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Quantitative diagnosis of apical cardiomyopathy using contrast echocardiography
R Parker Ward1, Lynn Weinert, Kirk T Spencer
1Department of Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL 60637, USA.
Insights
Contrast echocardiography enables quantitative diagnosis of apical hypertrophic cardiomyopathy (ACM) when traditional echocardiograms are inconclusive. This imaging technique improves diagnostic accuracy for ACM, guiding further medical decisions.
Area of Science:
- Cardiology
- Medical Imaging
- Diagnostic Techniques
Background:
- Echocardiographic diagnosis of apical hypertrophic cardiomyopathy (ACM) is often limited by poor visualization of the apical endocardium.
- Contrast agents may improve visualization and enable quantitative diagnosis in suspected ACM cases with nondiagnostic echocardiograms.
Purpose of the Study:
- To evaluate the utility of contrast echocardiography for quantitative diagnosis of ACM.
- To determine if contrast agents can overcome limitations in visualizing the apical endocardium in nondiagnostic echocardiographic studies.
Main Methods:
- Contrast enhancement was performed in 26 patients with suspected ACM and nondiagnostic transthoracic echocardiograms (TTEs).
- Measurements included apical wall thickness (A) and ratios of apical to posterior (A/PW) and septal (A/SW) wall thicknesses.
- Asymmetric apical hypertrophy was defined by an A/PW ratio greater than 1.5.
Main Results:
- Contrast-enhanced apical thickness exceeded 2.0 cm in all suspected ACM patients.
- A/PW and A/SW ratios were greater than 1.5 in all suspected ACM patients.
- Healthy and left ventricular hypertrophy (LVH) groups showed ratios below 0.85.
Conclusions:
- Contrast echocardiography provides quantitative diagnosis for ACM in patients with suggestive ECG and SPECT findings but nondiagnostic TTEs.
- This method should be considered prior to more expensive or invasive diagnostic procedures for ACM.
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.
Conclusion:
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.