Usually, the assessment of prosthetic valves by echocardiography
is done at rest. For the patients with prosthetic valves, the
echocardiogram taken at rest will not represent the true functional status
of the valve. Patient`s day to day activities may induce symptoms. So in
order to assess the functional status of the prosthetic valves, it is
necessary that stress echocardiogram is done to mimic the daily activities
of the patient. So it is assumed that the abnormalities observed under high
flow conditions will not be seen at rest as the pressure gradients are
related to flow.
Resting studies of valve hemodynamics are found to be insufficient
to diagnose valve dysfunction sometimes. Earlier, studies were done
using cardiac catheterization with special emphasis on changes in
prosthetic function observed with various types of physical stress like
exercise or drug-induced stress. But these studies suffered from an
inability to adequately stress catheterized patients .Moreover the
procedures were cumbersome to the patient and also to the physician.
With the advent of Doppler echocardiography, it was possible that studies
could be done after significant exercise with increased ease and low risk.
Using Doppler echocardiography, studies of exercise-induced changes in
aortic and mitral prosthetic valve hemodynamics had started coming.
AIM OF STUDY:
1. To study about the resting echo profile of patients with prosthetic
mitral valve
2. To assess the function of the prosthetic valves by doing stress
echocardiography by treadmill exercise and dobutamine infusion.
CONCLUSION:
1. This Study helps in comparing the hemodynamic changes noted
with stress induced by dobutamine and treadmill exercise..
2. Normally functioning prosthetic valves in the mitral position can
produce significant increases in valvular pressure gradients under
conditions of high flow, and thus an estimation of diastolic cardiac
flow must be measured before concluding that the valve
dysfunction has occurred.
3. Dobutamine produces a greater augmentation in the effective mitral
orifice area when compared to exercise.
4. Exercise protocol produces much higher increase in the pressure
gradients when compared with dobutamine.
5. An abnormal increase in the pressure gradient without an increase
in EOA signifies significant valve dysfunction and these patients
should be monitored periodically for further deterioration and
further action. Thus this study helps in finding dysfunction of
prosthetic valves in the earlier stages itself
