Healthy, normal persons and patients with stable heart disease do not require repeated ECGs. This pattern reflects redistribution of blood flow from lower to upper lung zones as a result of elevated pulmonary venous pressure. With more advanced pulmonary vascular congestion, pulmonary vessels become increasingly indistinct, Kerley B lines appear, and, finally, alveolar pulmonary edema develops. As with electrocardiography, repeated chest x-rays are not required in stable cardiac patients. Two-dimensional echocardiographic study with color Doppler imaging of abnormal flow patterns has markedly increased diagnostic acumen.
Echocardiography demonstrates in clear, graphic fashion the four cardiac chambers and four valves.
Chamber hypertrophy, dilatation, or both can be discerned, as can systolic contractile function. Valvular stenosis and regurgitation, intracardiac shunts, and ventricular diastolic function can be quantitated by means of Doppler echocardiography. Most Doppler echocardiographic studies are performed with the transthoracic technique. The transesophageal technique improves image quality and hence increases diagnostic accuracy, albeit with a modest increase in morbidity. The transesophageal technique is more useful than the transthoracic technique in the diagnosis of infectious endocarditis, dissection or rupture of the aorta, prosthetic valve dysfunction, intracardiac thrombi, and intraoperative ventricular dysfunction.