Mk. Kyriakidis et al., CHANGES IN PHASIC CORONARY BLOOD-FLOW VELOCITY PROFILE AND RELATIVE CORONARY FLOW RESERVE IN PATIENTS WITH HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY, Circulation, 96(3), 1997, pp. 834-841
Background In this study, we both investigated coronary flow velocity
in hypertrophic obstructive cardiomyopathy (HOCM) and tested the hypot
hesis of differing coronary how reserve (CFR) of coronary arteries per
fusing left ventricular regions with nonuniform myocardial hypertrophy
by measuring the relative CFR. Methods and Results Coronary flow velo
city was assessed in left anterior descending coronary (LAD) and left
circumflex (LCx) arteries in 18 patients with HOCM and marked hypertro
phy only in the ventricular septum, in 13 patients without obstruction
(HCM), and in 9 age- and sex-matched normal subjects at rest, during
rapid atrial pacing, and after dobutamine infusion (5 to 30 mu g/kg pe
r minute). Relative CFR was estimated as the ratio between absolute CF
R of the LAD and absolute CFR of the LCx (LAD/LCx(CF)). At the peak of
rapid atrial pacing and during dobutamine stress, LAD/LCx(CF), was re
versed in HOCM patients (from 1.25+/-0.11 to 0.82+/-0.07 and 0.79+/-0.
06, respectively), whereas it remained unchanged in control subjects (
from 1.0+/-0.1 to 1.0+/-0.05 and 1.0+/-0.05, respectively; P<.001). In
HCM patients, LAD/LCx(CF) at rest was 1.10+/-0.11, whereas during rap
id atrial pacing and dobutamine stress, it was 0.92+/-0.08 and 0.90+/-
0.09, respectively. Relative CFR was 0.62+/-0.05 in HOCM patients and
1.05+/-0.05 (P<.001) in normal subjects. There was an inverse correlat
ion between relative CFR and peak systolic outflow tract gradient (r(2
)=.74, P<.001). Conclusions Regional distribution of hypertrophy in so
me patients with HOCM resulted in regional impairment of coronary flow
. Relative CFR can be used to estimate regional disturbances of corona
ry flow and may help in patient selection for new interventional thera
peutic techniques.