Ultrasound Diagnosis of Pericardial Effusion

The differentiation between a large, dilated heart and pericardial effusion is essential but frequently difficult. The clinician must often resort to diagnostic procedures which offer some hazard to the patient. The use of reflected ultrasound was found to be a highly effective and simple method of making this differential diagnosis. In five dogs with artificially produced pericardial effusion it was noted that without pericardial fluid only one ultrasound echo was produced in the vicinity of the posterior heart wall. When fluid was introduced, one detected two echoes, one which moved with cardiac action, the posterior heart wall, and another which moved only with respiration, the pericardium. The space between the two signals represented the pericardial fluid. Subsequent clinical studies confirmed the accuracy, reliability, and simplicity of this diagnostic procedure.