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Figure 4 Regional and global LV pressure volume loops during atrial overdrive and dual chamber pacing from different ventricular sites in a representative patient with EF <40%. Regions are numbered from apex (1) to base (6), corresponding to the sequential volume channels along the axis of the conductance catheter. These individual signals form the global pressure-volume loop when summed. Note that RV pacing from different sites changes the regional contributions to the global pressure volume loop. Right ventricular apex pacing has a greater impact on the apical segments. Conversely, RVS and RVF pacing primarily distort the basal segment. Left ventricular and biventricular pacing result in more homogenous distribution of regional work. Abbreviations as in Figures 1 and 2.
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