Objectives: To investigate in cardiac transplant patients whether post-transplantation time, graft arteriosclerosis, allograft rejection, or earlier cytomegalovirus infection affect the neural regulatory mechanisms of the donor heart.
Design: A consecutive series of heart transplant patients during a 12-month period.
Setting: A university hospital in Finland.
Subjects: Consecutive cardiac transplant recipients (n = 38) attending the hospital for their annual clinical examination were studied. Their mean (SD) age was 45.4 (11.5) years, 37 were male, and the median (range) time since transplantation was 36 (12-72) months.
Interventions: Power spectral analysis of R-R intervals (during 5 min of controlled breathing, the Valsalva manoeuvre, and deep breathing), routine coronary arteriography, cytomegalovirus serology.
Results: R-R interval (r = 0.67; P < 0.001), the root mean square difference of successive R-R intervals (r = 0.38; P < 0.05), the total R-R interval power (r = 0.45; P < 0.01), the power of the very low frequency (0.0-0.07 Hz) component (r = 0.53; P < 0.01), and the power of the nonrespiratory (0.0-0.15 Hz) component (r = 0.49; P < 0.01) were related to the length of time since the operation. Patients having had a transplantation 3 years ago or more had significantly greater median (range) total R-R interval power than those having had the operation less than 3 years ago (59 [10-265] vs. 20 [3-113] ms2; P = 0.02). There was also a difference between the two groups in the very low frequency component (18 [1-226] vs. 5 [0-45] ms2; P = 0.01), in the nonrespiratory component (30[1-227] vs. 9 [0-53]ms2; P = 0.02), and in the Valsalva ratio (0.995 [0.955-1.065] vs. 1.020 [0.975-1.155]; P = 0.03). Patients with and without graft arteriosclerosis, episodes of rejection, or earlier cytomegalovirus infection showed no difference in the power spectral measures.
Conclusions: The donor heart rate variability increases with post-transplantation time. Heart rate variability in transplant recipients is not related to the extent of graft arteriosclerosis, episodes of allograft rejection, or earlier cytomegalovirus infection.