Primary MR leads to LA and LV enlargement and an increase
in the compliance of both chambers, which attenuates the
increase in LA pressure. If LA compensation is incomplete,
mean LA pressure and right-sided pressures increase,
which is related not to LV dysfunction but to the regurgitant
volume entering the left atrium and pulmonary veins.
With LV diastolic dysfunction, a myocardial component of
increased filling pressures is added over time. The sequence
is opposite to that seen in primary myocardial disease such
as dilated cardiomyopathy, which leads to increased filling pressures earlier on and later to functional MR. Therefore,
in patients with secondary MR, echocardiographic correlates
of increased filling pressures reflect the combination of both
myocardial and valvular disorders.
Moderate and severe MR usually lead to an elevation of
peak E velocity and reductions in pulmonary venous systolic
flow wave and the S/D ratio. In severe MR, systolic pulmonary
venous flow reversal can be seen in late systole. Thus,
MR per se can induce changes in transmitral and pulmonary
venous flow patterns resembling advanced LV dysfunction,
with the possible exception of the difference in Ar 2 A duration.
70 Aside from PW signals, the MR velocity recording by
CW Doppler can provide a highly specific, though not sensitive,
sign of increased LA pressure, as discussed previously.
The ability of tissue Doppler parameters (E/e´) to predict
LV filling pressures in the setting of moderate or severe MR
depends on systolic function.69,156,157 In patients with
depressed EFs, an increased E/e´ ratio relates well to filling
pressures and predicts hospitalizations and mortality. In
patients with normal EFs, these parameters do not correlate
with filling pressures. In contrast, IVRT and the ratio of IVRT
to TE-e´ correlate reasonably well with mean PCWP, regardless
of EF.69 In particular, an IVRT/TE-e´ ratio ,3 appears to
readily predict PCWP .15 mm Hg in this patient subgroup.69
In patients with atrial fibrillation and MR, it is possible to use
matched RR intervals to calculate IVRT/TE-e´, which necessitates
the acquisition of a large number of cardiac cycles
(20).
Primary MR leads to LA and LV enlargement and an increasein the compliance of both chambers, which attenuates theincrease in LA pressure. If LA compensation is incomplete,mean LA pressure and right-sided pressures increase,which is related not to LV dysfunction but to the regurgitantvolume entering the left atrium and pulmonary veins.With LV diastolic dysfunction, a myocardial component ofincreased filling pressures is added over time. The sequenceis opposite to that seen in primary myocardial disease suchas dilated cardiomyopathy, which leads to increased filling pressures earlier on and later to functional MR. Therefore,in patients with secondary MR, echocardiographic correlatesof increased filling pressures reflect the combination of bothmyocardial and valvular disorders.Moderate and severe MR usually lead to an elevation ofpeak E velocity and reductions in pulmonary venous systolicflow wave and the S/D ratio. In severe MR, systolic pulmonaryvenous flow reversal can be seen in late systole. Thus,MR per se can induce changes in transmitral and pulmonaryvenous flow patterns resembling advanced LV dysfunction,with the possible exception of the difference in Ar 2 A duration.70 Aside from PW signals, the MR velocity recording byCW Doppler can provide a highly specific, though not sensitive,sign of increased LA pressure, as discussed previously.The ability of tissue Doppler parameters (E/e´) to predictLV filling pressures in the setting of moderate or severe MRdepends on systolic function.69,156,157 In patients withdepressed EFs, an increased E/e´ ratio relates well to fillingpressures and predicts hospitalizations and mortality. Inpatients with normal EFs, these parameters do not correlatewith filling pressures. In contrast, IVRT and the ratio of IVRTto TE-e´ correlate reasonably well with mean PCWP, regardlessof EF.69 In particular, an IVRT/TE-e´ ratio ,3 appears toreadily predict PCWP .15 mm Hg in this patient subgroup.69In patients with atrial fibrillation and MR, it is possible to usematched RR intervals to calculate IVRT/TE-e´, which necessitatesthe acquisition of a large number of cardiac cycles(20).
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