Figure 3

Comparison of Action Potentials and Calcium Handling in Human Ventricular Slices.

Action potentials (AP) and calcium transients (CaT) were recorded from the same slices stained with voltage- and calcium-sensitive dyes. (a) Comparison of local AP and CaT optical signal obtained from the respective donor and failing slices. (b) The baseline APD restitution curve is higher in failing versus donor slices, as expected. (c) CaT restitution curves demonstrate a similar difference in failing slice when compared with donor slices to that observed in AP. (d) Baseline restitution curve of donor slices is similar to that measured previously in coronary perfused wedge preparations. Acute β-adrenergic stimulation significantly lowers the restitution curve, while culturing slices for 24 hrs did not alter the restitution curve. (e) Slices obtained from failing hearts also demonstrate a response to acute β-adrenergic stimulation.