Quantitative diagnosis of apical cardiomyopathy using contrast echocardiography.
BACKGROUND
The echocardiographic diagnosis of apical hypertrophic cardiomyopathy (ACM) has been limited by the frequent inability to visualize the apical endocardium. We hypothesized that the use of contrast agents in patients with suspected ACM, but nondiagnostic echocardiographic studies, would allow quantitative diagnosis.


METHODS
Contrast enhancement was performed in 26 patients with nondiagnostic transthoracic echocardiograms (TTEs) for the diagnosis of ACM; 6 patients with suspected ACM based on unexplained symmetric precordial T-wave inversions and increased apical tracer uptake on single-photon emission computed tomography (SPECT) scans, 10 patients with normal electrocardiogram (ECG) readings and no history of hypertension (healthy group), and 10 patients with hypertension and ECG criteria for left ventricular hypertrophy (LVH group). Images were obtained with Optison (Mallinckrodt Medical; IV, 1.0 mL) using harmonic imaging and low mechanical index. Posterior (PW) and septal wall (SW) thicknesses were measured at end-diastole in the parasternal long-axis view. Apical wall thickness (A) was measured from the contrast-enhanced apical endocardium to the visceral epicardial surface in the apical 4-chamber view. A/PW and A/SW ratios were calculated for each group. Asymmetric apical hypertrophy was defined as an A/PW ratio greater than 1.5.


RESULTS
Contrast-enhanced apical thickness was greater than 2.0 cm in all patients in the suspected ACM group but less than 1.2 cm in all patients in the LVH and healthy groups. In all 6 patients in the suspected ACM group, A/PW and A/SW ratios were greater than 1.5. No patient in the healthy or LVH groups had thickness ratios greater than 0.85.


CONCLUSIONS
Contrast echocardiography allows quantitative diagnosis of ACM in patients with suggestive ECG and SPECT but nondiagnostic TTEs. This study suggests that contrast echocardiography should be performed before using more expensive or invasive diagnostic testing for this condition.
Ward
R Parker
RP
Department of Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL 60637, USA.
Weinert
Lynn
L
Spencer
Kirk T
KT
Furlong
Kathy T
KT
Bednarz
James
J
DeCara
Jeanne
J
Lang
Roberto M
RM
D000328:Adult; D000418:Albumins; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging*; D016022:Case-Control Studies; D003287:Contrast Media; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D005466:Fluorocarbons; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon
D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons