[Conductance catheter for determining left ventricular volume and end-systolic pressure-volume relations: its...

In this study, the clinical usefulness of the conductance catheter technique was assessed. The end-systolic pressure-volume relations (ESPVR) measured with the increase and decrease in the preload were also compared. Fourteen patients with various heart diseases who underwent diagnostic cardiac catheterization were studied. Using a right atrial pacing catheter, 8 electrical stimuli delivered at a fixed rate of 800 msec were followed by a single early stimulus of 500 msec coupling interval, resulting in premature atrial contraction and post-extrasystolic potentiation (PESP). Left ventricular (LV) volume was measured by 2 methods; namely, the conductance catheter technique and single-plane left ventriculography (LVG). ESPVR was obtained either with the inferior vena cava occlusion induced by balloon inflation, or with the rapid transfusion of saline with electrical resistance identical to the blood volume in the right atrium. The LV volume obtained with the conductance catheter technique (VCON) was correlated with the LV volume as obtained by LVG (VLVG) (end-diastolic volume, VCON = 1.09VLVG - 4.66, r = 0.95; end-systolic volume, VCON = 1.42VLVG - 18.2, r = 0.89). There was correlation of the change in LV volume (delta V) induced by PESP between the 2 methods (end-diastolic volume, delta VCON = 0.52 delta VLVG + 0.94, r = 0.76; end-systolic volume, delta VCON = 0.42 delta VLVG - 4.78, r = 0.72), suggesting that the change in LV volume estimated by the conductance catheter technique was smaller than that estimated by LVG. The LV volume curves were similar.(ABSTRACT TRUNCATED AT 250 WORDS)