Background: One way of defining an individual’s heart effort is to calculate the maximum
heart rate to be expected given their age, but the reinnervation seen in patients who have
received heart transplants makes for different calculations from patients who have suffered
heart failure. The purpose of this study is to evaluate heart rate dynamics (rest, peak and
percentage of predicted heart rate for age) in heart transplant patients compared to optimized
beta-blocked heart failure patients during a treadmill cardiopulmonary exercise test.
Methods: Twenty two (81% male, 46 ± 12 years) sedentary heart failure patients and
15 (47% male, 44 ± 13 years) sedentary heart transplant patients performed a treadmill
cardiopulmonary exercise test between 10 am and 3 pm. Heart failure optimization was considered
50 mg/day or more of carvedilol, with a resting heart rate of between 50 and 60 bpm.
Results: Basal heart rate was lower in heart failure patients (58 ± 5 bpm) compared to heart
transplant patients (93 ± 11 bpm; p < 0.0001). Similarly, the peak heart rate (percentage of
the maximum predicted for age) was lower in heart failure patients (60 ± 13%) compared to
heart transplant patients (80 ± 12; p < 0.0001). Maximum respiratory exchange ratio did not
differ between the groups (1.05 ± 0.06 in heart failure patients and 1.11 ± 0.1 in heart
transplant patients; p = 0.08). Moreover, the heart rate reserve between heart failure (49 ± 22)
and heart transplantation (46 ± 16%) was not different (p = 0.644).
Conclusions: No patient reached the maximum heart rate predicted for their age during
a treadmill cardiopulmonary exercise test. The heart rate reserve was similar between groups.
A heart rate increase in heart transplant patients during cardiopulmonary exercise test of
more than 80% of the maximum age-adjusted value should be considered an effort near the
maximum