Mh. Kim et al., Effects of beta-adrenergic blocking therapy on left ventricular diastolic relaxation properties in patients with dilated cardiomyopathy, CIRCULATION, 100(7), 1999, pp. 729-735
Citations number
33
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Background-The hemodynamic mechanism for the improvement in left ventricle
(LV) end-diastolic pressure in cardiomyopathy patients treated with beta-ad
renergic blocking agents is controversial. We hypothesized that the salutar
y effect of this kind of therapy on LV end-diastolic pressure would be indi
cative of an improvement in late, passive diastolic relaxation properties.
Methods and Results-We studied 14 cardiomyopathy patients in normal sinus r
hythm with no arteriographic evidence of coronary artery disease and an LV
ejection fraction of less than or equal to 40% by radionuclide angiography
both before and after 6 months of metoprolol therapy with simultaneous micr
omanometry and biplane cineventriculography. Four comparable patients who w
ere not treated with metoprolol were studied in a similar fashion and serve
d as control subjects. In those receiving metoprolol, LV end-diastolic pres
sure decreased (P=0.001). The isovolumic relaxation index, tau(in), shorten
ed (P=0.03), In a similar fashion, the LV chamber stiffness constant, kappa
, decreased (P=0.02), LV volume elastance improved (P=0.04), and the myocar
dial stiffness constant, kappa(e), decreased (P=0.02), A multiple regressio
n analysis revealed that the decrease in LV end-diastolic pressure was indi
cative of significant improvements in tau(ln) and kappa(e) with the relatio
nship: LV end-diastolic pressure= -4.73 +0.27 tau(ln)+0.54 kappa(e) (r=0.81
, P<00001). These LV diastolic relaxation properties did not change or wors
ened in the control cardiomyopathy patients.
Conclusions-We conclude that the decrease in LV end-diastolic pressure in c
ardiomyopathy patients treated with metoprolol is an indicator of improveme
nt in LV diastolic properties resulting from more complete myocardial relax
ation.