Endothelial dysfunction and effectiveness of treatment of calcium antagonis
ts are suggestive of coronary artery spasm as an underlying disorder in dil
ated cardiomyopathy (DCM). The aim of this study is to determine whether or
not the epicardial coronary artery spasm can induce severe cardiac dysfunc
tion like DCM. Thirty-four consecutive patients with angiographically norma
l coronary arteries and diffuse left ventricular hypokinesis whose causes h
ad been unknown underwent acetylcholine provocation test and left ventricul
ar biopsy. Eight patients were excluded according to the clinical and labor
atory data and biopsy findings suggesting myocarditis or other systemic dis
eases; According to the results of the acetylcholine provocation test, 17 p
atients were finally diagnosed as having DCM, and nine patients (35% of the
study patients), who had acetylcholine-induced diffuse and multivessel cor
onary spasm, were diagnosed as having DCM-like vasospastic angina pectoris
(VSA). Clinical and cardiac catheterization data including hemodynamics and
biopsy findings were similar between the two groups except that left ventr
icular end-systolic volume was significantly greater in DCM than in DCM-lik
e VSA. After the acetylcholine provocation test, DCM patients received both
a beta blocker and an angiotensin-converting enzyme inhibitor, and DCM-lik
e VSA patients received antianginal drugs. In echocardiographic findings at
predischarge and those after 6-month drug treatment, both DCM-lke VSA and
DCM showed significant reduction in end-diastolic and end-systolic diameter
s and significant increase in fractional shortening and ejection fraction,
whereas changes in ejection fraction and fractional shortening were signifi
cantly greater in DCM-like VSA than those in DCM. Epicardial coronary arter
y spasm can induce diffuse and severe left ventricular dysfunction like DCM
in VSA. Although antianginal drugs markedly improve left ventricular funct
ion of these patients, only the acetylcholine provocation test can identify
DCM-like VSA.