Patient characteristics.

<p>LBBB: left bundle branch block, LV EF: left-ventricular ejection fraction, LVEDD: left ventricular end-diastolic diameter, LVESD: left ventricular end-systolic diameter.</p

Averaged results over all patients - Box plots of %ΔLV +dP/dt_max, of all LVPCs, averaged over all 16 patients (5–95% percentile).

<p>RV stimulation consistently produced the least increase in LV +dP/dt_max. No differences were found between LVPCs with the same cathode.</p

Study flow chart – Distribution of the tested LVPCs.

<p>Study flow chart – Distribution of the tested LVPCs.</p

Comparison of optimal and worst LVPCs - Individual results in increment in mean %ΔLV +dP/dt_max (±95% confidence interval) in all patients in the optimal (white) and worst (grey) pacing configuration (p<0.0001 for all intraindividual differences).

<p>The red line indicates a 10% increase in LV +dP/dt_max, which has been proposed as a cut-off value to separate responders from non-responders (20). By this definition, individually tailoring the optimal pacing configurations in 4 patients (marked #) transformed non-responders into responders.</p

Age (days) and weight (kg) of LQT1 and LMC rabbits.

<p>There were no differences in age and weight among the erythromycin- or E-4031-treated groups. ns  =  not significant (p>0.1).</p><p>Age (days) and weight (kg) of LQT1 and LMC rabbits.</p

Spatial dispersion of action potential duration in LQT1 and LMC rabbits.

<p>Differences of spatial dispersion of action potential duration (APD₇₅) between LQT1 (n = 9 for erythromycin, n = 8 for E-4031) and LMC (n = 7 each) rabbits at baseline and during perfusion with erythromycin (A–C) or E-4031 (D–F). t =  trend (p<0.1), *p<0.05, **p<0.01.</p

E-4031-induced prolongation of APD in LQT1 and LMC rabbits.

<p>Exemplary, representative MAP in (A) LQT1 and (B) LMC rabbits at baseline and at different concentrations of E-4031. Percentaged prolongation of APD related to baseline APD (%APD) in LQT1 (n = 9) and LMC (n = 7) rabbits in (C) LV apex, (D) LV mid, (E) LV base-lateral, and (F) RV mid position during perfusion with increasing concentrations of E-4031. *p<0.05.</p

E-4031-induced triangulation of monophasic action potential in LQT1 and LMC rabbits.

<p>Exemplary, representative MAP triangulation in (A) LQT1 and LMC rabbit at baseline. Exemplary, representative MAP triangulation in (B) LQT1 rabbit and (C) LMC rabbit at baseline and during 0.1 µM E-4031. Triangulation of MAP at increasing concentrations of E-4031 in LQT1 (n = 9) and LMC (n = 6) rabbits in (D) LV apex, (E) LV mid, (F) LV base-septal, and (G) RV mid positions. t =  trend (p<0.1), *p<0.05, **p<0.01.</p

Erythromycin-induced changes in triangulation of monophasic action potential in LQT1 and LMC rabbits.

<p>Exemplary, representative MAP triangulation in (A) LQT1 and LMC rabbit at baseline. Exemplary, representative MAP triangulation in (B) LQT1 rabbit and (C) LMC rabbit at baseline and during 300 µM erythromycin. Triangulation of MAP at increasing concentrations of erythromycin in LQT1 (n = 9) and LMC (n = 7) rabbits in (D) LV apex, (E) LV mid, (F) LV base septal, and (G) RV mid position. t =  trend (p<0.1), *p<0.05, **p<0.01.</p

Erythromycin-induced prolongation of APD and in LQT1 and LMC rabbits.

<p>Exemplary, representative MAP in (A) LQT1 and (B) LMC rabbit at baseline and at different concentrations of erythromycin. Percentaged prolongation of APD related to baseline APD (%APD) in LQT1 (n = 9) and LMC (n = 7) rabbits in (C) LV apex, (D) LV mid, (E) LV base-lateral and (F) RV mid positions during perfusion with increasing concentrations of erythromycin. t =  trend (p<0.1), *p<0.05.</p