Norepinephrine remains increased in the six-minute walking test after heart transplantation

We sought to evaluate the neurohormonal activity in heart transplant recipients and compare it with that in heart failure patients and healthy subjects during rest and just after a 6-minute walking test.

Despite the improvements in quality of life and survival provided by heart transplantation, the neurohormonal profile is poorly described.

Twenty heart transplantation (18 men, 49+/-11 years and 8.5+/-3.3 years after transplantation), 11 heart failure (8 men, 43+/-10 years), and 7 healthy subjects (5 men 39+/-8 years) were included in this study. Blood samples were collected immediately before and during the last minute of the exercise.

During rest, patients' norepinephrine plasma level (659+/-225 pg/mL) was higher in heart transplant recipients (463+/-167 pg/mL) and healthy subjects (512+/-132), p<0.05. Heart transplant recipient's norepinephrine plasma level was not different than that of healthy subjects. Just after the 6-minute walking test, the heart transplant recipient's norepinephrine plasma level (1248+/-692 pg/mL) was not different from that of heart failure patients (1174+/-653 pg/mL). Both these groups had a higher level than healthy subjects had (545+/-95 pg/mL), p<0.05.

Neurohormonal activity remains increased after the 6-minute walking test after heart transplantation.