Article

This study aimed to characterize the ST-recovery loop and assess which range of heart rates (HRs) best discriminates between patients with and without significant coronary artery stenosis. Bicycle exercise tests were undertaken in 44 men and IS women with coronary artery disease (CAD) and in 59 controls (26 men, 33 women) in the same age range with no signs of CAD. The ST level and the ST-segment slope were continuously monitored, and changes from rest to peak exercise and to 4 min after exercise, respectively, were calculated. Plotting the ST level against HR gives the STHR loop, characterized by the normalized area (NA(alpha)) circumscribed by the ST level during and after exercise from alpha% to 100% of the HR range. Eight values of a between 20% and 90% were investigated, and chest and extremity leads were investigated separately. Optimal a was found to be less than or equal to70% in men and less than or equal to30% in women. Change in ST-segment slope was the only parameter that gave significant additional discriminating power in both men and women once the area had been taken into account. We conclude that NA(alpha) for extremity and chest leads have similar weights, and that a substantial part of the STHR loop should be taken into consideration, especially in women. NA(3O) was superior to end-exercise ST-depression and STHR loop orientation (as defined by the sign of NA(90) in both men and women, and to ST/HR index in men, in identifying CAD.

Langue : ANGLAIS

Tiré à part : OUI