A SYSTEM FOR POSTOPERATIVE VISUALIZATION AND ANALYSIS OF LEFT-VENTRICULAR PRESSURE-VOLUME LOOPS

A patient monitoring system for continuous real-time monitoring of lef t ventricular (LV) function in the postoperative setting was developed . Common hemodynamic parameters and LV functional indices are all calc ulated from left ventricular pressure-volume loops (PV-loops). Visuali zation of the PV-loops, along with the hemodynamic parameter derived f rom them, provides valuable insight into ventricular function and pati ent recovery. The pressure component is obtained via a pressure sensin g catheter placed during surgery. Volume is measured via non-imaging r adionuclide techniques using a modified Capintec-VEST. Following surge ry and transfer to the recovery unit, the patient's blood is labeled w ith Tc-99m. A portable gamma camera is used to measure baseline ejecti on fraction (EF) and to aid in placing the VEST. The specific radioact ivity of the blood is calibrated using the baseline EF and thermodilut ion cardiac output. To confirm the volume measurement accuracy of this technique six patients undergoing bilateral heart catheterization wer e studied. Single-plane cineventriculographic LV volumes were compared to those calculated from the VEST's time activity curve. (C) 1998 Els evier Science Ltd. All rights reserved.