CORONARY ENDOTHELIAL DYSFUNCTION IN PATIENTS WITH ACUTE-ONSET IDIOPATHIC DILATED CARDIOMYOPATHY

Objectives. This study sought to determine whether coronary endothelia l dysfunction exists in patients with acute onset idiopathic dilated c ardiomyopathy (DCM) and to explore its relation to recovery of left ve ntricular systolic function in this patient population, Background. Co ronary endothelial dysfunction exists in chronic DCM, but its importan ce in the development and progression of ventricular dysfunction is no t known. To address this issue me studied coronary endothelial functio n in patients with idiopathic DCM <6 months in duration and explored t he relation between coronary endothelial function and subsequent chang es in left ventricular ejection fraction (LVEF). Methods. Ten patients ,vith acute onset idiopathic DCM (duration of heart failure symptoms 2 .0 +/- 0.4 months [mean +/- SEM]) and 11 control patients with normal left ventricular function underwent assessment of coronary endothelial function during intracoronary administration of the endothelium-depen dent vasodilator acetylcholine and the endothelium-independent vasodil ator adenosine. Coronary cross-sectional area (CSA) was determined by quantitative coronary angiography and coronary blood flow (CBF) by the product of coronary CSA and CBF velocity measured by an intracoronary Doppler catheter. Patients with DCM underwent assessment of left vent ricular function before and several months after the study. Results. A cetylcholine infusion produced no change in coronary CSA in control pa tients but significant epicardial constriction in patients,vith DCM (- 36 +/- 11%, p < 0.01). These changes were associated with increases in CBF in control patients (+118 +/- 49%, p < 0.01) but no change in pat ients with DCM. Infusion of adenosine produced increases in coronary c aliber and blood flow in both groups. Follow-up assessment of left ven tricular function was obtained in nine patients with DCM 7.0 +/- 1.7 m onths after initial study, at which time LVEF had improved by greater than or equal to 0.10 in four patients. Multiple linear regression rev ealed a positive correlation between both the coronary CSA (r(2) = 0.5 7, p < 0.05) and CBF (r(2) = 0.68, p < 0.01) response to acetylcholine and the subsequent improvement in LVEF. Conclusions. Coronary endothe lial dysfunction exists at both the microvascular and the epicardial l evel in patients with acute-onset idiopathic DCM. The preservation of coronary endothelial function in this population is associated with su bsequent improvement in left ventricular function. (C) 1998 by the Ame rican College of Cardiology.