Steep left ventricle to aortic root angle and hypertrophic obstructive cardiomyopathy: study of a novel association using three-dimensional multimodality imaging.
BACKGROUND
Patients with hypertrophic cardiomyopathy (HCM) exhibit a difference in left ventricular outflow tract (LVOT) obstruction, independently of basal septal thickness (BST). Some patients with HCM have a steeper left ventricle to aortic root angle than controls.


OBJECTIVE
To test the predictors of the LV-aortic root angle and the association between LV-aortic root angle and LVOT obstruction using three-dimensional imaging.


METHODS
153 consecutive patients with HCM (mean (SD) age 46 (14) years, 68% men) and 62 patients with hypertensive heart disease of the elderly (all >65 years of age, 73 (6) years, 34% men) who underwent whole-heart three-dimensional cardiac magnetic resonance (CMR) angiography (1.5 T) and Doppler echocardiography. Forty-two controls (age 43 (11) years, 38% men) who underwent contrast-enhanced multidetector computed tomography and were free of cardiovascular pathology were also studied.


RESULTS
LV-aortic root angle, BST and maximal non-exercise LVOT gradient were measured in patients with HCM and in hypertensive-elderly patients. Additionally, LV-aortic root angle and BST were measured in controls.


RESULTS
The mean (SD) LV-aortic root angle was significantly different (p<0.001) in the three groups: HCM (134 (10) degrees ), hypertensive-elderly (128 (10) degrees ), control (140 (7) degrees ). There was an inverse correlation between age and LV-aortic root angle in the three groups (all p<0.001): HCM (r = -0.56), hypertensive-elderly (r = -0.35), control (r = -0.48). On univariate analysis, in the HCM group, LV-aortic root angle (beta = -0.34, p<0.001), age (beta = 0.23, p = 0.01) and end-systolic volume index (beta = -0.20, p = 0.02), but not BST (beta = 0.02, p = 0.8), were associated with LVOT gradient. On multivariate analysis, only LV-aortic root angle was associated with LVOT gradient.


CONCLUSIONS
Patients with HCM have a steeper LV-aortic root angle than controls. In patients with HCM, a steeper LV-aortic root angle predicts dynamic LVOT obstruction, independently of BST.
Kwon
D H
DH
Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
Smedira
N G
NG
Popovic
Z B
ZB
Lytle
B W
BW
Setser
R M
RM
Thamilarasan
M
M
Schoenhagen
P
P
Flamm
S D
SD
Lever
H M
HM
Desai
M Y
MY
D000368:Aged; D001013:Aorta, Thoracic / Q000473:pathology*; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D014694:Ventricular Outflow Obstruction / Q000209:etiology / Q000473:pathology*