Diagnostic value of left ventricular outflow area in patients with hypertrophic cardiomyopathy: a real-time three-dimensional echocardiographic study.
BACKGROUND
Earlier studies demonstrated the ability of real-time 3-dimensional (3D) echocardiography (3DE) to measure left ventricular outflow tract (LVOT) area (A(LVOT)) in patients with hypertrophic cardiomyopathy (HCM). However, its clinical value is unknown.


OBJECTIVE
We sought to investigate the feasibility and accuracy of real-time 3DE-derived A(LVOT) to diagnose significant LVOT obstruction in a large number of patients with HCM.


METHODS
A total of 162 patients with HCM had 3DE by using a volumetric system. The smallest A(LVOT) during systole was determined by moving a 2-dimensional plane in 3D space. The pressure gradient across LVOT was assessed by continuous wave Doppler method. Provocation was performed in patients without significant LVOT obstruction (pressure gradient across LVOT < 50 mm Hg) at rest.


RESULTS
Twenty (12%) patients with poor image quality of 3DE were excluded; 16 (28%) patients with a volumetric system, but only 4 (4%) patients with commercial equipment (P < .001). In the remaining 142 patients, A(LVOT) inversely correlated with pressure gradient across LVOT both at rest (r = 0.82, P < .001) and after provocation (r = 0.60, P < .001). The value of A(LVOT) less than 0.85 cm(2) and less than 2.0 cm(2) predicted resting and provokable LVOT obstruction with sensitivity of 87% and 81%, and specificity of 77% and 90%, respectively.


CONCLUSIONS
Real-time 3DE measurement of A(LVOT) was successful in diagnosing and quantifying LVOT obstruction at rest and after provocation in a large number of patients with HCM.
Fukuda
Shota
S
Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Lever
Harry M
HM
Stewart
William J
WJ
Tran
Hung
H
Song
Jong-Min
JM
Shin
Mi-Seong
MS
Greenberg
Neil L
NL
Wada
Nozomi
N
Matsumura
Yoshiki
Y
Toyono
Manatomo
M
Smedira
Nicholas G
NG
Thomas
James D
JD
Shiota
Takahiro
T
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003937:Diagnosis, Differential; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology*; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D017725:Ventricular Pressure / Q000502:physiology