Fig. 4

Multiparametric optical signals acquired from Langendorff-perfused rat and piglet hearts. a Normalized transmembrane voltage (RH237, red) and intracellular calcium (Rhod2, orange) fluorescence signals acquired simultaneously from an excised rat heart during electrical pacing (150, 200, 220 msec pacing cycle length). In this example, each individual image represents 384 × 256 pixels acquired at 814fps. b Normalized fluorescence signals acquired simultaneously from excised piglet hearts during electrical pacing (180, 200, 220 msec pacing cycle length). In this specific example, each individual image represents 640 × 512 pixels acquired at 406fps. Circle denotes region of interest (rat: 45 pixel region, piglet: 80 pixel region in this example). Note: Schneider 17 mm f/0.95 lens used for rat hearts, Fujinon 6 mm f/1.2 lens used for piglet hearts. Vm = transmembrane voltage, Ca = intracellular calcium signal. ROI = region of interest. Scale bar = 1 cm