Diastolic unloading and improved LV pump efficiency early after repair of the insufficient mitral valve.
BACKGROUND
This study aimed to evaluate the acute effect of mitral valve repair (MVR) on LV hemodynamics and geometry in patients with normal ventricular function.


METHODS
In 10 patients with severe mitral regurgitation undergoing MVR, pressure-volume relationships were recorded before annuloplasty prior to and after hemodilution and after MVR during stable circulatory condition, using the conductance catheter technique (CC). Analyses were done off-line; volume calibration was based on data obtained after completion of valve repair (mean +/- s.d.).


RESULTS
CC showed that only 61 +/- 15 % of left ventricular output was ejected into the systemic circulation, regurgitation volume being 39 +/- 15 %. MVR led to a reduction in LV stroke work index from 4.7 +/- 1.8 mm Hg x l x m (-2) at before valve repair to 2.2 +/- 1.0 mm Hg x l x m (-2) after surgery at unchanged cardiac index. LV diastolic filling parameters improved: LV relaxation time constant tau decreased from 52 +/- 15 to 37 +/- 11 ms and dP/dt (min) increased from - 873 +/- 231 to - 1286 +/- 283 mm Hg x s (-1).


CONCLUSIONS
Despite cardioplegic arrest, MVR leads to acute improvement of diastolic LV function early after the operation. This may explain why valve repair has an acute positive effect in patients with impaired LV function.
Günzinger
R
R
Deutsches Herzzentrum München, Munich, Germany. guenzinger@dhm.mhn.de
Heimisch
W
W
Augustin
N
N
Mazzitelli
D
D
Overbeck
M
M
Bauernschmitt
R
R
Lange
R
R
D001794:Blood Pressure; D001810:Blood Volume; D006328:Cardiac Catheterization / Q000379:methods; D005260:Female; D006438:Hemodilution; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000502:physiology / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000601:surgery*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*