TY - JOUR
T1 - Effects of β-adrenergic blocking therapy on left ventricular diastolic relaxation properties in patients with dilated cardiomyopathy
AU - Kim, Michael H.
AU - Devlin, William H.
AU - Das, Sunil K.
AU - Petrusha, Janet
AU - Montgomery, Daniel
AU - Starling, Mark R.
PY - 1999/8/17
Y1 - 1999/8/17
N2 - Background-The hemodynamic mechanism for the improvement in left ventricle (LV) end-diastolic pressure in cardiomyopathy patients treated with β-adrenergic blocking agents is controversial. We hypothesized that the salutary effect of this kind of therapy on LV end-diastolic pressure would be indicative of an improvement in late, passive diastolic relaxation properties. Methods and Results-We studied 14 cardiomyopathy patients in normal sinus rhythm with no arteriographic evidence of coronary artery disease and an LV ejection fraction of ≤40% by radionuclide angiography both before and after 6 months of metoprolol therapy with simultaneous micromanometry and biplane cineventriculography. Four comparable patients who were not treated with metoprolol were studied in a similar fashion and served as control subjects. In those receiving metoprolol, LV end-diastolic pressure decreased (P=0.001). The isovolumic relaxation index, τ(ln), shortened (P=0.03). In a similar fashion, the LV chamber stiffness constant, κ, decreased (P=0.02), LV volume elastance improved (P=0.04), and the myocardial stiffness constant, κ(e), decreased (P=0.02). A multiple regression analysis revealed that the decrease in LV end-diastolic pressure was indicative of significant improvements in τ(ln) and κ(e) with the relationship: LV end- diastolic pressure=-4.73+0.27 τ(ln)+0.54 κ(e) (r=0.81, P<0.0001). These LV diastolic relaxation properties did not change or worsened in the control cardiomyopathy patients. Conclusions-We conclude that the decrease in LV end- diastolic pressure in cardiomyopathy patients treated with metoprolol is an indicator of improvement in LV diastolic properties resulting from more complete myocardial relaxation.
AB - Background-The hemodynamic mechanism for the improvement in left ventricle (LV) end-diastolic pressure in cardiomyopathy patients treated with β-adrenergic blocking agents is controversial. We hypothesized that the salutary effect of this kind of therapy on LV end-diastolic pressure would be indicative of an improvement in late, passive diastolic relaxation properties. Methods and Results-We studied 14 cardiomyopathy patients in normal sinus rhythm with no arteriographic evidence of coronary artery disease and an LV ejection fraction of ≤40% by radionuclide angiography both before and after 6 months of metoprolol therapy with simultaneous micromanometry and biplane cineventriculography. Four comparable patients who were not treated with metoprolol were studied in a similar fashion and served as control subjects. In those receiving metoprolol, LV end-diastolic pressure decreased (P=0.001). The isovolumic relaxation index, τ(ln), shortened (P=0.03). In a similar fashion, the LV chamber stiffness constant, κ, decreased (P=0.02), LV volume elastance improved (P=0.04), and the myocardial stiffness constant, κ(e), decreased (P=0.02). A multiple regression analysis revealed that the decrease in LV end-diastolic pressure was indicative of significant improvements in τ(ln) and κ(e) with the relationship: LV end- diastolic pressure=-4.73+0.27 τ(ln)+0.54 κ(e) (r=0.81, P<0.0001). These LV diastolic relaxation properties did not change or worsened in the control cardiomyopathy patients. Conclusions-We conclude that the decrease in LV end- diastolic pressure in cardiomyopathy patients treated with metoprolol is an indicator of improvement in LV diastolic properties resulting from more complete myocardial relaxation.
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U2 - 10.1161/01.CIR.100.7.729
DO - 10.1161/01.CIR.100.7.729
M3 - Article
C2 - 10449695
AN - SCOPUS:0033578464
VL - 100
SP - 729
EP - 735
JO - Circulation
JF - Circulation
SN - 0009-7322
IS - 7
ER -