K. Okeie et al., Left ventricular systolic dysfunction during exercise and dobutamine stress in patients with hypertrophic cardiomyopathy, J AM COL C, 36(3), 2000, pp. 856-863
Citations number
28
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
OBJECTIVES We sought to characterize stress-induced left ventricular systol
ic dysfunction in patients with hypertrophic cardiomyopathy (HCM).
BACKGROUNDS Myocardial ischemia and diastolic dysfunction occur in patients
with HCM. We hypothesized that, in the setting of transient myocardial isc
hemia, left ventricular systolic dysfunction occurs during exercise and dob
utamine stress.
METHODS We studied 39 patients with HCM but without obstructive symptoms at
rest or coronary artery disease. A continuous ventricular function monitor
equipped with cadmium telluride detectors (VEST) was used to evaluate left
ventricular function during supine bicycle ergometer exercise. Dobutamine
stress echocardiography (DSE) was also performed. The left ventricular ejec
tion Fraction (LVEF) and regional wall motion were determined from echocard
iographic images.
RESULTS Changes in the LVEF correlated between exercise and dobutamine stre
ss (r = 0.643, p < 0.0001). The LVEF decreased more than 5% at peak exercis
e in 17 of patients (group IT), while the other patients had normal respons
es (group I). New regional wall motion abnormalities during dobutamine infu
sion were detected in 18 of 110 (16.4%) segments in group I and 42 of 85 (4
9.4%) segments in group II. Decreased or unchanged regional wall motion occ
urred more frequently in hypertrophied segments than in nonhypertrophied se
gments (p < 0.0001). There were significant inverse correlations between th
e LVEF responses during both stresses and the number of abnormal segments n
oted during dobutamine stress in all patients (VEST: p < 0.005; DSE: p < 0.
0005). Signs of left ventricular obstruction were observed in 11 of 39 pati
ents during DSE. However, there was no significant correlation between the
LVEF response and the dobutamine-induced left ventricular pressure gradient
.
CONCLUSIONS Exercise-induced systolic dysfunction occurred in 50% of patien
ts with HCM. In these patients, regional wall motion abnormalities were pre
sent in hypertrophied segments. (C) 2000 by the American College of Cardiol
ogy.