- Valvular Abnormalities
- Pericardial Disease
- Intracardiac Masses
- Aortic Disease
- Congenital Heart Disease
- Stress Echocardiography
- Chamber Size and Ventricular Performance
Visualizes heart in real time with ultrasound; Doppler recordings noninvasively assess hemodynamics and abnormal flow patterns (Table 114-1 Clinical Uses of Echocardiography and Fig. 114-1. Two-Dimensional Echocardiographic Still-Frame Images of a Normal Heart). Imaging may be compromised in pts with chronic obstructive lung disease, thick chest wall, or narrow intercostal spaces. Transesophageal echocardiography (TEE) is performed when higher resolution images of cardiac structures is required.
Chamber Size and Ventricular Performance 
Assessment of atrial and ventricular dimensions, global and regional systolic wall motion abnormalities (administration of IV echo contrast enhances myocardial border detection when needed), ventricular hypertrophy/infiltration, evaluation for pulmonary hypertension: RV systolic pressure (RVSP) is calculated from maximum velocity of tricuspid regurgitation (TR):
RVSP = 4 × (TR velocity)2 + RA pressure
(RA pressure is same as JVP estimated by physical examination.) In absence of RV outflow obstruction, RVSP = pulmonary artery systolic pressure.
LV diastolic function is assessed by transmitral spectral Doppler and Doppler tissue imaging, which measures velocity of myocardial relaxation (see Fig. 236-8, in HPIM-20).
Thickness, mobility, calcification, and regurgitation of each cardiac valve can be assessed. Severity of valvular stenosis is measured by Doppler (peak pressure gradient = 4 × [peak velocity]2 ); valve areas are calculated using additional Doppler techniques. Dobutamine echocardiography can clarify degree of aortic stenosis in pts who have poor contractile function or low-flow states. Structural lesions (e.g., flail leaflet, vegetation) resulting in regurgitation may be identified, and color flow and spectral Doppler (Fig. 114-2. Schematic Presentation of Normal Doppler Flow Across the Aortic (A) and Mitral (B) Valves) estimate severity of regurgitation.
Echo is noninvasive modality of choice to rapidly identify pericardial effusion and assess its hemodynamic significance; in tamponade there is diastolic RA and RV collapse, dilatation of IVC, exaggerated respiratory alterations in transvalvular Doppler velocities. Actual thickness of pericardium (e.g., in suspected constrictive pericarditis) is more accurately measured by CT or MRI.
May visualize atrial or ventricular thrombus, intracardiac tumors, and valvular vegetations. Yield of identifying cardiac source of embolism is low in the absence of cardiac history or physical findings. TEE is more sensitive than standard transthoracic study for masses <1 cm in diameter.
Aneurysm and dissection of the aorta may be evaluated and complications (aortic regurgitation, tamponade) assessed (Chap. 127 Diseases of the Aorta) by standard transthoracic echo. TEE is more sensitive and specific for aortic dissection.
Echo, Doppler, and IV saline contrast echo are useful to identify congenital lesions and shunts, such as patent formen ovale, atrial septal defects, ventricular septal defects, and patent ductus arteriosus (see Chap. 115 Congenital Heart Disease in the Adult).