An Echocardiogram is a Test of the Heart
An echocardiogram is definitively a cardiac imaging test that evaluates the structure and function of the heart, not the lungs. 1
What Echocardiography Evaluates
Echocardiography is specifically designed to assess:
- Cardiac anatomy and chamber sizes - including left and right ventricles, atria, and cardiac wall thickness 1
- Myocardial function - both systolic (pumping) and diastolic (filling) performance of the heart 1
- Valvular structure and function - assessing stenosis, regurgitation, and valve morphology 1
- Pericardial abnormalities - detecting effusions and pericarditis 1
- Intracardiac masses - identifying thrombi, tumors, or vegetations 1
Relationship to Lung Disease
While echocardiography is a cardiac test, it can provide indirect information about pulmonary conditions through cardiac effects:
- Pulmonary artery pressures can be estimated using tricuspid regurgitation velocity via the modified Bernoulli equation 1
- Right ventricular strain from pulmonary hypertension or pulmonary embolism can be detected 2, 3
- Cor pulmonale (right heart failure from lung disease) can be identified 1
However, these represent the cardiac consequences of lung disease, not direct lung imaging. 1
Clinical Context
The ACC/AHA guidelines explicitly describe echocardiography as "a powerful noninvasive tool to investigate possible causes of dyspnea of cardiac origin" with its ability to assess "cardiac anatomy, chamber sizes and myocardial and valvular function." 1 The test should be integrated with history and physical examination to establish pre-test probability of cardiac disease. 1
Common pitfall: Ordering an echocardiogram to evaluate primary lung pathology (pneumonia, COPD exacerbation, interstitial lung disease) is inappropriate - chest X-ray or CT scan would be the correct imaging modality for direct lung visualization. 4