Ward R Parker, Weinert Lynn, Spencer Kirk T, Furlong Kathy T, Bednarz James, DeCara Jeanne, Lang Roberto M
Department of Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL 60637, USA.
J Am Soc Echocardiogr. 2002 Apr;15(4):316-22. doi: 10.1067/mje.2002.119825.
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.
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.
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.
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.
