RESUMO
In 29 unselected patients, the left ventricular ejection fraction was evaluated using a mobile ECG-gated scintillation probe (Nuclear Stethoscope) after in vivo labeling of the erythrocytes with 15 mCi technetium-99m. To validate the method, the Nuclear Stethoscope measurements were correlated to the results of: 1. Single-plane contrast cineventriculography in the right and left anterior oblique projections (RAO, LAO), 2. Radionuclide ventriculography with a gamma camera computer system, 3. Two-dimensional echocardiography from the apical two- and four-chamber views. The ejection fraction measured by the Nuclear Stethoscope showed a close correlation to the values obtained by cineventriculography in the RAO projection (r = 0.748) and radionuclide ventriculography (r = 0.785). In this group of unselected patients, the correlations with the results of two-dimensional echocardiography were poor (r = 0.451 and 0.557). Cineventriculographic findings and radionuclide ventriculography correlated well (RAO: r = 0.786; LAO: r = 0.758). The Nuclear Stethoscope provides a simple, reliable, and noninvasive method for measuring ventricular ejection fraction. Ongoing studies indicate that the Nuclear Stethoscope is a valid method even at a lower dose of 5 mCi technetium-99m.
