Pulsed doppler echocardiography in diagnosis of pulmonary regurgitation: Its value and limitations

Ninety-eight patients were studied with two dimensional echocardiography combined with pulsed Doppler echocardiography to assess the usefulness and limitations of the Doppler technique in the diagnosis of pulmonary regurgitation. The diagnosis of pulmonary regurgitation by pulsed Doppler echocardiography depended on subjective interpretation of the audio signal and objective interpretation of the time interval histogram for the presence of wide frequency dispersion. During cardiac catheterization in 53 of the 98 patients, indocyanine green was injected into the pulmonary artery, and simultaneous sampling was performed from the right ventricle and femoral artery to diagnose pulmonary regurgitation. Pulmonary regurgitation was confirmed by pulmonary arteriogram in one patient. Among 62 patients with adequate pulsed Doppler echocardiographic studies, diastolic turbulence was noted in 21. When diastolic turbulence was less than 50 percent of the period of diastole, no pulmonary regurgitation was demonstrated in patients studied by indicator-dilution technique. However, three of the four patients with diastolic turbulence greater than 50 percent had positive evidence of pulmonary regurgitation. Audio output was more sensitive than the time interval histogram, and only five patients' findings suggested pulmonary regurgitation. Three of these patients underwent dye-dilution studies; two studies were positive for pulmonary regurgitation and one was negative.Thus, interpretation of pulmonary regurgitation based on the time interval histogram alone produces a large number of false positive results. When diastolic turbulence is greater than 50 percent of the period of diastole, both the sensitivity and specificity of diagnosis of pulmonary regurgitation are increased. Combining audio output and the time interval histogram results in improved diagnostic capability.