Article

Partial normalization of the heart rate (HR) response can take place
some time after heart transplantation (HTx), but the extent to which this occurs,
its time course, and functional significance remain unclear. DESIGN: Seventy-seven heart transplantation patients underwent an exercise test at
approximately 1, 6, and 12 mos after heart transplantation, consisting of a
resting period, a submaximal exercise test, and a maximal exercise test with
stair climbing, followed by a recovery period. An HR monitor was used for
continuous surveillance of HR. RESULTS: During the follow-up, HR at rest did not
change, whereas all other HR parameters obtained during and after exercise
improved, demonstrating a more rapid increase, a higher peak, and a more rapid
decline in HR after stopping exercise. Age-predicted maximum HR at baseline was
73% +/- 9%, improving to 83% +/- 10% at 6 mos (P < 0.001) and to 90% +/- 10% at
12 mos (P < 0.001), whereas the Chronotropic Response Index at baseline was 0.49
+/- 0.15, improving to 0.67 +/- 0.17 at 6 mos (P < 0.001) and to 0.81 +/- 0.23 at
12 mos (P < 0.001). CONCLUSIONS: Partial normalization of HR was achieved by 71%
of heart transplantation patients at 12 mos, with significant changes occurring
within 6 mos in most subjects. These findings should contribute to reducing the
exercise restrictions that apply to the denervated heart.

Langue : ANGLAIS