Intramural mechanics in hypertrophic cardiomyopathy: functional mapping with strain-rate MR imaging.
OBJECTIVE
To characterize systolic and diastolic intramural mechanics in hypertrophic cardiomyopathy (HCM) with a new metric of contractile activity.


METHODS
Eleven healthy subjects and eight patients with HCM underwent velocity-encoded echo-planar magnetic resonance (MR) imaging (6-8-frame gated breath-hold movies, 3 x 3-mm resolution). A scalar strain rate (SR) parameter was compared with wall thickness and symptoms.


RESULTS
The normal pattern of SR included regional uniformity, a monotonically increasing subepicardial to subendocardial gradient, and minimum transmural shear rate. In HCM, heterogeneity of SRs increased in diastole. Regional diastolic SR correlated with regional wall thickness (r = .785, P = .0001). Interobserver global SR assignment agreed in seven of eight patients. All four patients with New York Heart Association class 1 disease had a low global SR deficit score, whereas three of four patients with class 2 or 3 disease had a high SR deficit score (Spearman r = .775, P = .187).


CONCLUSIONS
SR characterization may provide an objective measure of disease course in HCM.
Beache
G M
GM
MGH-NMR Center, Department of Radiology, Massachusetts General Hospital, Charlestown 02129, USA.
Wedeen
V J
VJ
Weisskoff
R M
RM
O'Gara
P T
PT
Poncelet
B P
BP
Chesler
D A
DA
Brady
T J
TJ
Rosen
B R
BR
Dinsmore
R E
RE
D000293:Adolescent; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged