis was +57.3 degrees ~ +78.2 degrees that was deviated to left of body center according to the flight time. In horizon-tal plan, the range of QRS vector axis was -29.6 degrees ~ +47.2 degrees that was deviated to back of body center according to the flight time. In both plan, the amplitude of QRS vector was tend to decreasing against the flight time. Results of this study indicate that the cardiac function of fighter pilots was doubted to degenerate or weaken. Conclusionally, fighter pilots have to increase their cardioventricular fitness by the aerobic training and other methods.