Rick Schreurs

92 Chapter 5 -30 -20 -10 0 10 0 50 100 150 200 AV-delay (ms) -30 -20 -10 0 10 0 50 100 150 200 △ pressure (mmHg) AV-delay (ms) -30 -20 -10 0 10 0 50 100 150 200 AV-delay (ms) LVPmax LVEDP -40 -20 0 20 40 0 50 100 150 200 AV-delay (ms) -40 -20 0 20 40 0 50 100 150 200 △ dP/dtmax (%) AV-delay (ms) -40 -20 0 20 40 0 50 100 150 200 AV-delay (ms) LV dP/dtmax RV dP/dtmax -50 -25 0 25 50 0 50 100 150 200 MIVD (ms) AV-delay (ms) -50 -25 0 25 50 0 50 100 150 200 MIVD (ms) AV-delay (ms) -50 -25 0 25 50 0 50 100 150 200 AV-delay (ms) MIVD -50 0 50 100 150 0 50 100 150 200 △ SonR (%) -50 0 50 100 150 0 50 100 150 200 △ SonR (%) -50 0 50 100 150 0 50 100 150 200 RA SonR1 RV SonR1 BiV pacing BiV pacing BiV pacing Responders Non-responder AV-delay (ms) AV-delay (ms) AV-delay (ms) Δ SonR (%) MIVD (ms) Δ dP/dt max (%) Δ pressure (mmHg) Figure 2. Typical examples of non-responding (left, NResp4) and responding animals (Resp2) during BiV (middle) and LV (right) pacing protocol. The upper row presents the absolute changes of LVP max and LVEDP. Relative change compared to BL values are given for LV and RV dp/dt max in the second row and SonR in the last row. Absolute values are shown for MIVD in the third row. BiV: biventricular, LV: left ventricular, LVP max : maximal left ventricular pressure, LVEDP: left ventricular end diastolic pressure, MIVD: mechanical interventricular dyssynchrony, RA: right atrium, RV: right ventricle, BL: baseline. SonR1 did not show any consistent changes in NResp animals (see example in figure 2 and group values in figure 3 lower left panel). In the Resp group BiV pacing at varying AV- delays resulted in a sigmoid-shaped curve with the highest values at the shortest AV-delays in 3 out of 4 animals for RA SonR1 (see example in figure 2 ). RV SonR1 showed a similar sigmoid shape in Resp animals, however with a smaller relative increase. All Resp animals showed higher relative increases of RA SonR1 at AV short compared to AV opt (+129±77% vs +77±30% respectively), whereas RV SonR1 values did not consistently change between AV opt and AV short (bottom panels figure 3 ). While the absolute values of RA SonR1 were lower than those of RV SonR1 ( Table 1 ), the relative increase of RA SonR1 was significantly