Technical and analytical approach to biventricular pressure-volume loops in swine including a completely endovascular, percutaneous closed-chest large animal model

Fig 1. An example of an intraprocedural LabChart screen capture during a thermodilution. A, An intraprocedural LabChart view showing each of the data parameters being monitored and captured on the animal. Each row corresponds to one data channel capturing one parameter, which include blood temperature in the main pulmonary artery (MPA) (°C), blood temperature in the aortic arch (°C), arterial blood pressure (mm Hg), two electrocardiography (EKG) tracings, end-tidal CO2 (%), aortic flow (L/min), and MPA flow (L/min). The first two channels demonstrate an example of a thermodilution temperature augmentation as sensed by a thermistor in the MPA and aorta, respectively. B, The same temperature tracing shown in channel 1 in panel A, inverted and zoomed in as shown in the cardiac output module. BPM, Beats per minute.

Fig 2. Fluoroscopic technical progression for reproducible placement of a right ventricular (RV) pressure-volume (PV)-sensing catheter. A, Anteroposterior view of the chest with the left ventricular (LV) PV loop already placed. B, Catheter access into the right atrium (RA). C, Wire and catheter access through the RV into the main pulmonary artery (PA). D. Upsized catheter with access maintained to the RV. E, Deployed RV PV-sensing catheter. Here, the support catheter maintains durable access while keeping the PV-sensing portion of the PV catheter straight through the center of the ventricle, which allows for reliable and appropriate PV acquisition.

Fig 3. Fluoroscopic view of biventricular (BV) pressure-volume (PV) sensing catheters during an inferior vena cava (IVC) occlusion with a Coda balloon. A 7F wire-supported catheter is in the left ventricular (LV), with the tip positioned in the apex. A 5F pigtail right ventricular (RV) PV-sensing catheter is correctly placed in the middle of the RV, crossing the LV catheter in the middle of the heart and just below the level of the diaphragm, positioned to reduce preload from the IVC and the hepatic veins. Supplementary Video 2, online only, shows this same IVC occlusion in video format.

Fig 4. Determination of the correction factor as determined by thermodilution, compared against the cardiac output from a main pulmonary artery (PA) flow probe. The thermodilution involves the injection of 30 cc of cold saline into the right cavoatrial junction over 1 second, and sensed by a temperature probe in the PA.

Fig 5. Biventricular (BV) (simultaneously obtained left ventricular [LV], blue, and right ventricular [RV], black) pressure-volume (PV) loops obtained during inferior vena cava (IVC) occlusions, one without physiological modification and one with modification by administration of esmolol. The top two panels show contemporaneous LV and RV, respectively, and PV loops over 5 seconds of IVC occlusion. The bottom two panels show a second IVC occlusion after esmolol has been administered.