Rick Schreurs

70 Chapter 4 * * * * * * * * * * -10 0 10 20 50 100 150 200 250 ! Cardiac output (%) AV-delay (ms) -10 0 10 20 30 40 50 50 100 150 200 250 ! Stroke work (%) AV-delay (ms) * * -10 0 10 20 50 100 150 200 250 ! Cardiac output (%) AV-delay (ms) * * * * * -10 0 10 20 30 40 50 50 100 150 200 250 ! Stroke work (%) AV-delay (ms) * * -10 0 10 20 50 100 150 200 250 AV-delay (ms) -10 0 10 20 30 40 50 50 100 150 200 250 AV-delay (ms) * -10 0 10 20 50 100 150 200 250 ! LV dP/dtmax (%) -10 0 10 20 50 100 150 200 250 ! LV dP/dtmax (%) -10 0 10 20 50 100 150 200 250 BiV pacing LV pacing RV pacing Δ Stroke work (%) Δ LV dP/dt max (%) Δ Cardiac output (%) AV-delay (ms) AV-delay (ms) AV-delay (ms) Atrial pacing Atrial sensing Figure 5. Changes of cardiac output (upper panels), stroke work (middle panels) and LV dP/dtmax (lower panels) during BiV (left panels), LV (middle panels) and RV (right panels) pacing mode while atrial pacing (black bars) and atrial sensing (yellow bars). Data are presented as %change relative to the corresponding pacing mode with an AV-delay of 300ms. * indicates P<0.05 compared to AV-delay 300ms using paired samples T-test with Bonferroni correction. Effect of different pacing modes on hemodynamic parameters The optimal AV-delay did not differ between the various ventricular pacing sites and seemed to be shorter in A-S compared to A-P though not significantly. The hemodynamic improvement by AV optimization (as evidenced by %change in cardiac output, stroke work and mean arterial pressure) was not significantly different between A-P and A-S for any ventricular pacing site. The decrease of diastolic MR was significantly more during LV pacing in A-S mode compared to A-P (-3.5mL±2.4 vs -2mL±2.5, P<0.05, see table 2 ). No significant differences were present between the various ventricular pacing sites for A-S mode. In A-P mode the decrease in RAP max was significantly bigger during LV pacing compared to BiV and RV pacing ( table 2 ).