P-242 Which left ventricular pacing lead?

Results: Baseline (unpaced) interVA and LVdPdhmx did not differ signficandy before and after the S-week BiV pacing period (-30&71x and -30&8ms and 1867~456mmHgis and 1964&316mmHg/s, respectively). Maximal increase in LVdPdhmx was similar during acute LV and BiV pacing (10.5&4.8% and 12.0&7.3%, respectively). The chronic maximal increase in LVdPdhmx (17.0&5.5% and 17.5&6.7%, respectively) was higher than the acute response in all but one animal, in which acute and chronic response was similar. Acute and chronic maximal response occurred at the same interVA (-15&91x and -15&611x, respectively, both significantly different from baseline). The interVALVdPdhmx response curve was identical for LV and BiV pacing. Comparison of the acute and chronic LVdPdhmx at identical interVA values by linear regression showed that the shape of the acute and chronic response curves did not differ (r=0.91) but that the amplitude of the response increased over the entire range of interVA (slope=2.0&1.3).