Effect of loading conditions on myocardial relaxation velocities determined by Doppler tissue imaging in heart transplant recipients.
BACKGROUND
Cardiac allograft rejection is accompanied by cellular infiltration and tissue edema resulting in myocardial relaxation abnormalities. Doppler tissue imaging is capable of measuring myocardial relaxation velocities and is useful in the detection of heart rejection. However, the influence of ventricular loading conditions on myocardial relaxation velocities has not been studied. This study is performed to determine whether myocardial relaxation velocities are affected by left ventricular loading conditions.


METHODS
Twenty heart transplant recipients without evidence of rejection by endomyocardial biopsy underwent preload and afterload reduction with nitroglycerin. The pulmonary wedge pressure was reduced from 18.2+/-0.9 to 12.0+/-0.9 mm Hg 9 (p=0.001) and the mean blood pressure from 130.0+/-5.6 to 116.1+/-7.0 mm Hg (p=0.001). Pulsed-wave Doppler tissue imaging was performed before and after administration of nitroglycerin, and the peak myocardial relaxation velocities of the inferior wall were measured.


RESULTS
Myocardial relaxation velocities did not change with the administration of nitroglycerin; 0.188+/-0.009 to 0.178+/- 0.006 m/sec (p=0.4) in spite of a significant reduction in pulmonary capillary wedge pressure. Furthermore, there was no correlation between pulmonary capillary wedge pressure, mean arterial pressure, wall stress, and myocardial relaxation velocities.


CONCLUSIONS
Loading conditions on the left ventricle have no influence on myocardial relaxation velocities. Therefore in heart transplant recipients changes in myocardial relaxation velocities by Doppler tissue imaging may be useful in the diagnosis of rejection, in spite of diverse loading conditions.
University of South Florida College of Medicine, Division of Cardiology, Lifelink Transplantation Institute, Tampa, USA.
J M
JM
Aranda
M W
MW
Weston
J A
JA
Puleo
H L
HL
Fontanet
D018618:Echocardiography, Doppler, Color; D006084:Graft Rejection; D016027:Heart Transplantation / Q000000981:diagnostic imaging / Q000276:immunology / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D005996:Nitroglycerin; D014665:Vasodilator Agents; D016277:Ventricular Function, Left / Q000502:physiology
D014665:Vasodilator Agents; D005996:Nitroglycerin