Pressure-volume analysis in the left ventricle using radionuclide ventriculography and electromanometry

A method for the parallel assessment and recording of pressure-volume ratios in the left ventricle is described that was used in connection with angiographic studies. It gives a representative picture of the cardiac cycle, while requiring only very little additional time and doses of radiotracer, and permits numerous haemodynamic parameters to be registered at the same time. The volume evaluations were based on 99mTc-ventriculography with the radionuclide being evenly distributed and carried out immediately on conclusion of the angiographic examinations before the electromanometer was removed. The registration of gamma camera and pressure signals via an analog multiplexer followed on analog-to-digital conversion according to the list-mode procedure. The final analysis of the results was carried out in a data processing centre in such a way as to obtain information on the following parameters: ejection fraction, rate of volume changes, endsystolic and enddiastolic pressures, ventricular compliance, mean and maximum cardiac performance, work performed in each individual cardiac cycle. (orig.)