Rick Schreurs

71 Effective mechanical atrioventricular delay Table 2. Changes in hemodynamic parameters at optimal AV-delay based on maximal relative increase in cardiac output for each pace setting compared to the baseline setting with AV-delay 300ms. Atrial pacing Atrial sensing BiV LV RV BiV LV RV AV opt (ms) 157±7* 171±18* 157±13* 150±29* 142±24* 150±22* Δ CO (%) 10.7±6.9* 13.3±8.7* 12.2±8.8* 12.2±8.7* 12.9±8.2* 14.2±11.3* Δ SW (%) 22±24.1* 24.1±22.6* 23.5±28.4* 21.8±25.1 21.7±18.9* 32.5±39.5* Δ MAP (%) 9.3±8.4* 10.3±5.6* 10.1±4.5* 10.9±10.3* 10.4±4.5* 14±10.8* Δ LVP max (%) 7±5.2* 7.7±4.3* 8.3±3.5* 7.3±5.9* 7.1±2.8* 10±7.3* Δ LVEDP (mmHg) 2±1.8* 1.9±1.5* 2.2±1.3* 1.9±2.3 2.1±1.5* 2.1±1.7 Δ LVEDV (%) 18±16.8* 19.8±15.4* 16.8±14.8* 16.6±17.1* 14.8±13.9* 14.4±23.1 Δ LV dP/dt max (%) 1.9±5 4.3±6.2 3.2±7.4 1.4±5.6 5.5±6.4 8.5±10.9 Δ RVESP (%) 9.8±2.8* 10.9±3.2* 10.7±4.6* 12.2±8* 13.6±9.9* 10.6±4.6* Δ RVEDP (mmHg) 1.4±1* 1.5±1.9 1.5±0.9* 1±1.5 0.8±1 1.1±1.3 Δ RV dP/dt max (%) -1.5±9.4 -6.2±16.3 1.4±8.5 0.8±4.5 -4.9±7.7 5±11.9 Δ LAP max (mmHg) -0.2±4.2 -1.4±4.3 -0.8±4.7 1.2±3* 2.4±2.5 -2.9±6.5 Δ RAP max (mmHg) -2.5±3.2 -4±2.7* § -2.3±3 # 0.2±3.2 -0.1±3^ -3.5±4.6 ΔForward flow (mL) 1.6±3.3 2.4±3.6 -0.3±4.9 0.8±4 1.8±4.1 3.2±6.4 Δ Diastolic MR (mL) -1.8±2.4 -2±2.5 -2.9±4 -3.5±2.7* -3.5±2.4*^ -2.9±3.4 Presented are mean±SEM. Abbreviations as in table 1 . * indicates P<0.05 compared to baseline, ^ indicates P<0.05 compared to atrial pacing for same pace site, § indicates P<0.05 compared to BiV pacing for same atrial mode, # indicates P<0.05 compared to LV pacing for the same atrial mode. N = 7 animals. Table 3. Timing and intervals of intracardiac events at the optimal AV-delay. Atrial pacing Atrial sensing BiV LV RV BiV LV RV P-wave duration (ms) 116±3 114±5 113±5 77±7* 76±7* 75±4* IAD (ms) 29±5 30±5 26±6 20±5 14±5 18±6* QRS duration (ms) 86±5 109±4^ 85±5 § 83±5 111±5^ 85±4 § IVD (ms) -4±5 19±5^ -9±6 § -5±3 13±2^ -16±4^ § Right-eAVD (ms) 166±7 187±11 164±13 212±29 228±28 216±26 Left-eAVD (ms) 140±8 142±16 147±11 198±31 201±28 214±24* Δ right-left-eAVD (ms) 26±7 45±8^ 17±5 § 15±3 27±4^ 2±4* Mean-eAVD (ms) 153±7 165±13 156±12 205±30 214±28 215±25* Mean-eAVD-HR (%) 26±1 27±2 26±2 28±4 30±4 31±3 Presented are mean±SEM. BiV: biventricular, LV: left ventricle, RV: right ventricle, IAD: interatrial delay, IVD: interventricular dyssynchrony, eAVD: effective AV-delay, HR: heart rate. * indicates P<0.05 compared to atrial pacing, ^ indicates P<0.05 compared to BiV pacing for same atrial mode, § indicates P<0.05 compared to LV pacing for same atrial mode. N = 7 animals. 4